Tri-battery setup

[Yacatac]

I’m expecting there’s probably a “right way” and then the “get by” way to this question.....

I’m wanting to add a removable battery box from the rear compartment and also have a charge running to our camper trailer.

It was suggested I get an AGM battery for the rear. It will be running a 60l fridge, primarily.

I have a solar panel ( think it’s 120w) with controller on it.

I was thinking of running a Redarc BC1225D but I’m not sure how it would handle the 2 batteries?

What’s the best, but most affordable, solution for a 2006 NP 3.8l?

Thanks in advance
Stuart




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[Lance]

Gooday Stuart.
Gotta tell ya right from the start I'm no lectricity guru....

That said...........

I would definitely use an AGM, several reasons but you're probably aware of most of them.
Best bet would be 100-120ah depending on budget, but not a lot of difference.

The regulator on the solar panel is probably bottom of the list so that would be an early upgrade in my setup. Whichever way you go, mount the new regulator as close as you can to the battery.

I think the Redarc BC1225D would be OK in your setup but others with more knowledge will chip in shortly with more info for ya.

You having a great Satdy night so far ?

[Sparky3975]

From memory, the Redarc bcdc1225 can do up to 200Ah of batteries so it should cope with your setup easily. You could also remove the PWM module if fitted to your solar panel and use the 1225's solar input directly as it has a MPPT controller built in. As you also have the camper trailer, ideally the trailer should have its own bcdc but more costly.

[Dicko1]

I use a redarc dcdc to power the 2 batteries in my rear tub and a projecta dcdc to power my trailer batteries. Both fed via a nice thick cable from the main battery. I,d be opting for a 40 amp dcdc charger as you will have at least 200 amps of AGM batteries and there will be slight voltage drop to trailer. Hook the dcdc up to your battery in the rear and then run an anderson plug to your trailer. (have an anderson connection on the rear bumper so you can just plug trailer in when required and leave unplugged when not using trailer. 60 litre will use a bit of power ( probably 50 amps for a day. Hence a 40 amp dcdc would be better. I use a Victron MPPT regulator as they are a properly designed reg for solar. would be better than an inbuilt one on the dcdc. Mount dcdc and regulator as close as you can to rear battery. 6 B&S wire from start battery to dcdc charger. No need to run earth (even redarc say this is not needed) Use car body for earthing. I would run an earth and positive from rear battery to trailer battery though.

[Yacatac]

Thanks guys. Appreciate the comments.

Unfortunately funds won’t allow for one specifically for the trailer yet, but sounds like I should budget for one when I can.

I assume I would rig up a double adapter type thing - single plug end connected to Dcdc and the twin plugs to in cab battery and to trailer?

Cheers



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[Dicko1]

reply

Thanks guys. Appreciate the comments.

Unfortunately funds won’t allow for one specifically for the trailer yet, but sounds like I should budget for one when I can.

I assume I would rig up a double adapter type thing - single plug end connected to Dcdc and the twin plugs to in cab battery and to trailer? have sent you a private message.

Cheers








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Read my reply carefully....Simple way of doing things and you can add a dcdc charger to the trailer when finances allow. Use 6 B&S wire from tub battery to the trailer(all the way.)

[Having Fun]

I use a redarc dcdc to power the 2 batteries in my rear tub and a projecta dcdc to power my trailer batteries. Both fed via a nice thick cable from the main battery. I,d be opting for a 40 amp dcdc charger as you will have at least 200 amps of AGM batteries and there will be slight voltage drop to trailer. Hook the dcdc up to your battery in the rear and then run an anderson plug to your trailer. (have an anderson connection on the rear bumper so you can just plug trailer in when required and leave unplugged when not using trailer. 60 litre will use a bit of power ( probably 50 amps for a day. Hence a 40 amp dcdc would be better. I use a Victron MPPT regulator as they are a properly designed reg for solar. would be better than an inbuilt one on the dcdc. Mount dcdc and regulator as close as you can to rear battery. 6 B&S wire from start battery to dcdc charger. No need to run earth (even redarc say this is not needed) Use car body for earthing. I would run an earth and positive from rear battery to trailer battery though.

I'd be very, very careful doing that. I'm no expert, but when I was running the wires for my Anderson plug from the cranking battery to the bumper, I was advised by someone who should know, that earth leakage can cause catastrophic problems in the cooling system. His advise was to always run an earth back to the bumper with the positive wire.

[Dicko1]

I'd be very, very careful doing that. I'm no expert, but when I was running the wires for my Anderson plug from the cranking battery to the bumper, I was advised by someone who should know, that earth leakage can cause catastrophic problems in the cooling system. His advise was to always run an earth back to the bumper with the positive wire.

For someone "who should know"..he,s out of touch. The Pajero body and chassis is one large earth bank...the same as most modern vehicles on the road. The start battery is earthed to the motor and chassis in most cars. Otherwise all those small black cables with the round earth connector installed and bolted to the chassis/panel work wont work. If redarc recommend earthing via the body then they must know it works without any issues. Earth leakage occurs with an issue of the positive wire. Ensuring all wires , on any vehicle, are well insulated, clean and connected correctly...earth leakage wont be a problem.

[nj swb]

I'd be very, very careful doing that. I'm no expert, but when I was running the wires for my Anderson plug from the cranking battery to the bumper, I was advised by someone who should know, that earth leakage can cause catastrophic problems in the cooling system. His advise was to always run an earth back to the bumper with the positive wire.

That will only be a problem if there is a poor earth between the engine & body, or an unwanted electrical connection between the radiator & body, or heater & body.

Almost the entire alternator output current flows through the body to block connection. If there is a problem, corrosion will happen regardless of whether an Anderson plug is earthed to the bumper or the battery.