Alternator Regulator Advice Appreciated

[Patrick_C]

I have a Beta 38 with twin alternators (65 and 45 Amp), a 330AH domestic set and a separate starter battery. Everyone (Calder included) seems to advise some kind of alternator regulator to reduce charging time/increase battery life etc.

 

Should I:

 

• just get a regulator for the 65 Amp connected to the domestics, and leave the starter alterator/starter battery out of the equation completely?
• get a more sophisticated regulator/splitter/management unit (e.g. the Sterling Alternator-to-Battery Charger) which would allow me to run both alternators in and then have the unit split the charge etc?

I'm not keen to just increase the 65 Amp alternator BTW which some have advised, as it would involve putting extra brackets etc on the engine.

 

Any thoughts - integrated system or keep it simple? That said, the ease of wiring in the more pricey unit has its appeal ...

 

Patrick

Edited November 22, 2013 by Patrick_C

[Hawkmoth]

This subject has been addressed many times on these forums. I think the definitive answer can be found in the writings of Gibbo.

Try this link.

Bob

http://www.canalworld.net/forums/index.php?showtopic=33065

[Patrick_C]

Great - thanks for the pointer - that looks like a good summary. As he says, there's a lot of conflicting advice and people saying things like 'alternators fight each other' don't help!

[Tony Brooks]

First of all over recent times Beta seems to have supplied alternators regulating at well above 14.5 volts and in some cases this has damaged batteries when the boater ignored or was unable to follow the instructions in the manual. If your alternators' regulated voltages are like this the such devices would be a waste of time and money. However, I suspect form the output figures they are older and thus regulate at about 14.4 volts or less.

 

Now, in common with so may other questioners who simply do not understand batteries and charging systems (not having a pop at you, you could be a brilliant doctor or artist or something) you do not give anything like enough details as to why you think this may be a good idea. Very often it turns out that the questioner is suffering battery problems and is looking for a simple (but not cheap) way to solve them but this very rarely works.

 

If you have (which I doubt with 2 alternators) a simple diode charge splitter or other faults on the system causing volt-drop then fitting such a device will cover up those faults but it could be cheaper and get better long term results by solving those problems rather than covering them up.

 

 

You need to start with two pieces of information:

 

1. tell us the actual type of battery you have (make and models may help) nor better still get hold of the maker/distributor and get the maximum allowed charging voltage form them. It will probably be over 14 volts but the difference between 14 and 14.8 volts in charging terms is vast.

 

2. after several hours running at a good charging speed put a voltmeter across each battery bank ( + to -) so you can measure the regulated voltage.

 

If the regulated voltage and the batteries maximum of gassing voltage is within 0.1 volt then fitting any extras will not give much advantage. In my own case my new alternator regulates at 14.7 while the Adverc tries to boos the charging voltage to 14.4 or 14.5. AS the regulated voltage is higher than the Adverc voltage the Adverc is now simply ballast.

 

Having said all that is suspect you may be suffering from inadequate charging time or its inverse of excess electricity consumption and simply fitting some form of advance regulator will not be cost effective until you sort that out.

 

Now, only you know what electrical equipment you have on board and how you use it. Only you know how long you charge for each day and what equipment you use so only you can work out of your battery bank size, electrical use, and charging regime are more or less balanced so you need to do a power/energy audit, then from that calculate the battery bank size needed and finally see if your charging regime is adequate. You will find sample calculations in http://www.tb-training.co.uk/16elect.htm#bmn68

 

Note that over 3 to 4 hours the average alternator output is typically only about half its rated output and the longer the charging period goes on the lower the average charge becomes. Also note that no one knows exactly how much extra electricity you need to put into a battery to get it back to the original state of charge so my saying 30% more is a sort of informed guess.

 

Once you have worked through that lot you will be in a much better position to give us the details so we can give some valid advice but probably you will have found the problem.

Edited November 22, 2013 by Tony Brooks

[DaveC]

I have a Bete 38, the "domestc" alternator on mine is 70 amp. I had a Kestral 90 originally but when I replaced the 70 amp alternator I didn't connect it up as the new altenator charged at a higher voltage than the old one.

 

The small alternator should have no problem charging the starter battery as it is.

 

 

Dave

[Patrick_C]

 

[Once you have worked through that lot you will be in a much better position to give us the details so we can give some valid advice but probably you will have found the problem]

 

OK - will go and play with the multimeter! Thanks for this, Tony, - and for the other useful stuff you publish online.

Edited November 22, 2013 by Patrick_C

[smileypete]

65A + 45A (110A) might well be too much into 330Ah leisures, especially 'el cheapos'. Is there a noticeable problem at the moment?

 

First check the alt is the correct voltage as Tony says, also that there isn't excessive volt drops due to poor connections, duff isolators and undersized wiring etc.

 

cheers, Pete.

~smpt~

Edited November 22, 2013 by smileypete

[Arthur Brown]

Does your current installation have one or two belts? V belt or polyVee? With one single V-Belt you could be up to the belt's power transfer limit coming close to very short belt life. Two vee belts or a polyVee and things are better. Simplest plan would be a manual switch so that you can charge both batteries then when the starter battery is full transfer it's generator to the house battery.