Changing issues with Summit II

[nobodeuno]

Ok so I was able to do a run monitoring pack voltage and with the battery pack starting out at 51v running up the hill I saw it drop to around 41.5-41.9 volts. Is this normal? Problem is when the battery pack is running low maybe 70-80% voltage after driving around the neighborhood. Thoughts? Again these are new batteries about 2-3mos old.

[Fairtax4me]

Did you check the voltage of each battery?
Is the cart stock? Stock motor and controller? Tire size?

Voltage that low wouldn't be too out of the ordinary for a modded cart (bigger motor) at full throttle, but a stock cart shouldn't get below about 44-45v.
How long had you been driving when you went up this hill for the test?

[nobodeuno]

I have a 400a controller stock motor and that was at full throttle going up a hill. Tires are a bit larger 12” 215/40/12. The hill is right in front of my house maybe 1min driving to get to bottom of the hill and turn around.

Haven’t checked each battery voltage yet. Would I just hook the multimeter up to +\- on one battery then run it up the hill. Do that for each battery.

[nobodeuno]

So not sure if this is related but was just driving my cart and the entire thing shut down. Looked under the seat and saw this….the entire positive battery post came disconnected. This seems like a defect right?

Could the shorts have caused any issues with the other batteries or controller? Trying to see about getting a replacement battery…

[Fairtax4me]

That is almost always caused by the connection being loose, or Possibly over-tightened and pulled the stud through the lead.
Any loose connection will burn like that due to the amount of current being pulled by the cart.
You'll need a new fuse.
I would not mount the fuse to the battery terminal. Mount the fuse on the solenoid, or buy a fuse block to mount the fuse in. They're about $40, but you mount the block to the frame or to some other part of the cart, and that holds the fuse securely, and keeps it away from potential corrosion on the battery.

That battery can likely still be used, by drilling and tapping for a 5/16 stud on the smaller stub next to the original post. Don't drill deeper than about 5/8" to avoid going all the way through.

[nobodeuno]

Ok thanks. I had just tightened everything down and applied anticorrosion spray and I don’t think it was over tightened but I wonder if it was bouncing around and it loosened up that way.

Thanks for the tips. I will give that a shot.

Does the voltage drop I mentioned seem ok or should I measure each battery.

[Fairtax4me]

Do a voltage test on each battery. Need to make sure you don't have one that is dropping a lot lower than the others.

With the 400a controller that voltage drop may be normal, but it sounds excessive to me to have that much loss right off the charger.