Battery or Alternator

[jrbuete]

I have a 2008 R1200GS which I usually ride at least once a week... I wish more
Lately it's been turning over kinda slow but has always started.

Now the issue... Started fine, went for about a 30 ride, got home right after turning it off, I tried to re-start it ... For some reason..
It would not turn over... Waited, tried several more times... No luck

I was out for surgery for about a week but when I next checked it started fine...

Battery voltage - about 12.3 - 12.6
When I crank, it drops to the 8-10 volts range
After starts, goes to about 14.4 then over a 3-4 minute idle falls off to 14.32 - not sure if drop continues, turned off bike

My first instinct is to say the battery isn't taking a full charge but the fact that it wouldn't turn over after a good ride at 4k+ rpm makes me nervous...

Ideas???

Just want the bike to be ready to go once I am

Thanks!

[mikec]

I think your battery is dying. My '09 GSA was exhibiting the symptoms you describe and I dropped a new Odyssey into the battery box. That cured the charging problem. How old is your battery?

Mike

[pdxrmccgs]

Here is a link to a tasty little trouble shooting farkle that is a plug
into a cigarette lighter Battery and Charging system monitor. It has
a digital readout and around 15 USD. It gives a real time continuous
look at what the alternator is doing.

http://www.amazon.com/Digital-Plug-V.../dp/B0031EL1UK

[smartin108]

Battery for sure. The voltage should not drop that low while cranking. A healthy battery will drop into the 11 volt range.

[marc]

Originally Posted by smartin108

Battery for sure. The voltage should not drop that low while cranking. A healthy battery will drop into the 11 volt range.

Have you measured your R12GS?

The GS sucks a lot of current from a very small battery. Here's a graph of start up voltage from my bike.



That makes me think a fully charged healthy battery will drop further than 11 volts on these bikes. The numbers were captured with a GS-911. A Fluke meter at the battery showed a slightly higher voltage than the reported numbers.

[smartin108]

My measurements were with a Fluke VOM, so it would miss a spike. I perhaps erroneously assumed the OP was not using a GS-911 or other charting device.

[wilk]

I will bet with 95% certainty that your battery is the problem. 14.3 to 14.4 volts while running says alternator is good. A battery with 12.4 to 12.6 is only about 40 to 60% of full charge which means it needs a refresh charge. It should normally be between 12.7 and 12.9 volts to be fully charged. As high as 13 volts after a full out of the bike charge.

I just bought my bike and it seems to me that this bike is somewhat of a battery hog. Even with a new battery, the starter is not overly "enthusiastic".

[Plane Dr]

What Odyssey battery? I have read lots never seen the part number. I have also seen a couple where they trim them to fit?

My 05 is surly lately and I was thinking the battery might be the culprit.

I tend to go to the cycle gear and buy their "megaboost" battery. It's not necesarily "good" but lifetime replacement.

[mikec]

Originally Posted by Plane Dr

What Odyssey battery? I have read lots never seen the part number. I have also seen a couple where they trim them to fit?

I odered my Odyssey PC 535 here: http://www.odysseybatteries.com/battery/pc535.htm I did trim the fins off on each side of the battery and that took about 15 minutes.

Mike

[Plane Dr]

I got some surfing time in and hit ADV. I saw both the 535 and the 625 (!) not sure why the bigger higher output battery is cheaper.

Both looked a little fiddly but the 535 was definitely easier. The bigger one appeals to the more power me inside though. I will see how mine stands up then decide which way to go.

The cycle gear CTX14-BS is $90 with lifetime it should be approximately the same as stock. I would prefer to upgrade though. As weak batteries suck and it seems the BMW systems are voltage sensitive