Charging System Advice Please

[bigmart]

The Alternator on my Boat is knackered again. This is the second time in two years.

I've got an old Old Yanmar YSE12 engine that still runs well. This has been fitted with a Lucas 35 Amp car Alternator. My boat is equipped with a 95Ah Engine Starter Battery & a 105 Ah Domestic Battery. At present there are no fancy charging circuits just a simple change over switch.

The Regulator (Built into the Alternator) keeps packing up which leads me to conclude that the vibration & operating temperature of the Yanmar are too much for a feeble car alternator to take.

I went to SBS & got various prices from £400 to £550 for a marine job with a separate regulator pack & maybe split charging setup.

Are these posh jobs really worth the money, considering my fairly meagre power requirements, (Lights Radio Nav Lights etc. No fancy fridges or Nav equipment)? or can anyone reccommend a simpler system that will work reliably.

Ladies & Gentlemen I am in your hands.

Martin

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[steve28]

For starters i would go through the main pos and neg cables and check for faults. I would still go for the same type of alternator but maybe a 50 amp one.
Depending on how much you want to spend maybe go for a charge controller as well so it controls the output.
The stirling one i have has the ability to totaly disconect the charge if there is a fault.

steve

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[halcyon]

Do you change-over from one bank to the other with engine running?
Is the change-over switch make before break?
You could be getting spikes that are killing the reg.
If it's a ACR you could remove the reg and mount seperately.
Lots of options yet before mega bucks.

Brian

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[Robin]

Martin

The key question to resolve is why the regulators keep blowing, heat and vibration I doubt are the cause, is there perhaps a waterleak onto the alternator? The simple changeover switch you mention could be a culprit, it is essential that when you switch from one battery to another at NO stage is there not one of the batteries connected to the alternator, if there is a momentary disconnect of both batteries the diodes will blow. I am assuming that you do not switch from battery #1 to battery #2 by going via 'off'.

You could spend a lot of money as you have researched at SBS and you will certainly have a more powerful charging system, but if the root cause is not eliminated you could just be blowing up more expensive gear.

Robin



<hr width=100% size=1><font size=1>Sermons from my pulpit are with tongue firmly in cheek and come with no warranty!</font size=1>

 

[Gunfleet]

When I fitted my adverc I went from a 35 amp Yanmar (Hitachi) alternator to an 80 amp Lucas/Prestolite car type. In other words, the type of alternator shouldn't really make a difference. Have you had the alternator repaired by an auto-electricia?. A good one will be able to tell you what was wrong (unless it's in your boat wiring, which he won't have to hand). Mine told me I should go for the Bosch next time mine goes. Why? Because they're fitted to Fords and there are loads of really good 2nd hand ones sitting in scrap dealers. By the way I think your alternator is supposed to be rated at abt 1/3 of the amp/hrs of battery you've got on board, so I think the 35 amp Lucas is probably quite a bit too small for your setup anyway.

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[sailorman]

I used to have a YSE 12 & i fitted a Lucas altenator, the only trouble i ever had was due to "smart chargers" as the alternator used to overheat.
no s/charger no probs.
the point raised regarding change-over switch is relevent

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[bigmart]

The reason that I considered vibration to be the cause of the problem is that I took the Alternator to pieces & found that one of the Diode connections had broken. I re-soldered it & it appeared to work for a short time. The next time I used the boat I had trouble getting the Charging to kick in. I revved the engine to maximum, fiddled with the connection on the back of the Alternator, this had been checked & re-made when I dismantled the Alternator, the charging appeared to kick in. Being a trusting sort of person I checked the Charging with a digital voltmeter. The analogue meter, on the boat, showed a charge of 14 Volts or so. The digital meter showed No volts with the charger kicked in but a healthy 13.2 volts without the engine running. Any ideas?

BTW At no time has the engine been run without a battery connected.

