Inverters: Charging your boards in your car

i have a couple of walmart 12v to 110v for-the-car inverters i bought on impulse to see if they would work for charging my boards, but my 4 amp 12S chargers trip them immediately. We now use them for charging the remotes or blowing up air mattresses and anything else that won’t trip them, but they’re useless for boards. Obviously they can’t handle the wattage so i was wondering what i actually needed spec wise. the car is already wired with fat cables from the battery area to the trunk, so i just need to find something good to hook up to them.

what kind of ratings do i actually need to look for? Amazon has some that say they’re 1000 watts. I always get confused with inverter specs so i don’t really know how many watts i need.


Maybe post a few more informations. How much does the charger itself draw and what inverter you got :slightly_smiling_face:

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Why not get an adjustable DC-DC step up converter?

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I think because he wants to use his normal 110v wall charger.

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The one i have says its 150watts. Not sure what the max draw on my charger is, i’ll see if i can find out.

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In my oppinion you would need one with at least 400 watts. P=U*I I could be wrong tough…

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If I remember correctly watts is V*A… so 12s charger is like 50v * 4amps = 200ish watts… double for some overhead… something like a 400watt inverter should be good?


Got the whole nine yards in my truck dual batteries and redarc inverter system for camping trips. 2000w inverter charges the board fine. Doesn’t like the microwave though. You can buy a cheap 3000w inverter for 100 bucks. Surely you should be able to get similar.


there’s ya answer ^

Then i may be able to charge both boards with that then. Or if it works out well i can get a second one…


If it does bro keep putting your progress here as this is a very interesting topic

yeah i thought i might be of interest because i think everyone has driven their boards some where and wished they could have topped them off or charged them along the way, or even after they got there and rode around and found no outlets.


I’m gonna try this when I get home. I think my i inverter is 350 watts or something.


I have an older 500w inverter from Sams Club. My 12s 4a charger runs fine, and I can charge a smaller 10s 2a board at the same time.

The trick is to run a nice thick wire from the battery to the inverter, the little baby wires in your normal 12v lighter socket can charge your phone or push like a 100w inverter tops.

Next is heat, I’ve melted the binding posts from not having a good connection and having it shoved in some corner without airflow.

Finally, to draw large amounts of power, your engine needs to be on. That extra voltage from the alternator is needed.


That’s exactly the kind of info i was looking for. Thanks, man. Definite yes on the car running while charge is happening.

so i just ordered this monster:

We’ve already got 10AWG superworm going to the battery from the compartment where it would live, and i think i can place it where it will be able to breath. If i can’t get it in there with a nice air pocket then i’ll just have to have it in the main trunk space somehow.

It might charge two boards at once with 4 amp chargers but i’m not going to push it at first. It will definitely get a couple of 2 amp chargers going though.

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ok so this monster seems to charge almost everything you’d have on a trip at once just fine. i got the 2000 watt variant for about $80.

this problem seems to be solved.


I was just about to buy a 500w inverter, would it not charge two 4a chargers together? I don’t really understand the complexities.

Out of interest could you get away with using a 2a charger on the 150w 12v connector?

Just tossing some numbers around.

10s 2a charger is 42v x 2a = 80w

80w / 12v = 6.67a. Two of those would make it 13a. That’s a lot of current to move on skinny wires and a cigarette lighter port.

If you have a couple of 4a chargers, 42v x 8a = 336w, 28a on 12v. yikes.

Also, your car’s alternator has to have this excess capability. Otherwise you’re trickling down your car’s battery, and most car batteries are not meant to be deeply discharged. By deep I mean like 50%.

Plus, you’re risking your car’s electrical systems and all the fancy computerized stuff, for this convenience.

I think it’s fine for modest loads, but I’d read up before using 500w inverters regularly. Maybe bring a few golf cart batteries or that little red Honda gennie.


The alternator in my RAV4 allegedly puts out 100 amps, but there’s a 150 amp one i can get that comes as part of a tow package when you buy the car new. I may consider upgrading, i believe its a drop in replacement.

Plugging this into the lighter socket would probably result in something smoking. We ran 10awg wire all the way up the chassis.

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It isn’t just the power rating that can be involved…it can be the combination of the TYPE of inverter output and the design of the charger itself. SOME of the more recent “wall” chargers I’ve used don’t like the “simulated sine-wave” or “approximated sine-wave” inverters. They simply either don’t function (as a protection circuit kicks-in) or they smoke. I’ve lost 2 cheap chargers that way.

And, you definitely don’t want to get an cheap inverter that produces a square-wave output. That is really hard on solid-state chargers.

The best all-round inverter will produce an actual sinewave output at the power rating you need plus I’d give it at least 20% safety/functionality factor. For example, if I need 100W output I’d use an inverter that provides at LEAST 120W output in a pure sinewave form. You also have to watch for high “surge” requirements; motors for example.

Newer wall chargers don’t use transformers to change the voltage from 110VAC to TBD Volts DC…they’re all electronic, and in some cases…not all…that design difference can introduce functional issues when the input to the charger isn’t sinewave.

The sinewave inverters are more expensive. I’ve seen prices of 150% (and in a few cases more) above the price for the same rated “simulated sinewave” inverter.

Similar issues exist with computer power supplies. If the power supply has “active Power Factor Correction (PFC)” (as most modern computer PSUs do) then it may not work on an “simulated sinewave” output Uninterruptible Power Supply (UPS) when the AC mains power fails. Or, it may work for a few times, and then fail later on. The computer community is becoming more aware of this issue and more pure sinewave output UPS units are being sold…and it’s not just a marketing gimmick.