Power wise charger shutoff?

[Sethjamto]

If y'all remember my other thread a few days ago about getting a new to me cart (36v) with neglected batteries that had 3 of the 6 batteries much weaker than the rest.....I've been slowly trying to bring those three up with a 6v charger. They are getting closer, but not quite there yet. I put the entire pack on charge last night overnight and noticed that its still running at about 8-9 amps on the charger this morning and the pack is at 43.35v right now on charge. Shouldn't the amp rate be coming down more by now (12 hours of charging and counting).

[scottyb]

Check the voltage on each battery, if all batteries are not close to the same voltage that is keeping the charger in absorption mode. Read more here on my website > http://cartsunlimited.net/BatteryCharging_Tutorial.html

[Sethjamto]

Thanks. So I'd imagine the best course to take here is to take the pack off charge and continue bringing the other 3 up individually to get within 0.1v of the rest, right?

If so, should I let the entire pack rest before doing the individual batteries?

[scottyb]

Trying to revive old weak batteries is not always successful. Just keep pouring the coal to the weak ones..... you don't want to overcharge the good ones. So if you have 3 weak ones I would pick the lowest and the highest in voltage and put 12v on them until they read 15.75v together. Then let them sit for 12 hours and test. Take the lower of the 2 and couple it with the 3rd low battery for another 12v charge up to 15.75v and let them sit for 12 hours.

Then see what they are holding and post that info here.
Best if you could post the voltages for all 6 so we can see what you have there. All readings should be 12 hours AFTER charging has stopped.

[Sethjamto]

You would do this vice doing each 6v battery on its own? I have a 6v smart charger in the garage.

[scottyb]

Yes, but you can do it either way. The idea is to elevate the weak ones to the level of the strong ones before making a pack of imbalanced voltages. Charging an out of balance pack will harm the good ones. They get over charged waiting for the weak ones to come up.... . How many amps is your 6v charger? You need 20 amps Ideally

[Sethjamto]

15.75 together? Isn't that a little high??

I've got two going now and they're at 13.19 together, and individually are 6.57 and 6.62 while on the 12v charger.

[scottyb]

Originally Posted by Sethjamto

15.75 together? Isn't that a little high??

I've got two going now and they're at 13.19 together, and individually are 6.57 and 6.62 while on the 12v charger.

Google wet cell charging (wet cell voltage) and start reading, you are at the bottom of the scale right there.

[Sethjamto]

Roger that. It's still going. I was just curious. I'll leave it going while I go out for dinner and a couple of beers!

[Sethjamto]

So I'm still working the 3 weaker batteries. The good ones are sitting at, after 12+ hour rest, at 6.45, 6.45, and 6.62. Don't know why one seems so high....

I have two of the weaker ones rigged in series on a 12v charge, and the third on a 6v charger. I'm trying to get these up to the good ones so I can reinstall them and charge the pack together.

What about the one sitting at 6.62? Is that okay? Recommendations?