Alternators, chargers, regulators, batteries

[mregan]

A couple of questions.
Just bought an '86.  During the survey the surveyor noticed the alternator was only putting out 13.08 volts while the engine was running.  Said it should be putting out 14-14.4.  Said it may be the batteries are going.  They are 5 years old, boat has been on a mooring each season.
Had it delivered last week.  Captain mentioned the same issue and said it may be the batteries or may be the alternator.

Trying to get an idea of which way to go.  I'm going to replace the batteries but was figuring I'd wait until the spring and buy new ones then.  If it may be an alternator issue then I would pull it this winter and have it rebuilt.  My assumption is it's the original but I haven't had a chance to check the numbers on it.

The boat needs a charger.  Read the posts on the Trucharge 2.  Sounds like that's the way to go but got confused when it got too technical.  Do I need the remote panel.  I don't really understand what it provides other than the state of charge of the batteries.  The boat will be on shore power all week and mostly be used only on the weekends so the batteries are always 100% when we go out.  How do I determine which amp size I need?

Regulator.  What exactly is the regulator.  What does it do, do I need one?  Why would you need the 3 stage vs. 2 stage?

If I get a charger do I have to get a regulator?

Batteries:  Currently have 2 Group 27 deep cycle batteries.  Was thinking of added a dedicated wet cell engine battery and replace the 2-27's with either 2 31 deep cycle or 4-6v golf batteries.  If I got with the 6v.  Will I be okay with the battery charger since the engine battery & house batteries will all be deep cycle eventhough the 6v are 6v and not 12v?  I heard you are not supposed to mix battery types on the chargers but I didn't know if they included different voltages?

Thanks,
Matt

[Jim Hardesty]

Matt,
Congratulations, hope you are as happy with your C34 as I am.  A couple of months ago I installed a Xantrex tru-charge 2 20amp, I'm very happy with it.  Didn't buy the remote, didn't see that it added anything.  It did look like a great addition if the charger had a access problem.  And it's real simple to add if I change my mind.  I did buy the temp sensor.  I'll let others talk batteries.  The factory set-up works good for me.  I'm mostly at a dock.  Have gone a couple of days running lights, fridge, pumps, ect. without recharging.  Just checking the battery voltage for charge.  Battery needs are determined by how the boat is kept and used.  If you moore or anchor your needs are differnt than if you have access to shore power.
Hope this helps
Jim

[Stu Jackson]

Matt,

1.   Alternator voltage:  You said "13.08 V...when engine is running."  The question is "at what rpm was the engine running?"  The slower the engine runs the lower the alternator output.  And if the batteries are discharged, the voltage will take some time to rise to the regulator voltage setpoint.  Also see #4 below.  It could well be that the alternator is just fine.
2.   Boat on a mooring:  One of the most usual results of being on a mooring is that the batteries are regularly and chronically undercharged.  This shortens their life.  The solution is to provide a solar panel to recharge the house bank during the week when you're not using the boat.  Since it appears that the batteries are most likely dead or going that way, invest in new batteries, and also check your alternator.  Any good alternator shop will tell you what condition it is in.
3.   Chargers:  The excellent charger evaluation by John Nixon is about Xantrex chargers.  Since that was written, newer chargers have become available.  Xantrex's reputation has basically gone down the drain in the past two years.  Consider another charger, either the Sterling or new ProMariner (NOT the old Flyback models).  If you read the "Electrical 101" topic, accessed via the "101 Topics" sticky, there is a link to installing one of the Sterling chargers written by Maine Sail.  Charger sizing is also discussed there, but usually 25% to 40% (in amps) of the house bank size (in amp hours).
4.   Regulators:  Are used for alternator control and have nothing to do with shorepower chargers.  There are two types of regulators: internal like most cars and the OEM alternators on our engines, and external, like the newer Balmar regulators (ARS-5 and MC-614 at www.balmar.net).  All of the Balmar regulator manuals (available for reading and download from Balmar's website, have a good description of battery charging requirements, as well as the Electrical 101 topic.  Maine Sail has written a good description and evaluation of external and internal regulators, here:  http://forums.catalina.sailboatowners.com/showthread.php?t=125392
5.   6V batteries and chargers:  As you most likely know, the 6V batteries are placed in series to make 12V and if you use four of them, then series/parallel.  The charger is for a 12V system, so no problem.  Wiring 6V batteries together is discussed here:  http://c34.org/bbs/index.php/topic,7162.0.html

All of us have been in your shoes once upon a time.  I suggest you spend some time on the Electrical 101 topic (http://c34.org/bbs/index.php/topic,5977.0.html)and do some reading, then you can come back and ask some more detailed and specific questions.

Good luck, we're here for you.

[mainesail]

A couple of questions.
Just bought an '86.  During the survey the surveyor noticed the alternator was only putting out 13.08 volts while the engine was running.  Said it should be putting out 14-14.4.  Said it may be the batteries are going.  They are 5 years old, boat has been on a mooring each season.
Had it delivered last week.  Captain mentioned the same issue and said it may be the batteries or may be the alternator.

Trying to get an idea of which way to go.  I'm going to replace the batteries but was figuring I'd wait until the spring and buy new ones then.  If it may be an alternator issue then I would pull it this winter and have it rebuilt.  My assumption is it's the original but I haven't had a chance to check the numbers on it.

The boat needs a charger.  Read the posts on the Trucharge 2.  Sounds like that's the way to go but got confused when it got too technical.  Do I need the remote panel.  I don't really understand what it provides other than the state of charge of the batteries.  The boat will be on shore power all week and mostly be used only on the weekends so the batteries are always 100% when we go out.  How do I determine which amp size I need?

Regulator.  What exactly is the regulator.  What does it do, do I need one?  Why would you need the 3 stage vs. 2 stage?

If I get a charger do I have to get a regulator?

Batteries:  Currently have 2 Group 27 deep cycle batteries.  Was thinking of added a dedicated wet cell engine battery and replace the 2-27's with either 2 31 deep cycle or 4-6v golf batteries.  If I got with the 6v.  Will I be okay with the battery charger since the engine battery & house batteries will all be deep cycle eventhough the 6v are 6v and not 12v?  I heard you are not supposed to mix battery types on the chargers but I didn't know if they included different voltages?

Thanks,
Matt

The only way to know accurately what the output of the alternator is requires running it into a fully charged bank, or darn close to it, at 1500+ engine RPM or better and measuring the output at the back of the alternator, NOT at the batteries..

Course most surveyors have not a clue as to how electrics work and can be more dangerous with a DVM than they can be useful. My guess is he measured at the batteries and the batteries were discharged... Measuring at the batteries only ensures he blame's the alt when it may very well be the wiring causing voltage drop, the batteries being in bulk mode or the RPM being low..

PLEASE DO NOT trust your surveyor for electrical input as I can nearly guarantee he did not properly test the alt..... Let him bang the hammer on the hull etc.....

This is pretty typical voltage drop in factory wiring. If measured at the batteries looks like a bad alternator or a low absorption set point.
http://www.youtube.com/watch?v=Xf_cy0QFFwQ

This is a fairly standard Motorola alt on an M-25 from your vintage. The batteries were 100% full before testing and all DC loads turned off so as to only measure the alternators limiting voltage, at the alternator..
http://www.youtube.com/watch?v=M4sqc540PHU

This is a very simple test yet sadly most folks have no clue as to how to do it properly. Properly means full or nearly full batteries, no DC loads on and measured at the alternator output stud and with sufficient alternator RPM..