Not golf cart but 2009 72v Miles EV truck max 4mph

[Jamiemhansen]

I just purchased a 2009 Miles Electric Truck with a 72v lead acid battery pack. It was sitting for 2 years and wasn't running when I bought it. The guy had a lot of hills and I figured he burnt out the 500A fuse so I purchased it "as is" for super cheap. I got it home and charged it, fault code on curtis controller was 52 with charger plugged in and 37 off the charger. I then found a burnt out wire coming from the motor to the controller, so I split the wire and put a Polaris 3/0 connector. It then ran beautifully, the Miles EV Trucks go 25mph, and this one went 27mph, drove it around for 2 days, and then all the sudden it felt like the power just stopped, then only went 4mph, always 4mph even up and down steep hills, and in reverse it goes 8mph. I don't understand this. It doesn't have the usual magnet speed sensor like everyone has on a golf cart. I checked and cleaned ALL wires and no change, I cleaned the speed sensor with no change. Also Auxiliary battery not charging and 72v battery pack charge strangly, 1 battery way too high(over 80v) and some way too low(around 8v), but when charge complete, they even out to 12.7v each. Do you think it's a battery problem, speed sensor, or controller malfunction? Or something else, this is my first EV cart and is built almost just like a golf cart. Any help is greatly appreciated.

[Jamiemhansen]

I just found out tonight that my controller gets the battery pack 76V in, and only 36v to every wire to the motor weather the throttle is pressed or not, does this help someone answer my question?

[basshawk84]

https://www.publicsurplus.com/sms/do...&docid=8691690

Here's a link to a manual with troubleshooting.

[Jamiemhansen]

Thank you for the manual. I have it already downloaded but its a little confusing, I just was wondering if I could get a quick fix answer without going through hundreds of wires and relays and testing solenoids and speed sensors that I have no idea how to do, was also wondering if I could switch controllers somewhat easily with a good one they still sell online, and many of the obsolete parts and change over to lithium but keep the 3 phase A/C motor? May be expensive but I need this thing fully operational and reliable for work.

[Jamiemhansen]

Today I put the key in and turned it on in neutral with the charger on to troubleshoot and see if a new code would appear and something sizzled behind the dash or under the hood and the controller stopped flashing, so I quickly turned the key off and hoping I didn't just fry the controller, hopefully just a fuse under the hood or dash. Will keep you updated with my progress, any and all suggestions welcomed.

[Jamiemhansen]

I found out my solenoid is bad, going to replace that for about $135, a couple relays blew also, emergency brake switch relay and charge control relay. Hard to find relays online, will try the auto store tomorrow. Still hoping someone could tell me something they may know that I don't on here, the manual doesn't show everything.