Batteries, leads & electrical bits

[andrewbarker]

Can anyone tell be if there's a good way to join main battery leads up? I want to move my main batteries (4x175amp ones). As I've only just had the boat rewired, I don't want to replace all the battery leads that are there - just extend them by about 8 feet. Would big bus bars do? Nuts & bolts?
before you ask, I want to move the batteries because:
a) The boat trim is all over the place - bow light, stern heavy
b) The batteries are right in the bottom of the bilges & twice now I've had them flooded. Ruined 4 batteries each time & acid all over the bilges.

Also, does anyone know of good suppliers of thick battery cable, terminals, etc., etc., around Southampton or anywhere in S England where I can get the bits I need??

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[burgundyben]

Try Liz at Onboard Power at hamble point and her fella Dave, very knowledgeable, plus they sell Cobra wire which is expensive but each strand is tin plated and so much more corrosion resitant than cheapo stuff, all of mine is wired with cobra wire. They will also sell you all the terminals and bus bars you might need etc.

<hr width=100% size=1>Sod the Healey - I think I'll buy an E-Type.

 

[ccscott49]

You could solder the leads together, then heatshrink sleeving with glue inside over the joints, double up on the heatshrink, until its the same or thicker than the original insulation, failing that, you could put terminals on the end of the new cables and bolt them together, with stainless bolts/nyloc nuts and then the heatshrink trick. I would solder mine, the cables end up thick at that point, but no matter. You could also use busbars, which could be a good idea, then you have a pick up point, away from the batteries for ancileries etc. I'm sure any motor factor would have leads and connectors, battery specialists, would even make them up for you.

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[andyball]

I'd use crimped cable joiners, covered with heatshrink, not soldered joins.

Busbars OK too (but cost more, 'tho cd be handy later?)

Any decent auto-electrics place shd sell the terminals/cables/heatshrink & make up/join the cables for you.

I use untinned battery cable & take extra care with glue-lined heatshrink etc so no air/water can get past the end into the cable strands. Whether pvc is porous enough to give problems in typical boat wiring life, I don't know- ask in 20 years.

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[Chris_d]

I'd be wary about doing this if these are your starting batteries, 8ft is a lot of extra length and could produce a voltage drop which will reduce your cranking speed, so possible starting problems. If you have to make them longer, route them the shortest possible route and uprate the cable size to say at least 35mm, and use a single length, any joints will increase the resistance and cause problems later.

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[jon_bailey]

Try

<A target="_blank" HREF=http://www.indexmarine.co.uk/>http://www.indexmarine.co.uk/</A>

Never tried them but they have a good selection of the type of bits you require.

PS At the bottom of the cables page they have a formula for calculating voltage drop.

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by jon_bailey on 25/06/2003 12:23 (server time).</FONT></P>

 

[ccscott49]

Didn't know you could get crimped cable joiners that big, otherwise I would have reccomended them. Much superior to soldered joins. Thanks.

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[andrewbarker]

Thanks for your comments, esp about cable thickness. Actually, the total length of cable would be more than 8 feet because of the additional length of what's already there. I just don't want to start ripping out complex runs to the existing battery compartment: to extend them is relatively simple. BTW, the starting system is 24v. Does this help overcome resistance problems?

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[Chris_d]

Yes 24V is better but still the same problem if too long, if your existing cable is already large enough then you maybe ok, best way to join the cables will be using a butt-crimp then seal it with heatshrink.
You can get the butt-crimps from RS components, you need part number 119-227,
look at rswww.com
Measure the voltage at the starter whilst cranking, then measure it afterwards, should be more than 20V if your batteries are good, if its less then you may have problems.

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[andyball]

See your point about not removing existing cable runs....I'd extend with 70mm+ sq cable to minimise voltage drop. <A target="_blank" HREF=http://www.indexmarine.co.uk>index marine</A> do cheap(ish) "commoning posts" that might be suitable for fitting your existing leads and the extension to (i've used them, & they handle a 6 litre diesel starting current ok), and multiple entry terminal covers to keep things safe.

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[andrewbarker]

Thanks for all your help - v much appreciated. Will try some of the ideas over the weekend


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