2 year old AGM not taking a charge

[Dave P]

Ive got a Battery Tender Junior (.75 amp charger I think), It seems to charge fine on my 1200RT, but on my 1100RT the light just stays solid red, (charging) had it hooked up for 4 days. It's a 2 year old Westco AGM battery and I think I've treated it well, always have kept it in my heated basement on the Tender over the winter. I tried hooking it up parallel (both batteries loose) with the 1200 battery and putting the Tender on the 1200's battery, 1100 battery doesn't seem to want to take any charge. Any suggestions on what I might try to get some juice into this battery? Doesn't seem like I should have to replace it at only 2 years old. Dave

[Etienne Lau]

What is the voltage of the battery that's not working? Yes I know you connected it in parallel, but without data it's hard to know what your issues are. When was the last time you started the MC? When was the last time it was connected to the tender? How long has the battery/MC sat?

 

[Dave P]

Had to get a new battery for my multimeter! 
 

Currently the battery in question has 11.3v, my good battery has 13v. It's been about a month since I've started it, and since the dashboard power outlet didn't seem to be working, I haven't had it on the Tender. Up until a month ago I was riding it at least 3x a week. 
 

11.3 doesn't seem crazy low. I think I'll check it again in about 12 hours and again 12 hours after. Maybe that little Tender Junior needs a solid week to bring it back to life. D

[Hosstage]

11.3 volts is bone dead, bordering on a bad battery. Battery Tenders sometimes will not charge if the voltage is too low, I've read somewhere around 11 volts.

Try putting it on a regular 10 amp charger for a while if you have one, maybe for 1/2 hour, let battery cool, check voltage, repeat until you get at least 12.5 volts. Still only about 60-70% charged, but the Tender should work then.

 

For reference:

 

 

[Hosstage]

One of these can sometimes recover a dead battery, it can be manually put into a long term desulfate cycle. It can take weeks to work if the battery is dead, months if full size and completely discharged. But, I've seen it work. I use one on a bike with an 8 year old Duracell, and it still pops the big motor over just fine. I'm on borrowed time, but this has kept it going strong so far.

 

[dirtrider]

13 hours ago, Dave P said:

Ive got a Battery Tender Junior (.75 amp charger I think), It seems to charge fine on my 1200RT, but on my 1100RT the light just stays solid red, (charging) had it hooked up for 4 days. It's a 2 year old Westco AGM battery and I think I've treated it well, always have kept it in my heated basement on the Tender over the winter. I tried hooking it up parallel (both batteries loose) with the 1200 battery and putting the Tender on the 1200's battery, 1100 battery doesn't seem to want to take any charge. Any suggestions on what I might try to get some juice into this battery? Doesn't seem like I should have to replace it at only 2 years old. Dave

Morning Dave

 

As mentioned above at 11.3v your battery is dead. 

 

Even in parallel with another battery your tender might not output enough to get the dead battery charging.

 

You can fool around with another charger, or play some games but you probably need to give it a big hit of current to get it to start charging.

 

So either reinstall the battery in your motorcycle then jump start the engine from another source (probably a non-running car or truck) then allow the motorcycle to charge your dead battery. Once running you might want to ride it around a little as it charges better at higher RPM's. (caution: do not revv the engine in place as that can burn the plastics above the engine exhaust. 

 

Or, with the battery removed hook it in parallel to an automobile battery using jumper cables, THEN start that vehicle & allow the vehicle's high-amp alternator to charge the battery for a while.

 

Once you get it into the 12.3v-12.5v range then your tender should work on it.

 

If that battery has been low/dead for a while & just sitting unused it might be toast so keep that in mind.  

 

 

 

 

 

 

[Hosstage]

For me personally, that battery would never be trusted even if it recharges. It would head to battery graveyard or used in the lawn tractor and be replaced with new.

[Dave P]

Yeah putting a new one in there is probably the best thing to do, just puzzled as to what happened to this one. Yeah it sat unused for a month but it doesn't seem like that would kill a 2 year old battery.

