New Alternator - still not charging battery

[zzpich]

Hi everyone. I just installed a new alternator but my battery is still not charging and I need some help trouble shooting the issue.
The boat 94 ProStar 205 with LT-1. Last week the alternator died and after making sure I don't have a loose wire I ordered a new alternator from DB Electrical. I ordered this one:

https://www.dbelectrical.com/product...si-95-amp.html

I installed it today and while I was at it I also replaced the tensioner and the belt. I also upgraded the orange wire to 4GA due to the larger output of the alternator. I had a bit of trouble with fitment of the alternator because the grounding screw was in contact with the bracket, to the extent that I could not thread in the second mounting screw. I ground out the grounding screw housing a bit to make sure I can bolt on the second bolt.

However, I ran the boat and the new alternator is also not charging. I measured the voltage at the alternator and it was 12.3V, just about the same as the voltage at the battery. Since there is no voltage loss, that leads me to believe the new alternator is defective. While I was replacing the orange wire, I looked at the wires/connections on the chain between the battery and the alternator and all looked fine - tight, no signs of corrosion, no kinked wires. I ran out of daylight but will triple check in the morning.
Since the voltage at the post at the back of the alternator is 12.3V, it would appear the alt is bad, not the wire connections. I would think that if the alternator is working properly the voltage measured at the alternator should be 14+V - am I wrong? Just to be certain, I measured the voltage at idle, at 1.5k RPM, at 2k RPM and 2.5k RPM - since the exciter is built in I believe the DB Electrical alternator kick in somewhere in the 1.2k-1.5k RPM. Same results.

The wiring of the new alternator was straightforward given it only uses one wire and it also appears to be well grounded on the bracket.

So, how should I go about troubleshooting? I have been thinking over and over and I cant come to any other conclusion than a bum alternator - which I am a bit concerned about because I ground out some of the housing to fit it in the bracket. Or could i have gotten the wrong alt... like maybe a clockwise rotation unit.

As always - thank you in advance for any help/advice/ideas.

[Fullpass]

Yes, alternator should be 14v even at idle, and kicks in more charging amps at above 1.2K rpm…You can take the alternator out and have checked at an automotive parts store before returning…not sure the 11si works for older motor…for the reason can't remember would half to go back and research..Do an internet search, thinking some mods might be needed other members have done before.

[zzpich]

Thanks Fullpass - I checked everything again and did not find loose connections - that is probably irrelevant since the voltage at the back of the alternator is 12ish volts.
The new alternator has one terminal for the positive, which based on my research is the only connection needed. It also has what look like a 4-lead plug - others on this forum said these are not used/needed but I wonder that is indeed the case. Does anyone have experience with this model alternator?

[waterlogged882]

Thanks Fullpass - I checked everything again and did not find loose connections - that is probably irrelevant since the voltage at the back of the alternator is 12ish volts.
The new alternator has one terminal for the positive, which based on my research is the only connection needed. It also has what look like a 4-lead plug - others on this forum said these are not used/needed but I wonder that is indeed the case. Does anyone have experience with this model alternator?

I do not know that particular model but I use the single wire alternator on Ford Engines. Same principle. The way I understand the single wire (compared to the older models with four wires) is this: The one single wire is output back to charge the battery. The other (comparing to old style) three wires go away: 1) the brown was for a dummy light which is not used, 2) the black was for ground and the new alternator grounds itself to the block, and 3) the green was for the exciter which is now built in. The old four wire minus those three leave you with the single wire. Same principle for Chevrolet (your 94 VS the Ford other models).
.

[zzpich]

Thanks waterlogged882 - I wanted to make sure I am not missing anything and appreciate your feedback. I will take the alt off tomorrow and get it tested.

[zzpich]

Well - this has turned out to be a complete disaster... I brought the old and new alternators to 4 auto parts stores and neither could figure out how to test them - they were mostly clueless and I wonder how they stay in business.
Unfortunately I do all work on my cars and do not have a good mechanic/car shop that I deal with close by. I have a buddy that is an hour away from here that can test it at his shop but don't have time to go to him this week.
Similarly, I have called and emailed DB several(like 5+) times over the last two days but have not gotten a response. I don't really blame them though because I know everyone is stretched with the pandemic and probably some of their folks are working from home. Sorry if I am venting a little bit but a simple job has ended up being very frustrating...

