Non-solar simple power system, I need advice

I am looking to use a 100ah AGM battery and a battery isolator to run what will at first be only lighting a fan and diesel heater. I think I can survive without the solar panel with no fridge and I was wondering what components I can use that are cost effective and won’t become obsolete if/when I decide to add solar.

I can get an isolator for under 100 bucks and battery under 200. What else do I need other than fuses and the wiring to make this thing work?

Will a direct connection from the stock alternator/isolator on a 2013 E250 cook that battery without some sort of controller and if so what are my options for preventing it?

Has someone who has been down this particular path before me care to share what they did and what they did or did not like about the setup.

How much do I need to spend on an inverter to get a decent one? If it doesn’t say pure sine does that make it junk?




See my reply in your intro thread…

Isolators shouldn’t cost more than about $20… Try to buy locally if at all possible.


"Smiles are contagious, pass them on!" ~ Van_Dweller


if you don’t put an isolator, find out what the max operating amperage rating of you battery is and put an inline on the hot line coming in from the relay. Its probably going to be around 40-60A. I haven’t looked but I imagine that the output of your alternator is somewhere around there anyway. That way if you get a surge from your alternator it will blow out the fuse before it damages your batteries or anything connected to it

That should be all unless you wanna add in a cutoff switch between the batteries

Kreiger makes great inverters. I use them on all my builds. If you are only charging your laptop and running some lights but want to be able to run a small air compressor sometimes you won’t need more than a 1000W inverter. Pure Sine is most efficient.

You don’t need to spend a ton of money to get the right thing

I have a pretty good write up on my site about how to calculate your electrical consumption and systems needs along with installing solar panels

I think I’m going with the smart isolator since I tend to forget simple things while I daydream. Please let me know if what I have here will do the job and is the 30A correct based on the battery label? It doesn’t really say max anywhere I can find.



Those things look great.

To be safe you should check the max output of your alternator. Standard is around 30A but it goes up from there. The smart relay will take care of any over-voltage from your alternator. That’s what it there for!

Grab a handful of terminal lug/ rings for whatever gauge your cable is and you should be good.


This looks like my isolator:

price: $20.33

The $100+ difference in the price tag will buy a lot of wire…


"Smiles are contagious, pass them on!" ~ Van_Dweller

Do you need an inverter? Most everything I do from typing this on my laptop, the room light, the fan behind me and even my phone plugged in next to me is on 12v. Heck the MiFi & booster are plugged into 12v via a USB adapter.
I cannot remember the last time I used my inverter… yes I can, 2 months back to charge up my drill battery!

I ran for some time with my house batts hooked to my vehicle charging system thru a switch as the only way to charge them.