db electrical alternator

skalomenos wrote: Can anyone offer any help in regards to wiring? I am going from a three wire Mando alternator to a one wire Delco alternator. I know where the battery wire connects but I am stuck wondering what to do with the other wires. I have a black..I suppose this is the ground and then I have a green wire I think was connected to the exciter? I need help regarding what needs to be done with the green and black wires now.

Skalomenos, I'm pretty sure that the black and green wires are not necessary any more with your one wire alt. The one wire does not need an excitation circuit as this is done inside the alt. For now, just tape up ends of these two wires (temporarily and separately of course) and start your engine. Check that all your gages and accessories are working normally. Make sure you are charging. If you don't have a voltmeter installed, I would install one (in place of the amp meter that is). If everything works normally you can do away with the other two wires. One question - do the black and green wires join your wiring harness bundle and disappear?

05 210 wrote:      I got it Tim! Before reading all the above posts.In a perfect world,you don't need to upgrade the wiring,but if you were to get a short(high current demand)on that wire......ssssmmmokin!

well if that happens then you just learned a valuable lesson as to why you do not remove the fuse or curcuit breaker from the curcuit. Because if it does short then it will blow the fuse or trip the breaker depending what is used.

So I'm going to double the output of the alt so I better change all of the wiring going to the dash. No not true, might have to change the wire from the alternator to the first connection where it is attached to the battery cable. But not the dash you haven't done anything to it to change the load going to it that would increase the load or increase the current draw.

Oh but I'm going to add a killer system and some ballast tanks. Oh really cool you just added 10 amps more current by doing that so now when I flip everything on that is on the dash it will draw 30 amps instead of 20 amps. So if that 10 gauge wire is too small to handle the extra current it was marginal to start with and should have been a larger gauge from the get go.

So if you want to waiste your time and money re-wiring the boat knock your self out but all you need to change is one section of wire that is maybe 5' long because you are not changing any electrical load on the sytem by just upgrading the alternator. And even if you are adding pumps and a head unit you are barely increasing the load on the system at the dash but I've got amps big deal they should be connected directly to the battery to start with and the increased wire size from the alternator to the solenoid/relay takes care of that and the extra battery easily.

Jim_In_Houston wrote: I still think I can piss farther than anyone else.

The fuse is cheap . The wire is not very expensive. About 20 minutes to wire it all up. Protect your boat for a few bucks , NO BRAINER.

Tim, HTH are you reading my mind?!?.....thats twice now!

My comprehension?? This whole thread is based on you saying that it's not necessary to change the 10awg dash lead. I'm simply asking what would happen if you have a short in the dash with a 100amp alternator?

79nautique wrote: why do you need to do this if the current to the dash doesn't change. You don't

And in the event of a short in the dash? The breaker will still protect the circuit from the battery, but what about the alternator that can now produce twice the current that 10awg is rated for?

Tim, cut him some slack.....
He just got mixxed up as to what year he did the drawing for charge circuit.It would be an easy thing to do, after all the R&D he has done over the years.
Just simply overlooked, case in point.GM alternators.Two entirely different designs, dont even look simular. Yet he will come off with that BS that he designed them.
If I spent that much time on a project I would at least knew the type code (SI) and how the internals were laid out.
But he will bash someone as to the rebuildablity of this unit.
Chris go hide back under that rock, we need info, correct info. Not you trying to inflate you own ego.
And as far as the sexual slams towards a member of this site , that just shows your own "short coming"
I is hard to unpaint your self out of a corner, and here you have ended up in the corner with egg on your face and paint on your knees...........boat dr

Chris, clearly you have a reading comprehension problem. Ive addressed that in this thread 3 times already. I agree that the load to the dash doesnt change. Go back to page 2 and read my response to Mike (05 210) as to why you need to fuse the 10awg wire or replace it with a larger one when installing an upgraded alt. Its a safety issue.

You dont need to school me on basic electrical principles, Ive already got my degree. If J_I_H wants to chime in, thats another story- Im glad to listen to those who know more than I do.

79nautique wrote: I suggest you refer to the wiring diagram in the PCM manual and you will see the batter cable, alternator pos lead, and the pos lead for the ignition switch all go to the same post on the solenoid/relay. The breaker is the only thing missing in the diagram.

Im curious how you can be so adamant about how the breaker is wired when the best source you have is a diagram without one and you dont have a Correct Craft to verify it against.

The breaker is the only thing missing in the diagram.

79nautique wrote: Tim look on page 22 of teh 302 and 351 PCM manual instead of the 89, the diagram is a lot easier to read and I've got now clue where you see the ballast coming into play. Maybe thats the problem you need a lession in reading schematics

Actually, I thought the clearer diagram might help YOU. Please explain to me how the breaker is wired according to this diagram (pulled from page 22 in the PCM 302/351 manual).



*hint: There is no breaker in that diagram. Its even more inadequate than the one in the '89 manual.

Kevin we know how well you fix things, and it took how long to fix your boat? or is it still underpowered for some unknown reason you can't figure out still?

Hollywood wrote: Bremsen wrote: I know that on my boat, the main POS lead off the alternator and the main dash lead were located on the same terminal on the circuit breaker. The battery and starter were the only protected ciruits. I don't believe it had ever been touched. So you're basically combining Tim and Chris's arguments here. Tim says dash needs to be protected from the battery by the breaker, which it is. Chris says it does not need to be protected from the alternator. So basically Tim's diagram needs the orange alt output on the other side of the 50A engine breaker.

nobody said anything about removing or added a curcuit breaker or fuse Kevin

Tim look on page 22 of teh 302 and 351 PCM manual instead of the 89, the diagram is a lot easier to read and I've got now clue where you see the ballast coming into play. Maybe thats the problem you need a lession in reading schematics

Bremsen wrote: I know that on my boat, the main POS lead off the alternator and the main dash lead were located on the same terminal on the circuit breaker. The battery and starter were the only protected ciruits. I don't believe it had ever been touched.

So you're basically combining Tim and Chris's arguments here.

Tim says dash needs to be protected from the battery by the breaker, which it is. Chris says it does not need to be protected from the alternator. So basically Tim's diagram needs the orange alt output on the other side of the 50A engine breaker.