EV charging for AGM Camper batteries


Is anyone aware of an EV charging system that I can use to charge the house AGM batteries on the Cruiser? We presently have a Samlex Evo charger/inverter. We have two alternators on the truck as well as two solar panels. We spend some time in urban areas and some with no idle laws. It would sure be nice on a cloudy day to pull up to an EV charging station and top up the house batteries!



You already have the solution, just carry a 120V cord and plug into any outlet. Trying to use an EV charging station is adding complexity where you don't need it. A fast charging station is going to be high voltage DC and it's going to require negotiating with the charger to mimic EV battery management. Then being high voltage DC you'd need an intermediate AC step that looks a lot what you get from the grid already that can be stepped down to your AGM DC bus.


Thanks DaveInDenver. I was hoping for some sort of rapid charging situation. On the road it isn't always easy to find an outlet. We boondock all of the time so finding a spot to charge is tough.
It sounds like it is an overly complicated issue. Maybe we should just buy a Tesla battery lol


Charging housebatteries (or simply drawing power for whatever reason. Cooking, heating, etc, ) from a regular Level 2 EVSE charger is fairly easy with couple points.
Level 2 provides singlephase 208 or 240VAC.
Depending on the specific EVSE, Current maybe limited anywhere 20-60 amps.
But ’dunno what happens if an EVSE is overloaded. Obviously, there is supposed to be OCPD on its supply... But I suspect a public EVSE will just shut itself off if overloaded. Only relying on the supply OCPD as a backup protection.
At public chargers, you probably wont have a way to know what its maximum is. But I think its pretty safe if you limit yourself to 40A.

Obviously you need the inlet connector on your camper what fits SAE J1772. Also needed is ability to ’spoof the EVSE into thinking a EV car is connected. Otherwise it wont switch on.
That requires a measure of electronic know how which is a thriling adventure of an electronics hobbiest.
Using a Tesla inlet would be more versatile. You could charge from Tesla Destination chargers, or using a Tesla to SAE adaptor, you can charge from an ordinary Level 2.
Conversly, you could fit two inlets. One for Tesla, other for SAE. Then plug in whatever type you have access to.
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I’ve been looking into the same thing after seeing someone do this for a schoolie conversion, but after a few months and started losing hope.

Then, I found this site that seems to make all kinds of adapters to charge home brew EVs - https://www.tucsonev.com/

Now, I’m trying to find a way to use the 208/240 VAC with my Victron Multi charger/inverter.

I think it it’s possible - I’ll be following your progress :)

PS - This would be especially handy in Canadian National Parks where there are many free EV charging station that are under-utilized.


Lead batteries tske minimum 7 hours to get back to 100% Full

which they need at least half their daily cycli g if you want decent longevity.

Even with kW available, AGM highest CAR past the first 10min might be 0.4C, and will trail down to half that within an hour, you might get to 85-90% within two hours

but you're still five hours away from Full.

If you want fast charging, go LFP or maybe LTO.

The DIY circuitry to properly pull from J1772 EVSE costs many hundreds, not counting the actual charger which you have.

Many stations will be for EV use only, if lots of House bank users cause delayz for EVs thzt will increase a lot.


Sounds like you need more solar, We lived full time with our rig 7 out of 9 years and only plugged in twice (when the truck was inside).
Leave the EV chargers for the EV's.


The DIY circuitry to properly pull from J1772 EVSE costs many hundreds,
But the Legitimate ExPo Guy lets some Chinese guy pay the R&D plus manufacturing.
Then simply buys a product of slave labour.
Things like this from several manufacturers.
free EV charging station that are under-utilized.
The best kind of electricity is what somebody else pays for.
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