What is up with this battery?

[open1mind]

OK, I have searched dutifully in the Stator Papers and other GS resources- but no luck on this one. I have a relatively new battery in my 79 GS 1000e, about 2-3 years old. It has never been run down, and it has cranked the bike properly. In storing the bike this year, I arranged for someone to put a battery tender on it for about 8 hours, one time per week. Not ideal, but the best I could get give some space and other limitations.

So, it charges with another bike and I visit about once every two weeks to check on them. (it is in a heated space, about 55 Deg F). The other bike shows on my voltmeter at a consistent 12.8 volts every time I check it. The one in my GS never goes above 12.3 volts. I recall hooking up the battery tender last summer and leaving it attached for about 24 hours- it never got the battery to over 12.4.

Could the battery be on the way out? I know that voltage goes up while the charger is actually attached, but what do you guys show on a "good" battery that has been sitting static and uncharged for a few days?

[tom203]

"..... recall hooking up the battery tender last summer and leaving it attached for about 24 hours- it never got the battery to over 12.4."

Your tender and/or battery is no good. My tender/maintainer gets battery to about 13.3 volts and shuts off. Left alone my battery would sit above 12.6 for a few days of idleness. Try your tender on someone else's battery and see what it charges to.

[posplayr]

"..... recall hooking up the battery tender last summer and leaving it attached for about 24 hours- it never got the battery to over 12.4."

Your tender and/or battery is no good. My tender/maintainer gets battery to about 13.3 volts and shuts off. Left alone my battery would sit above 12.6 for a few days of idleness. Try your tender on someone else's battery and see what it charges to.

Yes you need at least 13V to even be considered "charging". So if the "tender can't even manage 13V it or the battery are bad.

The OP should do the Quick test; the first part tests the battery which will be the first step to diagnosis.

If the charger can pull the battery voltage up from where ever it is then it is probably OK. If it doesn't rise at all then it is probably bad.
The charger should be able to take a good battery from 12.6-12.8 up to over 13V. This wouldl confirm the charger is OK.

[open1mind]

"..... recall hooking up the battery tender last summer and leaving it attached for about 24 hours- it never got the battery to over 12.4."

Your tender and/or battery is no good. My tender/maintainer gets battery to about 13.3 volts and shuts off. Left alone my battery would sit above 12.6 for a few days of idleness. Try your tender on someone else's battery and see what it charges to.

Just to split the apple a bit- I have used the tender recently on my other bike recently. In removing that battery, it did push it to well over 13 while charging, but after it settled down (lets call it 1 day) that battery showed about 12.7-12.8V.

I admit that i have not checked the battery in the GS while charging on the Battery tender- just a day or two after it is disconnected. When doing so, it shows a consistent 12.3- 12.4 volts. So, when some of you say " it should get it to 13+ volts", do you mean while it is connected, or afterwards when the battery is disconnected and is allowed to settle for a while? I didnt think that a charged but disconnected battery would show north of 13V, will it?

[tom203]

".....Just to split the apple a bit- I have used the tender recently on my other bike recently. In removing that battery, it did push it to well over 13 while charging, but after it settled down (lets call it 1 day) that battery showed about 12.7-12.8V."

Your tender seems OK then, but the suzuki battery ain't making the grade OR you could have a small drain that's consuming the tender's output. Disconnect the suzuki's battery negative terminal from frame ground and see if tender now raises it to 13.2 volts.

[posplayr]

Just to split the apple a bit- I have used the tender recently on my other bike recently. In removing that battery, it did push it to well over 13 while charging, but after it settled down (lets call it 1 day) that battery showed about 12.7-12.8V.

I admit that i have not checked the battery in the GS while charging on the Battery tender- just a day or two after it is disconnected. When doing so, it shows a consistent 12.3- 12.4 volts. So, when some of you say " it should get it to 13+ volts", do you mean while it is connected, or afterwards when the battery is disconnected and is allowed to settle for a while? I didnt think that a charged but disconnected battery would show north of 13V, will it?

The simplest check of the charger is to see if when it is connected the battery voltage rises above what it would be with the charger disconnected.

Of course the amount of voltage the charger pulls up the battery and to what voltage will be a function of how bad your battery is. A battery load test of some sort is best (see Quick Test), although open circuit voltages do provide some indication.

And yes it is possible for a fully charged battery to hover just above +13V for a while after being taken off the charger. This is generally called "surface charge" and it is easy to unload it back below +13V.

To be clear, you should 1.) confirm the battery voltage rises when the charger is attached to the battery and 2.) do a load test on the battery to get an indication of it's charge. There really are no mysteries here, except the other methods you are pondering.

[1_v8_merc]

A charger will boost even the crappiest batteries up to 13.5, and the charger light will go Green! Yay! Then when you yank the charger off, it immediately drops back to 11v or whatever it was before. The voltage read-out you're seeing on the charger really means nothing. Let battery charge a few hours, then Yank the charger off, and see how long it takes for Static Charge to drop, or come back 1 hour later, and check your resting voltage. It should be 12.6 to 12.9 typically.

Of course even THAT means next to nothing, until you get a proper Load Test done.
Those are just standing numbers...you Still don't know how the battery Behaves when actually being put to use....you could have corrosion setting on the plates or cells grounding out.
Or just start the bike and listen how fast the Starter cranks over...is it lugging, or very rapid and healthy sounding? That's usually the quickest/easiest way to get a good idea on battery life.