Fullriver 120Ah AGM into 100 Series Cruiser

The batteries in the HZJ105 were cactus. They were the ones it came with and the whole system was dubious and time for an upgrade. When I purchased the car the wiring was a mess, although quite effective. I am still sorting some of it out.

My goals were as follows:

1. Seperate battery for starting
2. Maximum capacity for Aux items
3. 80Ah Useable Capacity
4. Option to expand to triple battery setup for winching

I’ll go into a debate on battery system choices in a seperate article, but to meet my needs I chose the following:

Odyssey PC925 – Small Start Only battery
These small expensive AGM’s are made to deliver spectacularly high starting currents from a small battery. If you don’t have room for a Dual Battery setup, or want to go to a Triple setup, then one of these should be your start battery. 925A for 5 secs, 620A for 10 secs – it starts my 1HZ with ease. I’ll update after a -5 winter day, but for the moment it works fine. I didn’t want a huge start battery that never used more than 5% of it’s capacity and wanted to be able to go to a triple setup later.

Fullriver HGL-120 – Aux Battery
These chinese AGM’s seem to be getting great reviews. Ultra low internal resistance means fast charging. AGM commentries are all over the web. The main things that are important to me are:

1. Fast Charge
2. Good resistance to deeper discharges
3. Great vibration resistance.
4. Adequate Capacity – 80Ah is easily acheiveable from a 120 rated batt

You’ll find out why the AGM costs so much and has higher capacity when you try to lift it. 35Kg as opposed to a conventional N70ZZ at 21 – 25Kg.

Piranha 150A Isolator – Conventional Voltage Sensing Isolator
It came with the car and after bodgy repairs to the cracked plastic case and corroded PCB tracks, now works fine.

Fitting the batteries

The Fullriver comes with an unusual terminal – basically a recessed nut and supplied bolt. You can either take off your conventional terminal and use theirs, or do as I did. Cut the lead terminals off your deceased battery, drill them to fit the bolt though – presto – conventional terminals in case you need to swap back for some reason.

To fit in the landcrusier cradle you’ll need to remove the plastic tray underneath. It’s not big enough and makes the battery sit up too high. I can’t see any reason for it’s existance, as the paint underneath is rubbed anyway, and it doesn’t have a drain making acid protection pointless.

You’ll also need to modify the rear “hook” bracket. It is too short and wont go over the slightly taller battery. 2 minutes with an turbo torch had it red hot and rebent. There is enough length in the bent peice hook to straighten and rebend it as a longer straight shaft.

 
Odyssey TEMPORARILY mounted in original position. This one battery replaced 2 batteries triple it’s size. Plan is to put it in the rear of the engine bay on a small tray. No need to move fuel filters and less weight.

Clearances are tight, but it fits. Modified terminals can be seen.

Modified rear hook mount needed for additional height. You can see the tight clearances.

Comments:

Conventional Wet cells don’t have enough useable capacity for my demands. Deep cycled they die.

Conventional Deep Cycle cells are slow charging. I doubt I’ll have the engine running for long enough to charge them fully.

I have concerns about AGM’s and heat. All Lead Acid cells have a positive feedback cycle when charging. ie, the hotter they get, the more current they adsorb, making them hotter, making them adsorb more current……
Normal wet cells will outgas if this gets out of hand, and you get to top them up with water. AGM’s recombine the gases, releasing more heat. This can be bad. 50deg is the theoretical max, but that is also said for conventional cells. Most people get away with it, some don’t .Ideally, mount them inside the vehicle. Personally, I’m going to put an aluminium heat shield in to keep the worst of the radiator heat from blowing on them, and rely on their forward position to feed them cool air. Some people do nothing and have no worries. Others have problems.

The isolator – like 90% on the market simply parallels the cells when the input voltage hits 13.6v. Many claim all sorts of wizardry, most are simply relays in a black box.