 

I do have one of those USB plug in things for phone charging that plugs into that dash outlet. Popping that in occasionally would probably be a good way to keep an eye on either bikes static voltage.

We're at the end of the season and Ive got another RT anyway. If I replace it I'll probably do it in the spring. Thanks for the assistance 🙂 DP

[Hosstage]

How old is your Tender? Those can go bad too, and if older, might not be a good match to the AGM battery.

[Dave P]

Well I think it's only 2 or 3 years old. I remember that this Tender Junior was rated to charge AGM batteries. Had an older Tender that wasn't so I bought this one. D

[Hosstage]

Sometimes batteries just go bad. It seems to happen more often in the last 10 or 15 years. There is talk that it may be due to using recycled lead, different manufacturing methods, etc. Not sure how much of that is true.

 

[9Mary7]

Yuasa......just sayin'

[Mike279]

The parasitic drain is usually not enough to kill a battery in a month.  So that would be worth checking.  I would consider buying another charger that has more amps and features.  It never hurts to have another option at your finger tips.  I would also consider a small jump pack as they can easily start a bike that has a weak battery.  I watched a guy start a bike with one at a bike show this Summer(it was a Guzzi convert which is an automatic).

[dirtrider]

1 hour ago, Dave P said:

Yeah putting a new one in there is probably the best thing to do, just puzzled as to what happened to this one. Yeah it sat unused for a month but it doesn't seem like that would kill a 2 year old battery.

 

I do have one of those USB plug in things for phone charging that plugs into that dash outlet. Popping that in occasionally would probably be a good way to keep an eye on either bikes static voltage.

We're at the end of the season and Ive got another RT anyway. If I replace it I'll probably do it in the spring. Thanks for the assistance 🙂 DP

Morning Dave

 

Does your motorcycle have an older Kisan signal minder turn-signal relay? If so those have a fairly substantial patristic draw & will run a battery down over a shorter time. 

 

Plus, the battery probably wasn't at full charge if all you did was ride it (no AGM battery charger on it). Most AGM batteries take a higher charging voltage than the BMW 1100/1150 alternator puts out. 

 

 

[Dave P]

No signal minder, I've just trained myself to always cancel the signal after my turn. 
 

Almost every time I would plug in the tender after a ride, then it seemed to stop charging. Like the red light just stayed on. I thought maybe my power port was having problems so  I guess I just stopped plugging in the tender. Probably should have pulled the battery out and  given it a good charge.
 

maybe Ive got a drain on the battery somewhere. She is an older high mileage bike.

 

heres the Tender I've got

[Dave P]

Tonight at 5:00 she measured 12.3v, gonna leave the tender on her for another 24 hours see where we are. D

[Hosstage]

After it is charged as high as it will go and the tender is removed, let it sit 24 hours and measure voltage again. 

 

[dirtrider]

8 hours ago, Dave P said:

Tonight at 5:00 she measured 12.3v, gonna leave the tender on her for another 24 hours see where we are. D

Morning Dave 

 

That is still pretty darn low for open circuit right after a charge.

 

Get it as fully charged as you can then install it in the motorcycle then measure the battery voltage while cranking. THIS will tell the story. (or just have the battery load tested)

 

On an AGM that is as dead as your battery was, & with the difficulty in getting it to start charging, there is good chance that battery is no longer serviceable for starting use. 

 

Even if it shows 12.7v or higher after fully charging then sitting overnight, there is still a good chance that it won't cut-the-mustard when it comes to engine starting duty.

 

Open circuit voltage testing is not a good indication of a good battery, if low it can be an indication of a BAD battery but if open circuit voltage shows decent that doesn't necessarily indicate what it will do under starting load.  

[Skywagon]

Dave… when you do get it sorted out, install one of these fused cords directly on the battery for future charging. CycleGear

 

[Dave P]

DR- ok will do. Won't break the bank if I need a new battery, just strange this thing dropped off the map like this. Good case for more frequent riding!

