RV install wiring layout?

[Isaac-1]

Which of these 2 wiring layouts should I use, Option be is a shorter wire run length to the inverter, also is it ok to have the switch first then just one fuse, or should I move the fuse to the negative return side ?

 

[time2roll]

I like A better. Otherwise you are using the inverter terminals as a bus.
Actually I would prefer 150a fuse near the battery, before the switch. Then skip the 300.
If you have solar to maintain the battery I might even skip the switch.

 

[Isaac-1]

The system also includes 400 watts worth of solar, with a Renogy DCC50S DC-DC charger with MPPT, as well as a Progressive Dynamics PD9260 converter. I like the idea of the dual bank A/B switch as it lets me isolate and run off a single battery if something goes wonky with one while traveling in the RV. I don't really like the idea of the switch before the fuse, but given the physical setup I don't see much of a way to do it without adding wire length. The A/B switch (which is a Blue Sea 9001E rated at 350a continuous), BMS is set to shut down on overcurrent at 110A on each battery. Wiring from each battery to the A/B switch, and to the negative stud by the switch are a 2 AWG 3 ft long each, these run through a 4 individual holes in a plywood bulkhead from the cabinet where the batteries are located to the placement of the switch and stud. From the output of the switch, and the negative stud 4/0 will be ran to either the inverter or the positive and negative bus bars.

Figure A would require approximately 14-15 ft of 4/0 from the switch output lug / Y point negative stud, Figure B would only require about 7-8 ft of 4/0 and the existing 1/0 currently connecting the inverter to the bus bars could be re-utilized to backfeed the distribution bars.

I know the more proper way is figure A, but is it worth deviating from standard to shorten the circuit by 7-8 ft of 4/0?

Thanks Ike

p.s I know 4/0 is probably overkill, but I have a couple of pieces of it on hand (a 9 ft piece of black and an 11 ft piece of red), other choice on hand is 1/0, and about half a dozen 3ft sections of 2AWG welding cable with lugs already on them (4 of which are used in this layout +/- initial leads from the batteries.

 

[eXodus]

I know the more proper way is figure A, but is it worth deviating from standard to shorten the circuit by 7-8 ft of 4/0?

Why do you want to have that switch? It's a mechanical thing which can fail.

When you want to do like in the Absolut correct way - you would have a fuse after each battery - both batteries going to a busbar and from that busbar you go to everything else.

 

[chrisski]

Nothing wrong with the switch if you have your reasons.

I have 950 watts of solar panels on my roof between two strings. When I store the RV, I only leave the smaller one connected. I have a circuit breaker do this, not a switch, but the principle is the same. Even easier to troubleshoot.

This will stop you from climbing on the roof and disconnecting the MC4 connectors or removing wires from charge controllers, both of unplugging cables and removing wires are lesser options than a switch or circuit breakers. The advantage to circuit breakers is if you add a third or more string of panels then it will need fusing or circuit breakers.

 

[Zil]

Sort of like 'A'. Each battery should have a fuse. The fuse should be sized to protect the cable wire gauge. If you must have the switch put it after the battery fuses. If cable size changes at the BusBar you need a smaller fuse there as well. I use a larger fuse at the battery and smaller fuses at the BusBar even if same size cable to isolate different devices.

 

[HRTKD]

Focusing only on the wiring, I prefer option A. I'm not a fan of daisy chaining like option B does.

I'm in agreement with what others have suggested regarding the switch, fuses and bus bar.