rangerovers.pub
The only place for a coil spring is up Zebedee's arse.
Member
avatar
Joined: Jun 17 2018
Posts: 142

Hiya Chaps!

I've heard of a good few peeps who have a T-Maxx duel battery set up on their P38.

2 things i've been wondering is..

Where does the 2nd battery go?

And How does it in a nutshell get wired into the vehicle?

AND is it for prurely accessory purposes or can it be used as a backup to the main battery?

Cheers H!

Member
avatar
Joined: Jan 05 2016
Posts: 941

Marty will be along shortly with some details on his install I'm sure - he went with the TMax setup and has spent about 3 years trying to persuade me to do the same...

And admittedly I relented not long ago and put in a similar but more basic setup. With the tMax you can manually as well as automatically link the batteries - great if you need to give yourself a bit of a jump start (though why? The battery should not be going flat unless left a pretty long time unless you have a problem that needs fixing).

My setup is a standard voltage sensitive relay setup to charge my second battery, which is then used exclusively for powering other things like my fridge etc. I think I have a thread on here about it.

Member
avatar
Joined: Dec 30 2015
Posts: 3582

If you've got a decent battery and aren't running other things, like Sloth with his fridge, then there isn't a lot of point. Being ex-plod, my car still has the split charge relay and cables to the boot area where the aux battery used to live, but that was to run lots of lights on the roof, etc, the car battery runs the car, that aux runs the other stuff..

Member
avatar
Joined: Jun 17 2018
Posts: 142

Thanks Gents.

I want to add a LR cooler in the boot aswell as spots.

She goes/went off road quite a bit so lights are a rather big requirement especially on the farm, in the winter!!

a good few "mods" i want to do and I thought it prudent to add this system.

Cheers Gents.

H

Member
avatar
Joined: Jan 05 2016
Posts: 941

Lighting shouldn't really be an issue for the alternator alone - I think the smallest was a 120amp unit, biggest being the 150amp on the Thor engined models.

I've modified my BECM so when I flash the head lights, the fog lights also come flash. They come on if full beam is selected too.

On top of that I have an electric fan that draws about 30amps running on low speed, and the electric condenser fans are now configured to run at high speed when the AC compressor is engaged - otherwise low speed all the time the AC is 'on'.

And at some point I'll be fitting my nudge bar with another pair of halogen spots.

But a fridge of any kind... if you want to leave it running with the vehicle not running itself - is best done from an auxiliary battery for sure. I used to leaev my compressor Waeco fridge running from the main battery and it would be okay for a day, maybe two at a push, when the battery was new. Engine would still start.

Now I don't need to worry about it and it'll probably go for longer on a battery being used just for that. If it does run flat, the worst that happens is the fridge stops working. A peltier or TEC type fridge will run for far less time on either setup though as they draw a constant 4-5amps instead of stopping/starting like a compressor fridge.

Member
Joined: Dec 30 2015
Posts: 1506

Of course... if you have converted to LPG you could have a go at an LPG powered fridge!
Well, maybe. I'm not sure how they work!

PAGING SIMON!!!! Simon to the LPG Phone please :)

Member
Joined: Dec 30 2015
Posts: 1085

As Sloth mentions... I've got the T-Max setup in mine.

I've fitted the battery on the RHR side of the loadspace and made a cover for it. I've got I think Twin 25mm2 cable running back to front, with the positive fused at 250A at each end through a mega fuse.

The digital T-Max setup will link the solenoid for charging both batteries when the engine is running and charging voltage is detected. It automatically disconnects the 2 batteries about 30s after engine switch off.

I have an Anderson connector in the boot for my jumper cables, and I run the rear accessory socket from the auxiliary battery too so it's permanent 12v. Good for charging phone etc when I've camped in the RR as no need to have the ignition on.

When I had 2 EAS compressors I ran the second one from the auxiliary battery too, with a trigger wire from the main one. Meant if I wanted to run a compressor for testing EAS etc with the engine off, I could unplug the one in the EAS box and run the second one off the other battery without draining down the main battery.