 

Sky- I think I've got one of those, should install it. I just always used the dashboard port. It would be good to have a couple of directly to battery lines- avoid taking bodywork off just to get a good grab on those terminals. D

[Hosstage]

I recommend putting a 15 amp fuse in that corded connector, it can be used for electric jacket and will take a little bigger load if you hook up a bigger charger. . It probably comes stock with 7 amp, which usually isn't enough for heated gear.

[John Ranalletta]

1 hour ago, Dave P said:

DR- ok will do. Won't break the bank if I need a new battery, just strange this thing dropped off the map like this. Good case for more frequent riding!

 

Sky- I think I've got one of those, should install it. I just always used the dashboard port. It would be good to have a couple of directly to battery lines- avoid taking bodywork off just to get a good grab on those terminals. D

I’ve got a spare. DM your address & I’ll mail it.  It has a barrel connector but I can include an SAE connector to splice in. 
 

[Dave P]

So with battery off charger we have 12.8v, during crank it went down to 9.0v, at idle we were at 14.0v. 

[Lowndes]

Dave,

 

You might try these in addition to the methods above:  https://www.batteryminders.com/testing-your-battery-for-sulfation/  and  https://www.odysseybattery.com/wp-content/uploads/2020/05/ODYSSEY_Battery_Reconditioning_Charge_Procedure.pdf

 

The Odyssey system has worked for me bringing back or greatly improving the performance of older AGM batteries.  I just use some little jumper wires to connect the battery to an old incandescent "sealed beam" car headlight bulb as a load to draw down the battery.

 

Most BatteryMINDer chargers have a proprietary desulfation cycle that has also worked for me on AGM batteries (PC680) that I thought were long gone.  They are also on the approved list of chargers for Odyssey batteries:  

 

 

 

[Redfoxx]

14 hours ago, Skywagon said:

Dave… when you do get it sorted out, install one of these fused cords directly on the battery for future charging. CycleGear

 

I went to a BMW Canbus capable charger, so far so good.  I have tender several tenders, newest is OptiMATE 4 CAN-bus edition, TM-351 8/9-step 12V 1A battery Saving charger-tester-maintainer and a 75 amp charger, for vehicles. 

[Redfoxx]

9 hours ago, Dave P said:

So with battery off charger we have 12.8v, during crank it went down to 9.0v, at idle we were at 14.0v. 

Your battery is toast,  you shouldn't drop even below 11v during crank.  My pickup has a AGM battery struggling to start and some times not  voltage would drop from about same 12.8v to 10v truck would not start,. battery was 13 months old. That was a warranty. new battery started perfect. 

[dirtrider]

16 hours ago, Dave P said:

So with battery off charger we have 12.8v, during crank it went down to 9.0v, at idle we were at 14.0v. 

Morning Dave

 

Your battery is sub-par at 9 volts engine cranking, it really needs to be above 10 volts cranking to be reliable. At 9 volts engine cranking (measured at the battery posts).  That means the fueling-electronics, fuel injectors, coils, fuel pump are operating at less than 9 volts.  

 

Actually I'm kind of surprised that the engine started at 9 volts cranking. 

 

At 9 volts cranking that almost certainly will cause an ABS fault on the 1100 motorcycles. Did you try riding the motorcycle after engine starting to see if the ABS dash lights were flashing?  

 

That battery (at 9 volts cranking)  is right on the knife's edge of letting you down. All it will probably take is one cold morning, or the motorcycle sitting for a week, or leaving something on for a few minutes then you will have a no-start. 

 

Those AGM batteries that lose some of their engine cranking capacity make a good bench battery for  electrical testing, most also work OK in less demanding starting applications than large piston 2 cylinder engines.  

 

 

 

 

[dirtrider]

11 hours ago, Lowndes said:

Dave,

 

You might try these in addition to the methods above:  https://www.batteryminders.com/testing-your-battery-for-sulfation/  and  https://www.odysseybattery.com/wp-content/uploads/2020/05/ODYSSEY_Battery_Reconditioning_Charge_Procedure.pdf

 

The Odyssey system has worked for me bringing back or greatly improving the performance of older AGM batteries.  I just use some little jumper wires to connect the battery to an old incandescent "sealed beam" car headlight bulb as a load to draw down the battery.

