

| Subject: | Re: Original Battery Wire Gauge |
| From: | M'obeechi |
| Date: | Tue, 16 Dec 2008 18:08:06 -0800 |
Ok, plugging Copper, 2/0 with assuming foot length, and 330 amps gives a voltage drop of 3.52 percent... and 11.577 volts on the load end of circuit, that sounds a lot better... so with a wire longer than stock, and with a Subaru, it would be good move to get a fatter than stock wire, it certainly couldn't hurt, like if your battery were ever weak... I have noticed sometimes some kind of lull right after starting, and then it goes away within a very small time frame. I just need to wait a second before moving into the highway. From: mdrillock <mdrillock@COX.NET> To: vanagon@GERRY.VANAGON.COM Subject: Re: Original Battery Wire Gauge > You are missing a key point. The current draw through the wire largely > depends on the starter motor itself. It will only draw so many amps > according to it's design and size. Using a much higher CCA battery does > not change this. As long as the battery is big enough, making it bigger > still just means it can crank for a longer time without the starter > motor slowing down. You will never see even half of your 1150 amps, IMO. > > If you look in the table for amps/wire size you can see that stock 2/0 > wire is only rated for 330 amps. I would guess that VW chose this as a > suitable size for the larger starter 2.1 models got. Thus I doubt the > stock starter current exceeds the 330 amps by much. Maybe someone else > knows about how many amps would be expected. > > (This topic brings up a problem seen in Subaru conversions perhaps more > than stock motors. Before the alternator is charging, the fuel injection > wiring gets its power from the starter motor post. Thus when the starter > motor is cranking and the voltage drops there may be too low of a > voltage for the ECU to work.) > > Mark > > > > M'obeechi wrote: > > Wow.. I went to this site, and put in for > > 1. Copper Wire > > 2. 2/0 AWG > > 3. 12 VDC > > 4. 1150 Amps... I used this figure simply because the Sears Platinum Group 31 is rated for 1150 cranking amps > > > > The results: > > 1. voltage drop 1.842 > > 2. voltage at load end of circuit is 10.158 > > 3. Percent voltage drop is 15.35 > > > > That seems too much of a voltage drop... like the wire is a weak link in this setup... I think this wire length is longer than stock, and the battery is bigger, so to take full advantage of the cranking amps... but even with 4/0 AWG the voltage the results are: > > 1. voltage drop 1.159 > > 2. voltage at load end of circuit is 10.841 > > 3. percent voltage drop is 9.66 > > > > Is there anything that can be done to up the voltage again, like a relay or something? > > > > But then again, if I change to 4 AWG and reduce the length to 4 feet while keeping the Amps the same, the results are: > > 1. voltage drop is 2.35 > > 2. voltage at load end of circuit is 9.65 > > 3. percent voltage drop is 19.58 > > > > So even 10 feet of 2/0 AWG is better than 4 feet of 4 AWG > > > > From: mdrillock <mdrillock@cox.net> > > To: M'obeechi <obeechi@RUNBOX.COM> > > Subject: Re: Original Battery Wire Gauge > > > > > >> For 86-91 models it is 2/0, one size bigger than 1/0. > >> > >> Here is a useful link for checking things like amps versus wire size. > >> > >> http://genuinedealz.com/voltage-drop.html > >> > >> Mark > >> > >> > >> M'obeechi wrote: > >> > >>> I no longer have this wire, but I remember it being very fat. Called the dealer, and they couldn't tell me, but they agreed with me that it was fatter than 4 gauge. Saw some 1/0 gauge wire (pronounced one-ought, didn't know that), looks nice, but I think the original VW wire was fatter. > >>> > >>> Does anyone know the gauge of this? > >>> > >>> ------------------------------------------------------------ > >>> + To unsubscribe from the Vanagon List send an e-mail to > >>> + listserv@gerry.vanagon.com with SIGNOFF VANAGON > >>> + in the body of the message. > >>> ------------------------------------------------------------ > >>> > >>> > >>> > >>> > >> > > > > ----- End Original Message ----- > > > > > > > > ------------------------------------------------------------ > + To unsubscribe from the Vanagon List send an e-mail to > + listserv@gerry.vanagon.com with SIGNOFF VANAGON > + in the body of the message. > ------------------------------------------------------------ > ----- End Original Message ----- ------------------------------------------------------------ + To unsubscribe from the Vanagon List send an e-mail to + listserv@gerry.vanagon.com with SIGNOFF VANAGON + in the body of the message. ------------------------------------------------------------
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