Battery Isolators, Fuses etc...

[AlastairCooke]

Hi All
I am trying to sort out the electrical components that need to go into the 'fighting compartment' of my Tiger 1. Although the model is based on the Tiger 131 kit I have upgraded the Armortek electronics to the August 2019 specification (red boxes). I plan to fit a disconnect isolator switch so that the two 12V in series LiFePO4 'power' batteries can be spilt for storage and charging. I also plan to fit a fused in-line circuit breaker similar to that shown in the installation manual. My questions are: what would be a suitable rating for this circuit breaker (80A, 100A ...) and what should be the rating of the blade fuse fitted to the Armortek Power Module? The module was supplied with a 15A blade (auto style) fuse which seems a little low considering the rating of the circuit breaker and the continuous discharge current capability of the batteries (45A).

Any advice would be appreciated.

Alastair

[Adrian Harris]

The fuse only protects the smoke element output, hence the low rating.

Could you put a second relay between the batteries, using the same power circuit as the supplied one ?
Then when you switch off, the batteries are isolated from the tank and each other.

I've charged AGM and LiFePO4 batteries in series without problems, as the charger outputs float.

Once my life gets back to normal I'll be able to spend more time on the telemetry and see what sort of currents the models use but I would have thought 80A would be plenty and still within the instantaneous rating of the battery. The brief tests I did with the Sherman showed that the peak current was under 30A but that was with no sound or smoke, which will add 5A or so.

The cheap bullet shaped Chinese isolators with the red arm aren't reliable. I had one from Ebay which didn't work at all and a friend had one which connected long enough to charge up the input cap on the electrics then broke contact. I'm much happier with blade fuses as protection and relays as the isolator.

Adrian.

[AlastairCooke]

Hi Adrian,
Thanks for the quick response and the advice. I still have the original switch/relay cable so will reconsider and also look at something similar to split the battery circuit.

Alastair