Battery for a e-campervan

I'm just researching/considering options for adding extra batteries to electric campervans.

I know people make stand alone portable batteries - but they're generally much smaller and more expensive per kWh. I was wondering if it would technically be possible to charge a givEnergy battery using a standard plug, then be able to power things using a standard plug?

Putting a 5-10kWh battery pack in the back of a campervan could be used to power appliances, lights, etc etc, and you could even charge the main vehicle battery using the granny charger and add range (up to 4 miles per kWh)

Ideally, I'd also put a couple of solar PV panels on the roof which could charge this battery - it would be nice to be able to charge the standalone battery over the day with solar PV, then discharge it in to the main vehicle battery when convenient

Thoughts/ideas?

jonshutt My brother has a diesel VW transporter custom campervan conversion with a single solar panel on the roof to charge his leisure battery. The battery powers 12V internal LED lights, radio and USB chargers when stopped. I don't know the capacity or technology of the battery but it won't be very big as the devices he powers are maybe 10-15W in total.

Rather than add a separate battery and charger, I'd have thought that simply looking to buy an electric campervan with the largest battery they provide might be a better solution, especially as I'm assuming they will have the ability to charge DC-DC at 50kW+ via a Type 2 connector.

I would of thought the way GE products are designed and installed are intended for permanent grounded earthed electrical systems. So I doubt they would produce the same required results in theory.

I think the likes of the Victron range would be more suitable as they are 'modular' and are suited to a lot of motorhome and also marine use, and of course they can handle normal domestic installations.

The GE inverters and batteries are a fairly big lump to shift around. You couldn't lay the inverter on it's back either as it needs airflow up behind the heatsink.
To change settings on it (for say "charge up right now while I'm hooked up campsite") you'd need to be able to either connect the Dongle to the internet (as all system commands come from the cloud still despite the data feed being in local on the new app) or conjure up a GivTCP instance on a raspberry Pi - Both are a bit of extra hassle (especially if you are out in the wild with no internet for option a)
The other issue is the PV startup voltage of the Hybrid would require multiple panels which may be a space issue on the roof.

@Tim I used to do that with my old Diesel van. With an electric van, I was just thinking a huge solar PV that could somehow charge a bigger 'leisure' battery, + the main drive battery could be nice.... especially if you're parked somewhere sunny and remote for a few days...

@DeanoC75 / @hoggy those points about how GE products are built makes sense, and right, put like that, probably not suitable.

Of course, the van could have a 70kWh + battery, and the driving range would probably be fine.

Thanks for the suggestions out Victron batteries - something like that could potentially be useful.