jumper cables as wire source?

[mike_c]

Hi all--

Quick question from an electrical noob: Are automotive jumper cables a good source for battery wires to run from the battery posts to the fuse block, i.e. are they heavy enough to carry all the necessary current, a full charging current, etc? This would be with solid connectors added, of course, not with spring clips. I mean, it just occurred to me that I've got two or three extra pairs of the things laying around....

Any advice would be appreciated!

--Mike C.

[IndyTom]

As long as they are quality cables I can't see any reason you couldn't. You would just need to be aware of the wire gauge used. I have seen some really cheap ones that were either 12 or 14 gauge wire. The set I carry in my truck I am pretty sure are either 6 or 8 gauge. So I guess my answer is "It depends"


Tom

[mike_c]

As long as they are quality cables I can't see any reason you couldn't. You would just need to be aware of the wire gauge used. I have seen some really cheap ones that were either 12 or 14 gauge wire. The set I carry in my truck I am pretty sure are either 6 or 8 gauge. So I guess my answer is "It depends"


Tom

Good point. I assumed they would all be heavy gauge. Also, I should have noted, I will be running the wire through exterior conduit between the battery box and the trailer so it will be protected from the elements and from twisting, movement, etc.

--Mike C.

[eamarquardt]

First you should decide what the maximum draw from your battery will be by adding up the things that you are likely to turn on at the same time. This is no different than how your house is wired. You can't plug in a 1500 watt appliance in every outlet of a circuit and not throw the breaker so you shouldn't count on running every light, pump, radio, cell charger, computer, and whatever else your going to install at the very same time.

Once you have an idea of what your maximum load is, then you can consult any number of charts (search on the internet or the forum for references) to determine what size wire you need for the wire and fuse/breaker from your battery to your main buss.

Another consideration is what size battery you have. The less current you draw compared to the battery capacity the longer it will last and the more juice you'll get out of it long term. As I recall (but I can't find a reference right now) you shouldn't draw more than 10% of the capacity of the battery for an extended period. So for a 100 amp battery that means a load of 10 amps. You can reasonably get away with more for a short period (a minute or so) but will pay in shortened battery life for high loads over time. It is generally recommended that you don't discharge a battery to less than 50% of it's rated capacity. So for a 100 amp/hour battery you shouldn't draw more than 50 amp/hours out of it.

So what does this all mean? Determine what you will usually be using at the same time and how many amps will be taken out of your battery worst case. IE a few lights, maybe a high load like a water pump, a radio, etc. Again, size your wire and main fuse/breaker to your distribution buss for a bit over that load. Then see how much current each circuit will draw, worst case, and size the wire/fuse/breaker for that circuit accordingly. Finally buy and install a battery(ies) large enough so that your typical load does not exceed, in amps, more than 10% of the amp/hour capacity of your battery(ies), and then look at your typical load in amp/hours/day and ensure you have enough battery to provide this without exceeding 1/2 of the rated capacity of your battery.

To answer your original question, jumper cable wire (unless they are realllllly cheap cables) will work. I don't think they are the best wire for the installation though. The big box stores/and others sell all sorts of wire by the foot and you can get the size you really need and the terminals for that wire easily. If the jumper cables are good quality the wire, IMHO, will probably be grossly oversized for the load and terminals will be more difficult to find and the crimper required to crimp them will be large and expensive.

Hope this helps.

Cheers,

Gus

[Optimistic Paranoid]

If the jumper cables are good quality the wire, IMHO, will probably be grossly oversized for the load and terminals will be more difficult to find and the crimper required to crimp them will be large and expensive.

Gus,

As to the last part of that statement, well, yes and no.

A pliers-type tool suitable for use on battery cables will look more like a pair of bolt cutters - 2 to 3 foot handles - and will indeed be very expensive. But a hammer style can be had for about 20 bucks.

Go to Amazon.com and search on "battery cable crimper" and several examples will pop up.

Regards
John

[Wanna Be]

HI ALL !!!!

FWIW; Any jumper cable that is as big or bigger than your little finger
will work,(minus the insulation).

A Electrician friend told me if it's to big of wire the only thing lost is $$$

As A welder, I have had to pull some HEAVY guage wire long distances,
and only used 30 + - volts, 300 Amps+...

In my shops I had the same electrician run bigger wire than what was needed just for SAFETY!!!
The end result is you WILL need FUSES, or circuit breakers for the end results to be safe.

Rembember YMMV, What works for me, Might not work for you !

Stay safe, and have FUN !!!!!

Wanna Be

[eamarquardt]

If the jumper cables are good quality the wire, IMHO, will probably be grossly oversized for the load and terminals will be more difficult to find and the crimper required to crimp them will be large and expensive.

Gus,

As to the last part of that statement, well, yes and no.

A pliers-type tool suitable for use on battery cables will look more like a pair of bolt cutters - 2 to 3 foot handles - and will indeed be very expensive. But a hammer style can be had for about 20 bucks.

Go to Amazon.com and search on "battery cable crimper" and several examples will pop up.

Regards
John

HI ALL !!!!

FWIW; Any jumper cable that is as big or bigger than your little finger
will work,(minus the insulation).

A Electrician friend told me if it's to big of wire the only thing lost is $$$

As A welder, I have had to pull some HEAVY guage wire long distances,
and only used 30 + - volts, 300 Amps+...

In my shops I had the same electrician run bigger wire than what was needed just for SAFETY!!!
The end result is you WILL need FUSES, or circuit breakers for the end results to be safe.

Rembember YMMV, What works for me, Might not work for you !

