Battery Charging

[Green RT]

I apologize if this has been discussed before. I looked but didn't find it.

 

I have a 2015 R12R and a charger labeled "Advanced Battery Charging System programmed for BMW Gel Batteries". I have an adaptor to plug the charger in to the accessory port under the seat. I bought the charger for use with an R11RT about 15 years ago.

 

Is it wise or safe to use it to charge my current R12R wethead? Through the accessory port?

 

I only ride the bike for occasional trips maybe once every few weeks. I am thinking it might be a good idea to leave it on a charger in between trips but maybe it is unnecessary for just a couple of weeks of disuse. Comments on that would be helpful as well.

 

Thanks,

Will

[dirtrider]

Morning Will

 

Your fist hurdle is-- I seriously doubt that old charger will be able to keep your Can Bus (era) accessory socket alive to allow charging (your power socket is computer controlled). So you will probably have to add an SAE type pig tail to the battery to allow that charger to work on your newer Can era bike.

 

Your second hurdle is-- it sounds like that old charger is designed & programed for the older BMW GEL battery. Your new bike has an AGM type battery so the charging voltage is slightly different.

 

Without knowing the specifics of the charger that you have I will say that it will charge your battery enough to start the bike in a pinch but probably won't keep it totally topped off. I'm also guessing that it won't work properly through your bike's accessory plug either.

[LAF]

I use a Battery Tender Solar Panel year round. I also use a Optimate Charger in dead winter once a month.

 

They both use the same plug wired right to the battery. For tending a battery I believe it is best, first out of the bike in a temperate climate using the alligator clamps.

 

However you should also have a battery pigtail. It is not always practical to pull the battery on any bike. Even my girls Vulcan 650 S pain to do.

 

It also connects my air pump also and I had to use it not long ago Plug Kit and a Air Pump are a must have in the bags.

[Green RT]

Thanks for the detailed reply DR. After posting I checked the voltage at the accessory outlet (zero with the ignition off) and realized that was not going to work. I pulled the covers off the two sides of the battery and it looks like access is easy (one of the advantages of an R over an RT I suspect). On the left side there are two posts, one with a black connection and one with a red connection. It looks like they bring both the positive and negative connection over to a box on the left side of the battery. The voltage at that box is currently 13.01 with the ignition off. I have an SAE pigtail (with the accessory plug end on it. I can convert that to a couple of ring connectors and attach to the battery there.

 

Then it looks like I will need to get a new charger designed for AGM batteries. Is it safe to buy one from somewhere like Amazon, or should I get a BMW one. Any recommendations for an alternate? LAF: Is the Optimate that you use the "OptiMate 4 DUAL PROGRAM BMW CAN-bus edition". It sounds like it is designed for these bikes.

 

Thanks to both of you for prompt replies,

Will

[reg26]

Best way is with a pigtail. This is what i got for my 2015 RT and it works fine.

https://www.amazon.com/gp/product/B00EDFPN1O/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

If you dont want the advantage of the 5 amp chrger you can go with this:

https://www.amazon.com/Battery-Tender-021-0123-Junior-Charger/dp/B000CITK8S/ref=sr_1_1?s=automotive&ie=UTF8&qid=1468505497&sr=1-1&keywords=battery+tender

 

You can buy these almost anywhere. I have used the cheaper on on my RT also as well as other bikes. They work great and I plug my bikes in and leave it on all the time for years now and have never had a problem

[Mike]

Best way is with a pigtail. This is what i got for my 2015 RT and it works fine.

https://www.amazon.com/gp/product/B00EDFPN1O/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

If you dont want the advantage of the 5 amp chrger you can go with this:

https://www.amazon.com/Battery-Tender-021-0123-Junior-Charger/dp/B000CITK8S/ref=sr_1_1?s=automotive&ie=UTF8&qid=1468505497&sr=1-1&keywords=battery+tender

 

You can buy these almost anywhere. I have used the cheaper on on my RT also as well as other bikes. They work great and I plug my bikes in and leave it on all the time for years now and have never had a problem

 

Yes, the pigtail with a direct connection to the battery and a Battery Tender Jr. has been my setup for quite a while. It works well with my RT-W, and it's much cheaper than the BMW charger.

[Green RT]

I looked for a Battery Tender Jr at a local auto parts store without success. Amazon won't ship it to Mexico. All the Autozone chargers were Schumacher. That prompted me to look for comparisons and I found this article:

Five Battery Maintainer's Performance

 

They suggest that the Schumacher may even be superior to the Battery Tender Plus. Any comments? I could continue to look for a BT Plus/Jr, but maybe I shouldn't bother if the Schumacher is as good or better.

 

Incidentally, I get the impression from reading about them that the AGM batteries are less fussy than the Gel batteries were. So maybe it is less critical which charger is used with AGM batteries. Does this sound reasonable.

