alternator controllers reviving the debate

[LeonF]

I know this has often been covered, in depth, but can I have a simple answer please. New boat --2x 85 AH batteries. One engine the other domestic. Both ordinary flooded cell . There is an A,B,Both switch and split diodes. I understand that the alternator charges whichever needs the most charge first, sensing until they are both matched. is this right ? Also that I must switch to domestic when sailing or risk draining the engine start batt. Engine is Volvo 2010 with 60Ah alternator wich I have been told has an internal temperature sensing facility. I have no idea of the benefits of this or otherwise. I would like to double the battery capacity (domestic) and install a intelligent controller. I had an Adverc on previous boat but may have had compatibility problems when I switched to AGMs so switched back again. The installer I use swears by Adverc , but reading a long thread started way back in February would I be better of with a Sterling ? I tried asking at the boat show but got conflicting advice. Don't dazzle me with science please- I know a bit about sailing but not a lot about electrics! I have electronics-instruments, chart plotter, small eberspacher and may get a fridge sometime. Only a manual windlass.

<hr width=100% size=1>L.A.R.Ferguson

 

[halcyon]

Simply, the answer to the first part is no. Current always takes the least line of resistance, the lower capacity battery will have a lower resistance, thus it will take more current until it's resistance is equal to the other bank. There is nothing deciding what goes were.
Unless it's a battery sensed alternator you will need to change the regulator to compensate for the voltage drop in the diodes.

Brian

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[LeonF]

Thanks, but for the current to take the line of least resistance should I turn the selector switch to both or risk not charging the domestic battery? What is the purpose of the diodes ? I was told that it didn't matter what setting the switch is on while the motor was running.

<hr width=100% size=1>L.A.R.Ferguson

 

[halcyon]

I would imagine that the starter runs throught the 1,2,both switch, the alternator runs through the blocking diodes, so the two systems are seperate. The blocking diodes allow the output from the alternator to go to both batteries, but does not allow current to flow back, they are like one way valves.
The problem is that they drop .7 - 1.2 volt, reducing recharge level to around 50%.
If you alternator runs around 14.4 volt you can fit a relay instead of the diodes, or you fit a seperate regulator to get round the volt drop.

Brian

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[William_H]

Further on Halcyons comments. You need a digital voltmeter to measure the voltage at the battery terminals when the engine is running. This should be 13.75 to 14 volts. If it is then the voltage drop of the diodes is being compensated for by the sensing point of the regulator or a higher voltage setting of the regulator. If the voltage is only 13 volts after a good charging period then someone has fitted the diodes without consideration of the volt drop hence the batteries will not fully charge. You could fit a voltage sensing relay to paralell the batteries when charging or fit a regulator designed for this situation. ie sterling etc. I find it difficult to imagine from a technical point of view how one alternator can charge 2 batteries so as to automatically treat them individually as to their charge level or capacity. I reckon 2 batteries in paralell should see the lower voltage battery ie most discharged take the charge until it's voltage equals the other where charge should be equal. A larger battery will take longer to charge untill it's voltage rises to that of the alternator.
Regarding your battery switch you should always start the engine on only one battery preferably alternating between the two from day to day. Assuming your domestic services are also switched to the same circuit as the engine if you discharge that battery you will have a fully charged battery for starting by selecting to the other battery position. The diodes will ensure that both batteries are recharged regardless of switch position and alternating from one to the other ensures that each battery is capable of starting the engine The both position then is an emergency position if neither battery alone will start the engine. Note however some say you should not fully discharge the battery because it will shorten it's life.

Now the problem with charging the batteries with the engine is that the current put into each battery is a function of the difference between the alternator regulator voltage and the battery voltage. A flat battery takes a lot of current but as the voltage rises (as the battery fills) the current falls so that theoretically you never fill the battery and the last half of the fill can take forever. A smart charger regulator will increase the alternator voltage to push more current in even near fully charged level however this needs to be carefully managed because once the battery is charged more current can damage it. Hence the original system as in a car is set at 13.75 volts it will not charge it too quickly but will not overcharge or damage the battery long term. regards will

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[halcyon]

Most modern alternators are regulating at 14.4 / 14.6, and the odd one at 15.+ something.
Once you have reached 14.6 volt the voltage curve rises sharply to nearly 16 volt, the current put into the battery is small, gassing though is very heavy.
As a rule of thumb, a flat battery on charge is 13.0 volt 13.5 volt is about 50% 14.6 volt about 80 / 90 % charged, varies with type, age, temperature, air pressure, and a number of other bits.
The second problem is that most yachts only motor for short periods ie as soon as sails can be reaised, this means that unless enough running is done you never get to the point when a smart regulator can do any work. That is unless you have blocking diodes, when you need the extra output voltage to compensate for the volt drop.
Some sealed batteries ( Delco Freedom ) need to charge to the higher level in normal ( or did in the 1990's when they came out ) due to there differant construction, so check what a battery needs, and what you have before changing battery type.


