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I snaked 2 #10 wires from the batt up under the hood. both on the + terminal of the battery. I connected the - to a bolt under the hood, now I have a 60A anderson connector that in an emergency I can connect power to unlock the doors or jumpstart. each #10 is good for 35 amps on the safe side, so 70 amps is no problem.
This would be a great mod to add to the library. Did you take any pics? I would really like to do this as I have had to access the battery on 2 different occasions already. Good job!
I snaked 2 #10 wires from the batt up under the hood. both on the + terminal of the battery. I connected the - to a bolt under the hood, now I have a 60A anderson connector that in an emergency I can connect power to unlock the doors or jumpstart. each #10 is good for 35 amps on the safe side, so 70 amps is no problem.
A potential hazard by using even 2 ea, #10 wires from the battery to a + connector. If you do a jump on a dead or nearly dead battery, your inrush amperage will be way more than 70 amps and you could literally burn off the insulation on them (and perhaps they could short to some ground source once the insulation is gone)with the heat that will be generated from the resistance of the wire with such amperage flowing thru it.
And besides all that, the NEC says #10 wire capacity is 30 amps, not 35 so your total is only 60amps.
Unfortunately power in the Smart is DC (as you know) so in order to complete the circuit you only still have 30 amps. Just because you have 2 wires does not mean that you double that amperage.
Anderson sells a red/black housing set with 45 amp contacts for 10 gauge wire. Yes, NEC rates 10 gauge wire them at a lower rating, but short runs of DC can go much higher than long runs of house wire. Anderson also sell a molded housing that takes two wires. They call it the SB series. This connector (SB 50) can use 6, 8 or 10 gauge contacts. They make large sizes too: 175 amps (Warn winches) and 350 amps (electric forklifts). I sell these at my company.
A potential hazard by using even 2 ea, #10 wires from the battery to a + connector. If you do a jump on a dead or nearly dead battery, your inrush amperage will be way more than 70 amps and you could literally burn off the insulation on them (and perhaps they could short to some ground source once the insulation is gone)with the heat that will be generated from the resistance of the wire with such amperage flowing thru it.
And besides all that, the NEC says #10 wire capacity is 30 amps, not 35 so your total is only 60amps.
Be careful with that!
NEC says 30A. unless you take into consideration the footnotes. they say you can use 35A as a calculation for derating.
I have used single #10 wire to start a motor load with a 120A breaker to cover the inrush. the NEC also says that you can overfuse a motor load to 1300 percent in certain situations to let the motor start. all of the diversity and conservitave ratings are very safe. in this application, if I was to connect to a very dead battery I would not attempt to start the car until it was mostly recharged. or just jump it until the battery is mostly charged without starting it, then disconnect the cables and start it.
[quote=8X5X5ft;196005]Unfortunately power in the Smart is DC (as you know) so in order to complete the circuit you only still have 30 amps. Just because you have 2 wires does not mean that you double that amperage.
quote]
Actually it does.
both #10 wires are on the positive terminal and both go to the connector on the positive side.
I also have 2 Black #10 wires going to a ground.
35A each, I went over that on the other post, 70A total.
This is a fairly common practice in modern autos. follow some of the power leads from some of the batteries to some of the power distribution blocks. a couple of #10 wires.
If the battery was total dead, I would use the connection to get the doors open and jump directly.
Interesting where this thread led.
I just wanted to let everyone know that I found my route for the wires without drilling any holes and I now have my air horn and my ding dong trolly bell installed. The air horn was an absolute ***** because I did not remove any of the plastic. But it's in and it is secure and I can now either give you a blast from the air horn or just a friendly tinkle from the trolly bell.
I think I'm pretty much through with projects for a while. So far I've:
Put in a side sunscreen - ugly but functional,
Put on a junkyard $5 rear hatch handle,
Put in footwell lights and a rear cargo LED,
Put my scangage in over the driver's visor,and,
Finished off with the air horn and trolly bell.
If you are interested, I've got a picture of the outcome of most of the projects (except the air horn/trolly bell) in my "favorites". I'll be putting a couple of pics of the air horn/trolly bell in my favs in a few days.
I think that's it for a while.
Thanks to all for your input.
Pete
There is a BIG difference between AC and DC loading on wires. I'm pretty sure NEC refers to house/business wiring for AC circuits - not DC.
Our company computers used 1/2" thick by 2" wide solid copper for 100amps at 20vdc. And the same was used for the negative 20vdc side as well.
I built a set of 10' jumper cables using some SJ 10-4 - and doubled two of the leads together for one side and the same for the other. Never got hot even when persistently cranking on a dead vehicle.
SJ wiring is a heavy duty rubber-jacketed lead used for flexible motor leads, extension cords and such. 10 gauge is NEC rated 25A and 300 volts. You can find it at most good suppliers, around $2-$3 per foot.
Hey mrc59;
I've got a tutorial and some pictures if you are interested. I can't get it posted on this site, but if you PM me with a email address I will be glad to send it to you
Pete
There is a BIG difference between AC and DC loading on wires. I'm pretty sure NEC refers to house/business wiring for AC circuits - not DC.
Our company computers used 1/2" thick by 2" wide solid copper for 100amps at 20vdc. And the same was used for the negative 20vdc side as well.
I built a set of 10' jumper cables using some SJ 10-4 - and doubled two of the leads together for one side and the same for the other. Never got hot even when persistently cranking on a dead vehicle.
SJ wiring is a heavy duty rubber-jacketed lead used for flexible motor leads, extension cords and such. 10 gauge is NEC rated 25A and 300 volts. You can find it at most good suppliers, around $2-$3 per foot.
In agreement with Mendo, too, about the super safe NEC regs they put out. most of my experiences have been with larger battery banks so I kind of opt for using the larger wires because of the inrush potential.
Knowing that a doubled #10 wire can handle the jump amperage is adequate and certainly easier to route than the much heavier wiring I had in mind.
I still think I would opt for the next larger size though (#8 single stranded copper) for alittle more safety factor. Just satisfying the engineer in me....
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