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2015 R1200RT Charging System

R

rftwrg

New member
My 2015 R1200RT has had 4 batteries (OEM, Yuasa, OEM, Interstate) in its short (36K miles) life, the newest being an "Interstate" battery meant for an ATV. It was the only thing available where I was when my second BMW OEM battery died while on a trip to Angel Fire, NM. Yesterday, after returning home and parking the bike in its stable, I immediately plugged in the BMW OEM Battery Charger whereupon the display (after recognizing that it was now attached to the battery through the front socket) immediately showed a voltage of 14.7 volts.

My question....is the bike's charging system overcharging the battery and is that why I've had to replace them so often? Currently, the charger shows Full at 14.0 Volts with a trickle charge of 0.2A.....
 
We can figure this out but you’ve got to make some measurements. 14V and 0.2A doesn’t reflect a charged battery.

Do you have any electrical add-ons?

Leave the bike off the charger for 24 hours and measure the voltage at the battery terminals, what is it?
 
Just a suggestion, put a pigtail directly to the battery and connect your tender up directly to it, unless you've done that with the socket. I have noticed in the past that this circuit will turn off after the battery is brought up full charge, and then it does not turn back on again for maintenance charging. Going direct to the battery removes the bike's "smarts"...

I suspect there is something else up here, but this is the way I'm connected on my 15 RT, and still on battery #1. I went 8 years on battery #1 on my 05 RT doing it this way, however YMMV.
 
Battery Charging while in bike

I don’t know how many owners realize this, but you can charge your bike battery directly (bypassing the bike electronics) by removing the right side cover that is removed to install the battery. I think there are two screws and a grommet. With the cover removed, you will notice one bolt painted red with a major cable attached, this is the bikes Positive terminal. The battery’s negative terminal is also easily accessible. Carefully attach your charger and you have a direct connection.
I own a 2014 RT with 36,000 miles and am still on battery one.
 
Are these batteries failing a load test after attempting to recharge them? I replaced my GS at 4 years preventively and my 1300 GT finally failed a load test at over 6 years.

It sounds like your batteries are going down quickly. However, does this year use a FOB? I believe a FOB left within a few feet of the bike keeps more circuits alive ready to start. True also with cars but most cars have more Amp Hours available than our bikes. As I read in the ON BMW is putting lower Amp Hour batteries in our bikes to save weight.

Of course a FOB should not take a battery down over just one night.
 
voltage data logger??

rftwrg said:
My 2015 R1200RT has had 4 batteries (OEM, Yuasa, OEM, Interstate) in its short (36K miles) life, the newest being an "Interstate" battery meant for an ATV. It was the only thing available where I was when my second BMW OEM battery died while on a trip to Angel Fire, NM. Yesterday, after returning home and parking the bike in its stable, I immediately plugged in the BMW OEM Battery Charger whereupon the display (after recognizing that it was now attached to the battery through the front socket) immediately showed a voltage of 14.7 volts.

My question....is the bike's charging system overcharging the battery and is that why I've had to replace them so often? Currently, the charger shows Full at 14.0 Volts with a trickle charge of 0.2A.....
Click to expand...


Of particular interest is your alternator's charging voltage when running. You might consider temporarily installation a voltage data logger (such as https://www.ebay.com/itm/Lascar-EL-...m1a63260fc2:g:5ZEAAOSwaeRZLhnR&frcectupt=true) Alternatively, you could get a digital display that you could hook up to, and just visually monitor it for a few days. Such has https://www.ebay.com/itm/LED-Car-Ba...m363f592f4f:g:JREAAOSwGmZb-CKO&frcectupt=true

Many vehicles' charging systems are regulated to around 13.8-14.2 volts. Yuasa says charging voltages above 14.8 indicate a problem with the vehicles charging system: https://www.yuasa.it/en/information/automotive-commercial-leisure-marine/how-a-battery-works/
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