I spent some time thinking about my observations and measurements of the alternator and determined that it has to be a defective alternator - after all it only has one wire and is properly grounded, I can't think of anything I did wrong. So, I will go ahead and order a second unit from DB - their shipping seems to remain expeditious. DB Electrical's website indicates that if you need a replacement quickly you can order a new one and then get credit when you return the defective unit, hopefully they will honor that statement.

The only thing I am debating is how to handle filing/grinding the ground bolt area - as mentioned above, I had to file a piece of the alternator housing where the grounding bolt attaches in order to clear the mounting bracket. See the picture for details... I have seen others on the forum do the same. I wonder if I should try to file the bracket this time instead of the alternator - in the unlikely case that the DB alternator works and there is something else wrong with my set up. But grinding the bracket will be harder than grinding the alternator housing. Has anyone tried to file the bracket?

[georgea0731]

Try Ron Tanis, Skiboatpartsonline, CEO - American Skier Boats

Here's a video where he upgrades to a large alternator.
https://www.youtube.com/watch?v=60DBfpSJ5Kw
GL

[zzpich]

Another update - the second new alternator also does not charge... this is becoming a little embarrassing now.

Again checked and triple checked everything - all wire connections are solid(upgraded wire from alternator to the post of the breaker, than from breaker post to solenoid, solenoid to battery), breaker is good, boat starts and everything works other than alternator.
Alternator spins freely when engine works - new belt and tensioner so no issues on that end. Ground is solid thru the bracket... there is almost no voltage drop at the back of the alternator, voltage pretty much the same as at the battery.

The new alternator should kick in at 1400 RPM - given that the alt pulley is probably 3 times smaller than the engine pulley it should probably kick in even at idle but just in case I ran the boat at 3k+ rpm... still not charging.

It is probably unlikely to have two bad alternators (unless DB Electrical has a bad batch) but I can not think of anything else that may be wrong here. I will see if I can find a car application for the DB electrical alternators so that the car part store can set up in their system and test it... Any other thoughts or ideas are much appreciated.

[88 PS190]

Wait - you're saying no voltage drop... but also no charging?

What are the volts @ the alternator and what are the volts at the battery?

Send the part number for the alternator.

[1redTA]

zzpich you close to Pensacola? I see your location is southeast

[zzpich]

88 PS190 - the last measurement this morning, while running, was 12.41V at battery and 12.39V/12.40V at back of alternator. Similar difference between the two locations while engine is off.
The alternator is model # ADR0424 from DB Electrical - Indmar Marine Alternator 8600002, 20827 11Si 95 Amp.

1RedTA - I am in Atlanta... boat is in north GA.

thanks guys!

[waterlogged882]

Another update -

Any other thoughts or ideas are much appreciated.

Edited;
The 94 has an ECM that may not be in alignment with my thoughts.

How old is the battery and have you put water in it lately?

I also came to realize your engine is the LT-1. A poster below this post may be onto the issue ==> here <==.

Patience...

.

[mikeg205]

Are you sure the alternator is getting excited? And +2 on battery.

How old are battery cables and how is changing connection to battery - how are the ground wires. Did you check voltage at alternator when it was connected to boats wiring?


Call DB electric, I would isolate the alternator from everything else to make sure output is correct.

Sent from my SM-G955U using Tapatalk

[CapeH20Skier]

The LT1 takes a specific alternator and needs multiple wires. I ended up getting the Arco 60055 from discount inboard marine - skidm.com. Call them - ask for Vince. He’ll walk you thru the multiple wire hook up. After talking with him my alternator I thought was bad was sending 14 volts to battery

[flyski]

The LT1 takes a specific alternator and needs multiple wires. I ended up getting the Arco 60055 from discount inboard marine - skidm.com. Call them - ask for Vince. He’ll walk you thru the multiple wire hook up. After talking with him my alternator I thought was bad was sending 14 volts to battery

I looked at the DB website and did not see the alternator you ordered listed as a single wire unit - are you sure it is being excited by the regulator? It doesn't sound like it is.