Electrical/chargiing question?

Dougal

Dougal

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I've been looking at getting a better charge from my alternator, but alas, have just become confused as a result /forums/images/graemlins/confused.gif

What's the difference between alternator-to-battery chargers and advanced alternator regulators?

On this subject, whilst in France last year, we fried the alternator and had to have another fitted (t'was VERY old anyway). The replacement (75Amp) has no branding marks at all. Just.... Made in Slovakia!! We paid way over the odds for this too. Do folk think this is it likely to be pile of %^&$
 
Your best bet for a trouble free charging system is ADVERC. Great guys who are really interested and will give you all the help you need. Have one of their systems for 9 years now...perfect!

www.advercbm.co.uk

Cheers
 
Have a Sterling advanced regulator, in use/abuse for 7 years now - absolutely no problems! /forums/images/graemlins/grin.gif
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hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
 
Yep! Adverc for me too. Definitely the best alternator control system currently available IMHO. Totally agree re the back-up too - excellent people to deal with no matter how 'dumb' the questions!!! /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif
 
As you have already started to see, you will receive a number of replies along the lines of "I've an X which has worked brilliantly for Y years", and "Zs are best". There are indeed several manufacturers of "advanced alternator controllers", "alternator boosters" etc. all of which seem to work despite their variations and each having its own following.

One of the difficulties is that there is no universally agreed nomenclature which ties a particular terminology to a particular technology. You have to look at individual manufacturers specs. to see exactly what is being offered. They should all as a minimum provide a high voltage to a battery with a low charge, and a sufficiently low voltage to a fully charged battery that can be sustained without damage. Within these limits there are various strategies employed to speed up charging: voltage is cycled to a pattern based either on fixed time intervals or sensed voltage or a combination of the two. Some measure the battery temperature and use this to vary the voltage, cycle time, or both. Some "ramp" up the voltage to avoid immediately imposing a heavy load on the newly started engine, some build in a fixed delay for the same purpose, some don't bother.

Which is best overall? Who knows - there's a "product comparison" article in the making here...

Most require the connection of an addional wire to one of the alternator brushes. To finally get round to answering your direct initial question, IIRC Sterling use the term "Alternator to battery charger" to describe their newer product which does not require an internal alternator connection. This clearly simplifies installation, but the unit is quite a lot dearer.

And, just for completeness, I bought the Merlin AMS and it's worked fine!
 
I think you will find.......

...that the forum is split in the same way as Swift's Brobdingnagians were split over the merits of opening one's breakfast egg at either the large or small end.

In one corner we have the Advercs. Fine traditional men who trust older technologies, Rover cars and condoms make of fine Dunlop Rubber.

In the opposite corner we have the desciples of the venerable Charles Sterling. His dedicated followers are more towards newer technologies, ones proven in the toughest proving ground of all (nautically speaking) vis. the US leisure boating market.

it is acknowledged by the senior prophet of the Advercians himself that his device "...does not BOOST the charge" (I heard it from his own lips in the last few minutes of the last day of the last pilrgimage to the Court of the Earl.)

However Vnlb. C Sterling will berrate you about the advanced capabilities of his machines and, to those with new- still under warranty engines the VERY IMPORTANT feature, that you don't have to have extra sensing wires soldered on to the alternator brushes as you do with his lesser machines and ALL of those black boxes of mystery so cherished by the Morris Minor Owners Club Afloat - the Advercians League!.

siisal.gif


So to summarise the beliefs of the two sects:-

If you want to turn your alternator from machine sensing, like a car in that it automatically regulates the alternator output to offset that which is being taken by the various loads and give a "bit extra" for charging, to battery sensing, by which it measures the battery voltage and runs a pre-set (but unalterable to suit varying conditions) stepped charging regieme - then pick an Adverc.

If, on the other hand you want to make your alternator work at maximum efficiency (ENTIRELY within it's design parameters), have this monitored AND have the staged charging intelligently controlled through all it's stages, have battery temperature and alternator temperature monitored so that, should circumstances like dangerously high ambient temperature, too high a loading or a failing battery threaten to put too much of a demand on your alternator, when the software steps in to return you to "Standard Regulation" until the situation returns to within normal limits -then a Sterling is for you. For someone like me who sails in the Med and whose on-board systems demand a lot of refrigerator running, a power windlass and other various high power usage, the STERLING is the ONLY choice.

Oh yes, a motor car analogy to the Sterling? well a BMW Z4 might just fit the bill.

Z.jpg


Steve Cronin
 
Re: I think you will find.......

