Battery Management Systems - Best value for money

[chris w]

It doesn't do them much good, I know. I don't yet know how often the former owner charged up his batteries and how good the batteries are. They could be clapped out. I'll remove them shortly and see if I can get them fully charged.

How do you plan on determining this... ie: that they are at full charge or not?

 

Chris

[Pretty Funked Up]

elecsol???? yeah great benchmarks!!! lol

 

maybe fiam, yuasa or maybe banner

Edited December 17, 2008 by Pretty Funked Up

[Eeyore]

I see where the error lies now. Wherever you read that, it's wrong.

 

For every reference you find that states 14.8 volts, I can show you at least 5 that state it is 14.4

 

Gibbo

Slightly off topic - any chance that you could recommend a reference book on this subject?

PM me if you prefer.

Thanks

Steve

[Gibbo]

Slightly off topic - any chance that you could recommend a reference book on this subject?

 

Unfortunately no. None of them are 100% correct and one has to use a mixture of various different texts. I learnt from a mixture of several dozen books, some very old electrical encyclopedias and several years research.

 

I put a link up on here a couple of months ago for an on old book that has now appeared on'tinternet but I can't find it now. It's one of the best too.

 

Gibbo

[smileypete]

Slightly off topic - any chance that you could recommend a reference book on this subject?

PM me if you prefer.

Thanks

Steve

 

My advice on this is fairly unusual and almost always unpopular.

 

Just get an old working leisure or truck starting battery and play around with it (observing precautions!!! see web link below)

 

Also do some research on the web, the Car and Deep Cycle Battery FAQ is a good start.

 

At the end of it you probably won't need an expensive battery monitor

 

cheers,

Pete.

[colin stone]

http://www.arttec.net/Solar_Mower/4_Electr...%20Charging.pdf

[FORTUNATA]

I decided to test my batteries today so took a multimeter with me and opened up the engine boards. The terminals read 12.2 volts. I didn't think that seemed very good. I don't like using an engine to charge batteries but I thought it was the best option. I started the engine and then did another terminal voltage reading. That came out at over 14 volts. Clearly my Lister alternator (probably a Lucas) is working well. After 35 minutes or so I switched the engine off, waited a while and then did another voltage reading. That was 12.7 volts. Better, I thought.

I took John C Payne's advice as well and made sure as much load was switched off when charging. Of course, a battery charger is always better than an alternator but certainly my alternator does do its job and raise system voltage.

 

3 - 5 hours charging is a fair long time. Is there any space on your boat to accommodate a generator? That would probably help matters.

 

 

Returning to the OP on my boat for Alternator/Charging control I have a Sterling Alternator to Battery Charger set-up. This seems to work well enough and shortly I am adding a Smartgauge for Battery monitoring purposes. Come on Father Christmas get a move on!

 

Although not all that cheap The Sterling A-B unit has the advantage over other alternator controllers that it is very simple to wire in, just 4 wires including it's neg return. There are some optional battery and alternator temp sensors as well. It internally has the charging split diodes etc so no other components required either.

 

However, if I had been aware of the Smartgauge and Smartbank (advanced) set-up before I fitted the Sterling I would have gone that route. This is particularly in the light that my alternator pushes out aprox 14.5v all on its own. So the Sterling bringing it up to 14.8v is only a small gain.

 

I find that the Sterling set-up takes 3-5 hours to re-charge my battery banks (3x110aA/hr domestic plus starter) from overnight usage. Mind you that is only going by the Sterling units cycle finishing and taking that as fully charged I should see if that is so when the Smartgauge is fitted. I suspect it wouldn't be much longer than that if I didn't have the Sterling unit. However, I only have one 70amp alternator (pushing out about 40amp at cruising revs @14.5v) I am hoping to improve things by fitting a 90amp unit at some point.

[chris w]

I decided to test my batteries today so took a multimeter with me and opened up the engine boards. The terminals read 12.2 volts. I didn't think that seemed very good. I don't like using an engine to charge batteries but I thought it was the best option. I started the engine and then did another terminal voltage reading. That came out at over 14 volts. Clearly my Lister alternator (probably a Lucas) is working well. After 35 minutes or so I switched the engine off, waited a while and then did another voltage reading. That was 12.7 volts. Better, I thought.

