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Slow Starting R1150RT


roger 04 rt

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Hi Stefan,

Yes, according to the folks at San Jose BMW you can purchase just the 4 output coil and mounting bracket for an R1150 dual plug per head motorcycle and not use stick coils just plain old HV wiring from the coil to spark plug. I am going to give it a try this winter or before. I know that San Jose BMW has been marketing dual plug conversion kits successfully for airhead motorcycles for many years so they have experience. Oh, you also must buy two HV plug leads as well. Total cost looks to be around 350 bucks. I can't see any reason why this won't work.

 

Actually, it looks like winter is about to arrive here on the Oregon coast with up to 6 inches of rain forecast for this weekend.

 

On the 4-output coil, see notes here: R1150 Stick Coil Data.

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Hi Roger,

We got two threads going here on same or similar subject it seems. Anyway, I just got off the phone with the owner of San Jose BMW and he told me that the 4 output coil system they sell has never been tried on an 1150 dual spark mc and he doesn't think it a good idea to do so. As he put it "we won't be responsible if you damage the Motronic on your motorcycle". He also said that BMW has come out with the improved stick coil and that it makes better sense to just buy a new set of stick coils and keep them in your saddle bag rather than roll the dice with the 4 output coil. Is it possible one could overload the driver to the secondary coils by replacing the secondary coils with these 4 output coils? I know what happened when I tried to drive the two Ford coils with the stick coil drivers. Actually, I didn't use OEM Ford coils I used ACCEL after market replacement coils.

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With two new stick coils (and the replacement of all four plugs), my '04RT is running like a dream. And it starts great ... other than the first start of the day, which still could take 4-5 seconds.

 

Yesterday I decided to take some data on the first start with the GS-911 via bluetooth to my phone. With it connected to the 911, the samples are logged every half second (400 mS) versus every second (800 mS) to the PC, nearly twice as fast.

 

Looking at the battery voltage in the log, here's what I saw:

 

12.19 V, 0 rpm

12.11, 0

12.11, 0

6.82, 0

10.24, 350 rpm

10.89, 350

10.73, 200 rpm

11.05, 1400

13.73, 1500

 

My battery appears to be in good health (a one year old PC680, it will crank the bike for a long time with a bright headlight) and the starter seems to turn over quickly. But looking at the voltage dip I decided to try jumping from my car with its motor running.

 

This morning I pulled the left-side panel, got good jumper connections all around--ground to the bike's battery and +12V to the starter lug. Set up logging and pressed the starter button ... er, er, vroom. According to the log (and my ears) the bike started in 1 second.

 

Here was the voltage log:

13.98 V, 0 rpm

9.99, 0

11.46, 300

11.95, 1350

13.9, 1400

14.06, 1450

 

Last winter, I pulled my starter because of a high drain on the battery and very hard starting every so often. The planetary gear cover had fallen onto the armature. Based on the test today, I'm leaning toward replacing the starter. My reasoning is the cables and connections look good, and even with the jumper cable to the starter lug the voltage dipped from 14V to 10V.

 

I'm thinking that without the jumper cable connected, the dip to 7-9 volts when the starter is pressed is upsetting the Motronic, or coils, or injectors.

 

Starter or battery?

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Roger,

 

What is the RESTING battery voltage on your bike?

 

HERE is a linky to an article on motorcycle battery voltage.

 

 

Edited by philbytx
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I received a PM that pointed me to pc680 technical data. Apparently the odyssey batteries are supposed to be charged at a MINIMUM of 6/7 amps at 14.2-15.0 volts.

 

I've looked through all my logs and the regulator never gets to 14.2 volts and is usually between 13.7 and 14.1. My charger, a battery tender jr., for trickle charge doesn't put out much current.

 

After a day and a half of rest, the voltage is 12.9v that seems okay.

 

With the headlight low beam on the voltage drops to and stays at 12.1 volts for 15 minutes.

 

Could my continual charging of the battery for a year and a half at lower than spec have affected the battery such that it drops to 7v during starting?

RB

 

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Morning Roger

 

Most BMW boxers that I have tested for alternator voltage output run around 13.8-14 volts. This is tested right at the battery posts, if taken in the system somewhere then slightly less -more like 13.6-13.7v.

 

That is probably just a bit on the low side for the Odyssey battery to be fully charged but I have used the odyssey, as well as a multitude of others, on the BMW boxer & no issues EVER.

 

Even at 4-5 years they seem to hold 12.8 volts so the BMW must be providing enough to keep them happy.

 

On your low cranking voltage--

 

You might start with a good full charged battery, battery load test.

 

Or, just hook your car to your bike (not running) with jumper cables & see what your cranking voltage is then.

 

If possible you might also run a voltage drop test on the large (+) battery cable (bat + post to starter solenoid large stud). Also do a voltage drop test between the battery (-) post & the starter frame (clean, paint free connection).

 

If the battery passes the load test, no major voltage drop in the large cables or connections, & alternator can provide 13.8+ volts, & you don’t have an overnight patristic drain, then look into a starter issue or tight engine (doubt a tight engine though) .

 

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Morning DR,

Here was the cranking voltage with jumper cables to my car.

 

This morning I pulled the left-side panel, got good jumper connections all around--ground to the bike's battery and +12V to the starter lug. Set up logging and pressed the starter button ... er, er, vroom. According to the log (and my ears) the bike started in 1 second.

 

Here was the voltage log:

13.98 V, 0 rpm

9.99, 0

11.46, 300

11.95, 1350

13.9, 1400

14.06, 1450

 

Or are you saying to pull the injectors or pump relay so in won't start?

