Running power to rear of 80 series

[RobfromYork]

Hi

I've just spent more money than I will ever admit to my wife buying a second hand National Luna fridge. I want to stick it in the rear of the 80 but don't have any power back there. Excuse my ignorance but could I run a cable from the drivers side battery (fused) back there?

I'm not going to be stationary for any extended length of time but also don't want to be stranded by a flat battery. Ideally I'd want a leisure battery and split charge system but can't afford it.

Would this work or am I going to cause myself a world of pain?

Rob

 

[Towpack]

I did just that to feed some power sockets, fused at 30A at the battery and 10A individually in the back. I chose to run mine through the bulkhead and inside the car rather than underneath the vehicle. Use a decent size cable to minimise voltage drop under load. If, as you say, you're not going to be parked up during fridge use for long periods and are mindful of the battery drain it should work fine IMO.

 

[Chris]

The fridge has a cut off battery protector which you can set, so if you do park up, the fridge will switch itself off before draining the battery to a critical level. I guess what ever cable you run is governed finally by the cable supplied by the fridge manufacture.

Typically a compressor fridge doesn't pull more than around 4 amps and the NL around 2.78A or something. So you can run 50mm2 welding cable to the back if you like, but you only need 3 amps capability.

 

[cmcmill01]

What ever you do, run in a big enough cable so you don't have to rip and replace later on.

 

[RobfromYork]

Thanks for all the help - much appreciated. I've been pondering this overnight and whilst it's probably the way that I will go. How hard is it to fit a split charge system? I'm not bothered about a battery monitoring system so what will I need? I've been confusing myself on the internet and you seem to be able to buy systems from the likes of CTEK but you also seem to be able to buy a VSR which does the same job for less money. I'm sure that it's not as simple as this!

Sorry about all of the questions.

 

[Chris]

Yes it is. However, I would do the following. By a VSR, don't spend a great deal on it. £20. Then buy a decent heavy duty 12 relay. Use the VSR to trigger the relay so that the charge current doesn't go through the VSR.

Why the hell would you do that? I know I can hear the questions already. Well, looking at the nice Durite VSR's and so on, they only seem to have very small terminals. Like 6mm. Do I want to connect 25 / 35mm cable to 6 mm terminals? No.

I had a Nat Luna and it failed twice so I binned it. Made my own as described for a fraction of the cost, put in a little voltage display and bingo. Been delighted.

 

[Gary820]

Rob you're welcome to have a look over mine at some point if you want.
I've used a durite and had to fit a second battery (petrol only has one)
I've run a 10mm2 cable into the boot and fitted another fuse box. I do run my air compressor, extra 12v sockets (front and rear) and have redundant spaces for some future plans.

 

[StarCruiser]

10mm is a nice respectable size cable. I was thinking 6mm minimum to avoid dropping too many volts during compressor starting. You need to consider the mechanical strength of the cable and size accordingly as well as the current draw. Always fuse close to the battery as mentioned by TP. Good idea to sleeve the cables like Chris has done and any time you drop a size in cable, fuse it to suit.

 

[Chris]

As an aside, I messed around with cable size on my compressor set up. I had it running with a load (tyre) and successively upped the cable size between battery and factory cable. OK look I am not an electrical engineer and I have never seen a volt actually in the flesh. It was a very interesting realisation for me. With a thinnish cable the pump struggled and the cable got pretty hot, as I upped the size you could hear the pump get faster and faster until I got to something like 16mm and it didn't get any quicker. Turns out that under load, it was pulling 38 amps. Now given that you could plug these things in the fag lighter socket supplied with 1mm cable, it's hardly surprising that they don't work that well. So just Ohms law and all that, but sometimes a physical demo really gets the point over. I now do consult wiring charts and put the proper sizes in over the measured distances. Sometimes it's a bit too much, but you have to use what's on the shelf. I avoid going too small though as it really does make a difference.

 

[Gary820]

So Chris has confirmed size matters

If you think you'll ever want to run more then a fridge in the boot it'd be worthwhile fitting a decent cable from the start, only have to buy it once then.

I have new lighting to go in etc when I've decided what/where I'm fitting it all and it's going to be powered from the aux battery.

As said above conduit is good to protect the cable, can buy on e bay in various sizes fairly cheap too

 

[RobfromYork]

Thanks for all of the help. Really appreciated. Gary I'll take you up on your offer if that's ok? I'll send you a pm.

Thanks again

Rob

 

[Firewout]

I use a 16mm2 cable in a sleeve. The first 5 cm is a piece of 1,5mm2 wire to act as a fusible link. In the rear I fitted a fuse box.

 

[RobfromYork]

Thanks again to everyone for their help. Special thanks to Gary for taking the time to let me come and ask stupid questions tonight. I will probably be asking many more daft questions in the future!

Rob

 

[Gary820]

You're welcome mate.
Even if wire it yourself and just want a 2nd pair of eyes before putting the fuse in give me a shout.

I feel responsible for the fridge purchase and causing you extra work lol.

 

[thelal]

if you run the wire yourself - thats the main work and worth spending the time to get that right. Hence only do it once

The rest -- either ends you can get help with on the wiring - both relays/fuses/VSR etc and then a fusebox (of some sort) at the other end (even if you are only putting in the one fridge (and nothing else)

In time if you do add onto it -- its very easy as you've done all the hard work

 

[Patty]

Hey All,

I already have a cable running to the back of my 80 series. There is power running through the cable but haven't tested the voltage with a volt meter yet. I'm assuming it's 12v.

Have no idea about electrics but need to find the right plug to run my engel fridge in the back.

Any ideas?

 

[Firewout]

Hi patty,
It looks that there is already some corrosion in the plug on the photo. You'd better cut it off and replace it by a new one.

 

[Towpack]

Personally, I'd go with new Powerpole connectors.

 

[SafariTecPeter]

Hi!

Pitching in abit late, but nevertheless;
I have fitted quite a few dual battery setups & accompanied kits such as winches, compressors etc.

I absolutely see the benefit of having both a battery monitor & a proper relay to split the cunsumers.

Amonhg the more affordable kits come from TMAX
http://www.paddockspares.com/ba2685-t-max-split-charge-system.html
I will be installing 1-2 of these myself the next week. Comes with 16mm2 cable which is on the small side IMHO, but as there only will be a 90AH battery on the Aux end, it will be OK for now.

Just finished a National Luna setup in a LC100 (see avatar) with a 90Ah battery in the back.
Fully detachable with Anderson plugs etc.

 

[Patty]

Hi patty,
It looks that there is already some corrosion in the plug on the photo. You'd better cut it off and replace it by a new one.

Thanks for that. I was thinking of replacing with an Anderson plug instead of just hard wiring into the plug for the fridge. Purely for the reason of interchangeability more than anything.

Thoughts?