What am I missing?

[DTR]

Have a 48v txt that is completely upgraded(f/r contactor, solenoid, controller, motor) I recently replaced my controller with an Alltrax SR48500 and Curtis 400amp solenoid. Everything worked great after initial install. I let the cart sit for a couple weeks as I was out of town and came back to a cart that wouldn’t run. I think it’s the solenoid but hoping I’m not missing something. Batteries are full, switches work, solenoid clicks, and controller lights up, but wheels don’t turn. I get full voltage on hot side of solenoid, but I have 48V on other side of solenoid and the controller at all times. When I push the accelerator pedal voltage drops to 39V on that side of solenoid and controller. I have disconnected the solenoid hoping it would “reset” but that didn’t work. I have a new solenoid on the way, but wanted to make sure I’m on the right path.

[bronsonj]

48v is dead. If you are reading 48.2V on the pack that's a dead pack and you need to charge it.

If you think it's the solenoid you can temporarily bypass it. Take the large cable from the battery and connect it to the same lug as the large cable that goes to the controller. THIS IS A TEMPORARY TEST, do not leave it that way. If that gets you moving (after you've charged) then you have a solenoid issue or solenoid activation issue.

Also, if you connect your laptop to the Alltrax it'll tell you why it isn't running. The software is free and the controller is the same as the one connected to your printer.

[DTR]

Thanks for your reply. I should have been more clear. I had 50.6V on one side of solenoid (cable from + battery) and 48V on other side continuously. Then it dropped to 39v when throttle pedal was pushed.

In case this helps someone else, I replaced he solenoid today and now the cart runs fine. I still get 50.6V on one side and 48v on the other, but with the new solenoid it doesn’t drop to 39. (39v is under voltage cut off programmed for controller.) The voltage goes to 49.9 and stays there until I let off the throttle pedal and then comes back to 48.2v

I’m not sure what the issue with the old solenoid is. I’m sure there is a sticky on solenoid diagnostics I can look up.

[bronsonj]

The reason for the partial voltage on the other side when the pedal is not depressed is the small resistor across the leads of the solenoid. They put a small resistor there so the capacitors in the controller are always partially charged then when the solenoid closes there won't be a big electric arc inside the solenoid and the contacts will last longer.

After you press the pedal the controller tells the solenoid to close the contacts and the V on one side of the solenoid should match the V on the other. If it does not, then your contacts in the solenoid are bad or the controller isn't telling the solenoid to close.

In your case the controller was telling the solenoid to close but it had bad contacts so the only power the controller had was whatever was in the internal capacitors and what little could come across that resistor, which explains why it dropped to 39v.

[DTR]

Thanks. I assume these are separate of the resistor that I have across the large terminals of the solenoid.