electrical approval needed!

[hobson]

I'm getting the bits together to give our 300tdi a good electrical sort out in the battery box area, as well as adding a few bits.

i've done a diagram to help me make sense of it all and hopefully someone on here with far more expertise than me can approve it or tell me where i need to make changes.

here's the diagram:

i intend on using a 300a rated junction box to split the feeds from the main terminal, and a 300a rated voltage sensitive relay for the split charge, possibly coupled with one of the Waeco fridge voltage sensors to prevent things getting too low.

any suggestions or approvals please?

[Lars L]

Why 300 Amps on split and relay? I now use a 70 A voltage sensing relay on my 110 to charge the extra battery used mainly for the fridge. Previously I used a simple relay rated 30 A that was governed/triggered from the alternator thin wire. Both have served well in keeping the extra battery charged.

[pete3000]

I'm getting the bits together to give our 300tdi a good electrical sort out in the battery box area, as well as adding a few bits.

any suggestions or approvals please?

Fuses all the way throughout, only wiring which doesnt need fusing is your anderson for jump start/winch. this should be short if on batt box/seat or double sleeved if you are running to front of truck. You may consider isolator switches to disconnect the batt so people dont fiddle with your winch or steal your 12v.

Remember to spec the fuse to protect the wiring not the equipment which it supplies. see max current carrying capability of the wire and fuse under that with a safety margin. You can think about wire sizing when you are looking what will be run off each leg.

i.e anderson cables 35-40mm2 for 150A fuse at 100A-120A

aux fusebox 25mm2 80A?

aux circuits on 4mm2 thinwall max 25A fuse at 15-20A (four of these at 20A could get you to 80A)

if there is a short you want to lose the fuse not your loom in a hidey hole somewhere.

HTH pete

[hobson]

after more research i'm going to use the 125A VSR from devon 4x4, i wanted a highly rated one as the last 40a one i had melted, apparently due to the battery getting really low and needing more than 40a to charge it, so i figured better have a high rated one, but as i'm not running a winch i think 125A will be fine.

everything is currently fused but with inline holders, so i thought it'd be a lot tidier to fit an aux fuse box and have everything together.

i forgot to put on i was going to fit a cutoff switch for the anderson connector, both of which will be fitted to the front of the seatbox, it'll be safer that way and there's no point having it live all the time.

wire, i was going to use some spare jump leads for the anderson connector and the listed thicknesses for the rest.

how's all that sound?!