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Date:         Wed, 16 Jun 2010 17:34:46 -0700
Reply-To:     Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject:      Re: 12.2 V at rest ('85 Westy w/2.1L)
Comments: To: "Mike \"Rocket J Squirrel\"" <camping.elliott@gmail.com>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
              reply-type=response

hi, sure, I am aware that an additional battery cable from alt B + to batt positive terminal is 'non standard.'

we all know that the batt positive terminal, the starter main terminal, and alternator B + terminal are all in common. So the 'more' they are all connected, the better.

and sure, you could bring your battery back up to full charge after starting through a small wire, but what's the point of even mentioning that ? .......like wire is too expensive to buy, or can't get decent size wire ? I know it was just for the sake of discussion, or course.

as far as I know ........the resistance of a conductor like a wire is proportional to it's cross section. Therefore.....'bigger is better' pretty much everywhere.

and the point in the entire van with the most voltage on it with engine running is that Alt B+ terminal.

The better you join .......4 points actually - batt positive terminal, starter main terminal, Alt B+ terminal, and that stud in the electrical connation box in the engine compartment ...... the more juice there will be for things to be nicely alive.

other than weight or cost penalty, there is no penalty in have 'more wire' ...as in larger conductors.

Everyone understands voltage drop in a DC circuit, right ? 'ideally' ...ALL the voltage drop in a DC circuit occurs in the device, the consumer, the head light, starter motor etc.....and the conductors and switches, and ground path and ground points all have as little resistance as possible. In practice of course, say in a 14 volt DC circuit ......maybe 1/2 a volt is consumed in the rest of the circuit ...switches, wires, etc. and only 13.5 volts is available to the device or consumer.

so .....say a circuit uses a give size wire. Say the van is 25 years old and resistance has increased here and there in conductors and switches and whatnot ......if you run two wires instead of just the one, more voltage will be available to the device or consumer.

like I said, now she goes 'click-VROOM ~!'and no amount of new battery, various starters and a couple different rebuilt alternators would make that happen until this extra cable.

and I have double redundant wiring from alternator to starter main terminal too. Da voltage goes to where it should nicely, and gets delivered to where it's needed nicely too now.

I had a maddening one where the problem was what we are talking about here. Subaru 97 Impreza 2.2 engine in an 82 diesel Westy ... always was dodgey to start ( I bought it as a running hack conversion ) .... ever seen this ?....just as you let off the key from 'start' back to just 'on' ...the engine would burst into life. Usually when you see that on a car, it means that there is just enough voltage to crank the engine, but not quite enough to power the ignition or fuel injection electronics, and when you let off the key ... while the engine hasn't quite stopped turning yet, the extra now-available voltage rushes into the ignition/EFI system, and the engine fires up.

that's what it was on this subaruvanagon .....and in the end ..........'more' in terms of battery cables fixed it.

the only reasons I can think of not to have bigger conductors, i.e. wires .. is cost, weight, and space limitations.

Scott ----- Original Message ----- From: "Mike "Rocket J Squirrel"" <camping.elliott@gmail.com> To: "Scott Daniel - Turbovans" <scottdaniel@turbovans.com>; "Vanagon Mailing List" <vanagon@GERRY.VANAGON.COM> Sent: Wednesday, June 16, 2010 3:19 PM Subject: Re: 12.2 V at rest ('85 Westy w/2.1L)

> Scott Daniel - Turbovans wrote: >> Hi Rocket, >> not sure if I made it clear ... >> though I think I mentioned it twice... >> I had a fat volt less charging voltage at the battery than at the >> alternator with engine running and alt. charging. > > Well, by golly, you're right. I did overlook that. > > When the battery has been freshly discharged turning the starter, it's > going to be hungry for energy and will draw a lot of amps and there will > be fewer volts at the battery than are present at the alternator due to > resistive losses in the alternator > battery wire. > > As one drives along, the battery will draw fewer and fewer amps as it tops > up, and pretty soon the voltage at the battery will be very close to > what's coming out the alternator. Other loads on the battery, like > headlights, will continue to cause fixed voltage losses. > > In other words, if you got no serious loads hung off the battery, you > could pretty bring a battery to full enough charge through a 22 gauge wire > if you drive long enough. > > But if one does not routinely drive very far, the battery may not have > enough time to become sufficiently charged so that its charging current > drops much. Under such conditions it would benefit the man or woman who > doesn't make long trips to provide a low resistance connection between the > alternator and battery, so as to jam as many coulombs into the battery in > as short a time as possible, especially if they do their short trips in > the dark with the headlights on. > > As for that alternator to starter wire . . . well, that's going the long > way around, isn't it? Why bring the current from the battery to the > alternator then to the starter? Just bang in a chubby wire from the batt > to the starter and be done with the middleman. > > My van would benefit from that. I'd like to find some hefty 2 gauge > primary wire for that but my Ace Hardware only has 10 gauge. Who's got the > good pricing on wire like that? > >> about what is good charging voltage .. >> I think lower is better for longer battery life. >> Higher is better for good starting cranking. > > It's all a balance. A little good beer makes me feel cheerful and > gregarious. Much more and I'm embarrassing Mrs Squirrel . . . and, the > next morning, myself. > > -- > Mike "Rocket J Squirrel" Elliott > 84 Westfalia: Mellow Yellow ("The Electrical Banana") > 74 Westrailia: (Ladybug Trailer company, San Juan Capistrano, Calif.) > Bend, OR > KG6RCR >


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