2005 EZGO Series Cart running slow then speeding up then slow again

[Nos800]

Hello all,

I am new to golf carts and recently got a 2005ezgo txt series car. When I got it last month it had 2010 Trojan battery’s and most of the termnals on top where blown off or melted. I had no history of the cart but got it for 100 bucks.

I replaced the battery’s last month and it ran pretty decent. GPS clocked at 14-16 mph. When o did the battery’s I noticed the tray was pretty rotted so I replaced it with an aluminum tray and when I put it all back together the F/R switch was backwards for some reason and it ran like that pretty well for about 3 days. Today it goes super slow and kinda try’s to take off but then goes super slow again GPS speed 7-9 mph. It still takes off good but then just fizzles out.

Any idea?

[Nos800]

I took voltage reading and I have 38.5 across the whole pack and 6.4 on each battery.

[cgtech]

Put your meter clips on the controller B+ and M- terminals, and check the difference from when it runs full speed and when it's going slow. These readings should be at top speed cruise, slower and faster top speed, not during acceleration. If your controller is not labeled as such, you need to identify which connections are B+ and B- and M-. Or post a pic of the connections at the motor controller and we will help you identify and understand which is which. I hope you are ready to get busy with a volt meter, and possibly some terminal cleaning. If you have no idea what to do with wires and a volt meter, well, we will still try and help. If you think you are ready to work on a electric golf cart, some familiarity with a volt meter will be a giant plus. If you aren't ready for this, a shop might be better for you. And yes, we do appreciate that you posted your at-rest pack voltage right off the bat! (Many expect a answer with not much input)

[Nos800]

I am very familiar with a meter and have worked on cars for a long time. I have read that my resting voltage should be higher and each battery should be around 7v is my charger just not putting out enough juice? When I measure across the pack with the charger on it I get 40v, I didn’t do each battery but I can.
I will also find the contacts on the controller and get voltages.

[yurtle]

A fully charged 6 volt battery should read 6.37 volts, 12 hours after charging is complete.

[JohnnieB]

Originally Posted by Nos800

I am very familiar with a meter and have worked on cars for a long time. I have read that my resting voltage should be higher and each battery should be around 7v is my charger just not putting out enough juice? When I measure across the pack with the charger on it I get 40v, I didn’t do each battery but I can.
I will also find the contacts on the controller and get voltages.

If you have an old charge the hums loudly and weighs a ton, it shuts off when the on-charge voltage reaches about 45V.

What was the ammeter reading at 40V? Should have been above 15A.

[Nos800]

46.2 across the pack, 1 amp on ammeter on charger. My charger is the old heavy humming power wise

[Nos800]

B+ and M- voltage at full throttle Fwd 36.6, it kinda speeds up and sounds super choppy. In rvs 25.5 and slow. Now it is super ch ch ch ch ch ch and trying to go faster but can’t and voltage is between 36.8-35.3

Also 37.1 testing across those contacts and then drops to zero in a second.

Still 38.5 across the pack

[Nos800]

4mph is my new top speed. I’m starting to think my motor is going bad.

[Nos800]

I jacked my cart up (now it doesn't go at all) and took measurements
Pack 38.3
Positive side of solenoid 38.3
Other side 38.2
Solenoid clicks like normal



B+ to B- 38.2 with pedal depressed and not depressed fully
B+ to M- 37 not depressed. 38.2 fully depressed