Alternator Model Number

[Ralph Masters]

If any one has installed recently an 85 - 90 amp alternator, what brand did you install and the model number, and most importantly, are you happy with it.  I'm only getting 13.6V - 13.8V out of mine and like to go up to 14.2 - 14.4V.

Ralph

[Stu Jackson]

We have the Blue Circle 100A mentioned in Jim Moe's electrical system writeup with a Balmar MC612 external regulator.

What did you install that you seem to not be satisfied with?  What kind of regulator?  Do you normally leave your boat plugged in when you're not there (and thus leave the dock with "full batteries)?

If the alternator is still good, you could also have an auto store possibly adjust the output voltage.

[Ralph Masters]

Just to clarify a few items.  I have the orignal alt.  I have two batteries, both old, not sure how old.  When I bought the boat 13 months ago there was one old battery in the lazzert and two batteries in the bat box, could not tell how old or which one is the oldest.  The charger is I think the orignal, big silver box in the locker under the nav table.  I get my voltage reading from the Garmin 740  GPS, while sailing it will dip as low as 12.2, almost did not get engine started last week.  When engine is running at 2000 voltage reads a max of 13.3 - 13.5, when plugged into the pier over night voltage goes to 13.6 - 13.8 max.  I am replacing the two bats this week, putting in duralast dual purpose for now.  I need to pull the alt and take it to NAPA and have them run it and see where I'm at there.  I just read the thread started by karista back in June of 2010 and think I have the answers I need.  If I need a new alt I'll stick with the 51 amp and look at replacing the charger, this is after reading your fine articl on battery care and charging.
I do thank you for your help, I'll get back to you as soon as I get a few more answers.

Ralph

[Ron Hill]

Ralph : Try Stu's suggestion first.

If you are bound and determined to get a new alternator here are a few thoughts :
1. Make sure that the mounting of the case is compatable with your engine mounting brackets.
2. Make sure that the mounting bolts size are compatable with the hole size on the alternator case OR get some sleeves to make them compatable.
3. Balmar recommends that you program your alternator amperage output based on the size of your drive belt.  In your case with a 3/8" belt they recommend 80 amps.

A few thoughts

[Stu Jackson]

Ralph,

1.  You really, really need to change your charger, especially if you stay plugged in all week when you're not there.   charger is KILLING your batteries.  Period.  

2.  Alternator sources:  Read this and then decide whether you want to spend $400 more for a white Balmar:  http://c34.org/bbs/index.php/topic,5686.0.html

Any other questions, please let us know.

PS - Ralph, if you read karista's 2010 post, could you please provide a "link" so we can know what source you're working from?  Thanks.

PPS - I suggest, if you haven't yet, you read the Electrical 101 topic in the sticky on the MMB.

[Ron Hill]

Guys : To make my self VERY clear, I'm NOT recommending a Balmar.

What I am saying is that an alternator company is recommending that your alternator be limited to 80 amps output because of the size of the small 3/8" drive belt.
If you want to change the pulleys to accommodate a 1/2" belt then up the amount of amp output above 80 amps!!

OUT !!

[mainesail]

Please DO NOT use your Garmin to measure the voltage of your alternator. The voltage readings on the Garmin's are HORRIBLY inaccurate. There is only one reliable way to properly test this. I have four Garmin's on-board and all read differently!!! Only on occasion do they agree with my Link-Pro, Blue Seas digital volt gauge or Fluke DVM. The only use for Garmin's voltage is to tell if the voltage changes when you fire up the motor. Beyond that it is most often garbage data.

#1 With known good batteries bring them to a FULL charge with a shore charger, wind or solar.

#2 Start the engine and let run at about 1500 RPM for about 15 minutes with NOTHING on. Do not turn anything on but the engine. If it is like most of these alts from that era you should see a set point of 14.2-14.5..

#3 Test the alternator voltage at the back of the alternator at the B+ of alternator output stud with a digital volt meter. Ground the meter to the engine block somewhere.


Do not test your alts regulator set point any other way or you'll be introducing any potentials for bad connections or voltage drop into the mix and can wind up with garbage data. Garbage in/garbage out....

Here's a video of a Circa 1985 Motorola alt on a Universal M-25 having the output voltage tested.. You can also see why the alternator bracket upgrade is critical. This motor already had the timing gear cover broken once and the PO still re-used the bad bracket.

http://www.youtube.com/watch?v=M4sqc540PHU

[Stu Jackson]

Here's a video of a Circa 1985 Motorola alt on a Universal M-25 having the output voltage tested.. You can also see why the alternator bracket upgrade is critical. This motor already had the timing gear cover broken once and the PO still re-used the bad bracket.

http://www.youtube.com/watch?v=M4sqc540PHU

Alternator bracket upgrade is on the Critical Upgrades topic, sticky.  VERY important for ONLY M25 engines.

[Stu Jackson]

Guys : To make my self VERY clear, I'm NOT recommending a Balmar.

What I am saying is that an alternator company is recommending that your alternator be limited to 80 amps output because of the size of the small 3/8" drive belt.
If you want to change the pulleys to accommodate a 1/2" belt then up the amount of amp output above 80 amps!!

Here's my 100 A Blue Circle with a 3/8" belt.  Works just fine.  Battery acceptance, even with our 390 ah house bank usually controls the amperage anyway, runs about 50A and I installed the Small Engine Mode as discussed in the "Electrical 101" topic.

[Ralph Masters]

http://c34.org/bbs/index.php/topic,5686.0.html

Stu, Ron, Mainsail
Thank you for the info and help here.  Will us the the digital multi meter today and test out put as suggested.
Yep I plan to replace that charger, it's on the to do list.  I do have the upgrade to the bracket, wiring harness also.  The POs how ever many there have been it some good things on the boat but left so much undone or not done.

More later.

Ralph

[Ralph Masters]

Got to the boat today and the batteries would not turn over the engine, so pulled them out to replace.  They were two DuraLast dual Purpose Group 24 dated 03/08.  Really not bad service.  Replace them with two Costco Dual Purpose.  I figure if they last the same I'm good.
Now in the next 5 - 8 months look at replacing the charger, and adding one more battery, so I'll have two tied together for a house bank and one for reserve.
Now do some more research on chargers to get a good quality three stage charger and do some rewiring.
The alternator goes to the 1-2-b switch now as does the charger.  Those need to be changed to go to the battery.
For the type of set up I have I have looked at the Xantrex 10TB charger.  Any thoughts??

Thank you, and good sailing,

Ralph

[Kevin Henderson]

Ralph,  If you look at my forum posts on my battery and charging issues, it seems we may both be dealing with some of the same challenges.  I have an upgraded alternator.  I also have a pretty nice layout for the Xantrex system.  I think I am also dealing with old batteries.  Swing by when you get a chance and I'll show you the alternator and my entire system.  Heck you may even be able to help me decipher what my issues are as well.
BTW.... Stu..... If your reading this, I'm still working on my schematic of my electrical.