Juicy Brucie - cable to use EV charging points as EHU for motorhomes?

[Ridgeway]

You think they'd be ok with you camping in their car park? At their EV points?

Why not, Tesla’s do and if you’re not hogging the spot and you are paying for the leccy then i don’t see the issue.

 

[Lenny HB]

If you want to fill your hab batteries with a relatively short stop, you need a very fast mains charger. Most of us only have 30 amps or so. Which will quite happily fill a large bank of lithium overnight. But that's hogging a charger for a very long time.

I have a 120 amp charger that still only gives me 30ah into the batteries in 15 min.

 

[Guigsy]

I have a 120 amp charger that still only gives me 30ah into the batteries in 15 min.

You are definitely not normal Lenny.

 

[Guigsy]

Why not, Tesla’s do and if you’re not hogging the spot and you are paying for the leccy then i don’t see the issue.

If it's a 22kW charger and you're using 0.5kW (40 amp charger). And you're probably only going to buy 4kWh (~300Ah) of juice while sitting there for 8 hours.

 

[Just smiffy]

Is there limits on charging at these points…?

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[autorouter]

There's literally thousands of these smaller Type2 chargers around. Most Lidls have a couple, so do most Morrisons and Tescos, and there's hundreds of others outside hotels and other car parks. Even a lot of lampposts in London have them. When you drive past them, they are mostly not in use. Yes, it's possible to find a busy site, and block an EV wanting to use it. But in all the time I've been doing this, it's never happened.

I know how fast I am using battery charge, how long it will last, and when I need to refill. I can choose a time and a place that's OK. If I'm on a motorway, I'm driving anyway and the B2B is charging the battery. When I need an EV charger it's when I'm staying in one area for a few days, so I can look around (using 'find-an-EV-charger' type apps) and choose a vacant charger.

My charger is equivalent to 140A at 12V, ie 1680W. In 1 hour it will put in 1680Wh, ie 1.7kWh. It will fill my batteries from flat in 4 hours max. So if not too flat a couple of hours is enough. If you're thinking of doing this, it's a good idea to get a fast charger to charge your batteries as fast as possible. Not normally top of the priority list when buying a charger to charge from campsite EHU.

 

[autorouter]

Is there limits on charging at these points…?

Not sure what kind of limits you mean. A Type 2 charger has a limit of 22kW, but that's for a 3-phase charger. If using a single-phase charger like a normal motorhome charger, then the limit is 1/3 of this, ie about 7kW. For comparison, that would be 32A from the mains plug. Motorhome inlets have plugs and sockets designed for 16A max.

There is electronics in the cable to communicate with the EV charge point, and two of the 7 Type 2 pins are for that communication. The electronics can tell the EV charge point that the cable can only take 16A, so the EV charge point will keep the power within that limit. The cable also tells the EV charge point to start charging, and to lock the plug so it can't be removed. When full, or at any time you choose even if not full, you can unlock the cable and disconnect. You may not want to wait until the battery is 100% full. There's never a situation like on a campsite where you can disconnect while the cable is still live.

The motorhome charger will only take what it requires. Most motorhome mains chargers are about 20A at 12V, ie 20 x12 = 240W, so will not stress a 7000W EV charger at all. It would take 5 hours to fill a 200Ah battery from 50% to 100%. If you are doing this often then it's worth getting the biggest mains charger you can find, as long as the batteries can take the amps.

My mains charger is equivalent to 140A at 12V, ie about 1.7kW, and it still doesn't stress the EV charger. It puts in a useful amount of charge in a couple of hours. I can boil a kettle or use an air fryer while connected to the EV charge point, and it still won't put any stress on the 7000W EV charge point.