Brian

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[LeonF]

Brian, does 'never get to the point where they can do any work' mean it is pointless to get a smart regulator if one only motors for short periods ? The Adverc and the Sterling seem to have very different features, the Sterling many additional ones. I was hoping someone could make an informed response. Perhaps its time PBO ran a major testing comparison as there are also quite a few others on the market.

<hr width=100% size=1>L.A.R.Ferguson

 

[halcyon]

For a smart regulator to do any additional work you have to get to the point were the standard regulator started to limit the voltage. Therefore if you have a regulator that's running at 13.6volt, or blocking diodes and a machine sensed alternator, you need to increase voltage and they will help. But if you have one that runs at 14.4 - 14.6 and a split relay you will not gain a lot in normal yacht running.
If like me you motor out of the moorings and put the sail and turn the engine off you do don't gain anything. Depending on battery size and alternator size, it can take sometime to get to the regulation voltage, it only then that you start gaining.
The trend now is to start pulse charging after this time ( introduced by Hella for cars in the mid 90's and retailed for around £60 ) it any then that you start gaining.
If your regulator is running around 14.4 - 14.6 volt you'll not gain a great deal, it's the old story of a quart out of a pint pot.

Brian

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[Heckler]

scenario
easter weekend, binlids want to socialise in marina in pwllheli. move off piles and get to marina, plug into shore power. fridge on, eber on, lights left on 12v tv etc.
next morning go to start engine off domestic bank which has been powering us all night. nothing!! check voltage on meter, 10 volts aaargh. check mains 4 stage charger and find out that it hasnt kicked in. it plays silly buggers now and again.
the batteries are 2 * 60 amp sealed ones. the popular theory is that the batteries would be half charged and need 30 amps each to bring them backup. have fitted a sterling voltage regulator so switched to the other bank and started the engine, charles sterling told me that the 60 amp alternator will put out 60 amps with his regulator. i then ran the engine for just over an hr and sure enough the batteries came back up to capacity giving me time to fiddle with the merlin mains charger.
bottom line is the sterling works for me
stu

<hr width=100% size=1><A target="_blank" HREF=http://www.beneteau-owners-association.org.uk>http://www.beneteau-owners-association.org.uk</A>

 

[LeonF]

Thanks for your advice a while ago. I monitored my batteries yesteray and they charge at 13.6 ish at around 750 revs and 14.1 at anything higher. I suppose the Adverc will help as it cycles higher than this. No battery probs at the moment but they are two 80 AH and I haven't used the autohelm etc for extended periods. Will probably add another in the winter.

<hr width=100% size=1>L.A.R.Ferguson

 

[TonyBrooks]

Leon

You have had a lot of very good advice of rather better quality than questions about advanced regulators usually get.

However no-one appears to have answered your question about Sterilng v Adverc.

Both, I am sure, will do the job, but from the feedback I get from my students I am afraid that there does appera to be a difference in customer facing skills.

From my observations Sterling appear to be classed as rude and not very helpfull rather more often than one would like, Adverc, on the other hand, is usually classed as very helpfull and obliging.

My one observation is that the Institute of Road Transport Engineers did a sort of Which report on such systems a number of years ago, giving technical details etc and leaving the engineers to make up their own minds. In my view this clearly showed Adverc as the superior product.

Since then Sterling have introduced their Digital unit. Now, untill I am told differently, I understand that EPROMS and EEPROMS have a mean time between failures of about 15 years. This means that some will fail well after this and some will fail well before. I do not fancy trusting my charging system to a memory device that the supplier gives no info on re-programing and who has indulged in some rather less than totally truthfull "knocking" advertising.

You pay your money and take your choice. I chose Adverc and would still choose Adverc, despite the cost implications.

Not sure this helps much

Tony Brooks

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[steve_cronin]

Rather sweeping?