[reg26]

Schumacher makes great products and has a good reputation. I would not hesitate to but one

[Green RT]

Schumacher makes great products and has a good reputation. I would not hesitate to but one

That pretty much cements it. I won't waste any more time looking.

Thanks,

Will

[roger 04 rt]

...

If you dont want the advantage of the 5 amp chrger you can go with this:

https://www.amazon.com/Battery-Tender-021-0123-Junior-Charger/dp/B000CITK8S/ref=sr_1_1?s=automotive&ie=UTF8&qid=1468505497&sr=1-1&keywords=battery+tender

 

You can buy these almost anywhere. I have used the cheaper on on my RT also as well as other bikes. They work great and I plug my bikes in and leave it on all the time for years now and have never had a problem

 

The Battery Tender Jr. isn't a good match for an AGM battery. AGM needs a maintenance mode voltage of about 13.7 volts and the BT Jr. only puts out about 13.1 volts.

 

Whatever charger you buy, make sure it has the higher charging levels needed for AGM batteries. The other day I saw a post where someone selected this model: http://www.batteryminders.com/12v-charger-maintainer-sealed-agm-lead-acid-batteries. Cost about $65 on Amazon.

[LAF]

The Optimate runs a test as soon as you fire it up where it shoots different voltages into the battery to determine if the battery is good. IMHO it is one of the best charges on the market. Mine is rather old but still does the job. I watch it on the volt meter and have seen 14.7 being sent into the battery. A pigtail to battery and a Optimate is all you need. If it gets really weak you pull the battery and then the Optimate will go into a de-sulfate cycle. Only when out of the bike.

[PadG]

...

If you dont want the advantage of the 5 amp chrger you can go with this:

https://www.amazon.com/Battery-Tender-021-0123-Junior-Charger/dp/B000CITK8S/ref=sr_1_1?s=automotive&ie=UTF8&qid=1468505497&sr=1-1&keywords=battery+tender

 

You can buy these almost anywhere. I have used the cheaper on on my RT also as well as other bikes. They work great and I plug my bikes in and leave it on all the time for years now and have never had a problem

 

The Battery Tender Jr. isn't a good match for an AGM battery. AGM needs a maintenance mode voltage of about 13.7 volts and the BT Jr. only puts out about 13.1 volts.

 

Whatever charger you buy, make sure it has the higher charging levels needed for AGM batteries. The other day I saw a post where someone selected this model: http://www.batteryminders.com/12v-charger-maintainer-sealed-agm-lead-acid-batteries. Cost about $65 on Amazon.

I have been using the "Sport" Battery Doc charger for several years now, on my previous '07 RT as well as on the weheads, and it had been really great. Totally CANBUS compatible, and will plug right into your aux. socket right out of the box. It isn't fancy, just a straight trickle charger, and can be had on Amazon for just a touch over $32! My RT gets hooked up as soon as I park it in the garage and stays on it all the time until the next ride. Here is the spec.: http://www.batterydoc.com/battery_doc_specifications.htm

[blackyam]

The Battery Tender Jr. isn't a good match for an AGM battery. AGM needs a maintenance mode voltage of about 13.7 volts and the BT Jr. only puts out about 13.1 volts.

 

Hi, roger. I have an old BT 800. It states 12V, like many of the BT chargers I see on their website. (I see 6V, 8V, 12V, 24V, and 36V.) How do I check to see how many volts it actually puts out? I don't know what type of battery I have in my 2010 R1200RT except that it is OEM (i.e., it is what the dealer put in). Thanks.

 

---John.

[JR356]

Should be a sticker on the BT800 unit that shows output volts/amps.Otherwise an online search will likley find the specs.

The 800 number suggests 800mA output,this is likely low for current AGM batteries.Battery labels often show required charging specs.

Only way to know actual voltage is put a volt meter on it while charging.

 

Your 2010 shold have an AGM battery,that is most common in the newer BMWs.

 

JR356

[roger 04 rt]

The best way to tell the output voltage of any charger is to let it fully charge the battery and then go into maintenance mode and then measure the voltage at the output of the charger with a DVM.

[blackyam]

Should be a sticker on the BT800 unit that shows output volts/amps.Otherwise an online search will likley find the specs.

The 800 number suggests 800mA output,this is likely low for current AGM batteries.Battery labels often show required charging specs.

 

On the back, it states

 

INPUT: 100-240V~, 0.275A, 50/60Hz

OUTPUT: 12V --, 800mA

 

JR365 wrote: Only way to know actual voltage is put a volt meter on it while charging.

 

roger 04 rt wrote: The best way to tell the output voltage of any charger is to let it fully charge the battery and then go into maintenance mode and then measure the voltage at the output of the charger with a DVM.

