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Older boat alternator upgrade on the cheap


UWSkier

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If you have a 2002 or older Indmar and are still running the original alternator, there's a cheap upgrade path if you're so inclined.  I wanted more juice because PerfectPass, a heater running on high, a circulation pump, and a blower motor running was a bit more than my old alternator was happy with to give enough extra charge to feed the battery.  So, I went with this.

https://www.dbelectrical.com/products/marine-alternator-crusader-pleasurecraft-5-0-5-7-litre.html

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and one of these

https://www.ebay.com/itm/New-Alternator-Repair-Harness-fits-Delco-5SI-7SI-Marine-Alternators-19020601/273250473079?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

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and got to work.  It's a pretty simple job to swap out.

First, remove old alternator.

Second, install new alternator.

Third, run an additional wire from the alternator + to the + stud on the starter, being careful to run the wire in a manner that it can't rub and ground out on the engine block over time.

Fourth, optionally run an additional wire from the alternator - to the - stud on the engine block.

Fifth, cut off the ring connector on your purple wire and solder the purple wire to BOTH LEADS from the pigtail.  Use heat shrink on all of your connections.

Result: Whereas my old alternator was only good for about 13.3-13.4v at the dash at idle with no additional load, this one gives me a nice solid 14.0v.  Before, when I'd switch everything on, my voltage would drop to a bit over 12.7.  With this one, the voltage regulator compensates for load and bumps up output to match the demand.  I can turn on every electrical accessory I've got and my voltage stays pegged at 14.0v.

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55 minutes ago, Woodski said:

@UWSkier - needing a heater in AZ is blasphemy, 'wimp'  :lol:

Thanks for the link, DB electrical is a great source for electrical stuff.

It's not always hot here. 😁 Average set from Dec to Mar is 60f air, 53f water. 

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30 minutes ago, Woodski said:

@UWSkier - the CFO felt the seat heater was the best addition and I have to agree it is really nice on those crisp ski sets.

If I felt confident about removing and reinstalling the skins, I'd look into one now that I have more juice at my disposal.  :)

 

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  • 4 weeks later...

Several years back I switched to a single wire alternator running a big wire from alt to starter, the three wires from old alternator just tied up away. Is this alternator better and what do the pigtail wires hooked up to purple wire do?

Thanks!

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The pigtail serves two purposes.  First, it "excites" the alternator.  Basically wakes it up at low RPM on initial start.  Second, it provides a reference voltage from the dash and tells the voltage regulator when it needs to feed more juice down the line.  Single wire alternator will send whatever it's set to, so if that's 14v, it'll send 14v down the line.  But if you add a load, it won't know that it needs to adjust to keep voltage in place.

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7 hours ago, Eagleboy99 said:

The one for $17 more needs no pigtail (10 bucks) so what, other than 6 bucks does this cheaper version really provide?  Asking for a friend. :)

It uses a different kind of pigtail that plugs into the side, rather than the back.  That, and the more expensive one uses a different style pulley.  I didn't want to have to change all my pulleys to a serpentine style just to get a little more oomph from the generator.  Wanted to stick with the original v-belt.

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1 hour ago, UWSkier said:

It uses a different kind of pigtail that plugs into the side, rather than the back.  That, and the more expensive one uses a different style pulley.  I didn't want to have to change all my pulleys to a serpentine style just to get a little more oomph from the generator.  Wanted to stick with the original v-belt.

My '01 has a serpentine belt.  Wonder why the difference.  I don't think that is LS1 specific for 2001 either.  

I am also doing an alternator upgrade.  It would be done except the seller felt sending me a car bra was better than the alternator I ordered.  Except instead of a 70 amp (barely an upgrade over the stock 51), I went with this 95 amp, from a different seller and a bit cheaper:

https://www.amazon.com/DB-Electrical-ADR0424-Alternator-1-3166-11DR/dp/B0081SE1CG

Either way, you should upgrade the ground wire and wire to the starter.  At 95amp, I am going 2awg.  70amp may get away with 4awg, I would have to look at the chart.  Not something you want to under rate or ignore.

 

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1 hour ago, Nitrousbird said:

My '01 has a serpentine belt.  Wonder why the difference.  I don't think that is LS1 specific for 2001 either.  

I am also doing an alternator upgrade.  It would be done except the seller felt sending me a car bra was better than the alternator I ordered.  Except instead of a 70 amp (barely an upgrade over the stock 51), I went with this 95 amp, from a different seller and a bit cheaper:

https://www.amazon.com/DB-Electrical-ADR0424-Alternator-1-3166-11DR/dp/B0081SE1CG

Either way, you should upgrade the ground wire and wire to the starter.  At 95amp, I am going 2awg.  70amp may get away with 4awg, I would have to look at the chart.  Not something you want to under rate or ignore.

 

LS1 was the only '01 to have the serpentine belt.  They didn't put that on the Monsoon or Hammerhead for several years.

Interesting they sell for slightly cheaper on Amazon.  That's DB Electrical.  Same I got mine from.

I did upgrade the wiring to the ground and starter as indicated in the OP.  I went with 2awg piggy-backed on the original wiring.  Capacity to spare.

