Do I even need DC in my solar system?

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Last seen: 3 years 6 months ago
Joined: 06/03/2020 - 19:00
Do I even need DC in my solar system?

Complete newb here, just bought my first RV a few weeks ago, a 13' Scamp.  Previous owners only used shore power, so other than the wire harness for the brake/turn lights, it has absolutely no electrical system in it.  My intention is to do some serious boondocking out in The Great American Southwest for 6 or 8 months or so, coming into towns to resupply about once a week.  So I'm looking to build a serious solar system.

I've been following Thomas' (from I'm Not Lost I'm RVing) Solar Basics video series ( and in it he assumes that your RV will already have a DC system in place (which mine does not) with batteries (don't have any of those yet) to power stuff like lights, water heater, water pump, 2-way fridge.  I'm not planning on having a water heater, and I plan to use a foot pump.  I'm actually considering foregoing the fridge and the complications that brings in exchange for a largely can food based diet.  I don't suppose setting up a DC system is worth it just for some lights that I could easily account for in what will be my high watt solar system, right?  Even if something does go wrong with my solar, I will have flashlights and a headlamp with rechargable batteries that can charge out of a cigarette lighter.

So I guess what I'm wondering is if my end goal is only AC 120v, do I need to mess with DC 12v at all?  Seems like I could save a lot of money and hassle and streamline a lot of my system if I could just skip DC.

Last seen: 11 months 2 weeks ago
Joined: 08/20/2018 - 13:45
night storage

You will need some sort of storage for the 120 Ac to operate from after the sun goes down and cloudy days. Inverting up to 120V AC has a efficiency penalty of a few to 15%  that will add to your requirements. larger Solar and wind systems often run at 24V to reduce the amperage but is slightly more complicated. A medium 12v solar with significant storage capacity does address your concern about a 12v system.  and would already give you the source to be used .  Things like a water pump only use power when operating and not much at the rate you might use it. If there are some of the 12v system in place it could be easy to have both.  I like your thoughts and good luck. What do you intend to use on the 120vAC that cant be done on the 12V directly? 

2019 Scamp 13 standard

Last seen: 3 years 6 months ago
Joined: 06/03/2020 - 19:00

Yes, this is what I was thinking, that AC is needed for night and cloudy days (although, I don't supposed New Mexico, Arizona, nor Nevada have too many of those, yeah?).  Do you think it'd be possible to run directly from the panels without storage, and then I could only use electronics in the sunlight?  Not that I would actually want to do that, I'm just curious if that'd even be possible.

So I have several appliances that I use at home that I intend to use while boondocking: computers, string lights, speakers, lamps, hair clippers...  Things that plug into a wall outlet can't run on 12v directly, right?

ac0gv's picture
Last seen: 2 weeks 6 days ago
Joined: 09/22/2016 - 13:57
You can't skip DC

Solar IS DC.

First, solar panels power nothing, they charge batteries and the batteries power things. Almost anything that runs on 120VAC has a 12 VDC version. That way you do not need to waste power running an inverter. Also, anything that can be ran on LP should be.

I simple 100 watt panel system with a group 27 battery should give you all you need for a few lights and fans.

Last seen: 3 years 6 months ago
Joined: 06/03/2020 - 19:00
What do you like about LP?

"Also, anything that can be ran on LP should be."

What makes you say that?

Greg A
Greg A's picture
Last seen: 1 day 8 hours ago
SOI-AdministratorLifetime Member
Joined: 11/02/2013 - 20:45
Solar - DC

As noted above the answer is Yes to the base system being DC.

You need to be familiar with our Solar Resource pages as this will help you in taking it step by step and not overspending on capacity that you don't need.

Our Trailers:
2015 19 Escape

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Last seen: 10 hours 20 min ago
Lifetime Member
Joined: 11/02/2013 - 20:08
LP Uses

Fridge, stove, heat. One LP tank holds a lot more energy than any reasonably sized battery bank. If you're boondocking, you'll want some of these things now and then.

Last seen: 11 months 1 week ago
Lifetime Member
Joined: 11/02/2013 - 20:13
Suitcase solar

I recently installed a converter, wet battery, and DC wiring in a bare bones trailer. I am also converting to a lithium battery and converter in my current trailer. If I were to build out a Van or rewire a small trailer I would seriously look at Jackery or Bluetty solar generator/suitcase/ battery pack and solar panel.

They are almost ready for prime time and every new product have improvements from lessons learned. They are selling for about $1 per watt for a complete compact AC/DC electrical system. Where as Lithium batteries alone are selling for about the same price. A lot of Van dwellers are doing very well with these units for light usage.