Alternator upgrade, wiring help?

[cadunkle]

I ordered a DB Electrical ADR0334 105 amp alternator to upgrade whatever low output jobbie is on the PCM 454 in my '89 Saltare. The existing alt has to be revved pretty high to start charging and occasionally stops charging at idle and must be revved to begin charging again. I figured this is good preventative maintenance and several here have used the ADR0335 from DB.

The new alternator is a 1 wire alternator. When I swap this out I plan to disconnect and tape the existing alternator wiring and run the charge wire with 4 gauge wire to the starter solenoid where the wire from the battery goes. Should I use a fuse between the solenoid and alternator? If so, where should I fuse it, at the alternator or solenoid? If relevant, it's a dual battery setup one starting and one deep cycle with a manual Perko switch. I don't have any amps or a fancy high output stereo. Just a decent head unit to the 4 speakers. I do have extra blowers for my heater core and heated drivers seat and plan to add additional seat furnaces.

[wotan2525]

No fuse required between alt and starter. Make sure everything is fused on the battery side of things.

[cadunkle]

ok, sounds good. I installed the DB starter I got and looked more closely at the alternator wiring but had to call it quits because the rain is moving back in (been every day for a couple weeks now). The factory alternator is run through the 50 amp breaker on the back of the engine. Is there any reason I should do similar or upsize the breaker? Or just leave the breaker in place, disconnect the existing charge wire, and run my new to the solenoid with the large wire back to my batteries and the small to the breaker on the engine?

[cadunkle]

I got the new alternator installed and working. Had to run around to find 4 gauge wire and the ends with right size ring for the alternator (1/4"). I couldn't figure out where the old charge wire went to, removed both wires from one side (port) of the breaker on the back of the engine and got continuity to both (red and orange, I believe) from the old charge cable. Not sure where they're connected so I just taped up the 3 wires that used to go to the alternator. I'd like to disconnect them from wherever they go if anyone knows where that is. If not I'll settle for taping, heat shrink and securing them. I also got some of that plastic split wiring loom to cover the new charge cable with. I did not install yet as it's getting dark but I'll install that this week before I use the boat this weekend. I feel it will give a little extra protection from chafing, though I routed the wire low so it doesn't really touch anything metal.

The pulley is not the right size, it's too narrow. It works and doesn't seem to slip from revving in neutral. The belt rides high though and doesn't have as much contact as it should. I'll contact DB and see if they can send me a wider pulley. I tried swapping the pulley off the original alternator, a 51 amp Prestolite, but the shaft is slightly larger on the new one from DB so the old pulley won't fit.

The alternator starts charging at idle as best I can tell. Start it up and volt gauge goes up immediately. Getting 14.6v at starter solenoid where the new 4 gauge charge cable goes, as well as 14.6v at batteries so all seems good in that regard.

Volt gauge on dash reads about 13.5v. I turned on everything, bilge, blower, heaters, heated seat, lights, radio... and got 14.5x at batteries. Tripped the main breaker on dash "ign" though. Heated seat and heater blowers are tapped off my deep cycle, not through the factory wiring. I had this problem last season if I turned the radio up too loud it would eventually trip that breaker and kill everything. Rewired radio so the main power goes direct to deep cycle and the in dash radio switch just cycles the key on 12v to turn radio on, seemed to help.

I did order some new breakers from SkiDIM to replace some that don't operate smoothly and hopefully I got the right size to replace the main one that trips too. I'll try replacing that and cleaning all the wiring connections I can find. Hopefully that will fix it. Seems like I'm getting a voltage drop to the dash according to the volt gauge, maybe dirty connections are adding some resistance and causing it to trip that breaker. Any tips appreciated!

[wotan2525]

I also get a voltage drop to the dash but have just chalked it up to old (and maybe too thin wires.) The blowers seem to especially take a toll which is weird because I put them on a relay run directly from the battery bank. I've learned to live with it as my stereo may draw a peak load of ~200amps and it doesn't cause any lights or cut-outs.

Sounds like you've got things all figured out. Congrats!

[gogger]

wish I had read this last night, I would have done the same thing instead of ordering another 51 amp prestolite from Skidim for $215......

[cadunkle]

Shame, so far it seems the 105 amp is a big improvement over my old Prestolite if only because it starts charging immediately and doesn't need to be revved. Under $70 too, probably about $100 when you figure the 4 gauge cable and misc stuff I had to buy.

I replaced the main ign. breaker yesterday. Put a a new 30 amp breaker from SkiDIM in. Old one looked a little flaky at the terminals like it had gotten hot before. Had to drill bigger holes in the terminals as the factory breaker used screws and backers to attach the terminals to this breaker. Did not trip in my test running in driveway with all accessories on and radio turned up so hopefully that fixed it. Also ring terminals were a little dirty so cleaned them up.

[TitanTn]

Good to know; thanks for the info. I think this might be a winter project for me. Let us know what DB does about the pulley, as I'll need the same thing as you.

[wspeedin]

I ordered this
http://www.db-starter-alternator.com...34-140amp.aspx
And installed it while I was rebuilding my boat. I know I was told to upgrade the size of the wire and the breaker, but to be honest....I didn't. I forgot to do it during the rebuild and I haven't messed with it since. It seems to be doing just fine with the old wire and breaker. Granted, I haven't installed a radio or lights yet. I just take the boat out and drive it for right now...are we sure changing the wire is a MUST DO?

[cadunkle]

Absolutely. Depending on if that charge wire is protected by a fuse of not you may have a fire risk on your hands. If unprotected and your electrical load, either through accessories or discharged battery, is higher than the charge wire's capacity you will overheat it and may start a fire. If it is protected by a breaker or fuse you will just keep popping the breaker or fuse. You cannot push 140 amps through an 8 or 10 gauge wire, it will melt and start a fire if anything flammable is near it. Please fix this before using your boat again, it is very dangerous.