Which Isolator for Dual Battery

Submitted: Monday, Apr 19, 2004 at 22:04
ThreadID: 12205 Views:6442 Replies:12 FollowUps:16
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Hi All,

In the past 10,000 kms of touring, I have been using single battery on mt L/C 80 series for my Waeco CF50 without any problem as I drove average 4 hours everyday.
After reading thethreads on this forum, I thought I better have a dual system before I stuck in nowhere during next trip. I went to ARB the other day and was given a solution for around $800 ( it seems too much ). As my electrical backgrounds, I think I should be able to set it up by myself.
One probelm I have is that there are so many sort of isolator on the market ranges from $50 from Jaycar ( product no.KA1782 ) to A$300 from Battery World. Which brand or product do you guys use and how do you like it? where can I buy it from?

Any comments are highly appreciated. Thanks!
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Reply By: Roachie - Monday, Apr 19, 2004 at 22:18

Monday, Apr 19, 2004 at 22:18
There are so many options available, but IMHO it depends on what sort of bloke you are (ssuming you ARE in fact a "bloke"....can't tell from your nickname??)
What I mean by that is......are you the type of bloke who tends to monitor things and like to take responsibility for switching things on/off etc.......or would you prefer a fully automated system that you put in and then just use it until one day it doesn't work and you have to scratch your freckle wondering "what's happened?"

I like the 1st option better and for that reason I use a simply manual isolator linked to a switch in the cab and also both batt's are linked to a voltmeter (I can switch it to monitor either batt, but when truck is running and isolator turned on to link the batt's together, the readout is the same whichever way the switch is facing). I also have a "fail-safe" in that the isolator cannot be ON unless the motor is running. This was simply achieved by running a wire from the windscreen wiper motor.....if the wipers won't work, the isolator is OFF.

It's sounds more difficult the way I explain it, but works well in practice and I can keep up to date with what power I have available in either/both my batt's anytime I like.

I have an inherent distrust in electronic things that can go phyyyysssssttt for no apparent reason; usually at the most inconvenient time possible.


AnswerID: 55051

Follow Up By: Member - Gajm (VIC) - Monday, Apr 19, 2004 at 22:50

Monday, Apr 19, 2004 at 22:50
I agree with your way Roachie, I don't like the electronic things that I would have no hope of repairing if they did go wrong, I have the same set up minus the wire to the wiper motor, i went with a flashing LED to let me know its turned off instead...3 position switch so if i need to i can just charge the main batt.

I just put a second solenoid in to charge the battery in a CT, so its a little more complicated now but all still manualy switched from in the car. Solenoid was only $30 as opposed to my first one that cost around $85, time will tell if its any good.

I also have the Jaycar voltage meter to check the batteries, but since the 3rd battery I had to go with a 4 position rotary switch for checking any battery and being able to have it turned off as well,.
FollowupID: 316750

Follow Up By: Member - Roachie (SA) - Tuesday, Apr 20, 2004 at 10:33

Tuesday, Apr 20, 2004 at 10:33
That sounds like a really well thought-out set up.
With solenoids, I've read that the so-called "good" ones have gold contact terminals which apparently work better.
FollowupID: 316793

Reply By: Peter 2 - Monday, Apr 19, 2004 at 22:20

Monday, Apr 19, 2004 at 22:20
I've used a Sure Power Diode isolator for nearly 30 years with absolutely no problems, my troopy had the same one your 80 series would require, 120 amp with a voltage sensing terminal, wiring instructions in the box, You just need to buy the Toyota battery box for the opposite side to whichever your battery is currently on. The isolator is/was around the $230 mark and the battery box is around $100 from memory, cheaper from a wrecker.
AnswerID: 55052

Reply By: myfourby - Tuesday, Apr 20, 2004 at 01:13

Tuesday, Apr 20, 2004 at 01:13
Hi Chenj3,
I just been through this process!!! - I've been running a dual battery setup for 5 years using the $50 jaycar isolator without a prob.... well that was until easter weekend - when it decided it had had enough and wouldnt charge my 2nd battery. Apparently the mosfets in the jaycar kits have a habbit of just giving up when they've had enough - static senstivie tempramental little buggers it seems.

I agree with the others - I don't like electronics - much prefer something more basic/relaible - so was considering a basic solonoid setup. However - I liked the automatic setup that the jaycar isolator had - charged and isolated automaically basically didn't even need to think about it - it was great!

So after deep thought - I decided that the electronic pirahana kit ($290 isolator) was the best option - yes its electronic - BUT - it has a 5 year waranty and has been around a long time now - and its automatic - no need to worry my little head while I'm on holidays. So I have just taken the punt that they have all the bugs ironed out now and have gone with that.