 

Edited by roger 04 rt
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Morning Roger

 

You can try a system disable cranking test but what you posted looks pretty good.

 

Next, try charging your motorcycle battery then letting sit over night then try the cranking test without the hookup to your car.

 

If the problem is still there (no car hook up) then run a patristic draw test-- 2.6mA is BMW max allowed (key off).

 

Otherwise, try a new battery or have yours load tested.

 

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Here's the charged battery data, no car:

 

12.19 V, 0 rpm

12.11, 0

12.11, 0

6.82, 0

10.24, 350 rpm

10.89, 350

10.73, 200 rpm

11.05, 1400

13.73, 1500

 

The 12.11 volts is key on, headlight on. The 6.82v is moment of starter press. The start in the prior post with the car attach was quick. This start was slow.

 

RB

Edited by roger 04 rt
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Since I couldn't do much today I ran a quick test to see what was being effected by the low battery voltage during cranking (maybe everything). I powered the Motronic and circuits from a second battery, but not the pump and injectors. Same slow, lean starting.

 

Since I previously measured the fuel pressure during starting, I think I've narrowed it down to the injectors and fuel pump which I will power separately tomorrow. My money is on the injectors ... now.

 

As to battery or starter as the voltage spike culprit, I didn't make much progress today but got many good inputs on the PC680 charging requirements.

RB

Edited by roger 04 rt
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I'm going to get a proper charger later this week, cycle the battery according to the Odyssey specs and see how it does. Since I've already serviced the starter twice, once with the planetary gear cover arcing on the armature, I will likely get a new starter anyway. But I've remained curious about why the voltage dip leads to the slow, lean start.

 

I ran another test this morning to see if I could out why the dip causes the problem: lights bright, starter turning over quickly but slow-start and lean afterstart condition. Yesterday I separately powered the the Motronic with no improvement.

 

This morning I separately powered the injectors and fuel pump from a second source (not hard, just pull the relay and plug in a jumper which I recommend carrying in case you lose a relay). BINGO! With only the fuel pump and injectors powered from a second source, the bike started right up. So low injector voltage is the issue with low-battery, hard-starting.

 

I should have known this because last year when I noticed my alternator taking time to come on-line after starting (about a minute) I also noticed that the mixture got much richer when the battery voltage stepped up due to the alternator starting to charge. This is easy to see with an LC-1 because it's always measuring the exhaust, and the Motronic is always in Open Loop until the engine is warm so the O2 sensor doesn't adapt to the low voltage.

 

So my theory is this: the voltage dip is coming at a time, on first cold start, that the Motronic usually adds a lot of fuel, perhaps for as little as the first few revolutions. At that time, the voltage dip keeps the injectors from squirting enough fuel to adequately wet the TP and injection track. From then on, it is behind the eight-ball and playing catch-up with the fueling.

 

The Motronic does compensate for low battery voltage but this is now the second time that I've seen its compensation to be inadequate.

 

Still TBD, battery or starter ...

 

Added:

Here's how the mixture varied when the alternator came on-line slowly. This isn't real bad but it is measureable. The start plot is much worse. The step down in AFR is the alternator coming on-line at 3 minutes 20 seconds.

 

plug3087.jpg

Edited by roger 04 rt
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Roger,

 

Your battery at "key on" indicates low voltage from the battery as a fully charged battery should indicate AT LEAST 12.6v.

 

Can't remember if you have your battery on a BT but I have both bikes on BT's (also on a PC680!), so here's a comparo for you with readings taken directly from battery terminals after overnight trickle charge.

 

My R1100R w/PC680 - removing BT plug and testing at battery immediately thereafter - 13.33v

My R1150RT w/Westco, same as above - 13.31v

 

Hope this helps.

 

 

Edited by philbytx
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Galactic Greyhound

Very interesting Roger! You have a lot of patience and tenacity to do this testing! Your posting gave rise to some thoughts:

 

The problem with OEM bike batteries is that they are generally specified at the motorcycle design stage to carry out their function for at least 2 years and be of minimum size and weight.

 

Battery problems arise as the battery ages and by the amount of neglect given by the owner.

 

However, even a well looked after battery will succumb to old age and the signs of this are poor starting when the ambient temperature falls to low levels. There is a theoretical finite number of work cycles that a lead/acid battery can complete in its life - some batteries will do more, others less depending on how they have been used/abused.

 

The most significant drain on a battery, and the one that has the greatest effect on battery life, is the starting cycle. Prolonged cranking for whatever reason, will draw very high currents from the battery plates which causes heat build up and eventual loss of material from the plates by heat and vibration.

 

This material falls to the bottom of the battery casing where excessive build-ups eventually cause self discharge of the battery and inability of the battery to provide the required power due to the loss of plate material. The continued high current demand on an already weakened battery further exacerbates the problem and so the decline of the battery begins.

 

So how can the life of a battery be maximised and how can reliable starting be achieved?

 

For motorcyclists, the main requirement is generally not so much minimum size and weight but of reliability - the ability to start the bike quickly on a cold morning first time and every time with no doubts that the battery will fail to do the job.

 

This might be achieved by the use of two batteries - one for starting the bike and the other for general use. The starter battery would be correctly sized in terms of the starting requirement and the other would be a smaller battery sized to the lower requirement of the general electrics i.e. lights, ignition etc. Both batteries would be charged by the one alternator through a split charging circuit keeping both batteries fully charged but separate.