Martin

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by bigmart on 21/10/2004 18:15 (server time).</FONT></P>

 

[roger]

I hate C/O switches. They are only satisfactory if neither you nor your crew ever nake mistakes even when seasick, tired or drunk. With a diode splitter and a system that senses battery voltage you would not have to use one thus ending the problem. Perhaps someone can tell us whether with a new type low loss diode splitter you even need to sense battery voltage.
With very high voltage at the alternator caused by momentary disconnection you might well blow the alternator diode stack. I dont know if wrecking the regulator is as likely.
I made my alternator run all the time at max voltage output until I started boiling th ebatteries by means of intermittent spikes so maybe that is the most likely problem area.
Its well worth as suggested already checking wiring quality but you might also check if the engine compartment gets really hot.
The usual recommendation for alternator rating is 1/3 of the total battery capacity which would mean a 60 amp one.
Smart regulators get more output out of alternators thus increasing loads all round; belt load, charging currents, alternator bearings etc. I've got one so I do try to keep spare drive belts on board.

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[Robin]

Martin

It seems perhaps that something had happened to break the diode connection, but whether this was mechanical or electrical is open to question. It also seems that something was still wrong because when you 'fiddled with the connection on ther back of the alternator' it appeared to kick in. This is tantamount to not having a battery connected (bad connection) and it seems if it DID start to work, it promptly blew the diode again. I'm not sure what you are measuring where with the analogue'digital meters, but you should see 14.2v at the alternator (on charge) and hopefully at the battery too. Off charge just after charging (ie engine off OR regulator blown) the battery will probably show 13v+ but this will drop back as the battery rests, 12.6v-12.8v is a full battery.

I know you say it hasn't been run with the battery disonnected, but please understand this can be unknown to you, some 1/both/2/off switches can break the connection when being switched from 1 to both to 2 albeit momentarily and that will do the damage nicely. Do you always make the changeover yourself or does a crew member sometimes do it and make the change via the 'off' rather than the 'both' route? Sometimes you will get away with a momentary disconnection sometimes not, sooner or later you will not!

I don't believe heat or vibration are to blame personally, there is another reason out there to be found IMO. One failure is unfortunate, several indicates a fault.

BTW I see Halcyon replied too and he is very knowledgeable on such matters, he may well be able to add to the list of possibles.

Best of luck

Robin



<hr width=100% size=1><font size=1>Sermons from my pulpit are with tongue firmly in cheek and come with no warranty!</font size=1>

 

[toad]

Check the rotation of the alternator as with a YSE12 the direction of rotation is opposite to an ACR alternator. The alternator will still work but the cooling fan will be blowing and not sucking and could overheat if its working hard.

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[sailorman]

i now have fitted a c/o switch to enable "access" to the engine batt.
the domestic batts r charger via the engine batt controlled by a relay that is controlled by alternator voltage & assume the relay was fitted when boat was new.

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[Guest]

My old Perkins 4-99 had a 'car 45 Amp' alternator. I bought boat over 7 yr ago and it was still a 'charger' when the engine was ripped out early this year.
Replacement 4107 engine had no alternator - so mine was duly bolted on...... given a slight mod to fit. Susequent trials showed the charge to be very weak and due test carried out in bench by service eng'r. He changed regulator and its charging better than ever ! In his words - nought wrong with that mate ..... good'un. no need to spend on another .....

So I would suspect the alternator may not be the best condition. As I understand it - the capacity of the batterys shouldn't cause trouble - just increase charge time req'd.

What about exchange alternator .... and up the rating at same time ??


<hr width=100% size=1>Cheers Nigel http://groups.yahoo.com/group/gps-navigator/ http://groups.yahoo.com/group/searider/

 

[oldharry]

Sorry - dont understand how you got a no volt reading with the engine running. Was this across the alternator output, or across the battery terminals - or where? The battery should have continued to supply a voltage even if the alt was dead.

