auxiliary battery

Submitted: Monday, May 24, 2004 at 19:19
ThreadID: 13127 Views:1925 Replies:9 FollowUps:6
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Any help on this one will be appreciated.
Last year I fitted an auxiliary battery into the 4WD.
The only place I could find was up under the rear guard where there was enough room to fit a smallish deep cycle battery.
I don’t know what size it was and it didn’t last very long.
I have now got to the stage of replacing said dead battery which was used to run the cooler, a fluorescent light and a transfer fuel pump.
When I started investigating the alternatives last years auto electrician now tells me I need a battery the same construction as the main battery which is one of things you pay a fortune for and can’t add any electrolyte.
The next guy tells me I need a battery the same size as the original which is huge and impractical due to limited space.
The charger system is some fancy thing which is supposed to balance everything and not foul up the fuel injection.
Can I fit a battery in the limited space and install a switch so that the system only works when it is under load?
Any solutions would be worth a go.
I am sure some one else out there must have had a similar problem so if you can help I would really appreciate it.
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Reply By: Rossco100series - Monday, May 24, 2004 at 19:55

Monday, May 24, 2004 at 19:55
Howdy Trev

What brand and model is your 4wd and you said you got a dual battery kit what type and brand ?

AnswerID: 59952

Follow Up By: Member - Trevor - Monday, May 24, 2004 at 20:19

Monday, May 24, 2004 at 20:19
Hi Rossco - the battery control was made by (for) Electro Parts Aust Pty Ltd. - I can't see a brand as it is mounted under the lip in the engine bay. Car is a 1999 Explorer XLT. Would it be better if the rear batterty was only charged when it was under load? Trev
FollowupID: 321574

Reply By: Rosco - Bris. - Monday, May 24, 2004 at 20:05

Monday, May 24, 2004 at 20:05
G'Day Trev

Been down a similar road it would seem. When I set up our rig with dual batts recently, it was pointed out by a number of batt smart ppls that you are best with 2 similar type batteries.

In my case ... similar to yours the OE batt was of the gel sealed type. True .. very exxy but in my case it was the best option in any event ....

1. Safety ... both are in the passenger compartment .. under herself's butt.
2. By the time I'd fitted both the bludgers in, there was little room left for a dead budgie, so the last thing I needed was to check the electrolyte level on a weekly basis. Cram in and forget about 'em 'til they die.

So, in answer to your 2nd question I'd have to say no ... based on my similar experience.

AnswerID: 59954

Follow Up By: Rosco - Bris. - Tuesday, May 25, 2004 at 08:11

Tuesday, May 25, 2004 at 08:11
P.S. Beware of a manual switch if your rig has a black box.
One spike and you've blown the ECU.
FollowupID: 321619

Reply By: Member - JEFF - Tuesday, May 25, 2004 at 07:05

Tuesday, May 25, 2004 at 07:05
G'day trev,
I cant solve your space problem but it appears you are concerned about the charging method as well. I would suggest you install a manual(oh such a dirty word these days) system of charging your aux battery. Just a 4 position switch(batt 1, batt 2, all, off.) connected to your alternater and batteries, then you just flick the switch (under the bonnet) and 'bobs your uncle' selected batt charged to your requirements very simple I've used this method for 2 years, no sweat works well and it's bloody cheap.Cost of switch around $45. from your friendly boat accessory store.Trust this helps some

Regards jeff
AnswerID: 60017

Reply By: Baz (NSW) - Tuesday, May 25, 2004 at 10:05

Tuesday, May 25, 2004 at 10:05
Trevor, i've member messaged you, i had the same prob with our Explorer.

AnswerID: 60037

Follow Up By: Doug Itchy Feet - Tuesday, May 25, 2004 at 12:32

Tuesday, May 25, 2004 at 12:32
Hi Trevor,

I've the same problem with a new Korean wagon. Where to put a 2nd battery? Whenever you locate the battery too far from the alternator you will invariably drop too much voltage for the battery to charge properly, so the rear of the car is not really an option.