 

The advantage of such a system would be twofold - the batteries would each be loaded less than a single battery and so each would last longer. The starter battery could be one specifically designed for that single purpose. If one battery ever failed, the second battery might be switched into circuit for emergency use only.

 

Another advantage, is that while the starting battery is cranking the bike, the general battery is only supplying a minor load and the 'ABS low battery voltage' problem often seen in Oilheads would not occur.

 

The only disadvantage is that space would be required on the bike for an extra battery.

 

 

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Roger,

 

Your battery at "key on" indicates low voltage from the battery as a fully charged battery should indicate AT LEAST 12.6v.

 

Can't remember if you have your battery on a BT but I have both bikes on BT's (also on a PC680!), so here's a comparo for you with readings taken directly from battery terminals after overnight trickle charge.

 

My R1100R w/PC680 - removing BT plug and testing at battery immediately thereafter - 13.33v

My R1150RT w/Westco, same as above - 13.31v

 

Hope this helps.

 

 

On the rt, what is the voltage at key on with low beam on?

RB

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Roger,

 

Its 12.63v at full on position and a 10 second wait :thumbsup:.

 

Thank you for making that measurement. It pretty well puts the nail in the coffin of my battery!!!

 

For no good reason, I tend to connect my Battery Tender Jr. when I'm gone. I think its low float voltage and my low altternator output have cooked the battery. When I turn on my bike it will hold 12.2V for 15-20 minutes.

 

I've got an Odyssey charger on order. Hopefully I can revive it.

RB

Edited by roger 04 rt
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Roger,

 

I had the RT on the BT and removed the BT plug about 1 minute before checking the battery, so it was actually just off float charge.

 

FYI - I use BT's on both bikes and both cars whenever I'm not driving them. Then again mate, I am entirely anal :) !

 

And I've used a regular BT on my R1100R with a PC680 for almost a year without any issues whatsoever.

 

 

 

 

Edited by philbytx
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Very interesting Roger! You have a lot of patience and tenacity to do this testing! Your posting gave rise to some thoughts:

 

The problem with OEM bike batteries is that they are generally specified at the motorcycle design stage to carry out their function for at least 2 years and be of minimum size and weight.

 

Battery problems arise as the battery ages and by the amount of neglect given by the owner.

 

However, even a well looked after battery will succumb to old age and the signs of this are poor starting when the ambient temperature falls to low levels. There is a theoretical finite number of work cycles that a lead/acid battery can complete in its life - some batteries will do more, others less depending on how they have been used/abused.

 

The most significant drain on a battery, and the one that has the greatest effect on battery life, is the starting cycle. Prolonged cranking for whatever reason, will draw very high currents from the battery plates which causes heat build up and eventual loss of material from the plates by heat and vibration.

 

This material falls to the bottom of the battery casing where excessive build-ups eventually cause self discharge of the battery and inability of the battery to provide the required power due to the loss of plate material. The continued high current demand on an already weakened battery further exacerbates the problem and so the decline of the battery begins.

 

So how can the life of a battery be maximised and how can reliable starting be achieved?

 

For motorcyclists, the main requirement is generally not so much minimum size and weight but of reliability - the ability to start the bike quickly on a cold morning first time and every time with no doubts that the battery will fail to do the job.

 

This might be achieved by the use of two batteries - one for starting the bike and the other for general use. The starter battery would be correctly sized in terms of the starting requirement and the other would be a smaller battery sized to the lower requirement of the general electrics i.e. lights, ignition etc. Both batteries would be charged by the one alternator through a split charging circuit keeping both batteries fully charged but separate.

 

The advantage of such a system would be twofold - the batteries would each be loaded less than a single battery and so each would last longer. The starter battery could be one specifically designed for that single purpose. If one battery ever failed, the second battery might be switched into circuit for emergency use only.

 

Another advantage, is that while the starting battery is cranking the bike, the general battery is only supplying a minor load and the 'ABS low battery voltage' problem often seen in Oilheads would not occur.

 

The only disadvantage is that space would be required on the bike for an extra battery.

 

 

The idea of one battery for starting and another battery for everything else is appealing. It could be mounted in the "glove box"/"radio" area and have the advantage that its 13 lb. weight would offset the Pull to the Right tendency.

 

I guess the hardware and electrical design exists as I believe the Police version supported two batteries.

 

Another option is to install a DC-DC converter that takes 7-14V in and outputs a steady 13.2V.

 

It's somewhat surprising that for the Oilheads it is Injector Voltage that looks most sensitive to Battery Voltage fluctuation. Of course if the electrical systems are kept in tune, what we have works fine.

 

RB

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Quick updates to this ongoing saga:

 

I looked at the grounds today, checked them by measuring high current voltage drop, they are fine. I also took out the BMW wiring CD. The grounding is certainly not obvious. In stock condition, there are four ground wires that connect to the battery and only one of them is a direct connection to the transmission. At some point I will do a thread on this. However, the Motronic, Alternator and Generator all get their grounds from the transmission/engine connection and as a result, any drop in the large cable from battery to transmission would affect measurements and operation.

 

Today I connected the fuel injectors to a car battery with the car running, adding a volt to the injectors during my cold start test (12.4V to 13.4V or thereabouts). With everything else connected normally, the battery voltage low as it has been. The motorcycle started quickly and ran smoothly. So the cause of my problems is low battery voltage during starting and the effect is lower voltage at the injectors that the Motronic can't/doesn't compensate enough for during starting, which is Open Loop operation.

