Power loss with full charge

[khoff99]

I need some help. I have a 48V cart that has been modified from top to bottom. I put all new batteries in it a couple years ago and all has been fine. All of a sudden it has lost power. I thought something was wrong with my charger because it was kicking off too soon. It would start at 30V and drop to 20 or less within 15 min and trickle off in a few hours after that. I read the voltage across the batteries and I have 50V and each battery is basically the same. 6.0-6.2V but when I take off the voltage drops to 30-36 when I put it to the floor. Does anyone have any ideas? Is it the controller? again, this problem all started at once, it's not like it has been coming slowly. I charge it about once a month because I don't drive it every day. Help me out guys!

Thanks
Kevin

[scottyb]

The two things that jump out at me from your post are 50v is too high of a bulk rate charge for 225 AH batteries and 30v is way too low a reading, indicating a battery problem.

[khoff99]

What type of problem are you thinking? a dead cell in one of the batteries? All the connections are tight and i've taken loose all the accesories.

[Andy4639]

Originally Posted by khoff99

I need some help. I have a 48V cart that has been modified from top to bottom. I put all new batteries in it a couple years ago and all has been fine. All of a sudden it has lost power. I thought something was wrong with my charger because it was kicking off too soon. It would start at 30V and drop to 20 or less within 15 min and trickle off in a few hours after that. I read the voltage across the batteries and I have 50V and each battery is basically the same. 6.0-6.2V but when I take off the voltage drops to 30-36 when I put it to the floor. Does anyone have any ideas? Is it the controller? again, this problem all started at once, it's not like it has been coming slowly. I charge it about once a month because I don't drive it every day. Help me out guys!

Thanks
Kevin

The underline purple statement doesn't sound right to me. 30 volts are 30 amps. If it is in deed 30 volts this is the problem. With the charger hooked up you should get 50=55 volts sometimes more at first depending on the charger.

Sounds like to me u have a battery with a bad cell are multipule batteries bad. Take your volt meter and put it on dc and put the negative lead on - terminal of each battery. Then put the + lead into each cell of water on each battery. See what each cell reads. 8 volt batteries should read 2 volts each. If it's anything less, then the cell is bad.

[khoff99]

Okay guys I have an update on the cart batteries. I checked all the batteries and all have 6.3 V except one. That battery had 5.2 V So I pulled it out to test each cell And the testing method from above didn't work. When I put the leads in the cell the first cell read .6v So I thought I'd found the problem. The next cell read 1.4. And the last 3.6v. I started checking Eather batteries and they had similar results With the first cell being point something In the last cell being 4.5 or greater. In my testing them wrong or what's going on ? I decided to switch leads on the meter And no matter how I use the meter I still never got 2volts Per cell. Any ideas? I'm going to try load testing this week

[buckmanmike]

I've never heard of being able to test cells that way. Not that it can't be done but just haven't heard of it before. But there has to be a problem with that 5.2v battery. Have you tried using a 12/6 v charger to bring that battery voltage up? Do you run accessories on this battery?
My experience with a battery with low voltage made the charger run longer, trying to bring up that battery up while maybe toasting the good batteries.

[khoff99]

I just took that battery out and put it on charge!

[Andy4639]

Well first I would like to know what you are reading.
It would start at 30V and drop to 20 or less within 15 min and trickle off in a few hours after that.
You didn't answer that question so I have know way of knowing what you are reading.
Either way 30 isn't right no matter. 30 volts for 48 volt cart is to low and 30 amps is very high out put for a regular cart charger.

If you put your meter on the - and + of each battery what does it read? It should read 8.4 if 8 volt batteries.
Fully chargered is 50.96 which would mean each battery should read 8.49 which in turn means each cell in the battery should read 2.12 volts. So to check this you put the - lead on the - terminal and then put the + lead in each hole into the water and see what it reads. The lead needs to be in the water to read the volts. After you have done all of them wash it off good with clean water.

[Andy4639]

Well first I would like to know what you are reading.
It would start at 30V and drop to 20 or less within 15 min and trickle off in a few hours after that.
You didn't answer that question so I have know way of knowing what you are reading.
Either way 30 isn't right no matter. 30 volts for 48 volt cart is to low and 30 amps is very high out put for a regular cart charger.

If you put your meter on the - and + of each battery what does it read? It should read 8.4 if 8 volt batteries.
Fully chargered is 50.96 which would mean each battery should read 8.49 which in turn means each cell in the battery should read 2.12 volts. So to check this you put the - lead on the - terminal and then put the + lead in each hole into the water and see what it reads. The lead needs to be in the water to read the volts. After you have done all of them wash it off good with clean water.

A 12/6 volt charger isn't a good idea on 8 volt batteries.

[khoff99]

The cart has 8 6v batteries. When the cart was plugged in it would start the charge at 28-30 amps then drop to 20 amp charge real quick. It had a total voltage of about 50-52v. When I test all the batteries individually they read 6.38-6.42. One battery had a low reading of 5.2 so I pulled that one and put it on charge by its self. I tried testing the batteries like you said with a meter and got individual readings that added up to the right voltage but the first cell was under a volt, the next was around 2 and the last was always over 4. I checked 3 or 4 of them like that.