Sat. Charging Fine - Sun. Charger Won't Charge

[konakid]

JohnnieB - you're a real asset around here. I sucked up all the knowledge in your comprehensive reply like I am starting to learn something.

Here's my situation. I have this cart sold to a friend. But I can't let him have it until I am fairly sure I have the minor issues it keeps having are fixed.

And since I already have a new board on the way, I'll just wait, replace it, and see what happens then.

My biggest fear is there is something wrong with the batteries. They are 2 1/2 year old Interstates. When I got the cart, they were about half full with water. And the relay had been jumped in the charger. So, from what I have learned around here - the batteries could have been messed up.

It is possible that the batteries may not have been fully charging for the last 5 months after I plugged the relay back it. Maybe the charger was faulty and that is why the relay was bypassed. I just assumed they were charging correctly after I plugged the relay back in - (I know, ***umed). And no telling what the previous owner did or didn't do.

How long can I keep the charger plugged in with the relay bypassed - in order to see if I can get the voltage up and the amperage down? Or should I just wait until I get the new board in and charge normally?

And last question. Should I be worried about the batteries? And if so, is the only real way to assure my friend isn't getting screwed is to do a full load test. I can trailer the cart to a battery shop (a long way, and a lot of hassle) and they can do a real test for me.

What would you do?

[JohnnieB]

The first thing to do. is find out what %SoC (State of Charge) the batteries are charging to.

Charge them all day or overnight with the relay bypassed. Disconnect charger, wait at least 8 hours (preferably 12 hours) and measure pack voltage.

You can determine the SoC based on that voltage. Attached is a SoC chart.

Also, check the individual battery voltages at that time. All six batteries should be withing 0.1V of the others.

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If the pack is charging to less than 100% SoC, repeatedly initiate a new charge every couple of hours. letting battery pack rest about an hour between charges.

Keep an eye on the electrolyte level. If the batteries are not charging to 100%, they will be gassing a lot during the back-to-back charges.

[konakid]

Thanks again Johnnie.

I will do that and report back.

[konakid]

OK - so I charged it up with the charger relay bypassed for 12+ hrs. And after 8 hours after disconnecting the pack voltage is at 37.9v I'll check again in a few more.

The amp meter on the charger was at 12 when I turned it off.

So I am not sure what all this means. But mostly concerned that I'm not selling bad batteries to my friend. We both know there is no guarantees - and I would think if he can get another couple of years out of these, he should be happy.

What do you think now?

[konakid]

And after eight more hours pack voltage at 37.8v

[kgsc]

After they rest from a charge check the voltage on each battery and see if one is lower than the others. You may have a bad one keeping the pack down.

[konakid]

Originally Posted by kgsc

After they rest from a charge check the voltage on each battery and see if one is lower than the others. You may have a bad one keeping the pack down.

24 hrs. after unplugging all batteries tested at 6.3v.

So - with all this info - do you think my batteries are good enough to sell this cart to a friend for a good deal, of course?