 

Also, I discharged the battery for 20 minutes with the headlight, rode the motorcycle for an hour. Came back, turned on the headlights, low and behold, the battery voltage with the headlights on but the bike not running was 12.5V for 5 minutes or so. This is 0.4V more than I have recorded in any log that I have in the past year for the same condition.

 

So it looks like GSAddict nailed it, the problem is that I've undercharged the battery for the past year and a half. I will discharge/charge it per detailed recommendations (that I'll post later) from Odyssey.

 

RB

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Here is what I heard from odyssey on the subject of pc680 maintenance.

 

Hello Roger,

 

Thank you for contacting EnerSys/ODYSSEY.

 

See attached manual reconditioning cycle for your reference. If your headlight will stay on, this would work fairly well for a way of discharging the battery.

 

Proper charger maintenance is critical to maximize the life and performance of the ODYSSEY battery. ODYSSEY Battery 101?

 

The usable energy of the ODYSSEY battery is from 11.2V (0% state of charge) OCV to 12.84V OCV (Open Circuit Voltage should be checked after a minimum of 6-8 hours rest period with no loads) or higher. When the battery goes below 10.0V OCV, you are getting into the chemical part of the battery and can cause permanent damage. At less than 8.0V the ODYSSEY limited warranty deems the battery over-discharged due to abuse or neglect. At less than 6V the battery can develop reversed cells depending on the condition of the battery. The ODYSSEY charger/maintainer can maintain the battery at a full state of charge indefinitely in or out of the application without harming the battery. If the battery becomes over-discharged (below 11.0V) then the sooner the battery can be fully charged the better and if the battery remains connected to the application during storage or extended periods of non-use. There is a link to a list of ODYSSEY approved 12V chargers located on the ODYSSEY website Product Support page for your reference. Any of the approved chargers can be used to maintain the battery indefinitely without harming the battery.

 

The list of approved 12V chargers is provided due to the many chargers that are programmed for the vast majority of batteries on the market that prefer low amp charging and lower float voltages that do not fully charge or maintain the ODYSSEY battery properly. The recommended charging current for an ODYSSEY battery is 40% of the 10 hour amp hour rating of the battery for cyclic applications (about 6A for a single 16Ah rated PC680), a constant float voltage of 13.5-13.8V and no constant voltages exceeding 15.0V in any kind of automatic de-sulfation/reconditioning/equalize mode. At greater than 15.0V the battery can overcharge, overheat, and/or go into thermal runaway. Maintaining the battery at less than 13.5V will bring the battery down and maintain it in an undercharged condition causing sulfation and premature failure.

 

For seasonal applications (non-daily use applications that set for more than 3 days in a row consistently) frequent use of an approved maintainer that meets the charge voltage requirements noted in the previous paragraph is highly recommended during the season. The preferred storage method is to fully charge the battery before storing and disconnect the battery from the application (shelf storage mode) Stored in or out of the application with no loads, the battery would not require charging for up to 2 years at 77?F or until it reaches 12.0V, whichever comes first. The self discharge rate increases significantly for temperatures above 25?C (77?F) and for every 10?C (18?F) temperature increase the storage time to recharge is decreased by half. Charge maintenance is critical to maximizing the life and performance of the battery. Freezing will not harm the battery and self discharge rates reduce significantly at colder temperatures.

 

It is recommended that the ODYSSEY battery be charged if it is less than 12.65V when put into use per the ODYSSEY Owner?s Manual (link provided on website Literature page for your reference). Most standard alternators/stators are not meant to be deep discharge recovery chargers and can damage the alternator/stator as well as not fully charging the battery with limited use. The Cyclic Charge Voltage range printed on the top label of the battery is the recommended voltage at the battery from the applications charging system (alternator or stator). At less than 14.1V the battery may not be getting fully charged for infrequently used applications. You can verify the battery voltage by checking the voltage at the battery at least 8 hours after application use (or off charge) and if the battery voltage is not at least 12.84V then the battery is not considered fully charged. Voltage readings taken right off charge or after use (alternator/stator charging) will be inflated and inaccurate so for a true OCV reading, you should wait at least 8 hours before checking the voltage (OCV) with 24 hours being preferred.

 

Any feedback is always welcome and appreciated. I hope this helps. Please contact me if you have any questions, concerns, or need further assistance.

 

Sincerely,

ODYSSEY Sales/Support Representative

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...

 

This might be achieved by the use of two batteries - one for starting the bike and the other for general use. The starter battery would be correctly sized in terms of the starting requirement and the other would be a smaller battery sized to the lower requirement of the general electrics i.e. lights, ignition etc. Both batteries would be charged by the one alternator through a split charging circuit keeping both batteries fully charged but separate.

 

The advantage of such a system would be twofold - the batteries would each be loaded less than a single battery and so each would last longer. The starter battery could be one specifically designed for that single purpose. If one battery ever failed, the second battery might be switched into circuit for emergency use only.

 

Another advantage, is that while the starting battery is cranking the bike, the general battery is only supplying a minor load and the 'ABS low battery voltage' problem often seen in Oilheads would not occur.

 

The only disadvantage is that space would be required on the bike for an extra battery.

 

 

Here is an way that a second battery might be added to a PC680 installation:

 

1) Boost alternator by 0.6v to better charge the odyssey

 

2) Connect the second battery (flooded lead acid) to the first with a power diode pointing with Cathode toward the second battery

 

3) Leave the heavy +12 wire connected to the PC680

 

4) Connect all other +12V wire to the second battery.