"From my observations Sterling appear to be classed as rude and not very helpfull rather more often than one would like, Adverc, on the other hand, is usually classed as very helpfull and obliging.
"

In MY experience Charles Sterling is a very talented designer (and a boat owner himself) who will speak - in a rather agitated Ulster accent I have to say- to anyone who needs advice and help. On the other hand the nice old gentleman at Adverc admits that his unit is "old technology" and "...if you want to get your batteries up to full charge as quickly as is safe" then "...our unit mightn't be for you as it is no booster"

You also have no justification for insinuating that the Adverc FET & diode system is any more reliable than the well engineered Sterling units. In fact, with the Adverc, you have to disconnect the unit yourself if it fails whereas the Sterling automatically reverts to the existing controller if one of several fault conditions manifest themselves. Indeed, with their latest unit, unlike the Adverc and the other two Sterling units, YOU DON'T HAVE TO CONNECT INTO THE ALTERNATOR WIRING AT ALL nor solder on any wires to brushes where there is hardly space nor drill any holes in the brush box, so your warranty isn't at risk. Also, "15years mean failure rate" is greater than that of the alternator so what point are you trying to make by your comments on this?

PersonallyI don't find C.S's odd "'effing" and "bloody s..ite" at all offputting because he doesn't shy away from saying it as it is. There is indeed a lot of old tatt out there, but your posting Mr Brooks looks rather biased and quaintly "old British" to me - if I may be so bold!

Steve Cronin

<hr width=100% size=1>The above is, like any other post here, only a personal opinion

 

[steve_cronin]

I agree with everything you've said.

Only one point worries me. The (Merlin) charger didn't "...kick in"

How come? If it's the french Dolphin sold by that company it would have gone to "boost" on connection to a 240 supply and then to "float" after 6 or so hours (dependant upon how you initially set it up) Could you explain?

Steve Cronin



<hr width=100% size=1>The above is, like any other post here, only a personal opinion

 

[TonyBrooks]

Re: Rather sweeping?

I deal with over 100 boaters each year and get to hear all their tales of woe and the interction between them when they discus various topics - advanced charging systems included.

I simply reported what I hear as no-one else had made any attemp to answer that particular part of the original question.

My only knowledge of Sterling customers service is via my students and comments (addmittadly self selecting) on other news groups/forums. I made no comment about Mr Sterling himself.

You have made no attempt to counter my argument abount MTBF of digital memory devices, and I would point out that unless things in the semi-conductor industry has changed I always understood that once "infant mortality" was overcome non-digital devices were likley to be extemely long lasting.

I challenge you to explain exactly how the Sterling unit can short out (because thats what these things do when they raise the charging voltage) the alternator's own controller without a connection to either one of the brushes or the internal wiring. Any particular alternator may be difficult or dead easy to make the connection, but unless we are dealing with some new, undisclosed technology, connect it we must.

I am pleased that you are happy to leave an admittadly failing device to its own devices to protect your electrical system (I have had about 140 volts out of a 12 volt alternator - what would that do to your other electronic equipment), but I view it as a distinct advantage to be able to physically disconnect the failling device if either my voltmeter or teh inbulit warning lamp indicates a fault.

I am sorry that you find my attempts to couch my post in a way that implies a certain unwillingness to accept certain hearsay as 100% true not to your likeing.

I would also state that the fact that someone is a boater does not imply their products are in any way superior, they may or may not be. I think that scrutany by proffessionals in such diverse areas as the ambulance service, mobile classrooms and showrooms, transport with electric regfrigeration and tail lifts to be just as valuable.

I detect a bit of personal interest in your post, if so tell your friend to have a hard look at his customer service area and also the ethics of his advertising.

Tony Brooks

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[LeonF]

Thanks Tony for your reply. I didn't mean to get the whole thing going again and was merely thanking William H but I appreciate your response, and the responses you triggered. My local installer who installed an Adverc on my previous boat refuses to supply the Sterling. Says he will fit it at my risk but cannot be held responsible for failure and associated costs attached to its rectification. I had some doubts over the Adverc when used with AGM batteries-- long saga, see previous postings, which I put down to a basic incompatibility and inability to set the Adverc for these batteries. Adverc tried to be helpful but I never had a totally successfull conclusion to the problem, but returned the batteries and managed to get a full refund. I reverted to standard lead acid batteries. It must be trying for Sterling to fight their corner if they are proposing new technology which gets refuted, but then I am no technician and rely on the expertise of others. I have however heard plenty of complaints against the Sterling but none against the Adverc other than accusations of being old hat.