 

How is this done? Do I touch a voltmeter to the battery terminals to which the pigtail is connected while the charger is still charging?

 

Anyway, bottom line, is the BT 800 unsuitable for my battery? Thanks.

 

---John.

[roger 04 rt]

John, The best thing to do is measure it as you described. Touch the battery terminals while the charger is charging but make sure you wait until the charger reaches its maintenance mode.

 

BTW, although it says 12V out, that would not be enough to charge any battery. The voltage will be higher.

[blackyam]

Howdy, roger. I put on the charger last night, and this morning I checked the voltage. It registered 13.38V. Is that too far off 13.7V? Should I be looking for a new charger? What I like about the BT 800 (waterproof) that I have now is that it packs into a small pouch, which makes it easy to carry on my bike. I also like that it is already paid for. :-) Cheers.

 

---John.

[strataj]

Howdy, roger. I put on the charger last night, and this morning I checked the voltage. It registered 13.38V. Is that too far off 13.7V? Should I be looking for a new charger? What I like about the BT 800 (waterproof) that I have now is that it packs into a small pouch, which makes it easy to carry on my bike. I also like that it is already paid for. :-) Cheers.

 

---John.

 

I'm no electrical engineer but 13.8 seems perfect to me.

 

Jay

[JR356]

13.38 is low.

 

I've been looking at these,actually going to get the next larger one(3500)for other reasons,but this looks good for maintenance charger.

 

https://www.amazon.com/NOCO-G1100-UltraSafe-Battery-Charger/dp/B004LX3AXQ

 

JR356

[Alfred02]

13.38 is low.

 

I've been looking at these,actually going to get the next larger one(3500)for other reasons,but this looks good for maintenance charger.

 

https://www.amazon.com/NOCO-G1100-UltraSafe-Battery-Charger/dp/B004LX3AXQ

 

JR356

It depends

13.38Vdc is not low if that was the resting voltage of the battery. So if the charger stopped completely charging overnight, then the resting voltage would be about that of a good battery for 12~24hrs with no load.

While charging and close to a fully charged battery, it should reach 13.9Vdc ~ 14.5Vdc.

It very much depends how clever the charger is.

[roger 04 rt]

Howdy, roger. I put on the charger last night, and this morning I checked the voltage. It registered 13.38V. Is that too far off 13.7V? Should I be looking for a new charger? What I like about the BT 800 (waterproof) that I have now is that it packs into a small pouch, which makes it easy to carry on my bike. I also like that it is already paid for. :-) Cheers.

 

---John.

 

Since your charging system is matched to the AGM battery you have a leg up over the Oilheads that have a low charging voltage.

 

Depending on the temperature when you made the measurement it might be good enough. Roughly what was the temperature?

[blackyam]

Hi, roger. I would guess that it was about 70F. Thanks.

 

---John.

[roger 04 rt]

Hi John,

At that temp your voltage is a little low but fine.

[blackyam]

Thank you, Roger. I seldom use my BT and, in fact, had not used it for a few years until last week. I had been have start problems over the last month or so. The bike had a hard time cranking over, like a weak battery, during the first start of the day, and sometimes later in the day as well. So I finally decided to use my BT, which seems to have solved the start problem for now. The battery is about three y.o., and I might change it this fall (or sooner) before I'm stranded somewhere.

 

Thanks again.

 

---John.

[Green RT]

It depends

13.38Vdc is not low if that was the resting voltage of the battery. So if the charger stopped completely charging overnight, then the resting voltage would be about that of a good battery for 12~24hrs with no load.

While charging and close to a fully charged battery, it should reach 13.9Vdc ~ 14.5Vdc.

It very much depends how clever the charger is.

When I started this thread, I had an old BMW Gel charger and a 2015 wet head with an AGM battery. Base on discussion here I bought a Schumacher 1.5 amp charger.

 

Now, I have a few weeks experience with both chargers. With the Schumacher charger attached, the voltage maxes out at about 13.38 V after a day or less. Out of curiosity, I attached the old gel charger. With it the voltage maxes out at 13.7 V after a day or less.

 

I am going to return the Schumacher charger to the store and stick with the old gel BMW charger.

[Green RT]

Battery update:

Shortly after bringing my 2015 R1200R home in March of this year, I realized I should probably keep it on a battery charger since it might be a week or two or more between rides. I had an old BMW Gel battery charger, but learned that that was not optimal for charging the AGM (Absorbent Glass Mat) battery in the wetheads.

 

I checked the battery voltage occasionally and found that it was sometimes as low as 12.7 or 12.8 volts between rides. After a short ride of an hour or two, it would be up to maybe 13.11 or so. I bought a Shumacher charger and found that it would bring the battery up to maybe 13.25 volts but no more.

