Re: Taking the Thundersky plunge
IF his leads are indeed total 20', from Controller + through all batteries to Controller -, then 1000A is not going to drop but 1.6V, just over 1% of a 144V pack.
Here's why I brought this up. I'm a contractor and never knew how to calculate losses in wiring based on it's size and load, even when I did industrial wiring. I had to learn that to get my license, its' part of designing circuits in buildings.
Buildings may have long runs of wiring with low currents, ie 500' building with a row of lights drawing 13A. But the 13A must travel 500' to the fixture and 500' back, a 1000' loop! Since wire IS a load, just like a motor it uses power, just like a motor.
Where motors draw high current in a short wire, a building uses a low current but on a long run it's a high resistance load and will have the same effect if not sized for the length and current expected.
Perfect example. In my home, wired by an idiot, I had a heater plugged in rated 1500 watts and noticed it wasn't producing heat nearly as good as at my other house. Upon checking the voltage at the plug, it would drop to 110V when turned on. The voltage at the panel was 120V.
After crunching some numbers, a 8.3% loss of voltage cost me a 29.6% reduction in power to 1056 Watts. The original wiring loop appeared about 250' total of #14 wire, a loop of 500'. I then had my guys replace the wiring to a few receptacles with new circuits to the panel with #12 and shortened the loop quite a bit. With the heater running on the new wire, the voltage only dropped to 119V.
That's why you need to size your pack right IF you're want to get the performance of your pack it can deliver. Otherwise you're wasting power warming your wiring.
Last edited by ElectriCar; 12-20-2010 at 10:41 PM.