Which power cable?

[HUMBER P4VWL]

Why batteries in bench, you then can't put them above the stuffed/flooded waterline. They should be on the shelf in the console with all other electrics.

[Pikey Dave]

Originally Posted by GuyC

+1 on what Chanchan is saying with the exception that I'd put the fuse as close to the battery as possible.

It looks like you have drawn a distribution post with one large incoming cable and then several outgoing cables. You could do it this way with a number of inline fuses but it would possibly be neater to terminate it at a fuse box. The link below is to a Blue Sea one but there are various different options.

https://www.bluesea.com/products/503...h_Negative_Bus

The key thing to remember is that the fuse protects the cable rather than the equipment but it is normal to size the fuse based on the maximum current draw of the equipment.

If your total current draw is 16A, for example and your cable is rated at 100A, then the main fuse can be somewhere between 16A and 100A. If you use 1.5mm cable between the fuse box and the consumer e.g. nav lights, then the fuse should be somewhere between the rating of the cable (20A) and the draw of the lights (2A). I'd suggest using 5A fuses for everything apart from your VHF and bilge pump where I'd use 10A.

https://www.12voltplanet.co.uk/maxi-blade-fuses.html
https://www.12voltplanet.co.uk/inlin...se-holder.html

Unfortunately, for you, using 25mm cable would force you to use mega-blade fuse holders or similar as they aren't built to deal with cable over 16mm. There's nothing wrong in that but bigger cable tends to give you fewer termination options.

Apologies for the over long e-mail and if I've confused you even further. I'd also like to add that I'm not an electrician but I've done a couple of 12V projects - motorhome and RIB.

Wot he said[emoji106]you need to fuse as close to the battery as possible. The thought of large cables connected directly to the battery worries me. I used these on BP
https://kojaycat.co.uk/fuse-boxes/-h...amic-cube-fuse

[Chanchan168]

My bench is sealed and the only way they’ll get wet is if the boat sinks. In that case, all is lost anyway.

Also my marine sparky suggested the shorter the run to the starter from the batteries the better, therefore in the rear bench.

Personally I don’t think it matters a great deal and it’s down to personal choice

[Pikey Dave]

Originally Posted by Chanchan168

My bench is sealed and the only way they’ll get wet is if the boat sinks. In that case, all is lost anyway.

Also my marine sparky suggested the shorter the run to the starter from the batteries the better, therefore in the rear bench.

Personally I don’t think it matters a great deal and it’s down to personal choice

You also need to consider the weight distribution. RIBs tend to be “arse heavy” bringing the batteries forward can make a significant difference to the balance of the boat.

[Chanchan168]

Originally Posted by Pikey Dave

You also need to consider the weight distribution. RIBs tend to be “arse heavy” bringing the batteries forward can make a significant difference to the balance of the boat.

Yeh I get that, I had a underdeck tank that failed, so I dug it out and decided to place a smaller thank in the console. I’m hopeful that this will counter any balance issues from moving batteries aft.