#1760  by Gerry
 Fri Nov 07, 2008 1:51 pm
I am rewiring the DC supply circuits in my caravan.
The least expensive way to buy heavy duty cable for the battery to controller unit was to purchase a set of jumperleads from Super Cheap ($38) and they are 3 meters long.
Problem is they are fitted with a surge protector to prevent spike damage to sensitive electronic gear in the event of being used for their real purpose - jump starting vehicles.
Can anyone tell me what is in the surge protector and will it give me a problem if I incorporate into my battery / load cables?


 #2703  by SteveC
 Sat Jan 17, 2009 9:11 pm
Hi Gerry. The surge suppressor wont do any harm in-fact it may even do some good one day. If you want to remove the suppressor most of them come off quite easily and only leave a small hole in each cable.

I would be more concerned with the cable size. Most “cheep” jumper leads are not worth the packaging. I got a set from the kids at xmas and I’ll swear that under all the insulation is no more than 2.5mmSq of conductor. They started a 4 cylinder car, just, and would not work on a 2.5l diesel. Cheap jumper leads are not what they seem.

Your best bet is to pop into one of the local electrical wholesalers and buy wielding cable directly from them, and some lugs at the same time.

Hope this helps SteveC
 #2709  by Gerry
 Sun Jan 18, 2009 9:04 am
Thanks for that Steve.
You are correct regarding the cable size. Huge insulation and smallish copper. On the 400 amp cables I bought the copper was about 10mm. That was more than OK for what I was using them for.
The surge suppressor is another thing! When I pulled it to bits it turned out to be a capacitor across the two leads. Would be OK for short term jumper use but I don't fancy leaving it across the battery full time. I have seen too many of these things fail and a dead short across my battery system is not something I could live with - so I removed it.
It was interesting the "400 amp" leads fitted into my solar panel controller with out me having to crimp on a smaller tail!

 #2830  by SteveC
 Mon Jan 26, 2009 9:32 pm
Yes your right however its not uncommon to need to place a small capacitor across the DC supply to an inverter to stop “screaming” in a radio especially the marine band 2 way radios. I have only had one fail and the capacitor lead acted as a fuse quite nicely. There is an old saying where I come from “ Any conductor will take any current, its only the duration of how long that changes” Food for thought.

 #2839  by Gerry
 Tue Jan 27, 2009 8:53 am
I like that!
“ Any conductor will take any current, its only the duration of how long that changes”.

I will pass that to some of my cohorts in the semiconductor fuse business.

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