Fitting 3rd Battery

I think you are being given a bum steer Topend.

Never heard that Deep Cycle batteries can't handle corrugations. They are made with thicker plates than a standard Starting Battery.

Check the facts here:- Battery FAQ's

I'd put the 3rd battery in but make it a gel cell, yes you 'may' reduce its life by not charging it fully but as they can last for anything up to ten years I don't consider that a worry.
By making it agel you can fit it inside the vehicle without a worry, Sonneschein are one of the better brands marketed under the Dryfit label.
Peace of mind by having a seperate battery to run the frig is worth heaps.

Hi Topend, a deep cycle battery is constructed in the same way and of similar materials to your every day cranking battery. So how many cranking batteries have you heard of that spat the dummy because someone took their vehicle over corrugated roads?

If I were you I would give that particular Battery World a miss.

Now, do you need two starting batteries to get your reg going, if not or if your not sure try disconnecting one and drive around for a week or two and see if every thing works OK.

If it does then just fit a battery charge controller between the two batteries you already have and the jobs done and done for a lot less that most of the suggestions the different shops have been giving you.

Cheers

Gday Topend
I have put the 3rd in my TD 100 and am pleased. I used a traxide sc40 (check it on google) isolator and had the stainless steel 3rd tray fiited by ARB as they have to relocate the fuel filter. Other than Tray fitment I did it myself and it is easy.

I went for a deep cycle marine from repco (75ah) for about $140 and it has worked faultlessly. Well worth doing. I dont have to run the car at all for 4 days ( if desired) during summer, and still have super cold beer.
cheers
JohnN

hi topend . as i have std.lc100.I have twin battery set up with a SURE POWER battery separator.Main battery is N70 and the other 1 i use is a ODYSSEY sealed lead battery 12v/ 1500amp.Went up to cape york last August for 4 week trip & use waeco cf 110 fridge.Had no problem with the battery and it still in the car now.I also put a thick rubber mat under the battery to protect it from corrigated roads.

cheers.. happy camping.

SNAP!(-ish) I am running a 24V two battery land cruiser. I installed a third battery (deep cycle - as recommended by Battery World Burleigh Heads ) to charge via a dropdown unit.

When the motor is going, I run the CF110 off 24V and charge the deep cycle at 12V. When the motor is off, the fridge runs off the 12V deep cycle. It all works well. I believe my better option is to set up 2 x Deep cycle and a solenoid, but I got out of it for under $100 and it all works well. Luckily I was able to remember some stuff from my Electronics Engineering days!

Your second battery on the 12V system is the subject of much discussion as to weather deep cycle is better or not. I would certainly go to a deep cycle, as they are more bullet proof. It will also handle a crank if your other battery dies. It should not shorten the life of your other battery.

Your fridge also has an auto cut-off which prevents the battery charge dropping below crank voltage. The only way you will find yourself stuck is if you use the emergency override on the little switch at the bottom. Hope this helps.

Cheers,

Scott.

Topend,
putting it very bluntly; the battery world guy is a seriously demented wanker.....

If you want some facts on what batteries, then ask people who have the system you want, ask what they think about them and also ask people who have the knowledge to be able to give you honest and factual answers....

Note, you can't, (well you can if you are obtuse) mix batteries when wiring them in parallel, even if it is only two batteries, so you can't add a gel battery or Deep Cycle battery to a wet cell battery and expect them to charge/discharge without problems as they will accept and also distribute charge at different rates.

A Rotronics isolator is a good brand, go the heavier model not the base model ($240?)
Use 2B&S wiring and tinned and crimped connections to ends of all leads to avoid power loss.
Use a third battery in the system, _ONLY_ if the existing two batteries are in as new condition internally, not their actual appearance, have them tested by a COMPETANT battery specialist, as by adding a third battery, even the same brand and specs to the existing 'average' batteries, will stuff the system so it is not getting the full benefit of the new battery, wasting your time and money.

Best method; add two ‘quality’ (N70 size) Deep Cycle batteries to your existing starter battery/s, and separated by the Rotronics isolator, giving you 160 (2x80a/h) to 210 (2x105a/h) Amp Hours.
As previously stated, DC batteries are not prone to shaking apart on corrugated roads any more than starter batteries.

Hi Topend,

All of the posted replies make sense, and we are all operating successfully. I have a degree in this stuff, but you don't need one. Just ditch the bloke from your local Battery World. Also, the deep cycle are better designed for corrigations.

If you are interested I can email you my circuit diagram, although I suspect you are running a 12V system.

For another opinion, talk to Steve at TJM Underwood or
Battery World Burliegh Heads. I have nothing but confidence in these guys.

The people that sell you stuff at TJM are the same people who work under your car and compete in events around the place, unlike another well known over-priced megastore.

Cheers mate!

hi
just get a 100 amp triple isolater solanoid
Snailbait

Thanks for all the replies. I ended up fitting a 3rd severe service battery with a Pirahna isolator. This battery has a 18 month warranty compared to only 6 months for a true deep cycle.

I almost bought an absorbed glass mat deep cycle battery but when reading the instructions in the store it recommends not discharging below 50% to prolong the battery life. Therefore I did not see an advantage over the severe service battery which can be taken down to 50% and cost $100 less.

I will get a 125 watt solar panel before the next big trip.

Thanks,

Topend