Topic: battery cable gauge

twostickmutt	-- 01-28-2018 @ 2:53 PM
	Would the 2 gauge awg cable be good for the ground ( +) from the battery to engine on a 6 volt system. Thank you. This message was edited by twostickmutt on 1-28-18 @ 2:55 PM
Drbrown	-- 01-28-2018 @ 5:45 PM
	I may be wrong but I believe 1 gauge should be used. I see 2 gauge being used for 12 volt systems.
twostickmutt	-- 01-29-2018 @ 2:42 AM
	thank you DR
Yokomo99	-- 01-29-2018 @ 5:06 AM
	If you are running 6 volt I would go as big as I could find. You only have 6 volts to play with so any voltage drop in the system is not good and will limit how fast the starter will crank. I run a minimum of 1/0 cable on 6 volt systems. I personally prefer 2/0 welding wire but it does look very thick. I also solder the ends on my wires. Most tractor supply shops have battery terminal ends for sale with solder already in them for various wire sizes. #1 wire is rated for 195 amps in free air but #2/0 is good for 265 amps. To measure the voltage drop of the power wire, on positive ground systems, take a voltmeter and put the negative lead on the negative battery terminal and connect the positive lead where the main wire from the solenoid connects to the starter, ground the coil high tension lead and crank the engine. Reverse the leads and battery terminal for negative ground. You should also test the engine ground circuit as told by Tom in the post below Zero volts would be best but that would be very unlikely, but obviously lower is better. Even a few tenths of a volt can make an amazing difference in the starter motor cranking speed. Also with higher cranking voltage the current drawn from the battery is reduced. A DC electric motor is designed to produce a certain level of power. Since power is volts times current ( P=E*I ) any reduction in voltage at the motor armature will generate a corresponding increase in current draw. The speed of an DC electric motor also depends on the armature voltage applied, so the two work hand in hand. Make sure all of the connection points are clean and tight. Don't forget the starter solenoid. It is also an important part of the system. Sorry for being so long winded. I have been repairing industrial electric motors and drive systems for over thirty years so it is somewhat of a passion for me. Matt Be sure to check out my YouTube pages at: https://www.youtube.com/user/MatthewBergin1 https://www.youtube.com/channel/UCJCdOfmXtM8xO9nXeQ-iSQQ This message was edited by Yokomo99 on 1-29-18 @ 3:11 PM
TomO	-- 01-29-2018 @ 9:35 AM
	Matt, I think you have a typo in your instructions. They should read: Connect the + lead of your lmeter to the POS post of the battery and the COM lead to the starter case mounting bolt. Crank the starter with the ignition off and read the meter. The reading should be 0.1 or less. If it is higher, you have a starter grounding problem. To find the source of the problem move the + lead of the meter to the body side of the motor grounding cable. If the reading is high, the battery grounding cable is causing the problem. If it is Less than 0.1v, the problem is in the motor grounding cable or the starter mount to the oil pan. Tom This message was edited by TomO on 1-29-18 @ 10:00 AM
Yokomo99	-- 01-29-2018 @ 10:04 AM
	TomO you are correct for testing the engine ground. I missed that. It needs to be included in the whole system. My description was for checking the starter power cable not the ground. I will modify my post to clarify. Both the power and ground need to be considered. I remember reading somewhere that positive ground systems don't rust the body but corrode electrical connections. This might be why our old cars seem to have so many electrical gremlins for such simple wiring. Matt Be sure to check out my YouTube pages at: https://www.youtube.com/user/MatthewBergin1 https://www.youtube.com/channel/UCJCdOfmXtM8xO9nXeQ-iSQQ This message was edited by Yokomo99 on 1-29-18 @ 3:08 PM
twostickmutt	-- 01-29-2018 @ 12:07 PM
	thanks for all the great info !
Drbrown	-- 01-29-2018 @ 7:11 PM
	Amending my above post and thinking about voltage drop etc .... I have a 12 volt negative ground system but use #1 battery cables to reduce voltage drop. I also run my positive battery post/cable directly to the starter, and ground the engine to the frame and two grounds to the body. In general, when I rewired the car I over-sized most of the wiring.
TomO	-- 01-30-2018 @ 10:21 AM
	Matt, there are a lot of fairy tales on the internet and some of them also make it into print. IMHO there is no proof that POS ground corrode connections more than NEG ground and the same goes for rust. Tom
Yokomo99	-- 01-30-2018 @ 1:56 PM
	Tom I don't actually believe that the positive ground issue is true. I do have a tendency to answer these type of questions by experimenting scientifically and see what happens. This I am doing and I will let you know what the result is if anything. Don't hold your breath. I does make a good story though. Be sure to check out my YouTube pages at: https://www.youtube.com/user/MatthewBergin1 https://www.youtube.com/channel/UCJCdOfmXtM8xO9nXeQ-iSQQ

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