 

Most BatteryMINDer chargers have a proprietary desulfation cycle that has also worked for me on AGM batteries (PC680) that I thought were long gone.  They are also on the approved list of chargers for Odyssey batteries:  

 

Morning Lowndes

 

That Odyssey battery re-claim won't work with Dave's 750mA battery tender.  For the re-claim to work it needs a higher amp hit than 750mA will be able to do.

 

Might as well put the money that a proper charger will cost into a new battery. 

[Dave P]

Yeah she started but yes my abs lights were flashing alternately. So guess I'll be buying a battery 😕. 
 

Originally I had a Battery Tender that was (I think) 800ma but wasn't correct for an AGM. This little 750ma Tender was rated for AGM so I bought it. Sounds like once again I have the wrong charger. Id like to just keep using this 750 charger and yes put that $ into a new battery.

 

By the way, what spec battery should I be shopping for? Dave

[Redfoxx]

2 minutes ago, Dave P said:

Yeah she started but yes my abs lights were flashing alternately. So guess I'll be buying a battery 😕. 
 

Originally I had a Battery Tender that was (I think) 800ma but wasn't correct for an AGM. This little 750ma Tender was rated for AGM so I bought it. Sounds like once again I have the wrong charger. Id like to just keep using this 750 charger and yes put that $ into a new battery.

 

By the way, what spec battery should I be shopping for? Dave

 I think your going to be buying both a battery and tender.  I both Optimate 1 amp and a couple Battery Tender 1.25 amp no issues unless the battery is very low then Schumacher 2a-12amp-50amp which also gives battery volts, and percentage, allows for selections of several different battery types. 

[dirtrider]

28 minutes ago, Dave P said:

Yeah she started but yes my abs lights were flashing alternately. So guess I'll be buying a battery 😕. 
 

Originally I had a Battery Tender that was (I think) 800ma but wasn't correct for an AGM. This little 750ma Tender was rated for AGM so I bought it. Sounds like once again I have the wrong charger. Id like to just keep using this 750 charger and yes put that $ into a new battery.

 

By the way, what spec battery should I be shopping for? Dave

Morning Dave 

 

The BMW 1100RT battery (BMW specs) is 7-1/8" (181mm) x 3" (78mm) x 6-3/4" (170mm), the AMP rating is 19AH, 170Amps. You can go higher in amp rating if you want without any issues. 

 

With you wanting to use your present 750mA (AGM rated) charger, as long as your new battery is not a unique outlier (like an Odyssey PC-680 or something like it that requires a special charging cycle & charging voltage) then you shouldn't have any issues using your present 750mA (AGM rated) charger. 

 

With a 750mA charger (AGM rated on an AGM battery) the secret to using a low mA charger on an AGM battery is to not allow the battery to get depleted in the first place, just use it to top off & maintain.  

 

As for a battery brand recommendation, that I can't give you in good faith as a lot of battery companies do not make the batteries they sell, they find a battery that meets their specs,  & price,  from an off-shore source (usually China) so what battery was a good 1 or 2 years ago might now be made by a completely different company. 

[Dave P]

DR thanks for the advice and specs. Ive had good luck with the Westco batteries for years, probably will check out them again. What I should do is either buy another Tender Junior or make a splitter (that would be ok right?) since I have 2 RTs 96 and 07. Both should be on a maintainer so Im not buying a battery for the 07 also. Dave

[dirtrider]

2 hours ago, Dave P said:

DR thanks for the advice and specs. Ive had good luck with the Westco batteries for years, probably will check out them again. What I should do is either buy another Tender Junior or make a splitter (that would be ok right?) since I have 2 RTs 96 and 07. Both should be on a maintainer so Im not buying a battery for the 07 also. Dave

Morning Dave 

 

I presume you mean a splitter on the 12v side correct?

 

That will only work IF both batteries on each side of the splitter are EXACTLY the same, the same age, & have the same persist draw on them. In most cases it will not work correctly.  

