View Single Post
Old 06-28-2019, 09:20 PM   #5
Gone Mad
Join Date: Oct 2009
Location: Buford, GA
Posts: 8,988
Default Re: Power and torque upgrade guidance

Originally Posted by ChuckW View Post
Thanks Johnny B

What is the cart's top speed on level pavement? - GPS Measured 15 mph with one person and 13 mph with two people

What does it slow to on hills? GPS measured 9 mph with one person, 7 mph with two

What is the measured tire height? 18 1/2"

What is the tire's max inflation pressure?
22 psi

I suspect you have some battery issue and high current cable issues. Stock cables - see attached photo

What is the pack voltage? - 37.8v 24 hours after last charge

what does the pack voltage drop to on hills? 32.1v one person on a 15% grade - 31.5v two people on same grade.

Beginning and ending pack voltage after running 30 min up and down some pretty steep hills in the neighborhood
37.8v - 36.8
Per battery
6.45 - 6.27
6.36 - 6.19
6.31 - 6.14
6.35 - 6.21
6.22 - 6.07
6.33 - 6.19

I noticed after running it I was smelling something burning so I took some temps. Do these temps seem reasonable? Again, I was running pretty continuously on some fairly steep hills. I also found a loose nut on the + post of the battery going to the controller, so I'm sure that didn't help any.
Motor - 140 degrees
Speed control and cables to batteries - 123 degrees
Battery posts 95 to 107 degrees
Batteries are borderline at the end of their useful life, based on age. Voltages while driving up a hill would be better.

They could stand a few equalization charges.

Smelling "burning" is never good. See if you can find the source.

Motor seems fine, but exterior temperature rises after stopping, as it has a lot of internal thermal mass, and cooling is reduced when there is no wind = parked. In other words, it could be WAY hotter inside.

How soon after your ride did you take voltages? Batteries recover after a while, so voltages may be artificially low. What was ambient temp? Some battery posts look hot. Other things also look hot. Good connections and fatter cables will help.
yurtle is offline   Reply With Quote