I took John C Payne's advice as well and made sure as much load was switched off when charging. Of course, a battery charger is always better than an alternator but certainly my alternator does do its job and raise system voltage.

 

3 - 5 hours charging is a fair long time. Is there any space on your boat to accommodate a generator? That would probably help matters.

There's something strange here.......

 

If the batteries are reading 12.2v then they are at approx 50% charge. Switching on the engine/alternator will not produce a voltage of 14v (even if the alternator's regulator is set at 14v) because the alternator's voltage will be pulled down by the battery itself. What will happen is that the battery voltage (and the alternator output) will SLOWLY climb to 14v, but it would need a good one to two hours to get to that value.

 

Chris

[steelaway]

Returning to the OP on my boat for Alternator/Charging control I have a Sterling Alternator to Battery Charger set-up. This seems to work well enough and shortly I am adding a Smartgauge for Battery monitoring purposes. Come on Father Christmas get a move on!

 

Although not all that cheap The Sterling A-B unit has the advantage over other alternator controllers that it is very simple to wire in, just 4 wires including it's neg return. There are some optional battery and alternator temp sensors as well. It internally has the charging split diodes etc so no other components required either.

 

However, if I had been aware of the Smartgauge and Smartbank (advanced) set-up before I fitted the Sterling I would have gone that route. This is particularly in the light that my alternator pushes out aprox 14.5v all on its own. So the Sterling bringing it up to 14.8v is only a small gain.

 

I find that the Sterling set-up takes 3-5 hours to re-charge my battery banks (3x110aA/hr domestic plus starter) from overnight usage. Mind you that is only going by the Sterling units cycle finishing and taking that as fully charged I should see if that is so when the Smartgauge is fitted. I suspect it wouldn't be much longer than that if I didn't have the Sterling unit. However, I only have one 70amp alternator (pushing out about 40amp at cruising revs @14.5v) I am hoping to improve things by fitting a 90amp unit at some point.

 

 

I have the same Sterling/Barrus set up but with two alternator (110A & 50A) wired together and I have seen 70A charge into the domestic batterys.

I have been very happy with it for more than 4 years and I have never been short of power, even with quite a high 240V demand

 

Alex

[FORTUNATA]

I must admit I was surprised myself. I expected the meter to read maybe 13 volts at most when the alternator was kicking in. Instead I got something like 14.4 volts!! Of course, there are actually two 12 volt batteries in parallel so I was careful not to accidentally cross poles when testing. I also tested each individual battery as it was in parallel. I'm aware the alternator raises the system voltage somewhat but was surprised by how fast this took place. One thing I do know is the alternator on my Lister SR2 certainly works fine. I don't know how much the batteries will drop down over night but guess they'll be around 12.6 volts.

 

There's something strange here.......

 

If the batteries are reading 12.2v then they are at approx 50% charge. Switching on the engine/alternator will not produce a voltage of 14v (even if the alternator's regulator is set at 14v) because the alternator's voltage will be pulled down by the battery itself. What will happen is that the battery voltage (and the alternator output) will SLOWLY climb to 14v, but it would need a good one to two hours to get to that value.

 

Chris

[chris w]

I must admit I was surprised myself. I expected the meter to read maybe 13 volts at most when the alternator was kicking in. Instead I got something like 14.4 volts!! Of course, there are actually two 12 volt batteries in parallel so I was careful not to accidentally cross poles when testing. I also tested each individual battery as it was in parallel. I'm aware the alternator raises the system voltage somewhat but was surprised by how fast this took place. One thing I do know is the alternator on my Lister SR2 certainly works fine. I don't know how much the batteries will drop down over night but guess they'll be around 12.6 volts.

A fully charged battery, if left to settle for a few hours, will read 12.6v.