 

 

The diode would block the starter from pulling the second battery down, and the 0.6v drop from the connecting diode would offset the increase of the alternator thus matching the charging needs of the second battery.

RB

Edited by roger 04 rt
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Galactic Greyhound
[

 

.................

 

Here is an way that a second battery might be added to a PC680 installation:

 

1) Boost alternator by 0.6v to better charge the odyssey

 

2) Connect the second battery (flooded lead acid) to the first with a power diode pointing with Cathode toward the second battery

 

3) Leave the heavy +12 wire connected to the PC680

 

4) Connect all other +12V wire to the second battery.

 

 

The diode would block the starter from pulling the second battery down, and the 0.6v drop from the connecting diode would offset the increase of the alternator thus matching the charging needs of the second battery.

RB

 

Roger,

The reply from Odyssey is very interesting. In my opinion, a lot of what is said could also apply to a flooded lead acid battery with some minor differences. However, the significant difference appears to be the high charge rate required by the Odyssey battery (40% of 10 hour rate = 6A for PC680 battery).

 

I'm not sure the figures are correct here. If the Odyssey PC680 is a 16 Ah battery then the theoretical 10 hour Charge rate is 16/10 = 1.6 Amps not 6 Amps. It would be interesting to see if the dedicated Odyssey Charger actually charges at the 6A rate and for how long.

 

Flooded lead acid batteries will charge at this high rate if they are in a low state of charge and the charger is capable of this output. However, as the lead acid battery voltage rises back to the full charge state, the charging current will normally reduce to a lower level. Current (no pun intended) 'intelligent' chargers on the market may maintain high levels of charge when the battery is getting near full charge and then reduce the charge rate significantly when the 'full charge' state is reached. I suspect that the Odyssey Charger might do the same.

 

Your scheme for a second battery option looks good and should not be too difficult to implement. Are you thinking of trying this as a solution?

 

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Afternoon Roger

 

I'm thinking more on the lines of a disconnect relay not a diode. A diode is active all the time so anything that would run the 2nd battery down would also run the main starting battery down. One of the big advantages of a battery only for starting is that it will still crank even if you leave something on.

 

The other problem is-- unless the batteries are well matched if the 2nd battery is lower OCV it will keep drawing on the main battery.

 

I have a lot of experience with old tractors that used multi batteries some in series & others in parallel & unless well matched there were always charging or run down issues.

 

Probably the best way to use twin batteries is to use the RT-P dual battery isolation/charging relay set up. Just wire it (the isolation relay) into your main load-shed relay so it goes off while cranking & off with the ign switch off.

 

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Roger,

The reply from Odyssey is very interesting. In my opinion, a lot of what is said could also apply to a flooded lead acid battery with some minor differences. However, the significant difference appears to be the high charge rate required by the Odyssey battery (40% of 10 hour rate = 6A for PC680 battery).

 

I'm not sure the figures are correct here. If the Odyssey PC680 is a 16 Ah battery then the theoretical 10 hour Charge rate is 16/10 = 1.6 Amps not 6 Amps. It would be interesting to see if the dedicated Odyssey Charger actually charges at the 6A rate and for how long.

 

Flooded lead acid batteries will charge at this high rate if they are in a low state of charge and the charger is capable of this output. However, as the lead acid battery voltage rises back to the full charge state, the charging current will normally reduce to a lower level. Current (no pun intended) 'intelligent' chargers on the market may maintain high levels of charge when the battery is getting near full charge and then reduce the charge rate significantly when the 'full charge' state is reached. I suspect that the Odyssey Charger might do the same.

 

Your scheme for a second battery option looks good and should not be too difficult to implement. Are you thinking of trying this as a solution?

 

The 10 Hr rate is 16A (see this document: http://www.odysseybattery.com/documents/US-ODY-OM-011_0213.pdf) so the charging rate is 4.8A. I've purchased their 12A charger to have some added margin. I've also purchased some power resistors so that I can discharge it at less than the 5hr life rate (see this document: http://www.odysseybattery.com/documents/US-ODY-TM-001_0411_000.pdf) which is 3A or less, and deep cycle it until I have the appropriate discharge duration to 10.02V (up to 5 times maximum).

 

Once I confirm that with a properly charged battery that my problem is truly solved, then I am thinking about trying a small amp-hour battery (with a relay). That battery would need to carry the load for a very short time (just during starting). If I use the relay approach then I could run a battery with the same characteristics like the Odyssey PC310.

 

Afternoon Roger

 

I'm thinking more on the lines of a disconnect relay not a diode. A diode is active all the time so anything that would run the 2nd battery down would also run the main starting battery down. One of the big advantages of a battery only for starting is that it will still crank even if you leave something on.

 

The other problem is-- unless the batteries are well matched if the 2nd battery is lower OCV it will keep drawing on the main battery.

 

I have a lot of experience with old tractors that used multi batteries some in series & others in parallel & unless well matched there were always charging or run down issues.

 

Probably the best way to use twin batteries is to use the RT-P dual battery isolation/charging relay set up. Just wire it (the isolation relay) into your main load-shed relay so it goes off while cranking & off with the ign switch off.

 

I think this is a good idea but I need a relay that operates a moment before the starter engages so that the injectors and Motronic don't see that instantaneous load glitch. I'm thinking of a relay that opens for 1 minute after they key is turned on. With the non-starter stuff all connected to the second battery.

 

Or it could be that the second battery remains disconnected whenever the bike is off and then not for a time until after the bike is running.

