How do I tell if I need a new battery?

[silverbird1100]

I charged it at 2amps for a few hours and it wouldn't go any higher than 13.1. 12 hours later it's at 12.4 but holding fairly steady. It used to stay at 12.85 for weeks. It's an interstate that had a very bad first 2 days use. I got it to get me home after my stator went bad. I was running it without a charge for probably 12 hours the first day I had it :???:

[AQUAMAX]

If you have a bike shop nearby, they should be able to load test it for you...that will tell if there's a weak cell or not.

How long was the battery dead before you charged it?

If it was only a couple hours or so, it should be ok...if it sat longer than a day while being dead, it might not come back fully.

[silverbird1100]

Well, the night before the stator completely died, I was able to get a weak start. I bump started it all the way home and and had just enough juice left for the bike to run. It was sputtering for last hour while decending :???: :???: :???: Since then it's worked fine but I have a huge trip coming up this year and although extremely low in funds, trying to do some preventative maintence.

[xrated]

Take it somewhere reliable and have it load tested. Thay way you know for sure.

[Pete in PA]

While chargeing the voltage goes down? 12 hours of 2 amp charge and it's at 12.4 volts, sounds shot to me.

Put it on that charger till while chargeing you see about 14.5 volts or where it peaks. take it off. 2 hours later measure and needs to be at least 12.8 volts without being in any circuit. (out of bike)

I've never been impressed with Interstate batteries.

[TechnoGecko]

Just replace it.. after all, a battery is cheaper than a tow when you're stuck on the side of the road in the middle of nowhere :grin:

[silverbird1100]

I'll take it to get it tested if I need to but I fully charged it, and it stayed at 12.86 for a few hours, than almost 48 hours later it's now at 12.7. It stay at 12.74 for a while but overnight went to 12.7. How much is need to get a strong start?