 

The fact that your batteries went from 12.2v to the regulator voltage of 14.4v in a really short time, tells me that the batteries are knackered (ie: they have very low capacity). It's a bit like a canal lock being full but having a stuck sluice gate... ie: the lock may be full but you can't extract water at the correct speed.

 

So the reason they appeared to charge so quickly is that they are now only very small batteries ie: their capacities are severely reduced. Either that or your measurements are not correct.

 

Chris

[Gibbo]

I must admit I was surprised myself. I expected the meter to read maybe 13 volts at most when the alternator was kicking in. Instead I got something like 14.4 volts!!

 

I've just stuck your figures through my special algorithm and making the assumption that your alternator was throwing out about 50 amps it calculates from the above that you have a total battery capacity of about 45 ahrs for both batteries together.

 

Your batteries are knackered. Or your meter is broke

 

Gibbo

[FORTUNATA]

The batteries may well not be at their best. It may be the case the former owner rarely came down to check on them as he was resident in a different part of the country. I'll have to test them with a bulb guage and see what that reveals. Funnily enough, though, the batteries did start the engine no problem even in cold weather. The inverter also works and appliances supplied via the inverter although I haven't yet spent a night on the boat to see how the electrics perform. Later I'll reveal what I discover.

 

I've just stuck your figures through my special algorithm and making the assumption that your alternator was throwing out about 50 amps it calculates from the above that you have a total battery capacity of about 45 ahrs for both batteries together.

 

Your batteries are knackered. Or your meter is broke

 

Gibbo

[paddy r]

A fully charged battery, if left to settle for a few hours, will read 12.6v.

 

The fact that your batteries went from 12.2v to the regulator voltage of 14.4v in a really short time, tells me that the batteries are knackered (ie: they have very low capacity). It's a bit like a canal lock being full but having a stuck sluice gate... ie: the lock may be full but you can't extract water at the correct speed.

 

So the reason they appeared to charge so quickly is that they are now only very small batteries ie: their capacities are severely reduced. Either that or your measurements are not correct.

 

Chris

 

 

Not sure about the Boat world (i work on car engines)but i was allways told that a batt showing less than 12.6 was dead!It will still start your car but it will let you down when you need it most!

[Sir Nibble]

I've just stuck your figures through my special algorithm and making the assumption that your alternator was throwing out about 50 amps it calculates from the above that you have a total battery capacity of about 45 ahrs for both batteries together.

 

Your batteries are knackered. Or your meter is broke

 

Gibbo

Mine are almost certainly in the same state, I don't KNOW because until things stop working I shan't check. No matter how stuffed the batteries, if your normal pattern of useage is unnaffected and you are not having to constantly run the engine to keep the lights on, you don't have a problem.

 

Not sure about the Boat world (i work on car engines)but i was allways told that a batt showing less than 12.6 was dead!It will still start your car but it will let you down when you need it most!

 

I am an auto electrician by trade. If someone told me that I would offer them travelling directions.

[Gibbo]

Not sure about the Boat world (i work on car engines)but i was allways told that a batt showing less than 12.6 was dead!It will still start your car but it will let you down when you need it most!

 

Well whoever told you that (presumeably the same person everytime) was always wrong.

 

Gibbo

[FORTUNATA]

It's quite normal for the alternator to raise system voltage. I have an article by Peter Hopley of Acorn engineering that addresses this issue in straightforward terms. D.C. appliances have to be able to deal with ranges of voltage due to fluctuation between static charge and then increased alternator charge. The alternator will lift the entire system voltage but load must be reduced to minimum for charging to be more effective. If the system is loaded while charging then this will also alter things.

Having said that, I suspect my batteries aren't at their best as they may well have been neglected if the former owner was in a different part of the country and the boat standing.

[chris w]

It's quite normal for the alternator to raise system voltage.

True

 

I have an article by Peter Hopley of Acorn engineering that addresses this issue in straightforward terms.

Is this the article in the "Narrowboat Builders Manual"? That article is riddled with electrical mistakes and misunderstandings by the author. You probably could have written a better article.