 

Edit: I have several schematics on my BMW CD. Are you thinking of a different arrangement than I described?

 

RB

Edited by roger 04 rt
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Afternoons Roger

 

I'm thinking of a relay to connect the 2nd (non starting battery) to the charging system only with engine running (not during engine cranking)

 

That way you can have the 2nd battery power the Motronic keep alive all the time so you don't lose the TPS learn or adaptives.

 

Or, basically you have one battery to power all the bikes fueling systems components. The other battery could be for starting & other accessories.

 

During key OFF, or engine cranking the batteries are separate from each other but during engine running they are both charging from the same alternator.

 

The BMW RT-P sort of does that now as one battery is for radios & police equipment with the other for bike's needs. They are separate at key off & starting but a relay hooks the second battery to the charging system after start up.

 

 

dual12vsystem_zps41b0b356.jpg

Edited by dirtrider
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Hi DR, this looks good. The load relief relay could be energized by D+ (through a diode) so the the headlight wouldn't run till the engine did. RB

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Still waiting for delivery of the charger. In the meantime ...

 

Below is a chart from East Penn (many thanks to Terry), a manufacturer of Gel and AGM batteries. On the chart you can see the expected battery voltage when an AGM battery is loaded at the 1-3 hour discharge rate. That would mean that my fully charged PC680 (16 aH) when loaded at a 5-16 amps should still have a 12.5 to 12.6V output. It seems pretty clear to me that my battery is not fully charged since at key-on the voltage drops from 12.9 to 12.1V or so.

 

With my key on I've got about a 4 amp load from the low beam and maybe a couple amps for everything else. That is within the 1-3 hour discharge range on the chart. I plan to measure my key on battery load.

 

While I wait for the charger and some time, I've been looking at old GS-911 log files to find the initial cold-start injector pulse length. It used to be about 3.8 mS. Lately it has been in the 4.5 mS range, up to 5.5 mS. This is due to guess what? Low battery voltage. The Motronic is trying to compensate, it's just not adding enough time. I now feel that I have triangulated this pretty well. Everything points to low voltage at the injectors due to the battery (and perhaps the starter).

 

It will still be a day or two before I begin reconditioning the battery.

RB

 

2009414153615343.jpg

Edited by roger 04 rt
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Galactic Greyhound
Does anyone know hue typical starter current draw for the 1150RT?

 

Hi Roger,

 

Under 'No load' conditions. i.e. on the bench and spinning freely, the Starter Motor is likely to draw about 60 Amps. The reason for this is that the back EMF generated by the starter spinning freely at high speed reduces the current flow.

 

Under 'Load' conditions, i.e. mechanically connected to an engine, the Starter Motor could draw anything between 60 and 200 Amps depending on the engine size, engine temperature and oil temperature.

 

The higher starting currents are more likely to be encountered with lower ambient temperatures particularly if the engine oil is also at a low temperature.

 

The important characteristic of batteries in this respect is the CCA (Cold Cranking Amps) which a battery is able to deliver at 0 deg F.

 

See here for battery useful info: http://en.wikipedia.org/wiki/Automotive_battery

 

 

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Galactic Greyhound

I found this interesting link on AGM batteries using the Russian Yandex browser. Of particular interest is the section; 'A bit about Alternators', which states that alternators are only designed to charge batteries to 70-80%.

 

This would make the case for using a dedicated AGM battery charger to charge your battery to 100% capacity to ensure reliable starting on a cold winter's morning:

 

http://www.fridge-and-solar.net/agm.htm

 

[also posted on the BM Riders forum 'Odyssey Battery Maintenance' thread]

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Interesting read ... Later today I'll start the discharge/recharge process. It's the next thing I need to do. Reading about the BT Jr. trickle charger, it has a 13-13.2V volt float. Odyssey says that this will sulfate the battery. So I've got two strikes: low alternator and low charger float.

 

The odd thing about my situation is that the battery is still powering the headlight and starter motor fine and because of that I never suspected a battery issue. The low voltage (and possibly the big initial dip) affects the electronics/injectors.

Edited by roger 04 rt
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Discovered this listing. Approved chargers for Odyssey batteries. Been using a regular BT on mine for ages now without any issues whatsoever....maybe just a little marketing hype involved??

 

 

 

Edited by philbytx
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Discovered this listing. Approved chargers for Odyssey batteries. Been using a regular BT on mine for ages now without any issues whatsoever....maybe just a little marketing hype involved?[

 

Thanks. I bought Odyssey's unit, will let you know how it goes.

 

Based on some numbers I got, the float & charge voltage requirements aren't looking like hype. It's looking more like the battery may operate well with only a 70% charge.

 

 

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To recondition its AGM batteries, Odyssey recommends discharging the battery at or slower than the 5-hour rate to a final voltage of 10.02V.

 

The PC680 is a 16 aH battery so the 5 hr rate is about 3 amps. I used a 6 ohm resistor and the discharge started at 2 amps, averaging 1.8 amps. For a fully charged battery, it should have taken just under 9 hours to discharge. The Open Circuit Voltage at start was 12.9V which theoretically indicates a full charge.

 

It took about 6 hours to get to 10 volts. My "fully charged" battery (by the alternator and then BT Jr.) sourced 11 amp-hours or 70% of the claimed 16 amp-hours capacity.

 

(Coming at it a different way, using the AGM curves for discharge-rate vs voltage, would say the 12.1 volts I get with the headlight on means that it is about 60-65% charged.)

