Hi Seano,
I have a HiAce poptop and have two 105AH AGM batteries, a 100W portable solar panel & a Morningstar regulator. AGM is safer in confined spaces as it doesn't give off hydrogen when charging. Also recommended is an MPPT regulator. You can also get a DC to DC charger to charge your batteries when the engine is running: The AGM batteries require 14.1 or 14.2 volts to adequately charge and the DC to DC charger will charge them at the higher rate. In the last six weeks I have spent two nites connected to power, to ensure the batteries get a full charge and also to top up my computer battery, AA & AAA rechargeables (I have a bucket load of these as I use LED lights when not connected to 240) etc. I was told that to get the longest life out of deep cycle batteries you shouldn't discharge them below half (12.1 V), which, after calculating my AH requirements, is why I bought two.

My power requirements are my fridge and my computer, my solar panel is able to keep the batteries topped up if there is enough sun.

Hope this helps, Anton

thanks happywanderer and Loki, now I have an idea what to look for your advice will help alot ta seano   

thanks Muso. Will start saving.

Is Full River the brand of the battery aussietraveller? I did see some on Ebay for around that price couple of days ago but wasn't sure of their performance.

Full River is the brand and they are made in the USA. The Bush Tracker club recommends them and I have done a fair bit of research without finding any negative comment on their AGM 105 amp hour battery, so far so good

Just be a little careful of cheaper AGM cells as they sometimes are made for static use and using them in a vehicle or trailer will cause the chassis to deteriorate and can cause premature failures.

You should be expecting probably around the $300 +/- 20 for about 100ah and upwards from there.

I would steer clear of fitting a DC to DC charger unless your upgrading your charging system on your vehicle at the same time as they tend to suffer massive losses unless you get a very high quality and expensive version.

Instead I would look at up grading your alternator and regulator for a higher amp rating and bump up the reg to be charging around 14.8 to 15.3.

At 15.3 you will even be able to keep calciums alive as I did for about 8 years in my Landrover dual bat system.

You will still need a battery isolator and charge regulator so it doesn't drain your start battery and you don't over charge your start battery but that will still cost about half if not less than a good quality DC to DC or DC to AC inverter and AC to DC charger which is basically all a DC to DC charger is but you have depending on quality between 5 and 25% loss.

Cheers Damo

I agree with you Mccanic. How many times do we here "I paid this for that and that for this, which is much cheaper" only to find they only get about half the life of the more expensive version, or when something goes wrong there is no backup. For example, last weekend we went away for the weekend and both mornings the fog was so thick you could only just make out the outline of the morning sun, yet my solar panels were still pumping in 14.4 volts into my battery (that's maximum because my battery was down a bit.

While I'm at it. My Waeco Dual zone fridge shut down at about 12.6volts, and I'm happy with the battery saver set to high. It re-started next morning (very foggy) at about 10.00 am.

My point is, buy the best you can afford. It pays in the long run.

What you have to be careful of with AGM batteries is is it truly an AGM battery as there are two types.
AGM was deveolped for the US Army some time ago and they were specifically made to give fast discharge and fast recharge and they were high recombination low resistance which means they have the ability to recombine the gases to a high percentage of charge current and are not as current limited as a lot of batteries.
They were normally of the names Optima,Oddessey, Lifeline and Decca Sea Mate and some lesser know brands.

Along came the Asian AGM as even though they can be called AGM do not have the same charging and discharging characteristics that the ones listed above have as they are low recombination and high resistance which reflects in the price difference as the higher the recombination and lower the resistance the dearer the technology is to achieve the desired results.

As much as the Asian AGM is low recombination and high resistance they are better in this sense than Sealed Lead Acid and Open Flooded lead acid batteries that have a higher resistance again.

Using a higher than manufacturers voltage recommendation with any sealed battery can damage the battery especially in an under bonnet application so I would be very wary of using an alternator putting out high voltages on a continuous basis.

The only battery that you can physically maintain is an open flooded wet cell battery as it is the only one you can add water to so it is more tolerant of an overvoltage application.

-- Edited by powerstream on Friday 3rd of August 2012 03:07:42 PM