Att JoeC!
You were talking about thicker cables in your wifes competition chair.
Driven into a wall... Stalled for 2 seconds on a stock f55 powerchair. Amps were 70 to 80 on clamp meter.
Voltage under 80 amp load:
At controller module = 21.4
At battery terminals = 23.7
Off load 26.1 at both points so fully charged.
Couldnt test at motors but would expect another drop due to controller resistance and another smaller one due to shorter motor cables.
Thats horrendous!
With 160 amps (your 2x 80 amp DX controller) the voltage drops will be 2x worse!
This was new (2 months) overnight charged group 24, 73ah Gel MK branded (as good as gels get) batteries. Thats why I fit AGMs...
Its also why we should keep battery cables as short as poss, and thicker than stock!
That means the 26+v we started with will be much less than 18v under full load with a big amp controller. agm's and thicker cables and the latest low loss DX or Pand G controllers will give a huge boost in curb climbing, wheelies etc...