The old Jacar one was great - but was a cheapo you have to assemble yourself - not much quality control or reassurance there at all - so I've now placed the crucial task of keeping my beer cold into the experienced hands of pirahna! Cold beer is now a certainty... well almost... ;)

AnswerID: 55078

Follow Up By: Bonz (Vic) - Tuesday, Apr 20, 2004 at 10:25

Tuesday, Apr 20, 2004 at 10:25
The Redarc does the same as the pirahna for about $150
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Follow Up By: The Publican - Tuesday, Apr 20, 2004 at 13:51

Tuesday, Apr 20, 2004 at 13:51
The Redarc is substantially superior to the Piranha. The Piranha one is a heap of manure and prevents your battery from proper charging by around 30%. If there is one place mechanical devices are still substantially superior to electronic mumbo jumbo and especially with there being so much electronic garbage on the market , it is in battery charging. A Redarc battery isolator cannot be beaten by anything for functionality and simplicity.
FollowupID: 316827

Follow Up By: Member - Bradley- Tuesday, Apr 20, 2004 at 14:10

Tuesday, Apr 20, 2004 at 14:10
Yep, have spoken with the guys from redarc in the past, it sure is a good piece of gear and you can even wire up a simple override for emergency use. Handles short bursts of high current around 400 amp for emergency starts. Automatically charges the aux when the main batt is at 13.5v or higher. Price is great -$ 150 for the 100 amp unit , about $300 for the 200 amp version . half the price of arb's 'smart solenoid' and aussie made.
FollowupID: 316833

Follow Up By: Member - Gajm (VIC) - Tuesday, Apr 20, 2004 at 15:04

Tuesday, Apr 20, 2004 at 15:04
off the subject completely, but whats the Pumpkin about Bradley?
FollowupID: 316839

Follow Up By: myfourby - Wednesday, Apr 21, 2004 at 10:14

Wednesday, Apr 21, 2004 at 10:14
The Publican,
Interesting that you say that the pirahna isolator is a heap of manure.

Its funny - because most repuatble 4WD stores sell them, and they are one of the best known brands on the market. Infact they stand by their product with a 5 year waranty and have support at most 4WD outlets around the country.

Just curious but what is redarc's waranty and which 4WD support it?

The pirahna unit cost $290 for the 150AMP isolator - redarc costs $150 for the 100AMP and $300 for a 200AMP unit - my guess is that the small amount of extra cost is well worth the country wide support and 5 year waranty that pirahna provide.

Mate - just pointing out - that theres more to consider than just the fact that a particualr unit may be functionally better. I don't know if it is or not - however it wouldn't surprise me if it was. Regardless - My unit is working well for me and I'll stick to Pirahna until Redarc get more mainstream and into the big 4WD stores - then I'll start really comparing.

FollowupID: 317044

Follow Up By: The Publican - Wednesday, Apr 21, 2004 at 14:05

Wednesday, Apr 21, 2004 at 14:05
myfourby there some real turkeys around and you certainly qualify for club membership. You are that stupid you would not even know that anything over a 50 amp unit would be a waste wooooohhhh what a dummy you are.
so called reputable 4WD sell because they have no idea about anything and PROFIT greed of PROFIT. Nothing wrong with profit, we live in a capitalist system, but GREED is bad. $290 for a Piranha WHAT A DISGUSTING RIPOFF. The reason why Redarc are not more mainstream in 4WD stores, Redarc prefer to deal with professionals not turkeys and ripoff fools that sell wrong gear they know nothing about to suckers like you. 4WD stores just LOVE turkeys like you. Come on in spinner we will gladly ripyourightoff. All those 4WD stores work on the REPCO principle Rip Every Poor Customer Off. They would much prefer to sell you a Piranha at $290 and make 165 PROFIT over a Redarc they would make $30 profit. Man you need financial and technical counselling.
FollowupID: 317079

Follow Up By: Bonz (Vic) - Wednesday, Apr 21, 2004 at 15:49

Wednesday, Apr 21, 2004 at 15:49
And The Publican...you need counselling in SOCIAL skills. Geez we're talking about relays here. There's absolutely NO NEED to be bagging someone personally for an opinion. Lay off or go back to bed and wake up on the right side of it next time eh?
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FollowupID: 317108

Follow Up By: Member - Bradley- Thursday, Apr 22, 2004 at 09:40

Thursday, Apr 22, 2004 at 09:40
My forby, check out redarc website , they make a huge amount of specialist gear for heavy transport and you can get it through almost any auto elec. aust wide.. If you know jaycar stuff then you must enjoy getting good stuff cheap :-) . Dont forget most 4x4 stores are just plain old re-sellers, they work on margins and markup to make a living. Those flash shops / displays and staff dont come cheap.
FollowupID: 317291

Follow Up By: myfourby - Thursday, Apr 22, 2004 at 18:11

Thursday, Apr 22, 2004 at 18:11
Sorry - The Publican - Unfortunately responding to abusive follow-ups is not something I do.