 

 

D.C. appliances have to be able to deal with ranges of voltage due to fluctuation between static charge and then increased alternator charge.

 

Not on Planet earth they don't

 

The alternator will lift the entire system voltage but load must be reduced to minimum for charging to be more effective. If the system is loaded while charging then this will also alter things.

 

True

Having said that, I suspect my batteries aren't at their best as they may well have been neglected if the former owner was in a different part of the country and the boat standing.

 

You know what Northeners are like - typical

 

Chris

[Sir Nibble]

load must be reduced to minimum for charging to be more effective.

Well that's true insofar as during bulk charge 5A going on running a load is 5A the battery won't get, but conversely once you get to absorbtion that's 5A extra from the alternator that the battery doesn't need to supply. If there are big loads to be applied I would sooner apply them with engine running.

Apart from anything else, you should always turn off a load you're not using on charge or not.

[FORTUNATA]

"Is this the article in the "Narrowboat Builders Manual"? That article is riddled with electrical mistakes and misunderstandings by the author. You probably could have written a better article."

 

Indeed! Indeed! And indeed!!

Just kidding.

I have that book on hand. The author was capable but not an expert on electrics so he turned an entire chapter over to that particular engineer. Personally I can't help but think you've gone a bit too far down the road of skepticism since if every technician (either in Canalboat mag or other publications) is written of as a no hoper, we're all in a sorry state. Heaven help those of us who've been guided by these folks if they all happen to be quacks!

In a lot of cases, when you board a vessel you see many things that are inefficient, not logical or even dangerous. As John Payne stated many times the principal problem seems to be that of battery charging, either battery banks that aren't rated correctly for the system load or underpowered charging. So, I find most of these technicians are more of a help than hindrance to those who wish to get some insight into how electrical systems function.

"Not on Planet earth they don't..."

He was pointing out D.C. equipment must be capable of operating over 12 volts in cases where alternators are lifting the D.C. circuits up. With the engine off and just battery power being used the voltage may only be as low as 12.4 However, as I found the other day my own batteries were giving out over 14 volts. He's not talking about using 12 volt equipment on a 24 volt bank of batteries in series.

 

 

 

 

True

 

Is this the article in the "Narrowboat Builders Manual"? That article is riddled with electrical mistakes and misunderstandings by the author. You probably could have written a better article.

 

 

 

 

Not on Planet earth they don't

 

 

 

True

 

 

You know what Northeners are like - typical

 

Chris

 

 

The bottom line is I suspect my batteries are knackered. Or if not, in need of serious maintenance. I suppose the former owner didn't have time to clean and charge them as much as necessary and such is life. I did find the electrolyte levels in one or two cells were down and, not only that, there appeared to be grass or straws floating about in the electrolyte!! This is partly why I have this thing about rainy and dirty engine bilges. I figure someone had been maybe checking the battery in such conditions so contamination resulted. I'll remove the batteries from the boat later, check the cell capacity and top up where required.

We fitted some sort of a cover today (a runner up to the real thing) and when that's done the battery area is to be sorted out, drained and cleaned.

 

 

Well that's true insofar as during bulk charge 5A going on running a load is 5A the battery won't get, but conversely once you get to absorbtion that's 5A extra from the alternator that the battery doesn't need to supply. If there are big loads to be applied I would sooner apply them with engine running.

Apart from anything else, you should always turn off a load you're not using on charge or not.

 

 

 

 

 

 

Well that's true insofar as during bulk charge 5A going on running a load is 5A the battery won't get, but conversely once you get to absorbtion that's 5A extra from the alternator that the battery doesn't need to supply. If there are big loads to be applied I would sooner apply them with engine running.

Apart from anything else, you should always turn off a load you're not using on charge or not.

Edited December 18, 2008 by FORTUNATA

[chris w]

"Is this the article in the "Narrowboat Builders Manual"? That article is riddled with electrical mistakes and misunderstandings by the author. You probably could have written a better article."

 

Indeed! Indeed! And indeed!!

Just kidding.

