Electrical safety when using 12 volts.

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adam2
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Post by adam2 »

The use of the fuses illustrated within a battery enclosure is not ideal since the fuse element is probably not enclosed and will spark when it fails.
The risk is minimal IMHO with two relatively small batteries and reasonable ventilation.
It might be better to use a main fuse in the enclosure (mains rated non sparking type) and a fusebox outside the enclosure, this would facilitate adding any extra circuits when needed.
I have used cheap domestic fuseboards for small 12 volt systems, choose one with generous internal space to allow for the thick cables often needed.
A basic install that I did recently, consisted of a 60 amp main fuse in the battery cupboard and a cheap 8 way mains fuseboard outside the cupboard.
Cables into the fuseboard were 35mm.
Outgoing circuits were 2.5mm on 10 amp fuses for lighting with 6.0mm on 20 amp fuses for sockets.
If heavy power circuits are contemplated, then provision for at least a 100 amp main fuse, and subcircuits up to 45 amps needs to be considered.

Presuming that you dont intended moving the battery once installed, then I would go for the Rolls battery, obtaining extra labour or plant to put it in place.
Options include slinging the battery from a piece of heavy timber, and carrying this by 4 men, or use of a trolley, or an engine hoist.
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
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