Bradley - Yeah - I hear what you are saying - and I have looked at their website. To be honest I had never heard of redarc until now.

I have another simple reason for purchasing Pirahana - it fits in the same place as my old Jaycar unit does without major adjustments - gotta love that!

You know what those flash displays / shops and staff also come with (other than big markups) - a reputation and good service - something I don't mind paying for - especially on important stuff.

Any idea what the waranty on the redarc unit is - can't seem to find it on their website?
FollowupID: 317400

Follow Up By: William - Thursday, Apr 22, 2004 at 19:53

Thursday, Apr 22, 2004 at 19:53
myfourby you are a true sucker if you think these big 4WD shops come with a good reputation. They are disgusting ripoff technically bereft dummies that have no idea about what they are selling. They sell stuff no technically competent person with a any self respect would sell. If you did some basic homework and research you would see you can always buy anything cheaper and better elsewhere than being sucked in by the supposed big boys in the 4WD rip-off gouging market place. The likes of ARB, TJM etc. just love suckers like you. Come on in stupid spinner we will rip you right off because you are a complete and stupid ignorant dummy and we don't care what we sell you and don't care if it is good or not as all we are interested in is correlated selling and making as much profit as possible.
Myfourby you are the *ULTIMATE* consumer fool and stupid dummy.
Incredible there are so many of you failed fools around.
FollowupID: 317420

Follow Up By: Member - Gajm (VIC) - Thursday, Apr 22, 2004 at 20:42

Thursday, Apr 22, 2004 at 20:42
William and The Publican, you are a class act, and I have to agree with every comment you have said regarding members, Diggers, Police, firey's and other people too numerous to mention, so if I can ever buy you a beer simply name the time and place, it would be an absolute pleasure to meet you in person.
FollowupID: 317427

Follow Up By: Member - Bradley- Friday, Apr 23, 2004 at 09:53

Friday, Apr 23, 2004 at 09:53
Hi myfourby, not sure on warranty period, but they make stuff for b-doubles etc. so it should be pretty good. I hadn't heard much on them either until a while ago, if they did a little marketing in the right areas they would give a few established players a good shake up.. There are some places that actually know their stuff and can back it up, but unfortunately a lot just sell based on maximum margin.. I agree with loving the easy changeover option..love jaycar as well..

Hey gajm, like the sound of the drinks get together, got a few friends who might shout a few rounds as well..
FollowupID: 317486

Reply By: Gandalf56 - Tuesday, Apr 20, 2004 at 03:07

Tuesday, Apr 20, 2004 at 03:07
Hi Chenj3,

As others have said, the choice is wide. If cost is a consideration, a simple solenoid is an easy and inexpensive option. It's also fairly foolproof. Just connect the activating wire to someplace that only has power when the ignition is in the 'on' position. You can also wire it up so that you have to manually switch it on - avoiding the risk of a flat battery sucking power from the starter battery, although I've never experienced this as a problem.

If you're handy with a welder, a cradle is easily made from some 25mm angle iron. Get a hold-down bracket from Kmart and you're in business. I have used this setup in several vehicles and it's survived for many years in places such as Gibb River Road, etc. Have a look at some of the commercially available ones - there's not that much to them! A good coat of anti-rust primer, some decent paint and you'll never know the difference.

AnswerID: 55080

Reply By: Member - Andrew R (VIC) - Tuesday, Apr 20, 2004 at 07:40

Tuesday, Apr 20, 2004 at 07:40
Hi Chen3,

There is a lot of merit in what is said above. However, if you just want to buy a kit and fit it, I would also go for the Piranha. I went for the ARB unit and fitted it myself. Very easy, but you pay a premium.
In retrospect I would have done the Piranha.

just another opinion.

good luck
AnswerID: 55086

Reply By: Member - JohnR (Vic) - Tuesday, Apr 20, 2004 at 10:03

Tuesday, Apr 20, 2004 at 10:03
Local workshop doesn't like electronics much either so they used a voltage sensitive relay in mine with nice large cables to jumper and use for a winch when I exentually get around to fit one. Just needs a minor charge and it connects to charge the second battery.
AnswerID: 55106