The first question you should consider is "why". Is the alternator not up to the job - Ie 75 amp = about 60 amp hours /hour due to lack of efficiency ( a notional value). How much are you trying to replace in how short a time? Smart controllers are good ( sterling for me ) but can't do magic if the basic sums are wrong. You can temporarily wire the alt to look like it's 'smart' (short the regulator- that's what these controllers do) to see how much it's actually capable of giving - and how good it is at cooling itself while it's doing it - and how strong the fan belt is - and how warm the wiring loom gets - and how much your poor old batteries enjoy getting a real charge. As you can see, there could be a lot to this depending on what you've actually got at the moment. Good luck !
 
Re: I think you will find.......

Don't short the alternator, by which I assume you mean delivering the full battery voltage into the rotor unless you want to burn the thing out.

It is a FACT that ALL cruising boat alternators sense incorrectly for their purpose. What is required is a generator that will replenish the batteries in the morning following a large overnight discharge as soon as possible before the engine is switched off and sailing re-commences.

If you only run loads when the engine is running then a car type regulator, as fitted to ALL standard marine engines, from birth, (why?) is perfectly satisfactory. However in a yacht or even a serious cruising motor boat, demands like fridges, lights TVs, windlasses etc are used overnight and possibly all of the following day and their consumption needs to be put back and quickly. A machine sensing regulator, no matter how high the POTENTIAL output of the alternator is, just cannot accomodate this so without the luxury of a permanently installed (or even a suitable suitcase) generator, you have to rely upon your main emgine's alternator to provide the source of replenishment. For this it needs to be controlled in the most efficient way. And YES, the drive belt WILL be put to the test as will the robustness of the alternator itself. in my view set-ups like the Sterling controllers do this in the most optimal way.

Steve Cronin



Steve Cronin
 
Could be anything.

There was a time when we thought "Femsa" Spanish electrics were, well, "Uncertain". Now they're part of the establishment.

My wife's Ford has Czech "Continental" Tyres as Original Equipment. Seem OK.

I'll sniff around about Slovak electrics and get back

Steve Cronin
 
Re: Could be anything.

High Dougal. Just because you are not familiar with the non branded Slovak alternaor doesn't mean it is not good. Or at least as good as any other mass produced alternator.

Battery charging is done by presenting a voltage to the battery. The amounnt that voltage exceeds the inherent battery voltage (depending on charge state) dictates how much current goes into the battery. So a flat battery will have a great differential between the 11.5 volts of the battery and the alternaors regulated 14 volts. Lots of current goes in and the battery voltage rises so current falls.
Unfortunately the battery voltage rises quite quickly compared to the actual amount of charge in (amp hours) the battery.
So you might get 20 amps in initially but this fairly quickly falls to about 5 amps or less. if you still need 50 amp hours to fill the battery you have a long wait.
So smart chargers increase the regulated voltage of the alternator to eg 15 volts which gets a lot more amps in. The trick as already described is for the controller to know when to reduce the current because the battery is full and so to accomodate further engine running.
So it is not that the alternaor is not up to the job but rather that at the standard setting of 14 volts which is safe for long term running (as in your car) the battery will not take much current so takes a long time to charge.

The concept of shorting the regulator ie full battery volts to the field coil in the armature is not really so silly. You would have to have an ampmeter in the alternaor to check actual charge current and a way to adjust the field current to get the charge current you want.
In theory the internal resistance of the alternator coils should automatically limit the current by having the output voltage droop at current near it s rating. However because alternators do not usually run any where near their ratings it is likely you could get a failure from overheating or even belt drive failure. (get a spare alternator) So far safer is a large rating alternator run at half of rating than a small one run at full ratings.
Note that at the voltage you would need on the battery to get the charge in you may damagee other electronics or lamps if they are used at the same time.
This manual voltage regulation setting (actually more like current setting) could work well for an engine run of say 1/2 hour. But it is not automatic and if the battery gets too much charge overheats and boils there is no automatic cut off.
If I had an engine driven alternaor and a refrigerator on a sail boat I think I would set up a manual regulator control perhaps with a timer to revert to normal safe 14v regulation after a period like 1/2 hour. In the meantime back to relying on my 5 watt solar charger... olewill
 
I reckon that there are......

... more tales of woe from those following this course than success stories.

MANY years ago, there was an article in PBO by a bloke who installed a three way rotary switch in his rectified circuit. First position was normal machine sensing. Second was with a resistor in circuit which gave about 80% of battery voltage into the rotor and the third was full voltage. See - itisn't a new idea at all.

So many people forgot to switch down or were distracted at the vital time that battery boiling and alternators de-soldering themselves were common.

Fine theory but in PRACTICE an automatic device Is the only answer. Would you leave your washing machine to run indefinately or rely upon remembering to switch it off? What happens when you rremember that it's still running with your wife's delicates in it at full boiling power when you get to work?

