Can you folks check out this config

[MalibuDave42]

I think I'm on right track, but don't have the confidence yet. I have not bought anything. This system will be added to my 5th wheel camper. Though lots of folks put panels on the roof, I prefer to park in the shade. Therefore, I want to have portable panels. The first build out is 2 -100w panels, but I do want to design for 4 - 100w panels (no need to replace pieces parts). Open to all suggestion, thanks in advance!

 

[Rednecktek]

A couple questions:

The 50a breaker to the batteries, why? Just as a disconnect?
No inverter planned?
I assume 12v system?

Other than that it looks good.

 

[MalibuDave42]

50a breaker - seems like extra safety. If you feel it's only for disconnect, I suspect the 30a adds safety and disconnect. Right?

No inverter here, this is only the solar side. Yes, 12v.

Are the inline fuses overkill or a good idea? Are my calculations and nomenclature correct?

 

[Rocketman]

Here are my thoughts…
100w panels tend to be expensive per watt. See if you can handle 200watt panels instead.

Also the MC4 connectors do not like to be constantly connected and disconnected- see about just using extension cord wire and putting an automotive connector on it.

If you can find a couple of used larger panels- mount those to your 5th wheel roof - yes you will not get rated output- but you may get enough you don’t need the expansion. (You would need a second SCC for those ones. My dad added two used 250watt panels from Suntan solar - he only needed one - but he likes the shade too.

 

[MalibuDave42]

Well worth the consideration for the rooftop panels. In the portable panel config, storage of the panels is a challenging consideration.

Good to know about the MC4 connectors, plus I suspect a 10AWG extension cord is much cheaper.

 

[Bluedog225]

Am I wrong in thinking he needs a Class T fuse on those batteries?

 

[Rainwater01]

Correct me if I’m wrong but I don’t think the fuse is necessary. Even with a direct short it won’t trip the fuse.

50 amps seems ok from the scc to the battery. I assume you’ll go much larger for the inverter?

 

[Rainwater01]

Out of curiosity… what’s the down side of running 24 volts on these campers? If I was building one that’s the way I would go. An 1800 watt load pulls 150 amps on the 12 volt side but only 75 amps on a 24 volt system. They make plenty of converters to step back down to 12 volts for lights etc if needed. Also if I could find a way to store a 400 or so watt panel that I could pull out of the truck or camper and set it where it gets the best sun I’d do it! 400 watt panels are just over $200. Seems like the best bang for the buck.

 

[chrisski]

Am I wrong in thinking he needs a Class T fuse on those batteries?

I think he does. For his circuit beaker, perhaps it has a high enough AIC he does not need it. I use class T fuses, but I have seen some duel pole DC breakers rated high enough of an AIC. That breaker does not look it.

The breakers pictured to me are used in auto and marine builds, so please check the voltage readings also. The Lithiummay see 29 Volts - 30 volts, probably closer to 28. Whatever the charge specs are need to handle it. Two of those panels in series could make between 45 and 50+ volts on a cold day. THe breaker would need to be rated for that.

 

[12VoltInstalls]

what’s the down side of running 24 volts on these campers

There isn’t a downside in use.

There are three downsides that always occur to me from a practical perspective, though:
1) anytown, USA you can usually source 12V stuff or even if an inverter dies 12V inverters are in walmartha or an auto parts store. So quick accessibility of 12V components is something to consider
2) everything you have is probably 12V now and changing all that may not make sense.
3) vehicle charging is more easily integtrated.

4) bonus round: there’s a plethora of 12V RV and marine lights, devices, pumps, etc in the marketplace. 24V has plenty of choices just not as many and not as widely available.
Your tolerance, faith, and expense comfort should make your decision

 

[Rainwater01]

There isn’t a downside in use.

There are three downsides that always occur to me from a practical perspective, though:
1) anytown, USA you can usually source 12V stuff or even if an inverter dies 12V inverters are in walmartha or an auto parts store. So quick accessibility of 12V components is something to consider
2) everything you have is probably 12V now and changing all that may not make sense.
3) vehicle charging is more easily integtrated.

4) bonus round: there’s a plethora of 12V RV and marine lights, devices, pumps, etc in the marketplace. 24V has plenty of choices just not as many and not as widely available.
Your tolerance, faith, and expense comfort should make your decision

Well said and exactly the answer for which I was looking. I guess you could parallel 4 12v batteries to a bus bar and get your per battery amperage down to around 38. It probably matters more on lead acid than lithium where the efficiency drops a lot when the amperage increases.