H.A.M.B.ers I'm wanting to install a key'd Battery Cutoff switch. My Battery is installed in the trunk...with the Positive cable running up the p***enger side to the starter. is there any concerns or issues with me putting this switch on the drivers side...underdash...sorta by the dimmer switch but up at dash level...running battery cable under my dash from the positive battery cable on the p***enger side...over to the new switch and back to the starter? issues maybe being amperage draw due to extended length...or any thing like that?
If the cable size is big enough, the extra length won't matter. My concern would be if anything happened (switch failure, short to ground), the possibility of a really big fire in the p***enger compartment will be high.
If your using correct size cable and protecting the cable from sharp edges. If you have to splice the cable do it right.
That is kind of a long run, depending on the gauge of the cable. You could lose amperage over that distance. Can you not put the switch on the p***enger side where it would simply be in the existing cable ? I realize you want it near the driver for convenience, but it might work better. I would also be concerned about that much cable being under the dash, it could short out and cause a fire. In any event, I would put a Maxi Fuse right at the battery positive terminal just to give you some extra protection. Don
Ok...is it 'ghetto' to use battery jumper cables...2 awg...mostly because it's moulded paired cable...or would it be better and "safer" to run two 2 awg cables from side to side?
Go to a marine store and buy your cables there. They are higher quality, less drop per foot, heavy walled construction, and each strand is individually tinned so you won't have corrosion problems. A little more money but well worth it. We carry Ancor brand where I work and it is really good stuff. I wouldn't want the pos and neg cables running that close together either, as with the jumper cables. Ok for a quick jump but not so much for extended use. Don
Depending on how the frame is constructed, you might think about running a ground to the frame back at the battery, then another from the engine block to the frame. Do put a overall system fuse or circuit breaker on the hot leg by the battery.
Yep, that's ghetto.... Being a retired electrician, I blanche at a lot of the 'wiring solutions' I see on cars. And the aftermarket vendors are some of the worst offenders; their wire size selections and switch/relay ratings always makes me marvel that more cars don't burn to the ground.... Number 2 cable (unless it's quality copper welding cable or 'superflex' cable) is only rated for 100 amps. You can get away with more, but only for intermittent use. The average starter current when starting the car will be in the 200-300 amp range, which number 2 will carry for a short amount of time. Hard starting, dragging starter, extended tries at starting the car can all quickly overheat the wire. And because heat increases the resistance (leading to yet more current draw), it can quickly become a vicious circle. Even installing a fuse won't prevent a fire if the fuse rating is above the wire amp rating. A fuse is there to protect the wire, not the connected device. Jumper cables are also known as 'booster cables' and aren't designed to carry the full starting load, merely to add enough capacity to the installed system to overcome a low battery. This is why when you try to jump a car with a dead-flat battery, you usually have to charge the dead car for a bit before the jump will work. For a trunk mounted battery, I would consider 1/0 as the minimum safe size to use. I just dismantled a Jaguar XJS with a factory trunk-mounted battery, and one part I was careful to salvage was the OEM positive battery cable.... which is 1/0.....
Arc welder cables work too. Make sure they are fastened well with Adel clips and not in a spot where they can rub or get pinched. Remember they will be shaking around and the body and ch***is moving around when the car is on the go.
Yeah...figured it was a bit ghetto...and whenced when I typed it out...I kinda knew the answer...I was just thinking of the dual moulded cables would be easier to run... but as they say...if it were easy...everybody would be doing it : / thanks Guys
I am a big fan of welding cable, probably because the welding supply store owner likes me,and hooks me up. Long red heat shrink tube takes care of identification, in exposed areas.
When I trunk mount a battery I go to the local electrician and but 0 or 00 cable. I like my starter to spin as well as possible.
AKA 1/0 and 2/0 (one ought or two ought)..... I'll note that if you get aluminum welding cable (cheaper, but just as good if it's installed correctly), go up two sizes as it's not as good a conductor. DO NOT use any other type of aluminum wire, it can't take vibration.....
I'm in the process of building a '53 International truck and using a 7.3 diesel. The batteries are going to be housed in a "tool box" on the p***enger's side running board right behind the cab and would never use anything less than 1/0 welding cable, even though the cost is around $10 a meter ( 1 meter = approximately 39"). I'll need about 3 meters for the positive cable. I already have the ground cables made up from a job I did last year.
While you are running wires to the back through the ch***is next time you wire the tail and signal lights, try #12 Ga household extension cords. Very easily installed and durable. The cost is also low. They also work good for the headlights. (hi, low and signal lights.)
Hi Crazy Steve, " heat increases the resistance (leading to yet more current draw).." I don't follow how increased cable resistance will cause cause >>more<< amps to flow. regards, Dan T
When you decide on what cable to use you can get a remote battery cut-off switch to put in-line and have the actuator switch wherever you want it. These switches are commonly used in the RV/Marine industries. Here's a link; http://rvpowerpartsplus.net/index.p...id=216&zenid=115cc785fd6a95e7db0eb33bd1c43492
Only thing I will add is a battery disconnect should be as close to the battery as possible and if the battery is in the trunk that is were the switch should be. Less cable between the battery and switch.
You beat me to it!!! My thoughts, as well. And make sure the SWITCH will handle the MAXIMUM amps that will EVER be pulled through it. Ben
They're kinda pricey but you might get one cheaper at a RV salvage yard like this one that may be near you; http://en.visonerv.com/
I have keyed battery switches on both my hotrods, but I didn't want the extra length, or the cables inside the car, so I mounted both on the floor. I have them just in front of the p***. side seat, so there wasn't much cable added to the length. I can easily reach down and put the key in to turn them on from the driver's seat, and they're close to the seat, so out of the p***enger's way too.
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