Battery issue - 12v but weak crank

[rb608]

First the problem - The bike won't crank worth a darn. The voltmeter shows 11.85 volts, but the starter just turns over a few times and quits. Yeah, I know that's a little under 12v, but I'd expect a better effort . So I'm thinking the amps just aren't there.

Now some detail. When I first checked the battery, one cell was about half empty. No idea how that happened, but I filled it with water & put a 3 amp charger on it overnight. The max voltage across the charger is the same 11.85v, so the battery is holding that charge.

So I'm thinking two things. One, I could use a better charger, and two, I probably need a new battery. Yes?

Lastly, I have to wonder how I got here. This battery is only a few months old. Just a fluke, or did I damage it riding with heated gear? Would a heated jacket liner draw so much that it would prevent the battery from charging?

[Rock]

Yes it is possible that your heated gear is drawing enough juice that your battery cannot be charged.

Pull the battery and take it in to a real battery store and have it load tested. That will tell you if you need a new battery.

Or put it on your battery tender on trickle charge mode and see where it is after a few hours. (3 amps is a bit hot for these tiny batteries)

[rb608]

Thanks. Alas, 3v is the lowest setting on my charger, but since Santa didn't bring me a trickle charger, I guess I'll have to go buy one. Ever since the cold weather got here, the bike has been a bit hesitant in the mornings, but I attributed that to temperature. It's quite possible it also correlates to the use of the heated gear. I'll probably go for the charger today when I take the battery in.

[dernp]

For about $25 you can get a Battery Tender Jr. They are very popular and do a good job at keeping your battery in top shape. If you have drained your battery, I wouldn't even bother taking the chance and being caught with a dead battery when you're away from home. Peice of mind for me to have a good strong battery.

[rkjjeep]

under 12v is low for a good battery. Should be closer to 13.2 volts with no load.

If you can get it running make sure the voltage goes up when you increase the RPM's from idle. Not the best way to check the charging system but at least you'll know it's charging.

[Chillable Red]

Its more than about voltage. You need a reserve of amperage to get the engine started. Remember, batteries are rated not only by voltage but Cold Cranking Amps as well. When you hit the starter, you are drawing on the available amperage to not only turn the engine over with the starter, but also using amps to energize the coils so that the spark plugs will fire. As batteries age they loose their ability to provide the required amperage to meet the demand. Yes, I would say it is probably time for a new battery. Also, due to their size, it is best not to use larger than a two amp charger on a motorcycle battery.

[old dad]

Sealed battery.

[rb608]

Well, we'll see. I dropped off the battery at the store where I got it for them to charge overnight and test. On the way home, I bought. a Battery Tender. Between the two, I should be good to go tomorrow.