 

On a whim, I decided to see what the old Gel charger would do with the AGM battery. It brought the charge up to around 13.7 volts, essentially the maximum for a Gel battery. At that point I realized the Schumacher charger was a waste of money, so I returned it to the store and they gave me my money back with no problem. They asked if it was defective, and I told them it worked fine. I didn't get into whether it was putting out as much voltage as it should, because I really don't know.

 

Last weekend I took a trip that involved a couple of long rides, 3-1/2 hours last Friday and and another 3-1/2 Sunday. After those rides, the voltage was 14.25 V. I wasn't sure of the advisability of using the Gel charger on a CAN-Bus AGM battery. So a charger specifically designed for it seemed like a worthwhile expense. I decided to spring for an Optimate 4 CAN-Bus charger. It arrived today and is charging the battery now and is in "maintain" mode. It alternates 30 minutes of charging with 30 minutes of rest. During the rest period the battery read 13.12 V. When it was charging the battery was reading 13.25 V, but it has only been on the bike for a few hours, so I doubt that steady state has been reached yet. We will see how it does. Incidentally, the bike was a demo and probably had been on the shop floor for 6 months when I got it, so the battery is currently around 12 months old.

 

[dirtrider]

Morning Green RT

 

Using the correct battery charger is always the best thing but all those 13+ voltage readings are pretty useless as that is surface charge & not actual base charged battery voltage.

 

To get TRUE (charged) battery voltage you need to take the charger off the battery & allow it to sit for 24 hours with no load on it. OR, remove the battery charger from the battery, then allow to sit overnight, then put a small load on the battery (like headlight on for a short time) to flash off the surface charge--THEN measure the static voltage. (on a good AGM the static battery voltage should be around 12.8v-12.95v)

 

 

 

 

[LAF]

Morning Green RT

 

Using the correct battery charger is always the best thing but all those 13+ voltage readings are pretty useless as that is surface charge & not actual base charged battery voltage.

 

To get TRUE (charged) battery voltage you need to take the charger off the battery & allow it to sit for 24 hours with no load on it. OR, remove the battery charger from the battery, then allow to sit overnight, then put a small load on the battery (like headlight on for a short time) to flash off the surface charge--THEN measure the static voltage. (on a good AGM the static battery voltage should be around 12.8v-12.95v)

 

 

 

 

This is correct by all I have been shown.

 

A Battery should have a resting charge of 12.8 to 13.00.

 

A resting charge is 24 hours after charging or running the bike.

 

Not sure where these higher voltages are coming into play but if you have 14 volts on a rested battery you have some kind of problem for sure. Or you have a super battery.

 

Maybe take a look at your volt meter ?

 

I have to say the best charger I ever bought is a Optimate. It does a voltage retention test as part of the charge process. It also can de-sulfate a battery that is removed or disconnected from the bike. I have maintained many battery's with it and it appears to hold up well.

 

As a side note I use a Solar panel from Battery Tender that charges my bike while it sits and it is a very cool device. I do pop the tender on every few months to make sure but for the most part the Solar Panel keeps the battery topped off. However it was not cheap but I have run it for 5 years now and it still is in great shape. I did run a bead of silicone around the edge of the panel and where the frame meets to seal it better as I had read a knock on it for that. Mine is as new so that worked.

 

Again, 12.80 is what you are looking for on a at rest battery.

[Green RT]

Morning Green RT

 

Using the correct battery charger is always the best thing but all those 13+ voltage readings are pretty useless as that is surface charge & not actual base charged battery voltage.

 

To get TRUE (charged) battery voltage you need to take the charger off the battery & allow it to sit for 24 hours with no load on it. OR, remove the battery charger from the battery, then allow to sit overnight, then put a small load on the battery (like headlight on for a short time) to flash off the surface charge--THEN measure the static voltage. (on a good AGM the static battery voltage should be around 12.8v-12.95v)

 

Good points. I know that but have been exploring the output when the charger is on the battery.

 

Thanks for the reminder.

[dirtrider]

Morning Green RT

 

Using the correct battery charger is always the best thing but all those 13+ voltage readings are pretty useless as that is surface charge & not actual base charged battery voltage.

 

To get TRUE (charged) battery voltage you need to take the charger off the battery & allow it to sit for 24 hours with no load on it. OR, remove the battery charger from the battery, then allow to sit overnight, then put a small load on the battery (like headlight on for a short time) to flash off the surface charge--THEN measure the static voltage. (on a good AGM the static battery voltage should be around 12.8v-12.95v)

 

Good points. I know that but have been exploring the output when the charger is on the battery.

 

Thanks for the reminder.

 

Afternoon Green RT

 

If you are looking at (comparing) battery voltages while it is on the battery charger then you need to also compare ambient temperatures during the comparison as a lot of the better modern smart chargers have built in temperature compensation so custom tailor the charging voltage based on temperature.