Yamaha 2016 new issue need help

[LearJet]

Hello,

2016 Yamaha lightly used. I have new Ranger Batteries, new cables, and new solenoid. Has run fine the last 6 months. I took it out last night and went around the neighborhood. It ran fine on flat ground, when I went up the hill I have always gone up, once I crested the top, it felt like it downshifted from 100 percent to 80 percent, then slowed and stopped. I tried the forward and back switch and nothing. I ended up resetting the tow switch and it worked but seemed slower. Once back on flat ground, it ran fine. Any suggestions? It has oem controller. I just did a hydro meter on the new batteries and they are showing all green. I will need some guidance on where to put the volt meter to measure.

TIA

Kevin

[Volt_Ampere]

Two weak points with these are the motors and the controllers. I would check the motor brushes. Sounds like worn out brushes could be your problem. I would also check your battery voltage under load to make sure that batteries are not your problem. In this forum, I think at least 90% of these problems turn out to be bad batteries. Check fluid levels and do a voltage test under load.

[LearJet]

Any guidance on how to check brushes? Also where to hook up volt meter under load? THX

[Volt_Ampere]

Hook up voltmeter across battery + to - and watch it while accelerating hard. See how much the voltage drops. To check brushes, you have to remove and disassemble the motor.

[LearJet]

Team,

Here are my findings.

I hooked and ran a 100 amp load test. All batteries passed.

I checked all cells again with the hydro and they all checked.

Ran the cart up the hill and my volts dropped from 50volts to 44 volts.

Thoughts?

TIA

[Volt_Ampere]

Batteries sound ok. I would check motor brushes if it's a stock Hitachi motor.

[LearJet]

Will do....

[LearJet]

I ordered new brushes to replace while I am taking a look, to cheap not to do it while it is open.

[Volt_Ampere]

Good plan. Clean things up inside and install new brushes. If the commutator needs cleaning up at least hit it with some emery cloth. If it's real bad, look for a motor shop to have it turned on a lathe.