Cart stalls out under heavy acceleration

[daddyscooltv]

Hi guys need some help...

I have a 2000.5 DS 48 volt cart that I put together about 9 years ago. Everything went perfect for 9 years. About a year ago my batteries finally died and needed to be replaced. So i finally got around to replacing the batteries a couple weeks ago. Got 6 brand new Trojan 875's.

Put the batteries in and nothing so after troubleshooting my solenoid had gone bad,so I replaced it with the same one that was on it. All is good now solenoid clicks and runs.

The problem that I am having is when I accelerate heavy when I push the petal to the floor the cart stalls out and my battery gauge jumps all over the place.. if I slowly push down on the petal the cart accelerates smooth.

I have 4 gauge cables, heavy duty forward reverse switch, upgraded solenoid, either 400 or 700 amp controller (can't remember ), and high speed motor.

Any suggestions?

Thanks in advance,
Chris

[Sergio]

Measure Your battery voltages individually.

A common mistake is to accidentally run the positive wire from the charger receptacle to the wrong battery.

If that wire is not connected to the pack positive, You will not charge the first battery and it could fail under heavy current demand.

[daddyscooltv]

I get 8.3 volts at each battery.. the charger lead is attached to the same positive terminal as the large positive cable going to the solenoid..

Is that correct?

[Sergio]

That is correct, but 8.3v is low if You just charged the cart.

What is the total pack voltage?

As long as it is close to 50v You don't have any battery wired backwards.

You can reset the OBC by disconnecting the pack negative cable for more than 10 minutes.

After You connect the pack negative back, put the cart to charge and check the voltage in the morning.

You should have close to 51v when You measure the pack.

[daddyscooltv]

Ok..i will try that... when I checked the pack today I had 50 volts. Tomorrow I will try to reset the obc and try that..

To me it acts like I am losing voltage since my gauge jumps all over the place.

Thanks for the suggestions...

[teecro]

Originally Posted by daddyscooltv

Ok..i will try that... when I checked the pack today I had 50 volts. Tomorrow I will try to reset the obc and try that..

To me it acts like I am losing voltage since my gauge jumps all over the place.

Thanks for the suggestions...

Try taking some main pack voltage reading while under acceleration to see if it drops rapidly to 42 or less volts. If you see big drop in voltage move the meter to each battery and keep trying till you find the suspect battery... You could very well have one or more defective batteries. Its uncommon but it does happen.

Keep in mind that 50 volts is ONLY 80 % state of charge....

[mrgolf]

Bad connection somewhere. Check all cable ends. Make sure you tightened all the battery nuts.

[daddyscooltv]

Now that I think of it ......the few minutes that the cart ran after I installed the new batteries before the solenoid took a crap on me it didn't stall out the way it is now...

Is it possible that my new solenoid would do that?

Can I bypass the solenoid for testing purposes and see if it stops?

I checked the total pack after charge all night and get 51 volts..

I have not had a chance to take any readings under acceleration yet..

[Volt_Ampere]

You almost certainly either have a bad solenoid or a bad connection.

[Sergio]

On Your first post You said the "battery gauge" was jumping all over the place.

If You have that "gauge" connected to the pack, then a bad solenoid cannot cause that voltage reading.

The problem would have to be:

1) Weak Batteries.
2) Bad cell in a battery.
3) Bad connection between batteries.

You already tested #1 and the batteries charged to 100% SOC.

IF the problem is a poor/loose connection between the batteries, it will cause the connection to heat up.

You can drive the cart for a while and then just feel the temperature in all of the cables and connections.

If Your battery gauge for some reason is connected to the solenoid, then you should also feel that connection for heat.

If none of the connections are heating up, You will need to check the voltage in each battery individually while driving to see if one (or more) of the batteries is dropping under load.