Dual Battery Install with RedArc BCDC charger

[Paul (SA)]

What is the most number of Anderson plugs you could have in this setup? Would it be possible to have one under the bonnet, one at the rear for the camper and one in the internal rear?

[sharkcaver]

What is the most number of Anderson plugs you could have in this setup? Would it be possible to have one under the bonnet, one at the rear for the camper and one in the internal rear?

Not sure I understand your question.....you can hook as many andersons as you like.

I have 3 in the rear fed from my aux bat and one direct from the dc/dc for solar input. One at the towbar fed from the starter. Have been thinking about one on the bull bar direct to the starter as well for ac and solar charging purposes, but I still need to go under bonnet to kill the dc/dc feed (otherwise I'm charging both batteries), so its sorta mute putting that one in.

[sharkcaver]

I’m pretty sure that is correct - NW v NX alternators behave very differently

Curious.....how so? does the NW dip lower and more often?

I found with the NX just running the cabin fan full time tricks the alternator into a voltage above dc/dc turn on threshold values for the majority of the time. Enough so that I didn't need to wire my dc/dc as an ignition variant.

Waiting for the flame, but IMO, if you run AGM, then go dc/dc. Your battery will love it. Wet cell is not so specific.

[Mambop]

My auto electrician/solar specialists put my Redarc up under the passenger side dash against the fire wall. Still close to the battery but away from the heat and in the summer has the aircon. Has been working perfectly for 3 years.

[reciprovac]

smart alternator

Out of interest, can the redarc BCDC charger be used in place of the old school method of putting in a dual battery isolator?

If your NW has a smart alternator the solenoid method will not work effectively,you need the Dc charger to get full voltage to the second battery.
Heaps of info on this site re this.
Regards

[Woodzy]

Hey everyone just wanted to post some photos of my dual battery installation on my NW Pajeroni.

• Redarc BCDC1225D charger (redarc no longer stock the LV model charger - this model has replaced it).
  
• Starter cabling wired from aux battery to solenoid for emergency starts if the main cranking battery fails.
  
• Installed a second ciggie plug in the boot on the LHS then piggy backed power across to the stock ciggie plug on the right
  
• Installed volt meter in the boot below stock ciggie plug on the RHS which includes 2x USB sockets.
  
• Installed spare power lead into the front where i can plug my CB radio into in the future.
  
• Installed push button main battery override button for E-starts beside the traction control button under steering wheel.
  
• Anderson plug installed under bonnet for solar panel.
  
• Fuses for the 2x ciggie plugs in the boot, fuse for the spare power lead for CB radio, and fuse for the override button. 2x large fuses for the BCDC. Circuit breaker for the Anderson plug at the tow hitch. All installed on the mounting plate for the BCDC.
  

Photos of the plugs in the boot and the spare still to come. Not that they are much to look at but still, i'll upload anyway. Would love to lay claim to the handy work but I can't. I had it done here in Perth at Nedlands Auto Electrics, told Brendon what I wanted and he delivered. Neat and tidy job. Very happy. Can't wait to run the fridge without it switching off with the car now.

Hey mate, great write up.

I'm based close to Nedlands and trying to figure what kind of dual set up I want for my 2010 NT... Almost too much info online, which makes things a bit frustrating at times.

Did you source the materials yourself and just get the auto elec to do the set up or just do the whole thing through them?

How much did it cost you from start to finish?

How is it going 18 months after install?

Cheers

Sent from my SM-G950F using Tapatalk

[PhilipK5]

Quick question is the 102 Ah battery a deep cycle one suitable for running a fridge?
I found that the biggest deep cycle battery I could fit under the bonnet as per the mount fitted when I purchased the car was only a 65 amp hour deep cycle. Still a lead acid battery. I have been able to jump start the car when the main went flat using jumper leads but only just.

[Angus4032]

Hey guys sorry for not replying for ages. Haven't been on here in ages!
Still have the car. Everything still running ok but I think my Deep Cycle Aux battery has hit the end of its life, as its not holding its charge like it used to when I first installed it, I used to be able to run my Waeco CFX65 for about 3 days / 2 nights without charging batteries or running the car.
I have a N75, which is a 105 Ah lead acid aux battery.
I swapped the cranking battery in against the firewall to accommodate a bigger aux battery in the stock cranking battery tray. The setup runs sweet, but one thing I would change if it was doing it all again would be to put the Solar input (anderson plug) in the front grill so I wouldn't have to pop the bonnet to plug in, I could move it but I'm lazy, and I don't use it enough (but for the times I do I wish it was there).
I used Nedlands AutoElectrics to do the install, the cost was about $1300 from memory with all parts supplied and installed.
But old mate Brendan got arrested last yr, so I'm not sure if he's back in business or still in the can. Sad because he was a great autosparkie.