Steve cronin

Steve Cronin
 
Re: I think you will find.......

[ QUOTE ]
...that the forum is split in the same way as Swift's Brobdingnagians were split over the merits of opening one's breakfast egg at either the large or small end.

In one corner we have the Advercs. Fine traditional men who trust older technologies, Rover cars and condoms make of fine Dunlop Rubber.

[/ QUOTE ] Nice one Steve!

Or like the split on anchor types, every man saying 'his' particular anchor is perfect for someone else's task . . .

There is clear evidence (and physics) demonstrating that if your electrical load period takes place at a different time from your charging period, you'll be much better off with an intelligent charger/regulator, ie, one that senses battery voltage while charging and tailors the alternator output to charge far more efficiently than a car type regulator can.

There are many such efficient regulators, all major improvements. Some have more bells and whistles, some cost more, some are more difficult to fit. These are trivial differences compared to the step improvement.

Unlike anchors, which cover a wide spectrum, some working well, and at the other end, some which have to be twice the weight to do a worse job . . . but are still perfect in the eyes of the owner.
 
I have had an Adverc instaled for the past 3 or 4 years and have to say that I have in reality noticed almost no difference at all in my 'state of charge' pre and post fitting. BTW I know it must be working okay as I had to put considerably more tension onto the alternator belt to avoid slipping.

If I was to do this again I would save the money and put it towards a wind generator.

Regards Nick
 
There has been a lot of very sensible and accurate stuff written in reply to the original question, but the one thing that always needs to be checked in alternator-battery-charging questions is the question about the whole discharge-charge equation.

The bottom line is the obvious one that if you use energy out of your battery bank, it needs to be replaced. A sailor I know, installed a new plotter a couple of years ago and after sailing the channel had a completely flat battery. Not only had he not worked out how many amp-hours his new system was going to use, but he also said to me, "I knew the battery was fully charged as we'd motored down the river before the channel crossing". The motoring down the river took half an hour, and there was NO WAY that his battery was fully charged from this amount of motoring. (He has the original internal alternator regulator still fitted).

I am a great supported of 'clever alternator controllers'. With a good alternator and a good control system (and adequate wiring) you can improve dramatically the time it takes to recharge your batteries. You can't do the impossible though, and it will still take some time to get the batteries back up to near full charge.

We use a Sterling - although I have no problem with other regulators. It certainly speeds things up, and with the battery monitor I know exactly what is happening. The monitor happens to be Sterling as well, and shows current in, current out, voltage, and Amphours used from the domestic bank. As the batteries recharge, the Amphours used deficit climbs back towards zero, and what the system really shows is just how long it takes to FULLY recharge a battery.

Not sure if this helps - but its really a reminder to make sure you are asking the right questions when you look at the charge-discharge equation.
 
[ QUOTE ]
Which brings up the next point - it's just as important to have a good and easy to use 'charge' monitoring system as it is to have an intelligent charger

What method did you use to monitor your charge state?

[/ QUOTE ]My verbose reply was superceded even as I typed it...!
 
Hey thanks so much for all this detailed and useful info. Folk have taken time here - much appreciated.

Although a terrible mathmetition, I did use a good reference chart to work out my Amp/Hr needs. When considering the 40% safety margin for batteries, my boat is however, close to overloading the supply. I have one high quality 108A/h cranking battery, kept ONLY for engine starting, and two 105A/h deep cycle domestics. Another would be nice, but would require some major surgery on the boat!

There is only a simple Ampmeter/voltmeter on the control panel, so i must manually check the batteries for health and status.

I have a good 40Amp 4 step mains charger for when alongside, and this looks after them nicely. When away from my berth though, the batteries are never FULLY charged. Although a motor-sailor, with a beefy motor and 75Amp alternator, the engine simply doesn't run long enough to finish the charge.

As mentioned earlier, I also MUST upgrade the charging circuit cables. That circuit was built with a 55Amp alternator in mind! When the new one is running at full tilt, the wires can get warm!!!!! Think I'll do BEFORE anything else, not only dangerous, but guess i'll be lossing power to make that heat.

I'm pretty sure we'll have to bite the bullit, and get wind generator! Will say pretty please to the bank manager!? I rather fancy the Rutland 913.

Thanks all
 
Re: I think you will find.......

Very nice analogy. This question about charging rates never seems to answer my simple question.

take a 100 ah battery, new condition at 50% charge condition. How long it take to recharge completely using a 55amp alternator fitted with Mr Adverc and How long with Mr Sterling fitted. The answer to that will soon tell you what you want to know. Anyone know the answer
 
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