 

I started recharging it this morning with the Odyssey 12 amp charger. After that Odyssey says to discharge it again and see how many amp-hours to 10.02V, doing it up to five times or until it stops improving.

RB

Edited by roger 04 rt
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Finished the first recharge. The Odyssey charger, like some others, charges in three steps: bulk at high current up to 14.7V, absorption at lower current at 14.7V, and float between 13.5 and 14.1V.

 

The bulk recharge to 14.7 volts took about 15 hours, absorption took another few overnight.

 

The open circuit voltage is now 12.9 volts, the same as before. However, the key-on, headlight on-voltage is now 12.6-12.7 volts (increased from 12.1 volts). I should run another discharge/recharge cycle to see if the battery capacity has been restored but I'll see how it starts first.

RB

Edited by roger 04 rt
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Starting Test After PC680 Battery Cycling (Thanks to Terry for all the help.)

I went out to the garage, set everything up very carefully to record data: er, er, vroom--1.1 seconds! The best start in 4-5 months. I would say normal and as expected. Success!

 

Setting up carefully means turning the key on but with the headlight fuse pulled, getting the gs-911 set up and configured for logging, putting a jumper in for the fuel pump relay (5 amps) and LC-1 (2 amps for the heater), starting the LC-1 logging software, putting the headlight fuse back in, and then pressing the start button. Total elapsed time with the key on before starting of about 2 minutes. The draw for the headlamp, fuel pump and LC-1 is about 13-14 amps total (plus whatever the panel lamps, gauges and ABS draw).

 

Fast idle lever in the detent position (1.92 degrees TPS open) and not touched from pressing the start button until the bike was warmed up and in closed loop.

 

By the time I pressed start, the voltage had dropped from 12.5V to 12.1 volts (that sounds worse than it is since I had a 14 amp load on it). Minimum voltage in the start log was 10V, low but not nearly as low as the 7-8V I'd seen previously.

 

Of note, the LC-1, which for the past several months had been resetting each time I started the bike, did not reset itself. I attribute this to better battery response.

 

After starting, the RPM, spark advance behaved well for the first time in a while. The idling quality was very good.

 

Also of note, the injection pulse times were longer than anything I've seen previously. Just before and just after start about 5 mS. But on the battery dip to 10V, a single pulse of 6.2 mS, the longest I've seen. It makes me believe that the battery induced starting voltage dips were affecting the Motronic.

 

Summary

At the start of this thread I was investigating slow starting on the first start of the day, and leanness in the first minute or so of idling. I found a fouled lower plug (replace all four plugs with Bosch), a weak stick coil (replaced both) and a significantly undercharged PC680 battery. Although the plugs and coils needed replacement and my bike better after replacement, it was the low voltage caused by the perpetually undercharged PC680 that was the root of the problem.

 

The PC680 was undercharged due to a mismatch with the R1150 alternator which only puts out 13.6 - 13.7 volts on average. That's only enough for a trickle charge of the PC680 AGM battery. I made the problem worse by keeping the battery on a Battery Tender Jr. whose float voltage of 13.1 V can lead to battery sulfation.

 

Low voltage at the fuel injectors causes their turn-on time to increase and thus shortens the duration of the cold start fueling, leading to lean mixtures just when they should be very rich.

 

The solution to my undercharged PC680 will be to add a diode to the Alternator's Voltage Regulator thereby increasing my alternator's output voltage to 14.4 to 14.7 volts. I will no longer keep my bike on a trickle charger, the PC680 doesn't need it.

 

Next steps are to cycle the battery again to see if it is at full capacity and to install the diode.

 

RB

 

Edited by roger 04 rt
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Good bunch of data there Roger.

I think your root case is correct. 13.6-13.7 alternator voltage would likely take weeks to charge the PC680 based on all I have read. This makes me wonder what my alternator is putting out.

 

So a diode will increase the alternator voltage? Where would the diode connect? Certainly not in series with the battery.

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there is typically a .7 volt drop across a zener diode, so if one was put into the circuit where the regulator senses the battery voltage, it would think the batter was actually .7 volts lower than actual.

 

there are other articles, but this one might shed some light

 

http://www.hax.se/alternator/

 

http://www.talkaudio.co.uk/ipb/index.php/topic/339231-increasing-bosch-alternator-voltage-using-a-diode/

 

http://www.bmwmoa.org/forum/showthread.php?45361-Voltage-Regulator-End-Voltage

 

Above are some links for alternator mods.

 

There are presently three choices for the VR: a diode mod to the stock regulator; a Hella 14.5V replacement regulator and an adjustable which I came across. Not sure which is best of if any but the diode mod are correct for our alternators.

RB

 

Diode Mod:MOF linked it earlier in the post

Hella: 5DR 004 242-051

Adjustable: http://www.davebarton.com/AdjustableVoltage.html

 

Edited by roger 04 rt
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Here's a quick update. I discharged my PC680 again last night this time it took an additional hour which means there was 13 aH of output, up from 11 hours on the first discharge. It's headed in the right direction. Bike continues to start well.

 

 

1st time: 6 hours to discharge (11 aH), 16 hours to recharge

2nd time: 7 hours to discharge (13 aH), 22 hours to recharge

 

Goal is 16 amp-hours, cycle can be repeated up to 5 times. Each cycle removes sulfate from undercharging.

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You know in my former life I did much work at remote mountain top communications sights and installed and maintained these sights most having solar panels and or propane generators charging banks of batteries which were mostly liquid cell deep cycle types. I have for years been under the impression that once sulfated a battery was history and that sulfation was not a reversible condition. I guess these AGM bats are a much different animal.

