How fully charged is your battery - interesting info

I'm still not going to put a battery on the cement :rulez: :laugh: I usually figure a battery needs charged if the vehicle won't crank :rofl: to my corner :moon:
Being digital doesn't make a volt meter accurate.

Frankly, most volt meters that mechanics use are terrible. They are only marginally better than a test light (even the really expensive meters). If you want to start talking accuracy, you have to shop somewhere other than Sears or the Snap-On truck. In other words, a couple tenths here and there could very well just be the tolerance on your meter.

If the bike starts, it's good. If it is acting like it's not spinning the starter the way it should, have it checked. O'reilly will check it for free. :thumbsup:
yesyes....use a load tester.

I take it out from my bike, bring it to a mechanic or gas station to have it tested. Mostly its free of charge
I stand corrected sorry... (some old school stuff that has gone away..) :)
That's some mighty old "old school". I don't think that cement floor thing has applied since rubber battery cases went away.

I strongly (STRONGLY!) recommend buying a pulse desulfator. This is the one I have (Battery Minder), but you can find it cheaper:
BatteryMINDer® Plus 12 Volt 1.33 Amp Charger-Maintainer-Conditioner (Desulfator) :: All :: Battery Chargers by

The operation of these things is based on good science - a coworker of mine was developing big versions of these for the Army, so I've actually looked at how they work.

But to make a long story short, I've saved many batteries with this device. Regular use can make most lead acid batteries last a long long time, and you can even occasionally rescue a battery that hasn't completely shorted out a cell. They make a newer version for sealed batteries, but I've been using the one above without any problems. It will pay for itself many times over.
Lots of good info. Few extra points.
1. I believe AGM battery (stock in Busa) voltage profile is slightly different than standard flooded batteries (stock in most cars). If anyone has good data on that, I like to see it.
2. While. desulfators may help some lead-acid batteries recover, my experience is that they won't bring back one that has sat a long time discharged.
3. The Battery Tender does shut-off after the battery is charged. At least one cheaper competitor did NOT shut off, even though it claimed to. That would eventually harm the battery.
4. I believe the self-discharge rate is lower on AGM batteries.