My First Solar System - Any Help Appreciated :)

[Siber]

I'm trying for a 24V system with a 3kWh inverter, into a 2000 Fleetwood Bounder 32' motorhome with 30A shore power.
I'll want it to switch between solar and shore power, and maybe the engine too but that's not a high priority since the vehicle will most likely be sitting most of the time.
I have some parts and a pretty good idea of what I basically want, but there's plenty more to get and I'm sure there will be many changes to my half-baked plan as I progress.
Here's my diagram

Flowchart Maker & Online Diagram Software

and my 3D Sketchup model

Solar1old.skp

drive.google.com

I'm not sure if I want to do the all-in-one thing or separate components. I think I'd like to do them separately, if it's not too expensive, so no Victron for this system
For an all-in-one, I was considering the Easun/Powland ISolar MLV3KW-U, but it seems it's too limited, so now I'm considering the Sigineer Power M3024NC.

For a separate component system, I'm considering these for the MPPT,
-GCSOAR 60A, GCIT6024(10Li) +WIFI Cloud Box
-HQST 60A, HCC60HTR-PL-US
-OAE 60A, the blue one
-Easun Power 80A, MPPT4880

these for the inverter,
-XWJNE 24V 3000W
-WZRELB 24V 3000W, VC300024U5WD-1
-WZRELB 24V 3500W RBP350024VCRT
-VEVOR 24V 3000W or 3500W

and these for the transfer switch.
-MOES Dual Power Controller 50A, ATS-11KW
-Spartan Power 50A, SP-TS4500PLUS
-PowerMax 50A, PMTS
-Go Power 30A, TS-30

Or instead an inverter charger like the Ampinvt FTS - 3000W24V or Sigineer Power APC3024NC.
Other than that, I'll also have to add a 24V to 12V DC converter and sort out the wiring and fuses, but that's basically where I'm at now.

I was considering two inverters, to limit no-load draw, but the Ampinvt 3000w inverter charger seems to be around the same as smaller inverters at around an amp or less, so maybe, maybe not.
I'm also not exactly sure what to do with the DC Out on the MPPT.
The 24V to 12V converter also has me stumped as to where to hook it into, if at all.
There is a single lead acid house battery that is installed in the rv, so maybe wire it to that or to the engine battery/alternator somehow?

I was at first thinking 2 AWG would be fine for the battery and inverter connections, but now I'm not certain and maybe it might be best to use 4/0, or maybe that's too big and something in between would be best?

Thank you for any help and insights into what I might be doing wrong, or right :D

 

[Zapper77]

I tried....way too much data.

 

[Zapper77]

Ok 3rd time reading.

I have a 3K 12v inverter in my 30 amp RV. I wish it was 4k or 5k, but my 12v system is limiting my inverter size.

I frequently use the vehicle alternator to charge my batteries...and on board generator. (Solar production is limited where I boondock)

I use AIO at home (in the detached garage)...but I'd like to try one in my RV, except the turbine blowers would keep my neighbors awake (ok joking a little)

In my RV I added a 2nd transfer switch. [(Grid, Generator), Inverter]. A fancy victron inverter would make wiring and transferring between sources easier.

MPPT (obviously solar),
Lithium Charger (shore or generator),
12v Alternator (factory controller with the house battery switch wire unplugged. This stops the relay from activating/charging the chassis battery. (higher voltage of Lithium will activate the relay)

 

[MisterSandals]

I'm also not exactly sure what to do with the DC Out on the MPPT.

No need to stress your SCC with loads on thee DC output. Connect loads to your battery.

I was considering two inverters, to limit no-load draw, but the ampinvt 3000w inverter charger seems to be around the same as smaller inverters at around an amp or less, so maybe, maybe not.

I think this logic of 2 inverters works if you will turn off inverters not in use. Better inverters normally have less idle draw per wattage.

There is a single lead acid house battery that is installed in the rv, so maybe wire it to that or to the engine battery/alternator?

This does not make any sense. But no.

I was at first thinking 2 AWG would be fine for the battery and inverter connections, but now I'm not certain and maybe it might be best to use 4/0, or maybe that's too big and something in between would be best?

Its all a matter of amps, volts and distance.

From diagram, solar as 4P will be 34A which is too much for MC4 connectors. 2S2P often an excellent solution but depends on your SCC max input voltage (and panel temp adjusted Voc).

I think I'd like to do them separately, if it's not too expensive, so no Victron for this system

An SCC is the heart and brains of your solar system. This is the most important place to spend a little more, up front, for a dependable and easy to use system.
960W solar / 28V charging = 34A

Money well spent(you'll LOVE the bluetooth setup and monitoring. Sleep well with 5 year warranty. You're welcome.)

