deep cycle battery

Shane,
They don't last longer (given that they have the same capacity). IE: a 100a/h wet cell deep cycle battery should last as long as a 100a/h AGM if it is being asked to run the same load.

Where the AGM will excell is in the charge rate it will accept and (if treated well) should last a considerably lot longer in terms of the number of cycles it will take. Typically, where a wet cell deep cycle battery might be expected to last for , say, 4 years..... a quality AGM used in the same manner, should last you around 10 years.

Well, that's what I'm banking on anyway.

I do tend to mollicoddle my batteries though. At the moment, sitting here at home, both my 4x4 and my camper trailer are sitting out in the shed/carport. They each have a Durst 15amp 3 stage battery charger hooked up to them to keep the batteries in top condition.

Roachie

Caution - you get what you pay for. The cheap AGM batteries will not last under the bonnet, or so I am told when I bought one for my Cruiser. If you are after long life, it would pay to get one that is "ruggedised" for 4WDs

viz

Without going downstairs in the cold and rain and dragging the Bruiser out and looking under the bonnet... ;) And the Missus glared at me when I asked her for the receipt...

I'm in trouble mate... :(

$525 for mine from Battery World - it is a Deka 92 Amp/hr. To make matters slightly worse, while the AGM battery seems to be very much the flavour of the month (I can attest to their performance) they do like being massaged gently with a stage charger while resting in the garage . This (so they tell me) will very much increase the life of the battery.

There is a guy on this forum who has a business in vehicle electrics (Sidewinder is the company name) who might also be able to give some advice.

viz

shane
You say;
"My fault, it went down to 3 volts while i was away and i did not realize it was running anything"

Any type of battery will die given the these conditions, use a battery cut-off device this time, set at about 11.6v if possible.

You obviously know by now you need to maintain your battery in a fully charged condition, how you do this is dependant on how it's fitted and what use it gets.

Maîneÿ . . .

Shane,

from top of my head, AGMs have the following advantages over liquid lead acid batteries:
the plates inside the AGM cannot deform/crack in extreme sub zero temps, as there is only very little water.
The AGM design recombines oxygen/hydrogen inside the glass matting back into water thus preventing water loss (under normal charging conditions).
They can be operated in any position except upside down as this might interfere with the safety valves in case of overcharging.
The glass matting is tightly packed between the plates and cushiones them which makes the design inherently more shock/vibration proof.
AGMs do not suffer from an effect which pertains to stationary liquid lead acid ones: stratification of the acid.
The self discharge rate of an AGM is considerably lower compared to liquid lead acid - the main reason for sulfation when kept in storage for extended periods of time.
And this last one is for you:
If accidentally left to totally discharge, the active material on the plates is held in position by the glass matting (a liquid lead acid battery sheds the material which sinks to the bottom of the battery and cannot be reformed onto the plates through recharging).
As to your question which battery type lasts longer? For under the bonnet and other 'hot' places: liquid. For all other mobile applications, AGM.

@viz,

.........The cheap AGM batteries will not last under the bonnet......

Neither will the 'expensive' ones as the laws of nature apply just as much - as a quick search/read on 'Arrhenius equation' would reveal.
Since we're looking at a series string of 6 cells we cannot control every individual cell separately when recharging. This necessitates a slight over/equalisation charge at every charge cycle to make sure the weakest cell gets fully charged, while other ones are already 'full'. The chemistry inside an AGM is optimised for 25 degC. At this temperature the recharge characteristics of all cells in the string are at their closest match possible. If charging takes place outside this temperature band, there will be an increasing mismatch between some cells in their ability to absorb charge (and recombine all gasses back into water) meaning the battery will deteriorate more than necessary with every cycle.
And this is precisely where the liquid lead acid battery shines: it can take an overcharge especially at elevated temperatures, because it is 'allowed' to gas at atmospheric pressure. The resulting loss of water is easily taken care of by the operator at the next service check.

As to the price of AGM batteries, anything above $250 or so for 12V100Ah, I consider a total waste of money ;)
Check out ebay.

Hope this was of some help.
Best regards, mr.batteryvalue

Personally, I believe that you are going to be better off buying a middle of the range ($) 'name' brand battery with a good warranty. I had an almost brand new battery give me problems and when I contacted the importer I was told to bring it to Dubbo (I was in Alice Springs) and it would be replaced for free. I now get my batteries from K-Mart as they have outlets all around Australia and they are not over priced. Batteries are consumables and have a limited life so I plan on useing them for 4 or 5 years and then expect to replace them.

KK

Why not just say I sell batterys CHEAP on Ebay and mine are the best.

Why are your batterys so good?

If I have a problem in Darwin can I get it replace then and there?

Are they a proven product?

Cheers Drew
I don't sell batterys

Thankyou for all replies, even though some were over my head.
So i have got out of this-

AGM's are no good under the bonnet
AGM's are more forgiving than lead acid.
Buy a battery with a nation warranty.
don't take bex with bourbon.

cheers. shane.

If I was going to put an aux battery in a 4x4 it would be a deep cycle wet cell (unless it was in the rear somewhere )

In a CT??....AGM....( especially if inside the CT ..or van.. ) Why ??......no maintenance.....

If it's like my CT....( charger is also inside the CT )....come home...plug in an extension lead... and 1 ( or 2 ) days later unplug it .....no checking....no watering...nothing......

thanks all.

cheers Shane.