High load shutdown without error code

[asnilles]

I have a conversion build with an Alltrax SR72400, and the issue is when a high load (>325A) scenario occurs, the controller shuts down without displaying or saving any error codes. It will recognize that it shutdown prematurely by showing a "Global Shutdown" flag, but no other error is thrown.

Below is a list of components in the circuit:

• Switching contactor: Kelly ZJWT 400A
• Main contactor: ALBRIGHT SU280AB
• Snubber diode: built-in to main contactor
• Pre-charge resistor: 1kOhm 10W, Yageo SQP10AJB-1K0
• Battery fuse: 250A 80V, Littelfuse 157.5701.6421
• Batteries: 6x 12V lead acid, 550CCA
• Throttle: 0-5kOhm linear potentiometer, unbranded
• KSI & run switch: from donor vehicle, separately fused at 15A
• All power wiring: 4 AWG, copper
• All signal wiring: 18 AWG, aluminum

The controller's settings are in Peak Amp mode, 360A, and 54V pack under-voltage. The attached diagnostics files were set in the following scenarios:

1. Startup: simply turning on the vehicle to an idle state. No throttle input given to establish a baseline.
2. Standstill: locking the brakes and applying throttle gradually until cutout.
3. Start stop: short run with a low-speed cutout. No feathering of throttle.
4. High speed: longer run with the throttle feathered until a higher speed was attained, then cutout occurs.

Has anyone else seen this sort of thing happen before? Alltrax has been given the same information above as well as the attached, but no response.

[asnilles]

It's been a while, but I thought I'd give an update.
Alltrax did respond a short while after I posted the issue above, and their suggestion was that it was a bad battery cell. This does seem to have been the case. It was one of the things that I never considered and didn't rule out, so I'm thankful to them for making me look at it.
The original battery pack was a piece-meal of older batteries which were intended for testing but were left in longer because of laziness. Replacing about 2/3 of the oldest cells in the pack has solved the cutout issue. They were replaced with their equivalent size code (still SLA).