 

Added: after some thought__ You can use a splitter cable as long as you use a double throw switch in the 12+ side of splitter. Using that switch you can select either battery to charge at a time but not both together. 

 

 

[Dave P]

DR that's an easy mod, I think I'll build one of those this winter. D

[Lowndes]

Dave P,

 

Part of the problem is that our beloved oilheads were designed and built for the old lead-acid batteries and came with lead-acid batteries.  This was before AGM batteries were popular or widely understood.  

 

Lead-acid batteries only require 13.5v to fully charge but AGM batteries like your Westco require 14.5 - 14.7v to charge 100%.  With an old lead-acid charger charging an AGM at 13.5v will only get to about 80% charged.  This seems like a trivial difference, 13.5v vs 14.5v, but 80% vs 100% makes a big difference in the life span of the battery, as you have noticed.  That 20% uncharged is what allows the sulfate to settle out and slowly kill the battery.  If you are using a charger that is not rated for an AGM battery it's kinda like trying to use a phillips head screwdriver on a torx head screw, or 75w-90 in the engine.

 

Also, the charging system on the bike was designed for lead acid batteries with the voltage regulator set at 13.5v.  That OEM voltage regulator in the alternator can be changed out for a 14.5v regulator.

 

https://www.euromotoelectrics.com/BOSCH-Voltage-Regulator-BMW-R-K-p/boalt-reg365.htm

 

 

I changed out the voltage regulator on my oilhead without removing the alternator.  It can be done.

 

 

[dirtrider]

1 hour ago, Lowndes said:

Dave P,

 

Part of the problem is that our beloved oilheads were designed and built for the old lead-acid batteries and came with lead-acid batteries.  This was before AGM batteries were popular or widely understood.  

 

Lead-acid batteries only require 13.5v to fully charge but AGM batteries like your Westco require 14.5 - 14.7v to charge 100%.  With an old lead-acid charger charging an AGM at 13.5v will only get to about 80% charged.  This seems like a trivial difference, 13.5v vs 14.5v, but 80% vs 100% makes a big difference in the life span of the battery, as you have noticed.  That 20% uncharged is what allows the sulfate to settle out and slowly kill the battery.  If you are using a charger that is not rated for an AGM battery it's kinda like trying to use a phillips head screwdriver on a torx head screw, or 75w-90 in the engine.

 

Also, the charging system on the bike was designed for lead acid batteries with the voltage regulator set at 13.5v.  That OEM voltage regulator in the alternator can be changed out for a 14.5v regulator.

https://www.euromotoelectrics.com/BOSCH-Voltage-Regulator-BMW-R-K-p/boalt-reg365.htm

I changed out the voltage regulator on my oilhead without removing the alternator.  It can be done.

 

Morning Lowndes/ Dave

 

You don't even need a new regulator, all that needs to be done is to add an NTE-5812 diode to your existing regulator. Kind of a precision addition as there isn't much space to package the diode but once you have seen the diode install it does fit quite nicely. 

 

At least with a diode add you get the factory temperature compensation. With an aftermarket regulator who knows on the temperature compensation curve.  

 

The problem on the BMW 1100/1150 is that the battery is mounted  just about the engine & enclosed, so the battery gets pretty darn warm. That warm/hot battery takes a lower charging voltage than 14.6v when hot. 

 

The factory alternator regulator is a temperature compensating regulator so (within loose parameters) it modifies the charging voltage to meet the battery temperature.  

 

Most AGM's do OK with the factory charging, it's the outlier battery's like the Odyssey  (combo deep cycle/starting)  that require the higher (14.7v at 70°f) to fully charge. Dave's little 750mA (AGM rated) charger should work just fine on a standard run-of-the-mill AGM battery, it's just not enough for the outlier Odyssey type battery's.  

 

[6speedTi]

On 11/7/2023 at 10:29 PM, Dave P said:

Tonight at 5:00 she measured 12.3v, gonna leave the tender on her for another 24 hours see where we are. D

There is your problem. You called it a she and her. Woman are temperamental. 🤣