Stay safe, and have FUN !!!!!

Wanna Be

First, all of the above is true. Also, everything in life is a compromise.

IMHO, the wire from even a cheap pair of jumper cables is overkill (unless there are jumper cables out there with #8 gauge wire but I can't believe you could "jump start" a car with them unless you took a fair amount of time to charge the dead battery first).

You can do anything if you put your mind to it. You can connect a large lug using a "hammer crimper". However, IMHO, the lug is going to be so big that it will be difficult to connect to a typical converter or buss bar used in automotive/trailer applications.

I think a reasonable max load from a 100amp battery is about 20 amps and that draw shouldn't be maintained for long. At that draw rate, a 100 amp battery will last 2.5 hours which, again IMHO, won't satisfy many folks. Better to reduce the load and stretch the time you can use your lights, etc.

So, a wire/breaker/fuse that will carry 20 amps should be sufficient. Depending on which chart you believe, a #8 wire should be sufficient to carry 20 amps from the battery to the main buss bar, particularly if the battery is near the buss bar, both in the back of the trailer (versus the battery on the tongue, which I don't like as the weight is all on the hitch).

If a hammer crimper is purchased it will only be used for a couple of lugs. For for about $14, you can buy what looks like a nice ratcheting crimper that can be used for all the wiring connections during a build and should make very nice crimps compared to a simple pliers like crimper.

http://www.google.com/products/catalog? ... IoBEPMCMAI

The cost of a few feet of the correct size wire will not be much when compared to the total cost of the build. I'd sell the jumper cables and buy an appropriate sized wire if that's what it took to raise the additional money to buy the wire. I'm up over $1,000 this past couple of weeks selling stuff I'll never use on Craigslist and EBay.

It just seems to me that using an old pair of jumpers is more effort (special crimper, big lugs, etc.) than simply buying, maybe, $10 of wire.

In the end "Mike_C" will read all of the above and do what he want's to do. I just like to point out all the options and the compromises of each option.

By the way: I routinely run 300 amps through about a 12 gauge wire. My point: You can do virtually anything if you put your mind to it. Is it practical to go though what I do for the 300 amp/12 gauge wire for the wiring of typical circuit to save a bit on the wire, no, but is is worth it to do what I want to do with the wire.

See my disclaimers.

Cheers,

Gus

[H.A.]

.

[mike_c]

My reason for asking was that I've read elsewhere that it's best to use the beefy wire between the battery and fuse block so that charging currents won't be limited from the converter to the battery, or from a solar charge controller to the battery.

My current draw will likely be low-- ALL lighting in my teardrop is LED and I'm not planning on running pumps or any motors other than a ceiling fan. I don't have figures in hand for current draw right now, but with all LED lighting and only occasional fan use I don't anticipate it will be high. We do want to install a solar panel for charging, and we will use the battery for charging other devices, like a cell phone, camera, or laptop. The battery is 120 Ah deep cycle wet cell-- it's a brute. We want to camp for weeks at a time in wilderness.

I had intended to run 6 ga. wire from the battery to the shunt, bus, and fuse block, but couldn't find color coded 6 gauge at my local hardware store-- no big box stores up here on the north coast (well, there are but the nearest is 1.5 hours away and it's pretty poor, frankly). Then I recalled having several unused jumper cables.

--Mike C.

[rossjools]

, g'day Mike,
You could get some heat shrink material in red and black and shrink it onto your battery cables to identify the positive and negative cables. I don't know how much that would cost in California but here in australia it's fairly cheap and we can get it at almost any auto parts or accessory store or your local auto eleccy. HTH.

Also, for the lugs I generally solder them. I once years ago did a battery cable job for a neighbour's car using the giant crimp type tool and unfortunately they gave her a lot of trouble until I decided to solder the lugs on. After that, not a problem and I do it that way all the time now and don't have any issues.

,
Ross.

[dh]

Try a car audio installer, they usually have the heavier wire in stock. I couldn't find 8g "color coded" myself, just red, so I put a bit of black heat shrink on the ends of one wire. If needed, I could have heat shrunk a band every 1 - 2 feet for identification along the entire length of the wire.

[dh]

:), g'day Mike,
You could get some heat shrink material in red and black and shrink it onto your battery cables to identify the positive and negative cables. I don't know how much that would cost in California but here in australia it's fairly cheap and we can get it at almost any auto parts or accessory store or your local auto eleccy. HTH.

,
Ross.

You must type faster than I do

[rossjools]

, LOL dh .

,
Ross.

[eamarquardt]

From another string:

My only problem is that the only way I can find the stranded 2+gound is by the foot at either HD or Lowes and it is $.55 per foot for 14 gauge (ouch).

I know a guy who sells [Boat Cable Marine Wire] UL tinned flat 14/3 (AC) awg 100 ft for $24.27. He also has tons of other sizes, and 14/2 (DC) and single stranded wire in dozens of different colors. If you want more info etc let me know.

Perhaps you can contact him.

I "Googled" buy wire online and came up with this site:

http://www.onestopbuy.com/omni-wire-cab ... -36633.asp

The statement in the search results was that they sell by the foot and on their site it seemed as though they offered virtually every type of wire under the sun (more or less).

I love shopping from my recliner with my computer and having my purchase shipped to my door for less cost that it would cost for the gas to go pick it up (even if it is reasonably near by).

Good luck.

Cheers,

Gus

[bobhenry]

Any good auto parts store or electrical supply house should be able to fix you up.

Those parts are out here an many are ready made.......




P.S.

If you dont like the colors just paint them with the new "for plastic"
spray paint.