battery pack voltage drops to near zero when negative hooked up

EasyD · 10-20-2018, 06:09 PM

New to golf carts. Got a 2001 36V EZGO PDS that won't go. Worked fine one day, then died overnight. Pedal provides a slight jerk and then nothing. Batteries seem to be draining quickly. "ignition" switch, F&R switch and pedal box seem to be working fine. I could not get any fault codes. Unhooked and charged batteries (2014) and they seem weak, but took a charge. I disconnected the wires connecting to battery pack. Upon reinstallation, when I hook the ground up to the controller, the voltage drops to near zero. 36volts before hookup, then 1 or 2 if I touch the ground to the terminal. Any next steps would be appreciated.

cgtech · 10-20-2018, 07:26 PM

Probably have one shorted battery.

Volt_Ampere · 10-20-2018, 09:16 PM

Not shorted but high resistance failure. Load test the batteries or measure each one with a meter when your negative is hooked up. You will find a bad one.

EasyD · 10-20-2018, 11:22 PM

Thanks for the tip. I will try that. I figured that since all the batteries had over 6volts and the total was over 36 that I was good there. Learning is a wonderful thing.

Volt_Ampere · 10-21-2018, 09:13 AM

I have seen a couple battery failures where voltage looks fine but you can't draw any significant current from it. Not sure what failed internally but it happens. My car battery did that once and went from working fine to useless in an instant.

EasyD · 10-22-2018, 01:47 PM

Problem Solved. I assumed I had more knowledge than I did. I followed the recommendations and load tested each battery individually. All seemed fine. The voltage in each and total were acceptable. I guess I should have load tested them in pairs, then I would have found THE BAD CONNECTION between two of the batteries. So the high resistance diagnosis was correct. The connection did not appear bad. I haven't tried, but I guess you could load test two batteries at a time and maybe that would have revealed a bad connection. If that is possible, that may be a good way to INSURE you have a solid wire to each battery. Does this sound legit? THANK YOU for all the help.

cgtech · 10-22-2018, 04:52 PM

Yep, that's one way, or test one battery at a time, but include the cable that links it to it's neighbor.

10-20-2018, 06:09 PM	#1
EasyD Not Yet Wild Join Date: Jul 2017 Location: Texas Posts: 4	battery pack voltage drops to near zero when negative hooked up New to golf carts. Got a 2001 36V EZGO PDS that won't go. Worked fine one day, then died overnight. Pedal provides a slight jerk and then nothing. Batteries seem to be draining quickly. "ignition" switch, F&R switch and pedal box seem to be working fine. I could not get any fault codes. Unhooked and charged batteries (2014) and they seem weak, but took a charge. I disconnected the wires connecting to battery pack. Upon reinstallation, when I hook the ground up to the controller, the voltage drops to near zero. 36volts before hookup, then 1 or 2 if I touch the ground to the terminal. Any next steps would be appreciated.

10-20-2018, 07:26 PM	#2
cgtech Over This Interview Is... Join Date: Jun 2012 Location: AZ Posts: 17,449	Re: battery pack voltage drops to near zero when negative hooked up Probably have one shorted battery.

10-20-2018, 09:16 PM	#3
Volt_Ampere Gone Wild Join Date: May 2012 Location: Rio Verde, Az Posts: 7,192	Re: battery pack voltage drops to near zero when negative hooked up Not shorted but high resistance failure. Load test the batteries or measure each one with a meter when your negative is hooked up. You will find a bad one.

10-20-2018, 11:22 PM	#4
EasyD Not Yet Wild Join Date: Jul 2017 Location: Texas Posts: 4	Re: battery pack voltage drops to near zero when negative hooked up Thanks for the tip. I will try that. I figured that since all the batteries had over 6volts and the total was over 36 that I was good there. Learning is a wonderful thing.

10-21-2018, 09:13 AM	#5
Volt_Ampere Gone Wild Join Date: May 2012 Location: Rio Verde, Az Posts: 7,192	Re: battery pack voltage drops to near zero when negative hooked up I have seen a couple battery failures where voltage looks fine but you can't draw any significant current from it. Not sure what failed internally but it happens. My car battery did that once and went from working fine to useless in an instant.

Today
BGW	Sponsored Links __________________ This advertising will not be shown in this way to registered members. Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum

10-22-2018, 01:47 PM	#6
EasyD Not Yet Wild Join Date: Jul 2017 Location: Texas Posts: 4	Re: battery pack voltage drops to near zero when negative hooked up Problem Solved. I assumed I had more knowledge than I did. I followed the recommendations and load tested each battery individually. All seemed fine. The voltage in each and total were acceptable. I guess I should have load tested them in pairs, then I would have found THE BAD CONNECTION between two of the batteries. So the high resistance diagnosis was correct. The connection did not appear bad. I haven't tried, but I guess you could load test two batteries at a time and maybe that would have revealed a bad connection. If that is possible, that may be a good way to INSURE you have a solid wire to each battery. Does this sound legit? THANK YOU for all the help.

10-22-2018, 04:52 PM	#7
cgtech Over This Interview Is... Join Date: Jun 2012 Location: AZ Posts: 17,449	Re: battery pack voltage drops to near zero when negative hooked up Yep, that's one way, or test one battery at a time, but include the cable that links it to it's neighbor.

Similar Threads
Thread	Forum
Battery pack voltage	Electric Club Car
Battery pack voltage is 46.4	Electric Club Car
Battery pack voltage	Electric EZGO
Pack voltage drops under load but individual batts don't?	Electric EZGO
battery voltage drops within an hour	Electric Club Car