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2 hours ago, UWSkier said:

LS1 was the only '01 to have the serpentine belt.  They didn't put that on the Monsoon or Hammerhead for several years.

Interesting they sell for slightly cheaper on Amazon.  That's DB Electrical.  Same I got mine from.

I did upgrade the wiring to the ground and starter as indicated in the OP.  I went with 2awg piggy-backed on the original wiring.  Capacity to spare.

It has to be because of the LS1's water pump; GM was never going to develop a V belt setup for that, where the GEN-1 SBC had that developed long before.

Did you trace out the ground/power wiring to where it splits off?  I haven't dug into it yet, so I didn't determine whether a separate wire vs replacement was the right way to go.  What wire routing did you go with to get to the starter?

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1 hour ago, Nitrousbird said:

It has to be because of the LS1's water pump; GM was never going to develop a V belt setup for that, where the GEN-1 SBC had that developed long before.

Did you trace out the ground/power wiring to where it splits off?  I haven't dug into it yet, so I didn't determine whether a separate wire vs replacement was the right way to go.  What wire routing did you go with to get to the starter?

Followed the existing wiring up and over.  There's a wire loom that runs from the alternator up to the ECU housing then back out the other side to the ground and the starter.  I just zip tied my wires to that making sure they weren't oriented in a way they could possibly ever rub up against anything.

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  • 2 weeks later...

1997 Response with 320 Monsoon. I am switching from the Mando 55 Amp to the 70 Amp as you describe. I have the alternator and pigtail. I understand that I join the existing purple wire to the 2 wires from the pigtail. New alternator has a "spade" fitting in the back of the alternator. Is this used? Did you upgrade your positive lead to a thicker wire a Fusible link?

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39 minutes ago, RODONNELL said:

1997 Response with 320 Monsoon. I am switching from the Mando 55 Amp to the 70 Amp as you describe. I have the alternator and pigtail. I understand that I join the existing purple wire to the 2 wires from the pigtail. New alternator has a "spade" fitting in the back of the alternator. Is this used? Did you upgrade your positive lead to a thicker wire a Fusible link?

I ran a piggyback heavier gauge wire from the alternator positive to the positive stud on the starter, yes.  I didn't fuse it.  I also ran a heavier ground from the alternator to the ground stud on the engine block though this is probably not as important.

Spade connector is not used in this application.

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22 minutes ago, RODONNELL said:

"Piggyback" meaning that you left the original wires and added the heavier wire?

correct.  Others had done the same with good results so I copied their idea.  I ran my wires up and over the block though.  I've heard of others running their wires through the bilge under the engine.  I wanted mine where I could ensure they were zip tied up and away from anything they could possibly rub on.

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So the above mentioned alternator will fit the indmar 320 lcr engine as in the 2007 wakesetter ?  Is that a the monsoon engine ?? 

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On 6/26/2020 at 4:15 AM, Aussieluke said:

So the above mentioned alternator will fit the indmar 320 lcr engine as in the 2007 wakesetter ?  Is that a the monsoon engine ?? 

yes, that will work.

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I'm considering doing this upgrade. I think I only get mid 13 volts at the dash and starter. Also, I'm seeing a voltage drop on the dash below 13 when I turn on accessories and my gauges will all rise (engine running), which I assume is a symptom of the voltage drop. Battery is new last year and I've cleaned all terminals at the starter and ran an additional cable from negative battery terminal to grounding bar under the dash. Engine ground looks good.

I say all this to ask - could the alternator be the source of the voltage drop? This problem popped up again this year. I thought I had it resolved with the cleaning and extra cable a couple years ago.

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3 hours ago, drh said:

I'm considering doing this upgrade. I think I only get mid 13 volts at the dash and starter. Also, I'm seeing a voltage drop on the dash below 13 when I turn on accessories and my gauges will all rise (engine running), which I assume is a symptom of the voltage drop. Battery is new last year and I've cleaned all terminals at the starter and ran an additional cable from negative battery terminal to grounding bar under the dash. Engine ground looks good.

I say all this to ask - could the alternator be the source of the voltage drop? This problem popped up again this year. I thought I had it resolved with the cleaning and extra cable a couple years ago.

do you have a DMM and know how to use it?  That's where I'd start.  You can do voltage drop tests pretty easily with a cheapie DMM from Harbor Freight.

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I do but going off of memory I'm not getting much voltage drop (.3 volts maybe) from the back of the alternator to the starter and battery. I think I'm getting around 13.5v at the back of alternator

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UW- 

Did you figure out where the ground wire terminates?  The black wire wound up being too short to reach the back of the alternator, so I spliced a section on, but I should add a better ground wire. I am thinking I will just run a 6 gauge wire to the block in addition to the 12 (?) gauge wire that I had to add a section to. Sound right?

Also, the lower bolt on my old Mando alternator had a 5/16" x 4 1/4" coarse thread bolt. That bolt will go in about 1 turn and stop. I tried a the same size bolt with a "fine" thread, and it too is not right. Is it metric? I may be being too gentle, but I don't want to ruin the factory threads. Did you have any issues with that bolt?

Thanks!

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