<hr width=100% size=1>L.A.R.Ferguson

 

[halcyon]

If the battery is reading 10 volt, they are flat, and need 60 AH each, therefore 120 AH, so your 60 amp alternator must have charged 120 amp. Sure you have not got surface charge, how did you measure that they are full?

Brian

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[steve_cronin]

Response to your challenge....

As I only have a few minutes before going home to light the BBQ, I'll be brief.

The Sterling advanced controller puts a dummy load on the alternator which fools it into increasing it's output but this is sadly at a lower voltage than is useful to charge a battery. A voltage "Amplifier2 is then used to increase this to a useful charging voltage.

As to Digital devices being les reliable than analogue or simple transistors, I'll say one word:- HEAT. Also if you really believe this, go tell it to Ford, BMW, Mercedes, Cessna Corp., Yamaha, Honda, Boeing. All use digital devices as do heart pacemakers. I repeat the alternator itself will have it's brushes wear out long before 15 years of use are up, not to mention the bearings or the rectifier.

Oh Yes,

Although our fathers were born on the same island (but at opposing ends of it) I have no connection with Charles Sterling except that we happen to keep our boats in the same marina. We have never met and I'll put your seemingly snide insinuation that I have some commercial connection with his business down to unfortunate mis-typing.

Steve Cronin

<hr width=100% size=1>The above is, like any other post here, only a personal opinion

 

[howardclark]

Ok here's my twopenny worth.
I had a similar problem when buying my boat - getting a proper comparison between Sterling & Adverc is very confusing. I wanted to have more domestic power, protect my engine start battery from being depleted and from my 4 daughters who have never learned to switch anything off.
I made the following choices:-
Replaced the (well worn) batteries with AGM - reason - they would take the Adverc charge and were much smaller than the old batteries so I could have more amps in the same space. They can also be exhausted without permanent damage.
Got rid of the selector switch - now the little devils cannot run down the engine battery! The larger domestic battery is ample. If absolutely necessary I can always temporarily join the batteries should need ever arise. I have an On/off switch for each battery.
Fitted an Adverc - reason -they explained things carefully over the phone (and after I'd messed up the installation helped me sort it out too). They also advised on battery types and any other item I enquired on. By comparison Sterling were disorganised.
Three years on I'm very happy with the set up; getting rid of the selector switch was definitely correct. The only thing I might reconsider is fitting a RedFlash for engine starting to give even more space for larger domestics - but I don't really need to do it. (Purists may argue about mixing Redflash and AGM, but with only the engine to start this would be OK)


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[LeonF]

Interesting. I found that I was overcharging upto 15.1 V on the AGMS when they had been fully mains charged--ie: plugged in and using the onboard Mobitronic charger. No problems when they had been depleted a bit. From my understanding this is too high and will cause flooded cells to boil but at least they can be topped up. Not so with AGMS. Found many postings of sudden death of AGMS. I was disappointed as the Lifelines seemed to be very good quality batteries. E_mailed one of the major sailing mags asking them to investigate. They approached a major dealer for advice. His opinion was contentious and never forwarded to me.By chance I had phoned them to canvas opinion of Carbon Fibre Elecsols. Bells rang and they asked if I had approached ***** for advice. (Not PBO) Were surprised to hear that his response was never forwarded and sent me the e-mail direct. Gist was that Adverc and AGMS were not compatible. All got too involved and all I wanted to do was go sailing so I returned my batteries and forced the retailer to give me a refund. Legal protection on Boat Insurance covers goods purchased and a little leverage from that direction helped. I offered them the chance to investigate but they wouldn't so I got my £400 back.

<hr width=100% size=1>L.A.R.Ferguson

 

[Heckler]

hiya steve
it sulks and refuses to light up, dead, phoned merlin and they said that it is supposed to sense connection, fire full charge at the battery in pulses until it sorts itself out and then charge according to state of charge, but it doesnt, he said send it back and they will check it out, but it works if i fidle with it so am putting up with the inconvenience until it craters
stu

<hr width=100% size=1><A target="_blank" HREF=http://www.beneteau-owners-association.org.uk>http://www.beneteau-owners-association.org.uk</A>