Sometimes if I'm doing a load of electrical work in the RR and have the radio on etc, I'll manually link the batteries so I don't run the main one down.

Once I've got my A into G and bought a winch to fit in the factory winch tray, then having the second battery will hopefully help with the oomph for that.

I managed to fit the twin cable in the RH sill with the other cable looms and through the firewall, under the fuse box and to the solenoid which is mounted on the back of the battery tray/ECU box.

Member
Joined: Jan 16 2017
Posts: 499

Morat wrote:

Of course... if you have converted to LPG you could have a go at an LPG powered fridge!
Well, maybe. I'm not sure how they work!

PAGING SIMON!!!! Simon to the LPG Phone please :)

Thats usually called a caravan on the towbar

Member
Joined: Nov 16 2016
Posts: 785

BrianH wrote:

Morat wrote:

Of course... if you have converted to LPG you could have a go at an LPG powered fridge!
Well, maybe. I'm not sure how they work!

PAGING SIMON!!!! Simon to the LPG Phone please :)

Thats usually called a caravan on the towbar

Possible... Good points are gas consumption is economical, work better (when level, i.e. not parked on a steep hill) than a thermo-electric fridge, no flattening of batteries to worry about. Bad points are you've got a flame inside the car, it would need an exhaust flu to prevent gassing vehicle occupants (with engine off / ventilation off) so that's a hole in the roof or side of the car, usually need to be level to work properly (though some fridges are much more forgiving than others in this respect), the flu's can lead to the flame being blown out in wind/while driving (some setups seem much better than others in this respect too). Best practice is to fit the fridge with not only an exhaust flu but also it's own intake air setup (hole in the floor under the flame), the LPG tank would need modding to have a vapour take-off fitted to run to a manual shut off valve to the regulator to the fridge.

Would usually be a caravan type fridge but freestanding 240/12v and gas fridges are available (I've always had one). The freestanding type aren't meant to be ran on gas in confined spaces, no easy way of connecting to a flu.

I do fit vapour take-offs on autogas tanks, as part of the setup I insist that I supply and fit the gate valve and regulator (both external) running a length of pipe from the regulator to where the customer needs (usually the gas inlet for their campervan). On most installs I fit the gate valve so it can be accessed by reaching a hand under the vehicle. To fit the vapour take-off (on external autogas tank) I drill a 3mm hole in the top of the tank, cut a 'hidden filler' boss in half (leaves a steel hexagonal pipe with 8mm pipe compression fitting, total length about 20mm), grind the hex down so it's round, weld it onto the tank over the hole, fit a cut down/shortened 90degree fitting into the compression fitting and run pipe (copper or Faro) from this to the gate valve which is fitted directly onto the regulator. I shouldn't really be modding/welding tanks but it is safe when the tank is external, could be safe internal if I came up with a way of fitting a gas tight housing around the mod (wouldn't be too difficult). This way there's only a 3mm hole in the tank (so if the worst happened and the fitting came off it wouldn't be toooo bad) and since the internal area of the fitting is only about 8mm diameter (50sq mm / 0.1sq inch) there'll only be around 30pounds pushing against the fitting/weld if the tank sees 20bar pressure (reckon the weld would be good for about a ton).

Recently bought a thermo-electric heat pump type fridge from Halfords to slot between the front seats on long trips, it will keep stuff cool if it's cool when it goes in but takes an age to pull temperature down if stuff isn't cold when put in. Will only cool to about 15degC below ambient temp, OK in an AC cooled car and only draws 6Amps at 12v. An electric compressor type would be a lot better, or would be possible to tap into AC lines and fit another evap in an enclosed box to make a very powerful fridge that would obviously only work with the engine running... I thought about doing this when I recently had AC problems and had to change my engine, would have been the ideal time to fit it, but in the end I just wanted to get the car running again.

Member
avatar
Joined: Jan 05 2016
Posts: 941

Compressor fridges are the way to go :) Waeco/Dometic are basically the defacto name to go for here. ARB are popular in the states I think.

I have a Waeco CDF-45 and have on a couple of occasions accidentally turned cans of pepsi etc into slushies...