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Old 06-17-2009, 01:16 PM
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So.............
I am about to order a new alternator from DB electric.
My orig was a typical 3 wire Mando 55a version.
As I see it, I can go to a 105a 3 wire, or a newer 105a one wire. Does it really matter? Thinking about staying with what was orig. just to justify the extra wiring already in the harness but, with a one wire version, obviously less chance of any wiring issues in the future. Is this really a slam dunk answer?

Maybe a better understanding of how the one wire alt functions would do me well. My question is this. If no longer using excitation wire or sense wire, how does electronics in one wire system perform these duties?
Thanks
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Old 06-17-2009, 09:35 PM
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I had 3 wire and alt died. I was able to get 1 wire way cheaper. I believe the one wire is even cheaper to repair if it dies again. The only problem I have found with the one wire is you have to rev engine up in order to get alt. to start charging.
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Old 06-17-2009, 09:44 PM
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Originally Posted by rich allen View Post
If no longer using excitation wire or sense wire, how does electronics in one wire system perform these duties?
Thanks
You need to bring the rpms up to about 1500 on your engine to get the exciter to work. (you will see your voltage gauge go up) Then you can drop it to regular idle and it will charge. Just use the orange wire is all you need. I ran both of my engines off of one 1 wire DB 105 amp alternator for part of the season last year. (2 engines and 3 batteries) Its simple and inexpensive.
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Old 06-18-2009, 06:36 AM
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There's no advantage to using a one-wire setup other than installation simplicity. For maximum battery life and electrical system performance stick with your 3-wire setup, especially when increasing alternator output. The one-wire system sacrafices remote voltage sensing to make the installation easier. OK for a race track car or farm tractor but short-sighted IMO for marine installations.

Last edited by NightHawk; 06-18-2009 at 06:42 AM.
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Old 06-18-2009, 04:08 PM
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Thanks for the input guys. Prices for both versions are the same. I'll probably end up with same 3 wire as I already have, except higher amps.
What's the old saying?
" If it ain't broke, don't Fu#! it up"
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