However spurious readings suggest there is a bad connection somewhere. With the engine running, and the alt charging, connect your digital meter + lead to the alternator output terminal, and the dvm - lead to the + pole of the battery itself (NOT the battery connector). If you read more than around .75volt, then you have a bad connection. Repeat the process between the alternator metal body, and first the battery - terminal, then bare metal on the engine block.

If there is a voltage difference along the lead, then you have bad connections - almost certainly what is blowing your alternator. It only takes a moment of disconnection on a loaded alt to blow the electronics!

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[Graham_Wright]

Just what does the alternator need to see to constitute an acceptable load? Does it need to be a voltage reference or will an indicator light/fridge/bilge blower etc suffice? Any of these could be permanently connected to the alternator to avoid no-load over-voltage.

<hr width=100% size=1>GBW

 

[fishermantwo]

Marton,
The first thing I would do is pull apart your rotary battery switch. I used these for years and even the expensive ones were crap. The brass plates that slide behind the switch eventually come loose so that the switch eventually does not make before it breaks and this will kill the diodes. I now use a pair of knife switches I made myself. My fishing vessel is Gardner powered, the alternator is a Bosche off a 6 cylinder Ford. Cheap and easily repaired. Make sure the alternator is spinning fast enough, car alternators need to be spinning between 5000 and 15000 rpm. It also has to have a "dash" light, 12v supply to flash the fields to get the alternator to start charging, it should start charging while the engine is at idle.

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[bigmart]

The voltage readings with the digital voltmeter were taken across the Battery terminals. I was guessing that the no volt readings were caused by the un-rectified output (presumably AC) cancelling out any voltage present from the batteries.

For those asking questions about the change over switch this can be discounted. The boat is also fitted with cut out switches on both batteries. I am the only person who switches the batteries over & for the past year or so I have been using the cut out switches to do this ie. connecting both batteries before disconecting the other.

The broken connection on the diode pack seemed to be a fatigue break rather than one caused by an over heating fuse type break.

BTW thank you all for your interest. The replies are quite thought provoking. I am sorry if I keep feeding in extra data but I was trying to keep the original post as simple & direct to the point as I could.

Martin

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[Robin]

I don't know, though someone surely will. There are devices you can connect to the alternator to protect it, one I saw somewhere was I think called a Zap Stopper but I dont know how it works.

<hr width=100% size=1><font size=1>Sermons from my pulpit are with tongue firmly in cheek and come with no warranty!</font size=1>

 

[sailorman]

a permanant live to say vhf, stero memory, or similar does help ( i think)

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[andyball]

A number of even quite good quality digital meters suffer from interference in certain conditions ( usually, running the very engine that you need to test!) causing zero or spurious readings, & that may be why yours showed 0 volts until the engine was stopped, then 13.2V which certainly suggests it was charging just beforehand.


& no, don't think you need to spend £500 to get a reliable system.

 

[William_H]

If you had a failure of diode wire in the alternator I doubt you could do a permanent good fix with solder. Most of those connections are spot welded or crimped. Suggest a new diode pack or alternator. Did you say it is a standard auto type available from S/H source? Thats the way to go. As for failure of the regulator i imagine that is the the type with the 2 brushes to the sliprings as part of the regulator.
They give very little trouble and failure due to old age is due to wear on the slip rings or the brushes. An electronic failure of the regis almost unheard of but may be due to battery disconnection. I doubt that heat or vibration would cause the problem. I don't expect you need a high current alternator. Unless the batteries are stone flat you would never approach the rating of the alternator and then only for a short while. The high rating of the alternator is for operating loads asin a car with headlights heater aircon all that stuff. You do not see large loads on a boat unless you have a fridge so stick with an alternator that is cheap. The charge controllers are to enable you to charge large batteries in a short period of engine running as in liveaboard on anchor so unless you really want to quickly recharge batteries the standard car type system is ok and cheapest. (there might be disagreement here from those who use them, me I rely entirely on a 5w solar panel) don't spend money regards will


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