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K1200GT battery recommendations?

merrittgene

2006 K1200GT, 1986 K100
My new-to-me 2006 K1200GT was garaged for 3 years, and I fear the battery is not good. I can't get it tested right now, but I can ask for advice about what to replace it with, if the need arises.

What's the current wisdom?

Maybe more importantly, what/which should I avoid?

Thanks!
 
Starting issues? Or just sitting w/out running or charging?

Have bought a replacement from BatteriesPlus stores... just a bump over $100. Looks exactly like the OEM and has the same warranty

Don't know if they are a national chain or not... Take your old one with you...to make sure it's the right size and get the core deposit back.
 
Details...probably more than you want to know.

Yeah, starting issues. I have all my accessories switched via relay *except* for my Autocom and my GPS, but I leave the GPS off when it's parked. I also added switched PIAA lights that are on during cranking, so that's 110W to think about.

The previous owner had kept the battery on a shelf for most of the three years that the bike sat idle, but he said he put the battery on the BMW-branded BatteryTender occasionally during that time.

The BMW tender has two status lights, and when I connected the bike via the convenience port, the lights would progress to "greater than 80% charged" but then go back to "not connected". I found that if I turned the key on and then off, the tender would change to "charging", but the end result was the same.

I've had the bike out for 2000 miles this year, so the battery should be charged, but it left me stranded Saturday morning. The only drain on the battery overnight was the Autocom and a cell phone charger connected to the battery.

I was thinking it was the battery just due to age, but the charger issue with the key made me think it was CANBUS issue.

After my post last night (after riding 200 miles yesterday), I connected my Deltran BatteryTender Junior via the convenience port and it instantly read "full-charge". Baffled, I connected it directly to the battery and got the same result. Then, I connected the BMW charger directly to the battery and it when through an entire charge cycle and finally reached "full charge" for the first time since I've owned it.

I need to take the battery to a shop and have it tested directly, but I'm confused about the behavior of both of the BatteryTenders. Also, is there some secret handshake needed to get the charger to work via the convenience port? I don't understand why the BMW charger shuts off and then wakes up when I turn the key.
 
the common procedure on the acc port use with battery tender is to turn on key, plug in charger,then turn off key.
My 05 RT was the only one that wouldn't let the charger cycle if I did not do it that way. Our K12S's don't seem to care.Others will chime in with exactly what you experienced on the full charge indicator...it happens a lot. A battery may take a charge and show good,it's the cranking amp capacity when called on that immediately takes it down.

I have had to replace every OEM battery in our current late model bikes...two K12S's and in my 07GSA before I got the 09,that one lasted less than 2500 miles...And they were ridden either daily as a commuter or weekly year round. I would just go with a battery...the chances it's anything CANBUS related are very slim.
 
I have a BMW tender that I use for both my 2008 K12GT and 2009 R12GS. The thing is unpredictable on the RT. I follow the routine: plug charger into accessory port, turn on the key, plug charger into AC and wait for red charge light to come on, turn off the key. Use to go through the four colored lights and then maintain a nice green light for days on end. Now sometimes it charges normally but then if I come back a few hours later, the tender is showing a red base charge light and it stays that way for days. Bike starts fine regardless! :whistle

With the GS, no problems. Follow the routine above and it keeps the bike in perfect charge status as long as the tender is connected.

Ah the Canbus...mysteries of the BMW...can't for the life of me figure out what causes this odd behavior. GPS (Zumo 665) on GT is disconnected from the bike while charging.

I'd rather be riding than charging anyways, so once I leave the garage, it's ear-to-ear grins! :clap
 
Charger instructions

The instructions included with my charger just say to observe polarity and plug it in. Where can I find instructions for the voodoo needed to make this thing work?

(I'll probably just wire the accessory port directly to the battery, and/or add a charger lead to the battery also.)
 
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