Inverter to charge battery

Ah, Mickey. Think solar, me boy, think solar. Small batteries scream for solar.

Unless the inverter ALSO has a charger then it is NOT doing any charging of battery

With truck running your truck alternator will be supplying a minimal charge to battery......

Fridge on 110 via inverter....and only one single 12V group 27 battery------NO

So you have a regular inverter in the truck and want to plug in the trailer to power it's onboard charger to charge your trailer battery, correct? This will work but is kind of complicated means of doing it.
Your fridge will pull about 300 watts on 120v AC so that's about 30 amps at 12v coming out of your alternator. If you truck is just idling I don't know how much it will put out but likely not that much. Your camper should have an electric cord that plugs into the truck for 12v power as well as marker lights and maybe signal and brake lights. This cord should allow the truck alternator to charge the battery when running without using the inverter or the camper's charger. If it's not set up that way I would make it that way. You eliminate 2 pieces of equipment and lots of inefficiency and inconvenience.
Running the fridge on 120v this way is probably less fuel efficient and cost effective than just running it on propane but I guess you could do it if you wanted to. Most people just run them on propane like they're designed to do. They typically cool better on propane than electric anyway.
It's impossible to say how long this set up would take to charge your battery. Nobody here knows what charger you have in your camper or if your truck's alternator puts out enough power at idle to power it.

Thanks for the info.. Electricity is a black art to me so I'm a bit confused. I easily ran a 7 cu foot freezer full of fish off the inverter while underway from Alaska to Maine last fall. If the inverter is producing 110 volts/1100 watts, how is that different from shore power? Camper is wired with 3 flat plug for truck. Truck has 4 flat plug for my boat. I can't find any info. about what my truck alternator produces at any rpm's . I plan on mostly boon docking and don't have room for a generator.

Mickey Finn wrote:
Thanks for the info.. Electricity is a black art to me so I'm a bit confused. I easily ran a 7 cu foot freezer full of fish off the inverter while underway from Alaska to Maine last fall. If the inverter is producing 110 volts/1100 watts, how is that different from shore power? Camper is wired with 3 flat plug for truck. Truck has 4 flat plug for my boat. I can't find any info. about what my truck alternator produces at any rpm's . I plan on mostly boon docking and don't have room for a generator.

add a front receiver hitch and use a tray to carry the generator up front

like one of these
https://www.torklift.com/rv/lock-and-load-sidekick

It is the same as utility power. How long does the charge take plugged in at home?

Otherwise you need to post the model number of the converter in the camper. Generally a low battery takes 3 to 24 hours to get to 90% charged depending on the converter.

I recommend about 200 watts solar for off-grid camping... assuming you have some sun.

Mickey, me boy. RVing and electricity are inseparable. Learn, lad, learn.

Year, make and model of the camper to let us figure out how it's equipped?

13 volts / 900 watts the converter will want is about 70 amps. This will be what your alt needs to put out to power the converter and a discharged camper battery

What size wire is going from your inverter in your truck to the batterys.

1. Even 2 gauge wire will get warm. Ask me how I know.
2. Unless you have tow package I doubt your alt puts out 70 amps. Or its just 70 amps. I think the tow package tacomas put out 130 amps.


Your better off just using jumper cables from truck battery to camper battery..

If you do insist on trying it, please try it at home,.

This way you dont get stuck in the woods when the alternator over heats and stops working.

Hope your fused properly too... Electrical fires are no fun...

Camper is 1999 Shadow Cruiser Model 700 truck camper pop up w/small Dometic 3 way Fridge, 3 burner atwood stove top and can't recall furnace brand(its buried in snow right now). Not sure of wire gauge between inverter and truck battery but appears to be same as battery cables. The wires didn't heat up when we were running the freezer. We have solar lanterns, portable propane heaters and head lamps so on board DC is mostly a luxury I think? I'm a tech dummy for sure but have done a fair bit of back country camping by canoe in the Maine Woods and by sea kayak on the coastal islands(Registered Master Maine Guide). Thanks again for all the great input