Design review help for Motorhome.

[Aegis]

I am in the process of completing my build of a 580ah 12v (2P 4S) battery pack to replace the 2 Lead Acid house batteries in my 30 foot class A RV. I will also be installing three 200 amp Rich solar panels on the roof in the near future. I would appreciate feedback on my proposed wiring for safety.

 

[time2roll]

Looks good. I would probably skip the 250 ANL and reduce the 250T to 150-175 amps for that 1500w inverter. I would also skip the house battery switch and just pull the cable for service. Mine goes years between needing disconnect so for me it just adds resistance and another fail point.

Possibly reduce the 75 amp blue sea breaker to match the 65 on the other side. Or maybe there is a reason for that?

Doubt the 50 amp combiner breaker is needed except to use as a switch. Again once in service it could be years before a disconnect is needed.

I always hear good things with the Tripp-Lite inverters. Will that run the microwave?

 

[Aegis]

Looks good. I would probably skip the 250 ANL and reduce the 250T to 150-175 amps for that 1500w inverter. I would also skip the house battery switch and just pull the cable for service. Mine goes years between needing disconnect so for me it just adds resistance and another fail point.

Possibly reduce the 75 amp blue sea breaker to match the 65 on the other side. Or maybe there is a reason for that?

Doubt the 50 amp combiner breaker is needed except to use as a switch. Again once in service it could be years before a disconnect is needed.

I always hear good things with the Tripp-Lite inverters. Will that run the microwave?

Thanks for the feedback time2roll.

I realized after having things set up on the test bench last week that the ANL fuse is not needed, mainly because the Tripp Lite inverter has an internal DC breaker. I had it there to protect the wire from the inverter to the busbar when the inverter is in charge mode.

As a sidebar, I don't think I want the 250 ANL anywhere in the circuit anyway. When bench testing the setup with a 1500 watt space heater, the ANL fuse got too hot to touch within about 5 minutes of running! I took it out of the circuit and installed the Class T, which stayed comfortable to the touch after running for 3 hours straight.

The class T is a 250 amp because this particular inverter/charger unit can run at 3000 watts for 10 seconds, it can also run at at 2250 watts for 60 minutes. I had this inverter/charger combo installed in my converted shuttle bus, and it ran a 800 watt microwave fine. The RV1512UL by Tripp Lite is a beast, it weighs 46 lbs. most of that weight is the transformer, the windings are massive. It has served me well for the 7 years I have had it.

The fuse arrangement with 65 amp on one side and 75 on the other side is per the Renogy installation manual for the DCC50S.

The breaker on the solar combiner was built in to the preassembled unit, so I will probably keep it. It will be a handy disconnect for the solar panels as you mentioned.

 

[time2roll]

Yes 3000w / 12 is 250 amps. And this is very temporary. The Class T will allow 2x rating for close to a minute. So a 150 will pass 300 amps for about 50 seconds. This is where I get the 150/175. This also tightens it up for if solar or alternator are feeding in at the same time.

 

[Aegis]

Yes 3000w / 12 is 250 amps. And this is very temporary. The Class T will allow 2x rating for close to a minute. So a 150 will pass 300 amps for about 50 seconds. This is where I get the 150/175. This also tightens it up for if solar or alternator are feeding in at the same time.

Yes 3000w / 12 is 250 amps. And this is very temporary. The Class T will allow 2x rating for close to a minute. So a 150 will pass 300 amps for about 50 seconds. This is where I get the 150/175. This also tightens it up for if solar or alternator are feeding in at the same time.

I was not aware of this information on Class T fuses, thanks so much. I will definitely follow your advice and reduce my fuse size.

 

[eXodus]

If possible put the combiner box inside the RV. The plastic doesn't like the sun and gets brittle - run all the Solar wires inside and hook them together.

Do you got the specs of your solar panels? VOC and amps?
What is the maximum input voltage of the Renogy MPPT?

Just as a feeling - I would put all the panels in series and not use a combiner box at all - a higher voltage also gives you an early start time in the morning and longer runtime in the evening. Makes wiring and troubleshooting much easier.

Series panels are a bit more prone to shading but not much.

600W is not much for 30ft RV. I have 2x 450w + 1x 100W panels on my 24ft so I would expect you could fit much more.

 

[chrisski]

As a sidebar, I don't think I want the 250 ANL anywhere in the circuit anyway. When bench testing the setup with a 1500 watt space heater, the ANL fuse got too hot to touch within about 5 minutes of running! I took it out of the circuit and installed the Class T, which stayed comfortable to the touch after running for 3 hours straight.

There’s a couple type of ANL fuses. There are some intended for audio builds that are much cheaper and actually look different then better designed ones that are more expensive. The good ones are ABYCC rated for main battery protection. I did not see my ABYCC fuse heat for usage.

I also agree with the combiner box inside the RV. The amperage you’re dealing with exceeds MC4 limits and though Y connectors are available for those amperage’s, MC4 connectors aren’t. If you do run six cables through, I recommend conduit from the roof to the floor painted to color, and big enough for growth. I did the internal combiner box with one of my roof mounts.

There still is six cables that need to go in that will likely still need to be put through a plastic entry box. In that case, just paint the box for extra protection.

If panel specs are such that 30 amps won’t be exceeded, IME the Y cables are much easier installation. I have a separate 3s2p setup on the roof that is with a 3 to 1 y cable with inline fuses.