Thread: D4 dual battery isolators - what options

Hi Guys,

Perfect timing for this thread, just picked up my new MY2015 D4 SE on friday, loving it.

I am a little dubious about the whole traxide concept, i.e. I have always had traditional voltage sensing relays and always kept my cranking battery setup to cut out around 12.6/12.7 volts.

Is it really safe to let your cranking battery run down to 12.0 when camped in one spot for a a few days?

My auto-electrician is steering me towards using a RedArc BCDC charger/isolator instead. My concern is though it seems we are very limited with size of the second battery in the D4?

Can you swap the position of the cranking and aux batteries, i.e. fitting a bigger 100/120 amp hour AGM into the original cranking battery position?
This ios what I ahve now in my Pajero and my aux battery is 130amp hour agm.

I am only considering this as we camp in the nullarbor (cave diving) and in our old 4wd we run a 130 amp hour battery running 2 x 50 Litre fridges.
I am a little worried the traxide setup with an optima might struggle with this.

I do have a yellow top optima already, so I ghuess I could buy one more, run 2 x optima's and with the traxide setup, this gives me 65% of 180 amp hours I think.

We of course run a solar panel for trickle charge and generally run our genny and fully charge every day or two, but knowing I have 130amp hour capcity is comforting.

Feedback greatly welcomed on any of this.

Hi JamesAdelaide
I'm in the same situation too, about to setup my dual battery, I was going to get traxide system, but 2 autoelecs have steered me to Redarc too. They probably don't understand how it works. They were concerned how the isolator would fully charge the 2nd battery fully. But everyone here has glowing reports of the traxide system.

Originally Posted by JamesAdelaide

I am a little dubious about the whole traxide concept, i.e. I have always had traditional voltage sensing relays and always kept my cranking battery setup to cut out around 12.6/12.7 volts.

Is it really safe to let your cranking battery run down to 12.0 when camped in one spot for a a few days?

Hi James and if you want, I can run through all the advantages my isolators offer over every other type of dual battery system, but some basic facts may help you.

The SC80 has been in production in it's present form for more than 25 years and there are more than 4,000 D3s and D4, world wide, fitted with my gear.

You can find my isolators in D3s and D4s throughout Australia, Asia, the Middle East, Europe, North America and that includes up in the Arctic Circle and no one has problems.

Hi Dave

We've been grinning all day . It goes like a dream and am very much looking forward to our trip to Arkaroola next month in it.

Your install looks great and will put the tow-pro controller in the same place. I decided not to pull the car apart on day one so will install it tomorrow.

I haven't made my mind up about the aux battery install yet as I will run the fridge in the Tvan for the upcoming trip and deal with it later, so no need to rush.

I also had reservations about a low voltage cutout but it would appear by all accounts to be working well on a number of D4s so perhaps the OEM starter battery can handle the cycling down to 12v with no loss of life.

Gary

Originally Posted by aquanaught

I also had reservations about a low voltage cutout but it would appear by all accounts to be working well on a number of D4s so perhaps the OEM starter battery can handle the cycling down to 12v with no loss of life.

Gary

Hi Gary and the opposite is the case. Because of the way my isolators work, they extend the operating life of both the auxiliary battery and the cranking battery.

The reason for this is that while you are camping, yes you are drawing from both the auxiliary battery and the cranking battery, so this lessens the load on the auxiliary battery over what it would have to do in any other setup.

Again, because of the way my isolators work, in normal daily use, the batteries work the other way round.

Because both batteries will normally be connected at all times, when you start your motor, the bulk of the energy used to start the motor will come from the cranking battery but a good portion will also come from the auxiliary battery.

This has a number of advantages.

First, the obvious is that the cranking battery does not have to be worked as hard as it would in any other D4.

Next, because less energy is drawn from the cranking battery while you start your motor, the cranking battery will be fully charged in a shorter driving time.

