A forum for van conversions, van living and travel

The vanlife => Van Conversion => Topic started by: Imawle on May 15, 2018, 04:12:42 PM

Title: Take a look at my 12V Circuit Diagram!
Post by: Imawle on May 15, 2018, 04:12:42 PM
Hey guys,

Firstly, Thanks for setting this up Mike. I'm a big fan of your site and you've really helped me out.
I' still pretty new to all of this and I'm a the point where I need to start considering my wiring before I go any further.
I've knocked together this circuit diagram and would love any feedback. It may not have all of the info you'd need to give the best feedback, but anything glaringly obvious that I've missed would be great.


Title: Re: Take a look at my 12V Circuit Diagram!
Post by: Camper_Dan on May 17, 2018, 07:16:53 AM
Greetings and Welcome!

I would  delete the solar and the inverter and go with a much more reliable generator instead.  Newbies like solar, veterans hate it, unless they're getting paid to promote it...

Inverters are terribly inefficient, and you can get almost everything in 12 volt models these days...

12 volt compressor fridges will never pay for themselves, either a 3-way or a simple ice chest are much better choices. 

If you insist on solar, I would at the very least double the amount of solar.  You want an absolute minimum of 300 watts of solar panel for every 100ah of battery, and even more solar is better.  With 300 watts of solar, on the best day of the year, you'll be lucky to get 600 watts out of it.  600w/12v = 50 amps of charging power.  Most of the year it will be even less.  Also keep in mind that solar typically kills batteries within 9 months to a year due to it's improper charging algorythms.  When I dumped solar, my battery life went up to 6-7 years.  I also switched to cheap deep cycle junkyard batteries.  Power can be very cheap and efficient if done right, or very very expensive and inefficient if done wrong.

The promoters and other sales sharks are after your money, not your best interests, and the newbies that brag about this stuff don't have enough experience to qualify as good or legitimate advisors.  99% of the time, just driving keeps my house battery charged.  If I'm stationary for a prolonged period, a $99 generator coupled with a $17 silent muffler, and a $29 battery charger can charge both my house and starter batteries, and provide house style power as well.  My no name generator will run for about 8 hours on a gallon of gas, and about 1/2 hour per week provides me with more power than I need.  With the quiet muffler, my generator makes less noise than my quiet van does while idling. 

The advantages of versatility can't be stressed enough, and a generator offers much more versatility and reliability than solar does.  Looking back to when I had solar, a generator would have greatly improved my life even with solar, and I have never regretted ditching  solar.

Title: Re: Take a look at my 12V Circuit Diagram!
Post by: Imawle on May 17, 2018, 11:20:25 AM
Thanks for the input Dan,

Was actually after more of a technical review of the circuit diagram as it stands, as opposed to suggestions on the setup.


Points on the generator noted. I got a good deal on my solar and will give this a go before going to a generator. My wife and I are pretty into the environmental side of it too. I also have a NOCO genius trickle charger than I plan on using when we do have grid access to fully charge and repair the leisure batteries if needed. This should keep them good and healthy.

I hear you on the 12V. We plan on rarely using the inverter, but would rather have it than not as we plan on being off grid primarily.

We were super lucky and got a compressor fridge second hand for 125.

Thanks again
Title: Re: Take a look at my 12V Circuit Diagram!
Post by: Camper_Dan on May 18, 2018, 02:02:13 AM

If that fridge is old enough, it may have an original Dan Foss compressor instead of a cheap chinese knock off.  The new ones only last long enough for the warranty to expire if you're lucky, but the really old ones would make it about 10 years under constant use.

Size your fuses slightly smaller than the max amps your wire size can carry, and put your fuses as close to the power source as possible, fuses come before switches, as close to the battery(s) as possible.  Each lesser size wire gets an appropriate fuse, as close to the junction with a larger wire as possible...  Hopefully you get the  idea...  Any wire between a power source (generator, alternator, solar panels, charge controller, or battery(s)) and a fuse/breaker can short out and cause a fire or explosion, because they are unprotected, so you should always keep the lengths of unprotected wiring as short as practically possible.  A disconnect switch between the solar panels and the charge controller can be very handy, and a total master power disconnect switch right at your batteries can help save you in an emergency.  Propane and electrical are the top two causes of RV fires, so it's always better to err on the side of extra precautions.

Personally, I prefer breakers to fuses, even though they cost slightly more up front, but the advantage is that you'll never find yourself without a replacement fuse, and it can also be used as a switch.

Also always remember that the solar panels get connected last, and disconnected first, before the batteries.  Never disconnect the batteries with the solar panels connected or it can fry the controller, unless you have a dump load connected.