2kw Inverter + 4 GC2 6v batteries = wiring???

2oldman wrote:
Good luck being 'flexible' with 4/0 ! :)

LOL!



Greetings, I introduce myself here as a new member, I've been monitoring this thread and see one or two issues that may need to be addressed.

I qualify my reply with over 40 years as an EE, I have an MSEE and a PE for over 20 yrs. I have worked in various industries including
Solar power, NASA and process control.

I would like to help here, sharing my professional experience and perhaps contacting a moderator/admin to set up some sticky posts with information and tutorials about solar,batteries and the like..?

My RV experience extends over 15 years, mostly with a toy hauler. the last 10 concentrating on boondocking in this beautiful country. I turned 60 years young this year.!



from the quote.

1. NOTHING gets ground wires to the battery bank, except the shunt.
ans: correct, the load end of the shunt is now your "new" negative terminal or return point.


2. It ALL goes to the frame ground?
ans: Ideally, only one ground point should exist, and this should not carry high current loads. passing high currents through ground is not recommended due to unknown contact and weld resistances. it is better to return high currents through defined conductors to defined points.

3. Can it go to different locations on the frame,
ans: above.

4. or best to all be at the same point?
ans: ideally yes, all the power returns meet at one point, this point could be the battery or the load end of the shunt. also this point is were you would connect to ground.
( imagine the conductors wired in a star with the center point the shunt.. )


also, attempting to draw 2000 watts from a 2S2P string
is very bad for those batteries. you will experience considerable voltage drop.. the internal resistance of T105's is about 0.01 Ohms
typically so using ohms law we have: 0.01 * 200A = 2 Volts.
you have 2P ( now gives (0.01 / 2 ) * 200 A
so you might see 1 Volt of drop. this is on a new battery.. internal resistance increases with age.. so don't expect this high level of performance in a year or two..

I would say from a personal point of view that you are "maxing out"
those batteries and it will have a noticable effect on lifespan.

BTW: my name does not come from smoking power circuits !!! although I have had many close call's.. LOL