Battery guard cut-off Voltage

[100SRV]

A 300TDi Defender - decided to start using an electric cooler box to keep provisions fresher when camping, the cooler being powered by a dedicated battery live outlet.

Options were split charge or a battery guard, I decided on fitting a battery guard because it was the easiest of the two solutions.

I've fitted a Durite battery guard, 0-852-02 and set the program as P9 which isolates the accessory socket power at 12V battery Voltage and reconnects at 13V. The instructions have a variety of settings and I'm wondering how low I can go for terminal Voltage with a standard starting battery and not experience the "click-nothing" failure to start.

I left the cooler box running overnight and the engine started easily this morning, however the cooler box wasn't that cool inside so the battery guard did it's job at some point in the night and isolated the power to the cooler.

I was thinking of trying P7...or is that a bit ambitious?



Bottom line is that I need to take some measurements of current drawn and terminal Voltages - a job for this evening.

[Penelope Stopit]

Everyone to their own and all that but.....

Would it have been better to take the split charge relay route and wire a battery guard int0 the slave battery supply to the fridge?