I have a question for the autosparkies out there: When charging, does the BCDC charge both batteries in parallel? If so, does this effect how well the aux gets recharged from flat?

I know that when the redarc isolator senses a voltage drop (when you switch the car off and the fridge is still on), it isolates the cranking battery so you only draw from the Aux. But I'm not sure if the same happens when you go to recharge the Aux battery (i.e charge starter battery first then isolate the starter and charge the Aux).

Reason being is when I charge the batteries, I'm wondering if the charger gets a false voltage reading (since they're in parallel) because the cranking battery is supplementing the voltage.
For example if you put a multi-meter on the aux and it reads 12.0v and then on the cranking battery it reads 13.4v but in parallel you get a combined reading of somewhere around 12.7v. Therefore the whole first few ramp-up stages from the charging unit (either the BCDC or a CTEC wall charger) is skipped because charger thinks the battery is almost fully charged, and it jumps to float mode pretty quick (in an hour or so). Just wondering if you have to disconnect the terminals to the Aux and charge only that battery to get a proper full 7 stage charge from the charger. Maybe this is why my Aux only lasted 2, nearly 3 yrs. If anyone can explain this to me it'd be greatly appreciated. Cheers.

[OldEmmGee]

G'day Angus,

I'm not quite sure I understand your question, but will attempt an answer regardless!

The BCDC charges in one direction only; it charges your Aux battery (anything connected to the BROWN wire) from the input battery (RED wire) and/or solar input (YELLOW).

You should never short circuit the input and output (effectively connecting RED and BROWN wires) as the BCDC will go into maximum current drive trying to boost the input to the output (if they are connected together you get a 5W heater, in effect).

Assuming you have a conventional installation, RED connected to your Start battery and BROWN to your Aux battery, the BCDC will 'boost' or 'reduce' the output voltage to maximise the Aux charging. It will do this for as long as the Start battery can take it (you select the voltage drop-out with the connection of the small BLUE wire - usually 13.5V or 12.0V).

Feel free to contact REDARC Technical Support during working hours - our helpline is on 08 8322 4848 and if always manned by experience technicians here in Adelaide.

[2bad4u]

I think I understand your question. This may help....

https://youtu.be/rDXixCzg6iw

[Angus4032]

2bad4u - That's it mate.
God dammit! That's exactly whats been happening. I'm a bit upset about it cos it's just cost me a couple of batteries now. Glad to know now though.

Cheers for the link.

Have any of you guys found a good work around for this so you can hook up either a solar or mains charger while the car is off without draining the main battery? Did you hook up an isolator switch or something to allow you to turn off the DCDC charger?

Also what about the signal cable for the DCDC, is yours wired into your ignition?
In which case, if you turn your car ignition to accessory (with car off), to run your car stereo, the DCDC would then be draining the main to charge the Aux. I'm pretty sure mine is hooked up to the ignition switch like this.

[1533rl]

Dual battery Install with redArc BCDC charger

Angus, I don't havea dc2dc in the car (mine is in the camper) but my fm/am radio and uhf radio are both powered through the aux battery in the car. It is a way of running either or both without a key in the ignition. Just another way to save juice in the starter.
Cheers
Peter

[Dicko1]

2bad4u - That's it mate.
God dammit! That's exactly whats been happening. I'm a bit upset about it cos it's just cost me a couple of batteries now. Glad to know now though.

Cheers for the link.

Have any of you guys found a good work around for this so you can hook up either a solar or mains charger while the car is off without draining the main battery? Did you hook up an isolator switch or something to allow you to turn off the DCDC charger?

Also what about the signal cable for the DCDC, is yours wired into your ignition?
In which case, if you turn your car ignition to accessory (with car off), to run your car stereo, the DCDC would then be draining the main to charge the Aux. I'm pretty sure mine is hooked up to the ignition switch like this.

I had a project and a redarc...both had the unit connected to the ignition wire. Both only ever took power from the main battery when the key was in the IGN position. If you wire it to ACC then whenever you put the accessories on to say listen to the radio...your start battery begins to drain. I now have 40 amp Enerdrive and Renogy dcdc chargers. Both of these are wired into the ignition as well. I believe this is a foolproof way to avoid accidently draining the start battery as no one leaves a car key in the IGN position unless car motor is running. You must have a fuse near your start battery connecting to the cable for the dcdc. I use fuses that can be turned on or off. If not...put one on!! Use the fuse as a switch to disconnect the dcdc cable from the start battery when you wish to use solar or give your start battery a charge up.

[Angus4032]

Roger that mate, cheers.

Car is going into the autosparkie on Thursday to hook up some spotties and some rear lights. I'll get him to have a look at it at the same time.