Redarc duel battery system

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robbo3
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Joined: Wed Jul 08, 2015 3:33 pm

Redarc duel battery system

Post by robbo3 » Tue Nov 30, 2021 12:30 pm

I have a nissan navara, it had the above mentioned system in the car when i bought it. The car has 2 batteries in the front of the car. I have been told they are cranking batteries. There is also a 120 am deep cycle battery in the rear of the car. Firstly I have no idea about how any of this works, so I need any advice that anyone can give me ,in it's simplist form. Should both batteries in the front be cranking batteries? Or should one be a deep cycle? There is a heavy cable from the passange side front battery to the rear battery, I assume this is to charge the rear battery.
Does this all sound in order? The rear battery when not connected to the front is on 11volts, does this sound like the deep cycle battery is on the way out? I forgot to mention I have a small waeco fringe in the back running 24/7 and it's been there for the 4 years that I have owned the car.
Any would appreciate any advice as to whether the system sound as though it is in order oe if there is a fault somewhere. I have a few expert mates who keep giving oppinions, trouble is they are just like me ,after they turn the key , they have no idea.

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robcaz
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Re: Redarc duel battery system

Post by robcaz » Tue Nov 30, 2021 3:59 pm

Hi Robbo,

First up a couple of questions.

The Redarc DC to DC charger should be positioned next to the battery it is charging. Could you please tell me where the Redarc is? The Navara more than likley has a smart alternator. Is the Redrac a LV or low voltage model?

A battery should be 12.8 volts or better at rest fully charged, that is with no charging or discharging for more than two hours. Could you unplug the fridge & fully charge the battery, let is sit for a few hours & see what the voltage is? The rear battery is only charged when the motor is running, not at home via 240volt charger? How often & how far is the Navara driven?

Most likely there is an auxiliary starter battery under the bonnet. All batteries have a sticker with brand & model number. If you Google these you will find out the type of battery. Is there an isolator between the the two starter batteries that seperates them when the engine is turned off? It can be as simple as a relay wired via the ignition or a Redarc Smart Start relay with opitional push button to connect the second battery if the starter is dead.
happy camping
Rob & Carol
Australian CamperTrailers Group co-owner


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robbo3
Posts: 7
Joined: Wed Jul 08, 2015 3:33 pm

Re: Redarc duel battery system

Post by robbo3 » Tue Nov 30, 2021 9:21 pm

Thank you, I'll see what I can find out tomorrow.

robbo3
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Re: Redarc duel battery system

Post by robbo3 » Wed Dec 01, 2021 8:10 am

The car has 2483b (70lmf) 12v 630cca calcium batteries in the front of the car.
There is a redarc thing on the driver side inner guard and what maybe another part near the near side battery. I have no idea what model it is. The driver's side battery is 12.5v and the near side is 12.25v, however the rear battery was connected last night which could have drawn from the front. This has now been switched off, that battery is 11.45v , I believe this battery is on the way out, I had it on charge for 20 hours and couldn't get it above 11.5 v.
The car probably travels 10 ks on an average day.
The Navara is a 2013 model if it had a smart alternator ,surely the person who fitted the redarc system would have taken this into account.
I'll drive to car today with the fridge battery disconnect and check the voltage again after that.
I did have a flat battery a couple of years ago on a fishing trip, I don't believe there is anyway of switching the batteries, if there is I don't know about it. I was lucky at the time a couple of blokes near me had solar panels and we put them on for the day and got enough charge to start the car. I believe it was caused by the fridge draining all the batteries. But as I say I'm no expert. One other thing I recall I had just had one of the front batteries replaced with what they said was a cranking deep cycle battery. When I got into Cooma, I had the 2 car batteries checked and the cranking deep cycle was dead, if I recall they said you should have both batteries the same. So that's where I'm at

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robcaz
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Re: Redarc duel battery system

Post by robcaz » Wed Dec 01, 2021 11:39 am

Hi Robbo,

The ideal charging voltage for a calcium battery is 14.8 volts so it will never be fully charged via the alternator alone. They are best charged from a DC to DC charger. Under charging causes sulphation & ultimately a dead battery. There should be an isolator between the two batteries under the bonnet.

Another alternative is the auxiliary battery under the bonnet is run in parallel to the battery in the back, making one big battery. It is hard trying to diagnose your battery system without checking it over in person. Your best option would be to drop into an auto electrician & ask him to explain the set up to you so you know what is exactly going on. Knowing your 12volt set up is a big advantage as well as knowing where breakers & fuses are located.

If you have the fridge permanently running from the rear battery you should plug the battery into a 240volt charger over night. The rule of thumb for a multistage charger is around 10% to 15% of the battery capacity.

Hope this helps.
happy camping
Rob & Carol
Australian CamperTrailers Group co-owner


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We're just two lost souls swimming in a fish bowl, year after year

robbo3
Posts: 7
Joined: Wed Jul 08, 2015 3:33 pm

Re: Redarc duel battery system

Post by robbo3 » Wed Dec 01, 2021 7:47 pm

Thanks for taking the time,to go through it with me, yes you are right I need to see someone about it, there is a place near me who, they say specialize in this area. I'll try to make a time next week.
thanks again, regards malcolm

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