Retro Fitting Electric Hookup (EHU)

Jim Dawson · May 30, 2017

Hi all,

Looking for technical clarification on the best method to retro fit a 240Vac Electric Hookup to my 2013 VW Cali Beach (missed out on EHU as standard by 6 months

).

I'm not concerned with the location of plugs, sockets, cabling etc. What I am interested in is the electrical hardware / wiring schematic.

As far as I am aware the simplest method (rough sketch attached) would be to install the usual 240Vac supply, including 16A Breaker and RCD, and to use this to power an intelligent battery charger to charge the existing 80Ah leisure battery.

What concerns me with this setup is that I plan to have my Waeco CF-25 Fridge permanently connected to the 12Vdc supply, therefore the leisure battery would be under load (approx 6.5 Amps) whilst charging whenever the fridge compressor is running.

What I would like to know is:
Is charging a battery that is under load good / common practice?
Is there a better way than the one mentioned above?
Can anyone recommend a good silent charger?

Thanks in advance,
Jim

:cheers

briwy · May 30, 2017

I fitted a system to our Mazda Bongo years ago using CTek battery charger. These seemed to be popular for this kind of application.
Only difference I had to your wiring was a consumer unit with two breakers, one for the mains plugs and one for the battery charger.
Shouldn't be a problem charging with load on the battery but make sure you get a good size charger.

owen_h · May 30, 2017

My setup on a 2012 Beach is very similar. Charger is a CTEK MSX 7. Difference I have is that my fridge/coolbox has a built in transformer and will auto switch between 240Vac and 12Vdc . I have taken another 240V circuit off the consumer unit to feed the fridge when on hookup. Maybe you could do similar but with an external transformer?

PS thats the best 'rough sketch' I've seen in a while.

sidepod · May 30, 2017

When you say "the usual 16A breaker/RCD" you obviously mean a double pole RCBO. Not something you'll find in an electrical wholesalers.

FYI The double pole negates any reverse polarity issues.

Que another monumental reverse polarity debate!!

Jim Dawson · May 30, 2017

sidepod said:
When you say "the usual 16A breaker/RCD" you obviously mean a double pole RCBO. Not something you'll find in an electrical wholesalers.

FYI The double pole negates any reverse polarity issues.

Que another monumental reverse polarity debate!!

My plan was to butcher and fit one one of the Hi Gear Mobile Mains Kits (http://www.gooutdoors.co.uk/hi-gear-mobile-mains-kit-p337211) from GoOutdoors under the drivers seat. So hopefully that is a double pole RCBO?

sidepod · May 30, 2017

"Hopefully"? WOW!

jts46 · May 30, 2017

If you go down this route, remember to use 16a cable at least from the rccd to sockets etc

Stoneybroke · May 30, 2017

Load Vs charge... Won't this happen on all vehicles when on EHU ass charger is permanently wired, or with solar for that matter?
As for the fridge, swap to mains when on EHU?

Popular method for retrofit EHU, is to pop the wire through the grommet in the bulkhead behind the starter battery, with a socket added - want to hook up, then pop the bonnet, attach, then drop bonnet to first catch. No drilling required.

Jim Dawson · May 30, 2017

sidepod said:
"Hopefully"? WOW!

Sorry, I didn't know the specification of the Hi Gear Mobile Mains Kit off the top of my head.
From what I can see the box has an RCCB, Double Pole C16 Breaker and LED warning light for reverse polarity.

Jim Dawson · May 30, 2017

Stoneybroke said:
Load Vs charge... Won't this happen on all vehicles when on EHU ass charger is permanently wired, or with solar for that matter?
As for the fridge, swap to mains when on EHU?

Popular method for retrofit EHU, is to pop the wire through the grommet in the bulkhead behind the starter battery, with a socket added - want to hook up, then pop the bonnet, attach, then drop bonnet to first catch. No drilling required.

That's roughly what I've done, except I've used a grommet behind the Brake Servo as the cable route to under the drivers seat is easier.

I'd rather avoid having to swap the fridge to mains when on hook up (I'm Lazy), plus my fridge is only 12Vdc unless I buy an additional power supply (trying to keep things as simple as possible).

sidepod · May 30, 2017

Interesting they've gone for a "C" curve breaker as opposed to a much more common "B" curve.

C's are usually reserved for larger inrush currents (rows of fluorescent lights).
They do require a lower earth loop to achieve disconnection time from memory.

Whatever. Crack on.