Boondocking Camper set up

gallantmc

New Member
Joined
May 8, 2022
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2
Hey,

I am building a boondocking RV and had some questions about solar controllers, inverter chargers and compatibility.

I am planning on using a 12v LiFePo battery bank (3- 300ah batteries in parallel) and 600 watts of PV panels. Most of the time I will not be hooked up to shore power or a generator. I will have a 30 amp shore power connection when it is available.

I have been looking online and this is what I think I need.

1 - Multiplus II 2 x 120V Inverter Charger
1- Smartsolar 150/35 MPPT controller
1-GX Touch
1- Cerbo GX

I am in the US and so I need 120 V 60 hertz output.

I will also have a DC to DC charger in line when driving to charge the battery bank with the alternator.

Are the solar controller and the Multiplus II compatible? Do these devices seem appropriate for the job. I know my battery bank is large. I am oversizing it for days when we are off grid and the sun is not shining.

I know I will also need some fuses and a shunt and some isolation switches.
 

Ranger Rick

Here comes the sun
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Feb 23, 2022
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Location
SW Idaho
Yes, Victron SCCs and MP-II I/C work great together and can be monitored. The MP-II allows for future 50A expansion. You will need to know the VOCxT° coef of each panel. If you connect them in series, their sum total cannot exceed 150v of your SCC. You should be fine here.
With a 12v 900amp battery bank, you could increase the SCC’s amps out to decrease solar charging time.
The DC to DC charger is an excellent accessory in place of a second dedicated alternator.
I would look into a Lynx Distributor - a device that makes wiring simpler.
🍻
 
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gallantmc

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May 8, 2022
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I am looking at either Chins or Jita batteries. Has anyone had any issues with either brand?
 

A.Justice

Swears he didn't start that fire.
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I am looking at either Chins or Jita batteries. Has anyone had any issues with either brand?
Chins batteries are spoken of highly on here. That's what I would get if I was looking for a pre-assembled, "budget friendly" battery.
 

HRTKD

Boondocker
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Apr 24, 2020
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Somewhere South of Denver
If you have a 30 amp RV then you likely do not have a split phase system and you don't need/want the Multiplus II. The regular Multiplus 12/3000 will do the job.

Add the Victron Smart Shunt. You'll need this since there will be three batteries.

The DC-DC charger is a one-way circuit. Depending upon where you splice this into your system, and if you have a trailer, it may cause your breakaway brake system to not have power. You'll need to run a dedicated line from the battery bank (or a suitable common bus bar) to the breakaway system and isolate the breakaway system from the circuit coming from the tow vehicle. If this is a motorhome then nevermind.
 

rmaddy

Full-time Solar-powered Trailer Life
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Nov 16, 2019
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Something to keep in mind with your battery bank and solar panels.

3 12.8V 300Ah batteries is 11520Wh. You are planning 600W of panels that will likely be flat mounted on the roof. On a good summer day you might see 500W. 11520Wh / 500W = 23 hours. That might be 4 or 5 days in the summer to recharge your batteries. In the winter you might get 200W on a really good day. That's 57 hours. That could be 22 - 38 days in the winter to recharge your batteries. And that assumes no loads are used during that period.

This is all based on needing to fully recharge the battery 100% using only solar. Of course you will have the option of shore power charging. The MultiPlus 12/3000/120 inverter/charger can charge a battery at 120A with 30A shore power. So charging 900Ah of battery at 120A will take 7.5 hours. Again, assuming no loads while charging.

Having lots of battery will help you when boondocking. Your solar may be plenty for your typical daily needs on clear summer days. But your solar may be very inadequate if you are camped in shady areas or cloudy areas, or during the fall and winter when the sun is less intense and the days are shorter.

Make sure you do a proper energy audit of your daily power needs. Eliminate power hungry items if you can. Find alternatives if you can. Avoid electric heat, hot water, and cooking. Use propane or diesel for those. Be realistic in your usage patterns so you end up with a system that can actually meet your needs and not leave you plugged into shore power several days a week when you'd rather be boondocking elsewhere.


And please, don't buy anything until you work it all out. Don't waste money getting the wrong stuff that won't meet your needs.
 
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djnorth

Solar Enthusiast
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Jun 1, 2021
Messages
37
The Multiplus 12/3000 can charge at 120A. 900Ah battery bank / 120A = 7.5 hour approximate charging time using shore power.

For cooking you could consider an induction cooktop. You can buy a nice one these days for under $100 to test with a Kill-A-Watt meter and measure how much energy is used to prepare your favorite/everyday items with it.
 

rmaddy

Full-time Solar-powered Trailer Life
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The Multiplus 12/3000 can charge at 120A.
You're right. I was mindlessly thinking of the 30A input from shore power. But that's 30A at 110V so the charger is able to get the battery charge current up to 120A. I corrected my earlier post.
 

12VoltInstalls

…myself everything do I…
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cooking you could consider an induction cooktop. You can buy a nice one these days for under $100
Eliminate power hungry items if you can. Find alternatives if you can. Avoid electric heat, hot water, and cooking. Use propane or diesel for those
I’m sticking with rmaddy. I’d rather have lights and a fridge over not cooking with propane or wood.
consider an induction cooktop
You can cook forever on a couple 30# cyls. I love my antique magic chef gas range. And it doesn’t deplete my batts over s as couple cloudy weather days.
 

HRTKD

Boondocker
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Somewhere South of Denver
There's also a lot to be said for cooking outside the trailer so you don't stink up and/or heat up the trailer.

My Plan "A" is the microwave. I do have a toaster oven that is used infrequently, like if I want toast or something else that doesn't require a lengthy cook time.

@gallantmc, the point of the comments that you're getting is that certain appliances are doable, but they greatly increase the cost of the PV/LiFePO4/inverter system.
 

Newenough

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Sep 20, 2019
Messages
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I just finished a similar (requirements) install on a customers Airstream. I was looking at a lot battery options for the project, and Will just happen to do a teardown of one of the batteries I was considering was (4) of the Lossigy 12v 200ah. The reason I chose that battery was that it was quality construction, AND the foot print worked for the compartment/space I had available. As it used pouch cells within the one case, rather cells in a case, put together and installed in another case, made it a better option. They are 2 inch shorter and 1 inch narrower. Not much, but they fit. As they wanted to run AC for 5-6 hrs in the evening, 12v probably would not work, as that was a lot of amps for a considerable amount of time, about 140+amps during compressor hits. So I opted for a 24v system, with 40a 24v to 12v converters wired in parallel to handle the 12v house loads (cheap redundancy). Installed an EasyStart on the AC system, Easytouch thermostat, and of course a Victron BMV-712 with smart shunt. Paneled 600w on the roof, and 2 ground mount strings of 800w, 2s2p each with Anderson 50a quick disconnects at the hitch. As for the batteries? Did 3 full charges and discharges. Got 5.5-6 hours of AC at a temp differential of 12 degrees, with 30% battery remaining for morning coffee.
Cables where cool to the touch, a little warm at the battery disconnect which would be expected.

Hope some or any of this is helpful.
 
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