Electrickery!!!!!!!

[Graham B]

Morning,

We have got a bit of a problem with the electrics of the new boat and were wondering if anyone could help out with some much needed info. We have plumped for a brand new Tohatsu 50hp two stroke and want to run the set up with two batteries using the switch we bought as reccomended on here. The battery duplication is for safety more than anything with double redundancy along with the amount of electric gadgetry we are collecting and hopefully the distance we will be fishing from Amble marina!
The questions I have in my head are;

1) what strength of cable from the + battery terminals to the switch - its a 4-5 metre run.

2) What strength of cable from the common terminal of the battery switch to the switch / fuse panel - its a 4-5 metre run.?

3) Any recommendations for cable suppliers?They seem to be quite expensive bits of kit!
We just want to do it right so it doesn't have to be done again, even though these catch reports are killing me! We will get fishing soon I hope!
Thanks for the info in advance,

Graham.

 

[KeithB]

I'm no expert but think you need at least 50MM Sq cable for main battery leads, we used 70 for Shady as it was readily available.

Norland Cables at Gallowgate used to be good, not sure if they are still there.

 

[mark]

Coleman's, walker place, north shields

really helpful and friendly folks and you'll not find cheaper. either standard battery cable or they sell jump lead cable, the jump lead cable is more flexible

wasn't the expensive if memory serves.

do the job once and do it right I suppose, use the same heavy cable from both battery terminals to the distribution switch, fuse panel etc, least that way if its done proper from the outset you can pretty much forget about it

 

[davem2005]

Hi,

If you are talking about the feed for your dashboard (is that the right term )and electrics you do not need heavy wire.

The only large diameter cable is that from the solonoid to the starter and the soloniod to the battery. You should already have that in place.

The electrics on your cockpit are all low current draw...for example see how many MASSIVE wires your car has under the dash ...the answer is non. So a 2.5mm sq multi strand (the finer strands the better) will be more than capable of supplying all your boys toys requirements, the exception is if you want to run a spotlight (not running lights)

A 2.5mm wire will easily carry 30 amps @12v with no heat problems. Add up your dashboard requirements and it should cope. The electrics on mine draw 5 amps max if all lights/radio/two gps's and fish finder are on at once.

A good hint is to use trailer board wire (SEVEN CORE) this gives you a good quality fine wire and options to add split charge relays and relays for spotlights with no extra installation.

DO NOT run this feed wire along the same route as your fish finder transducer cable as you will probably get interference on your radio.

For the wire to operate your split charge relay you will need a 4mm wire to be on the safe side. As a guide line look at the wire coming from your alternator. I would be suprised if it is above 2.5mm so that determines what the engine manufacturer considers safe to cope with the output of your alternator, which is the maximum current your engine can give out.

You only need heavy wire from battery to starter..all the rest can be relatively cheep 2.5 or 4mm.

PM me if you need any further help.

Cheers
Dave

 

[George]

I have 2 core wire from old dyson hoovers running from my battery to the various bits and bobs had no probs up to now. The cables from the outboard to the battery are heavy duty which came with the engine.

I might be a millions miles wrong but it works ok for me

I just run the one battery as I have the pullcord option on the engine.

 

[mark]

if its cable for the 'house' electrics rather than starting/main battery, make sure you get tinned copper cable. it'll save you many headaches a couple of years down the line