Maybe you could just fit the largest deep cycle battery that the car will accomodate in the original position and carry a heavy duty 'jump starter pack' for the occasions when you run the main battery too low to start?

The jump starter packs all have a battery condition monitor and can be used to power all sorts of 12v applicances within the camp-site. I'm still in the process of looking at available packs and have not yet made a choice.



FollowupID: 321650

Follow Up By: Member - Trevor - Tuesday, May 25, 2004 at 13:57

Tuesday, May 25, 2004 at 13:57
Hi Doug - I think to smaller battery is the problem. I feel it may have been over-charged on long trips with no load on it. Trev
FollowupID: 321660

Follow Up By: Baz (NSW) - Tuesday, May 25, 2004 at 15:02

Tuesday, May 25, 2004 at 15:02
Sorry Trevor, i've sent another one, have a look at Arrid they have a system that might help, they have one for uping the voltage when you get voltage drop and smart charger's to give the right amount of voltage without over charging the second battery making it last longer. Rotronic's do as well. I'm in Sydney and we went to" All About 12v" in WA it's" The 12v shop" same company.

FollowupID: 321668

Reply By: ianmc - Tuesday, May 25, 2004 at 14:34

Tuesday, May 25, 2004 at 14:34
Doug, the right sized cable should eliminate any voltage drop!
AnswerID: 60076

Follow Up By: Baz (NSW) - Tuesday, May 25, 2004 at 15:04

Tuesday, May 25, 2004 at 15:04
ianmc is right 6mm min.
FollowupID: 321669

Reply By: -OzyGuy- - Tuesday, May 25, 2004 at 15:48

Tuesday, May 25, 2004 at 15:48
Use a Deep Cycle battery because they are what run best with the fridge IFF you are using the fridge for more than a few days at a time.. with decent cable the battery can be placed in the back of the vehicle in a decent battery box.
Only use a Cranking battery if it is recharged daily or every second day max.
Use absolute minium of 6mm wire, bigger the better, to eliminate voltage drop to basicly zero.
Use either a 3 position manual switch eg, Off, One or Both batteries connected, go 4 position if desired, and have it wired under the dash where you can change them over as required while driving and connect a battery voltage guage to the second battery to see when it requires charging, OR find out what brand of Isolator you have, it may be fancy and also fantastic.
AnswerID: 60084

Reply By: Member - Jeff M (WA) - Tuesday, May 25, 2004 at 16:46

Tuesday, May 25, 2004 at 16:46
I have a 17 plate cranking battery as a starter and a 4 plate deep cycle as an aux. I eliminate overcharge problems by running all my accesories off the deep cycle all the time. ie Radio, internal lights, CD/MP3 plater, laptop, GPS etc etc.
Works a treat, have a digital volt meter on dash that is switchable between the two bateries, keeps me aware of charge rates and levels and they work great. With the deep cycles, I always give it a good long charge overnight with a 240v car charger before we go away, it'll sit at 13v at rest that way, until the cooler starts sucking it dry anyway! ;-) Gives me about 0.5 of a volt more, which is a fair bit if I give it a 10 hour charge before we leave. While driving around town it sits at
13.8v-14v even at idle within 10 minutes of stopping it's dropped back to about 13v.
I use a jaycar electronic battery isolater kit, cost about $60 for the kit which you build youself. Easy to install, no switchs to worry about, it takes care of everything for you, trickle charges, priorities starter charging etc etc.
AnswerID: 60089

Reply By: Member - Trevor - Tuesday, May 25, 2004 at 21:49

Tuesday, May 25, 2004 at 21:49
Hi All - The latest advice, as of this arvo, was both batteries should be of the same construction ie lead/acid in this case (even though the main one is a non-top up) The battery in the back is to be a deep cycle again but this time fitted with a cut out when the voltage drops below 10 volts.
Tomorrow could be different again.
Thanx to all,
AnswerID: 60161

Reply By: TheUndertaker - Wednesday, May 26, 2004 at 17:18

Wednesday, May 26, 2004 at 17:18
Check your member messages.
AnswerID: 60260

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