Reply By: Bonz (Vic) - Tuesday, Apr 20, 2004 at 10:27

Tuesday, Apr 20, 2004 at 10:27
I have a simple solenoid here chenj3 if you want it. I paid about $75 for it and then went and bought the Redarc as it had spike protection and was automatic, my email is behind the pic below if you click on it, email me if you would like it.
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AnswerID: 55110

Follow Up By: Member - ramp - Tuesday, Apr 20, 2004 at 12:42

Tuesday, Apr 20, 2004 at 12:42
i agree with bonz, redarc is a good little unit i run a dual battery in the patrol as well as a connection to the camper trailer with a battery, and if need be you can connect a switch and use it to crank the engine if your main cranking battery is rs. cheers rob
FollowupID: 316818

Reply By: Member - Pennywise (VIC) - Tuesday, Apr 20, 2004 at 11:01

Tuesday, Apr 20, 2004 at 11:01
I have recently purchased the ARB dual batt kit for $525 and installed myself, came with full instructions so even a dummy like myself had no prob's installing. $800 seems a bit steep, did the price include labour? I have a 80 series n/a diesel.
AnswerID: 55114

Follow Up By: The Publican - Tuesday, Apr 20, 2004 at 15:48

Tuesday, Apr 20, 2004 at 15:48
Thankfully there are fools born everyday so easily relieved of their money.
FollowupID: 316848

Reply By: MrBitchi - Tuesday, Apr 20, 2004 at 13:11

Tuesday, Apr 20, 2004 at 13:11
I use the Redarc isolator, competely automatic. Has the added advantage of a manual overide via a switch if you need to use the second battery to start from.
AnswerID: 55129

Reply By: rolande- Tuesday, Apr 20, 2004 at 21:56

Tuesday, Apr 20, 2004 at 21:56
Agree to go with REDARC, guys on website are a lot of help as well. Have spoken to a couple of auto sparkies who use all the time, never had a failure. Isolator $150, Battery $110, Battery Tray around $100, then all you need is the wiring to connect, so around $450 all up. (Quote from %$B, around $800). Rest of ready made system is profit. Purchase a redarc and ask them for wiring diagram and recommendations, free advice is very good.
AnswerID: 55213

Reply By: chenj3 - Tuesday, Apr 20, 2004 at 22:25

Tuesday, Apr 20, 2004 at 22:25
Thank All,
I think all your valuable comments have me more confidient what I need and whai should I do next. Thank you for your time and your experience again.

Have fun 4WDing!
AnswerID: 55222

Reply By: Trevor - Thursday, Apr 22, 2004 at 03:32

Thursday, Apr 22, 2004 at 03:32
When we bought our car 5 years ago it was fitted with an Auxillary battery charged by a simple solenoid which parralleled the main and auxillary batteries whenever the engine was running.
Normally this isn't much of a problem, provided your two batteries are of similar size and in good condition.
Then we were struck by the dreaded voltage spike.
This caused the UHF radio to forget itself. It wouldn't scan, had no duplex, no priority channel, etc. Luckily the EPROM didn't fry itself.
The radio was reprogrammed free of charge by the great people at GME, even though it was well out of warranty. Thanks again fellas!
I then decided to install a Redarc Relay.
It was chosen because it has spike suppression, it monitors the main battery before charging the auxillary, it is Aussie made, a switch enables the two batteries to be parrallelled for emergency starting if the main fails, it has a 2 year warranty.
The redarc cost $110 at Ashdowns in Adelaide.
They have branches in other states.
Motor Traders quoted $160.
Redarc recommend installing fuses or circuit breakers for protection.
Two maxi-fuse holders and 4 X 60 Amp fuses (2 spares) were $23, also from Ashdowns.
The local Auto Electrician charged $30 for 3 Metres of 8mm cable plus a handfull of solder type lugs and joiners.
10 Metres of convoluted tubing (that corrugated stuff with the split along it) was $3.
Some heatshrink insulation was $5 from Jaycar. The Auto Electrician probably has it , but I forgot to ask.
Total cost, $171.
It took a day or so to remove the old solenoid and its wiring and install the new one.
I haven't yet installed the remote switch for the parralleling function. One of these days.

Before the Forum experts begin attacking me about the 60 Amp fuse size, let me explain.
When the main battery is flat and the redarc is closed, using the pushbutton, to parrallel it with the auxillary, the idea is to wait a while before starting the vehicle. This enables the main to be partially charged, otherwise it could be damaged by excessive current draw.
Therefore, 60 Amp fuses are sufficient to control the current flow.
If you don't believe me, ring Redarc. They told me.

Redarc has a free technical assistance line on (08) 8186 5633.
Their informative website is www.redarc.com.au
I hope this is of some assistance.

AnswerID: 55435

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