Amazon.com

 

[Zapper77]

You will want a shunt, get 200-400 ah of Lithium. That lead battery is a waste of time and honestly will be dead in a matter of minutes running any real load. Wire the MPPT to you house batteries.

 

[Siber]

I frequently use the vehicle alternator to charge my batteries

I suppose that's what I could use the 24V to 12V converter for? If so, I may need some help figuring out exactly where to splice into the rv system, hopefully someone familiar with the 2000 era Fleetwood Bounder comes along.

to charge my batteries...and on board generator.

That would be nice too, but that might be something I add to it later. For now I'd just like to get the batteries, panels, scc, inverter and monitor hooked up properly.
The generator on this thing works, kind of, but the fuel line isn't hooked up and it's whole other thing before I even get into that, which is why I didn't bother to put anything about it in the original post. I'm considering alternatives to the Onan, as shown in the diagram parts list.

I use AIO at home (in the detached garage)...but I'd like to try one in my RV

For me, the big things are the aio's are rated to draw more power at idle than a decent standalone inverter or inverter/charger, and if something goes wrong with one piece then pretty much the whole thing needs replaced but in a way that may not be so bad since they are about the same price as just the Ampinvt inverter charger.

A fancy victron

Yeah ok, but are there not other products on the market that could be used instead that don't cost as much? Are any of the items in the lists in the original post not worthy?
If so, what is wrong with them? They seem pretty decent spec-wise, unless I'm missing something.

 

[Siber]

I think this logic of 2 inverters works if you will turn off inverters not in use. Better inverters normally have less idle draw per wattage.

I think this logic of 2 inverters works if you will turn off inverters not in use. Better inverters normally have less idle draw per wattage.

That's what I was thinking, but like I said, the Ampinvt inverter charger states it only draws less than 1 amp at idle, which is very low and similar to the four inverters I listed above and others.
So while in theory it sounds good, is it really all that practica? Maybe just nice to have as a backup?

No need to stress your SCC with loads on thee DC output. Connect loads to your battery.

This does not make any sense. But no.

I made a mistake in the original post, sorry and edited. That was supposed to be about the 24V to 12V converter, not the MPPT.
Yeah, I've seen some add small 12V or USB outlets to them, but I was't really considering using them for anything, certainly not for anything big.

Its all a matter of amps, volts and distance.

Yeah, and efficiency of cable purchasing, if there's extra wire around that will do.
Obviously the wires are very short between the batteries, the longest are going to be about 24", as listed in the diagram, and then from the batteries to the inverter is total of about 4 feet.
So, I can go with the lowest rated, but should I?
Is 4/0 overkill to connect 200Ah batteries 2s/2p?
Is it also overkill to then connect those batteries to a 3000 watt inverter with 4/0?

From diagram, solar as 4P will be 34A

eah, the stuff at the bottom is just if it were done with and all-in-one and if all of the panels were connected in parallel.
The stuff at the top is the current most likely plan, which has both the batteries and solar panels configured as 2s/2p.

An SCC is the heart and brains of your solar system.

Agreed, but this one seems nice and very similar for half the price.

https://www.amazon.com/gp/product/B08L3H5KWV/ref=ox_sc_act_title_30?smid=A3QL2SDAQ02E3D&psc=1

 

[Siber]

You will want a shunt

Got it, as shown in the diagram.

get 200-400 ah of Lithium.

Got it, as shown in the diagram.

That lead battery is a waste of time

Agreed, but it's what came with the rv, so it's just there, lol.
The thing is, it, and more importantly the cabling, is on the other side of the rv from where I am setting up this solar battery bank, so that's a whole other thing that will have to be sorted out, probably later.

 

[MisterSandals]

Is 4/0 overkill to connect 200Ah batteries 2s/2p?
Is it also overkill to then connect those batteries to a 3000 watt inverter with 4/0?

3000W / 20V cutoff / .85 efficiency = 176A
This is barely (175A) 2/0 with 75C rated wire

Between the batteries current i do not known. 2/0 likely just fine with 75C rated stranded copper.

Agreed, but this one seems nice and very similar for half the price.
https://www.amazon.com/gp/product/B08L3H5KWV/ref=ox_sc_act_title_30?smid=A3QL2SDAQ02E3D&psc=1

Perhaps your reliance on power is lower than mine (and happy wife) and a "nice and very similar" SCC is good enough.

 

[littleharbor2]

Maybe I missed it but I wanted to comment on your solar panel selection. With a 100 Voc max SCC It is crucial you choose solar panels with relatively low voltage. Many of the latest panels have pretty high Voc ratings. If you look at the 60 cell (or 120 half cut Perc cells) format panels You should be able to comfortably series wire two at a time and remain within the 100 Voc limits.