 

Also, I think modifications to the charging system (increase alternator output voltage) to accommodate these AGM bats means that one should not re-install a standard lead acid bat as these high charging potentials (14.7) would likely boil the battery and severely shorten battery life. Don't think a PC680 is in my future.

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Hi Jim, I understand your point of view on this. I plan to stay with odyssey, now that I have the pc680 and special charger. That being the case at some point I'll modify the alternator. In the meantime I'll keep it fully charged. This battery deep-cycling is for the birds. RB

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Roger, what level of recovery did you reach with your battery? Also, how did you load the battery during the discharge? What do you use to determine when you have discharged to goal?

 

For the PC680 for the first two runs i used a 6 ohm 50 watt resistor. I monitored the battery voltage and stopped discharging at 10 V per Odyssey's instructions.

 

For the third run today I used a 4 ohm resistor (50 W) which is for he 5 hr. discharge rate. Estimated charge for the third discharge was 87%.

 

So the summary is 68%, 80%, 87%. This means the battery has improved.

 

I called odyssey today about the slow charging rate. After some discussion we agreed the charger is defective and they're sending another. Great customer service.

 

The charger's problem was it was tripping to a low current initial charge. In its place today I used my car idling for an hour and a half which charged the battery at an 8 amp rate, finishing with the odyssey unit.

 

I'm hopeful that when I get a working charger later in the week I can add some more capacity, maybe getting to 100%.

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While waiting for the charger to arrive, I ran a test yesterday. After pulling the Motronic and Fuel Pump Relays, and the Motronic fuse, I powered all those circuits with jumpers from a second battery.

 

The idea of this test was to see how well it started if the voltage supplying those circuits was not glitched by the starter load. The home alarm 7 aH battery I used resulted in a steady 11.4 volts with the 5-6 amp fuel pump load.

 

It turned over once or twice and started; the sensors were better behaved than I have ever seen. It ran very smoothly immediately.

 

1. The RPM jumped from 0 to 1350 RPM in 1.1 seconds.

2. The spark advance kicked in immediately and stayed at about 25 degrees. (This often moves from zero to 14 back to 7, all over the place during a cold start.)

3. The dwell moved smartly to 1.6 mS and stayed there reliably. (This often moves from 0.6 to 0.3 to 1.6, etc.)

 

RB

 

Chart of Start Sequence (RPM on Right Axis)

secondbatterystart1.jpg

Edited by roger 04 rt
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To try and further see what parts of the power system were being affected by starting transients I ran three more tests:

 

1. Connect only the Motronic to the second battery. Leave pump/injectors on the main battery.

 

Results: Not a bad start but longer and not as clean as the test in the prior post, when both the Motronic and Pump/Injectors were on a second battery.

 

2. Power everything as usual but use a second battery for starting.

 

Results: Okay, but kicking in the starter solenoid took the voltage on the main battery to 10.5 volts, and then the alternator came on line bringing the voltage to 13.6 volts. That was enough voltage changing to affect the fueling and maybe the Motronic. As a result it took longer to get a stable idle.

 

3. Run the test in the prior post--Motronic and pump/injector on a second battery.

 

Results: same good results as in the prior post.

 

Still waiting to see how things will be when my battery is recovered. However there is no doubt that a second small battery for the injectors and Motronic would produce a great starting R1150. A bit theoretical since I doubt I'll add a second.battery.

RB

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Today I ran a cold start test using a 13.7 volt source to power the Motronic and fuel pump/injectors. I found a very interesting result regarding dwell time. Keep in mind that I have new stick coils installed.

 

Before getting to today's result, yesterday when I cold-started with a stand-alone battery whose voltage was 11.7 volts powering fuel pump/injectors and Motronic, the after-start stick coil dwell was about 1.7 mS.

 

Today (same config) using a 13.7 volt source--my car's battery with the alternator running--the dwell time was 0.5 mS, that's 1/3 of the dwell compared to using the 11.7 volt source. And the start was not as robust as when I used the 11.7 volt source.

 

The difference is that the coils had 13.7 volts on them today (note to self: check voltage on the other side of the key which powers the sticks) and the Motronic read my second battery also 13.7. Yesterday, the Motronic read the second battery at 11.7 but the coils had actually 13.7V. So the combination of a high voltage at the sticks but the Motronic thinking it was a low voltage leading to longer dwell produced a spark that better combused the mixture.

 

I'm floored! Who would have guessed that the Motronic sets dwell partly based on battery voltage? And that a stronger spark would lead to a better start!!

 

RB

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Below is a chart of the starting parameters for 11.7 vs 13.6 (Motronic and injectors). One of the reasons that 11.7 works so we'll is that the sticks have 9-10 volts during cranking then 13.6 volts once running but the Motronic only sees 11.7 so calculates a long dwell.

 

Notice in the chart how much faster the rpm builds in the 11.7 volt case compared to the 13.6. That seems to be due to inadequate dwell at the higher voltage case.

 

Also note that the Motronic has no way to adaptively learn low battery voltage corrections for coils and injects during cold start.

 

secondbatterycompare.jpg

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Roger, new guy here and to my 1150RT. I was wondering if you have every tried contact enhancers like Deoxit or my favorite Stabilant 22?

 

I first got onto Stabilant 22 when chasing down voltage drops on various connections in car ecm wiring.

 

Good to follow the documentation of your thoughts and testing.

 

Dennis in Calgary

 

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