But you also have the major benefit of the auxiliary battery always being in a higher state of charge, so it continually back discharges into the cranking battery, keeping it in a higher state of charge as compared to any other vehicle's cranking battery.

So while you get the benefit of more usable battery capacity while off camping, around town my system helps to improve your cranking battery's condition and life span.

No other dual battery system offers these benefits.

Originally Posted by JamesAdelaide

Hi Guys,


I am a little dubious about the whole traxide concept, i.e. I have always had traditional voltage sensing relays and always kept my cranking battery setup to cut out around 12.6/12.7 volts.

Is it really safe to let your cranking battery run down to 12.0 when camped in one spot for a a few days?

My auto-electrician is steering me towards using a RedArc BCDC charger/isolator instead. My concern is though it seems we are very limited with size of the second battery in the D4?

Can you swap the position of the cranking and aux batteries, i.e. fitting a bigger 100/120 amp hour AGM into the original cranking battery position?
This ios what I ahve now in my Pajero and my aux battery is 130amp hour agm.

I am only considering this as we camp in the nullarbor (cave diving) and in our old 4wd we run a 130 amp hour battery running 2 x 50 Litre fridges.
I am a little worried the traxide setup with an optima might struggle with this.

I do have a yellow top optima already, so I ghuess I could buy one more, run 2 x optima's and with the traxide setup, this gives me 65% of 180 amp hours I think.

Have you considered LiFePO4 batteries? Half the size and weight per usable amp/hours. Redarc do a BCDC set up for LiFePO4's which also accepts solar input. This would be the Rolls Royce of DBS's.

Originally Posted by Silenceisgolden

Have you considered LiFePO4 batteries? Half the size and weight per usable amp/hours. Redarc do a BCDC set up for LiFePO4's which also accepts solar input.

Hi Silence and that is not the case.

While you would thing you would save on weight, you do not and you will loose because of the huge cost difference of setting up for lithium batteries, and yet you still end up with less usable battery capacity available.

I have set up a number of D4s with lithium batteries and unless you have a specific need or use, they are just not worth the cost, again, because one of my systems still gives you far more usable battery capacity for a fraction of the cost, and for around the same weight per Ah available.

BTW if anybody does have a need for setting up a lithium battery system, I have 60 amp DC/DC devices, for a lot less than the 40 amp Redarc and the Redarc unit can only be used with lithium batteries.

Whereas my 60 amp units can be set to be used with any type of lead acid battery or lithium batteries.

My 60 amp Universal DC/DC units are about $200 cheaper than the dedicated 40 amp Redarc units.

The only difference is that the Redarc has a solar input, but like all DC/DC devices, with solar, the input is useless when only one input source at a time can be used.

Originally Posted by Silenceisgolden

Have you considered LiFePO4 batteries? Half the size and weight per usable amp/hours. Redarc do a BCDC set up for LiFePO4's which also accepts solar input. This would be the Rolls Royce of DBS's.

Putting every thing else aside the key issues with LifePO4 at the moment is their price which is around 3 times that of any other battery and given the average user will not get the longevity benefits from this type of battery I suggest there is plenty of life left in the current range of normal (AGM, SLA & Calcium) batteries yet.

We have a dual LifePO4 system in our Ultimate which is a necessity for me as it runs the inverter and my CPAP machine perfectly so happy we can camp remotely for extended periods and rely mainly on the amorphous panels to keep the batteries topped up

In regard to our D4 we have been using the Traxide system over the last year since we purchased the car and our duty cycle on battery use is significantly higher than the average owner as we operate a tag along and training business so cars, campers and fridges are on the go all the time

So far the Traxide system has worked as described and a key issue is keeping the batteries conditioned on a regular basis. I have no issues with the reserve capacity of the yellow top thus far powering a 50L Waeco CFX. It gives us a few days if not topped up by the alternator but as the car is used daily that is not really an issue. As well we can plug the panels in if required

It is all about how you approach your needs in a systemic way

Rob