The best dual battery system

Submitted: Sunday, May 30, 2004 at 19:33


Hi all !

I am about to fit a dual battery system to my 100 series . I,ve looked at the ARB , PIRANHA and ROTRONICS . Can anyone give some advice on which is considered to be the " best " system .

Thanks in advance
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AnswerID: 60912   Submitted: Sunday, May 30, 2004 at 19:42

Lone Wolf replied:


Me thinks I better duck for cover for a while........... it's gonna get ugly here!!!!!

If only Willem was here to rescue us all.........Heeeeeeelp!!!!

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FollowupID: 322507   Submitted: Sunday, May 30, 2004 at 20:56

Big Dog posted:

Oh Oh Weres Trockster "..................................."
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FollowupID: 322508   Submitted: Sunday, May 30, 2004 at 20:59

Big Dog posted:

Sorry "Truckster"
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AnswerID: 60916   Submitted: Sunday, May 30, 2004 at 19:54

Mrs Diamond replied:

dont forget the $30 solonoid duel batt system.
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FollowupID: 322492   Submitted: Sunday, May 30, 2004 at 19:58

Lone Wolf posted:

That's what I use in both of my vehicles.
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FollowupID: 322713   Submitted: Tuesday, Jun 01, 2004 at 09:45

Gajm (VIC) posted:

Can't beat the solonoid system, cheap, simple, and repairable!

P.S Lone Wolf, got my cap and stubby holder from the auction in mail came with ANOTHER sticker!!
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FollowupID: 322770   Submitted: Tuesday, Jun 01, 2004 at 17:31

Lone Wolf posted:

Note to self.......

Gajm to be entered into black book, under heading of "Sticker Hoarder"

Do not speak to Gajm for 40 days & 40 nights.

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AnswerID: 60930   Submitted: Sunday, May 30, 2004 at 20:35

Member - Jiarna (SA) replied:

One with 2 batteries LOL
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AnswerID: 60941   Submitted: Sunday, May 30, 2004 at 21:27

Baz (NSW) replied:

ARRID, have a look at

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FollowupID: 322521   Submitted: Sunday, May 30, 2004 at 22:15

Baz (NSW) posted:

If anyone is interested i have a 70 amp Sure Power multi- battery isolator model #702-4 still in the box, sorry the instuction are not in there.

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AnswerID: 60942   Submitted: Sunday, May 30, 2004 at 21:29

rolande replied:

MOST RELIABLE - REDARC, that comes from an auto Sparky who has been fitting systems for 10 years, (not me!), when I asked the same question. Believe ARB system uses same or similar isolator
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AnswerID: 60980   Submitted: Monday, May 31, 2004 at 10:17

MrBitchi replied:

Redarc for me. Completely automatic and can use the second battery to jump start via an optional switch.
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AnswerID: 60995   Submitted: Monday, May 31, 2004 at 12:16

madcow replied:

I have the Pirahna system in my Gu. Having said that they are all good in their own way and it is all much of a muchness. Personally I like the ability to "get into" the workings to at least have half a chance of fixing one on the road. Not that it should happen but it did to me up the Cape and we had it "fixed" in about 20 mins. One of the solenoids had stuck open and need to gently closed as they were staying open. We put it down to the corrugations and dust combined with the humidity up there. Once cleaned appropriately I have never had a problem since.

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FollowupID: 322598   Submitted: Monday, May 31, 2004 at 14:43

brett posted:

What model Pirahna do you have? Have been trying to find out what's inside these Pirahna's for a while, I keep getting different stories, also how many solenoids did it have? tks
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AnswerID: 61006   Submitted: Monday, May 31, 2004 at 13:43

Member - Captain (WA) replied:

I runa redarc isolator, the same as the ARB smart solenoid but 1/2 the price. But as for the "best" system, I believe the charge/isolator by Rotronics is the best if you are talking about the ability to recharge the batteries properly.

A solenoid (redarc, ARB etc...) joins both batteries together and any internal resistance difference makes proper full recharging difficult. Now add a deep cycle battery into the equation (different internal resistances) and it will take ages to fully recharge it, if at all!!!

The rotronics overcomes this by individually charging the batteries as required and ensuring the starting battery stays charged. Add a 3rd deep cycle battery into say a van and it will also charge it. But a complete 3 bat plus winch setup costs over $1,000 just for the isolator!!!! Hence my redarc and manual switch to charge the van. Rotronics is great, but too $$$ IMHO


Its not what you drive, but how you drive it!
LC 200 + AOR Quantum
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AnswerID: 61069   Submitted: Monday, May 31, 2004 at 19:31

Member - Brian (Gold Coast) replied:

The simpler the better!
A solenoid setup does the job.... if it breaks, just bypass it by putting both the battery cables to the one terminal.... replacements are readily available. The deep cycle battery issue regarding a full charge can be bypassed by using the home battery charger at appropiate intervals to fully charge the battery.
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AnswerID: 62412   Submitted: Wednesday, Jun 09, 2004 at 13:44

-OzyGuy- replied:


It depends on many factors, most not mentioned here.

What type of battery are you using as the 2nd battery?

is it a Cranking or a Deep Cycle battery?

What are you going to use the 2nd battery for eg; power fridge, lights ect.

Some Solenoids are not suitable in duel systems when the 2 batteries are not identical!

So many variables - so many different answers ???
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Reply 10 of 11
AnswerID: 63712   Submitted: Friday, Jun 18, 2004 at 09:30


as an installer of dual battery systems please note that systems should be surge/spike protected, solenoids should be mounted verticaly, wired with the correct gauge cable, do not control a solenoid by ignition as each time you turn the key on and crank you put a high amperage through the contacts. the battery managment we manufacture does not patch into any other power source other then start battery to solenoid controlled by battery managment unit then onto battery bank. our system can contol second battery on vehical and other batterys on camper/caravan etc.

Glenn 12 volt installer of
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FollowupID: 324885   Submitted: Friday, Jun 18, 2004 at 10:57

Mad Dog (Victoria) posted:

What's the web site again Glenn ?
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FollowupID: 325113   Submitted: Saturday, Jun 19, 2004 at 23:25

-OzyGuy- posted:

I accept your battery choice LOL :) the 80 a/h has 145 mins Reserve Capasity @ 20 hours, well above any 80 a/h battery I am aware of, But I believe that Electronic Isolators are supperior to solenoids with their bi-metal switches, as moving parts tend to corode and pit as was mentioned above and do stop working in the most distant places available, yes they can be pulled apart and cleaned and reset but (Pirahna) Electronic Isolators have no moving parts inside and are totally sealed and can be bypassed the same as solenoids.

Mad Dog the site is -> <- No spaces! does not copy/paste from Glen's post... will from here.
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