I have that book on hand. The author was capable but not an expert on electrics so he turned an entire chapter over to that particular engineer. Personally I can't help but think you've gone a bit too far down the road of skepticism since if every technician (either in Canalboat mag or other publications) is written of as a no hoper, we're all in a sorry state. Heaven help those of us who've been guided by these folks if they all happen to be quacks!

I am not saying they are all no hopers. But I do know, that in the area of MY expertise, the article to which I alluded has some serious technical errors in it. I don't have the book to hand at the moment, as it is on my boat, but I will pick it up and make a list of the incorrect info in that particular chapter. I have no axe to grind - I give freely of my time because I enjoy helping others with my knowledge, just as I pick the brains of those on here who have knowledge in other areas.

 

"Not on Planet earth they don't..."

He was pointing out D.C. equipment must be capable of operating over 12 volts in cases where alternators are lifting the D.C. circuits up. With the engine off and just battery power being used the voltage may only be as low as 12.4 However, as I found the other day my own batteries were giving out over 14 volts. He's not talking about using 12 volt equipment on a 24 volt bank of batteries in series.

I was referring to "static" charge, which is why I underlined the word in my original reply (ie: static electricity), although on re-reading your post I think you meant quiescent charging and dynamic charging rather the words you did use, so ignore that point. As Sir Nibble rightly pointed out earlier, it is incorrect of you to say that all extraneous loads should be removed during charging. Excess charging capacity (ie: the charge available over that which the battery can take in at that moment) can be usefully used to run other devices and appliances and rather than subtracting from the charge, actually adds to the charge because the batteries don't have to supply the load current.

 

This is another example of where an author (John Payne in this case) is IMHO wrong to make such a statement which you have quoted a few times in your posts. His pronouncement is misleading and basically incorrect.

 

 

 

The bottom line is I suspect my batteries are knackered.

I suspect this too. It sounds like they are probably sulphated due to poor maintenance by the previous owner.

 

Chris

[FORTUNATA]

It's an exceptionally thorough book but it's also very easy to misunderstand someone in the context of a book since the writer is trying to convey information also to beginners. This book was really intended for those who own seagoing vessels and yachts so the various chapters on navigation equipment and radio aren't relevant. However, as the guy in question apparently worked as a refrigerator engineer as well as boat engineer for many years, the explanations on freezing systems are interesting. I've read this book from cover to cover and would highly recommend it, especially the chapters on batteries are helpful. After that, I try to read whatever else I can find and search for the really tricky questions later on.

At any rate, having read the book I would agree it's highly probably my batteries sulfated. My suspicion is the bilge pump was working quite a lot to keep the bilge dry but as the engine wasn't run very often, the batteries slowly went down. Plus, the cells somehow got dirty. I don't know if I can save the batteries or not. Today they registered a little over 12.5 volts after 24 hours rest. All I can do is top up the drier cells and see if I can get them up with a charger.Also clean them up with a little bicarbonate of soda. Otherwise I'll have to get new batteries.

Ironically I would expect the same thing with any older boat. Batteries are often neglected.

 

I am not saying they are all no hopers. But I do know, that in the area of MY expertise, the article to which I alluded has some serious technical errors in it. I don't have the book to hand at the moment, as it is on my boat, but I will pick it up and make a list of the incorrect info in that particular chapter. I have no axe to grind - I give freely of my time because I enjoy helping others with my knowledge, just as I pick the brains of those on here who have knowledge in other areas.

 

 

I was referring to "static" charge, which is why I underlined the word in my original reply (ie: static electricity), although on re-reading your post I think you meant quiescent charging and dynamic charging rather the words you did use, so ignore that point. As Sir Nibble rightly pointed out earlier, it is incorrect of you to say that all extraneous loads should be removed during charging. Excess charging capacity (ie: the charge available over that which the battery can take in at that moment) can be usefully used to run other devices and appliances and rather than subtracting from the charge, actually adds to the charge because the batteries don't have to supply the load current.

 

This is another example of where an author (John Payne in this case) is IMHO wrong to make such a statement which you have quoted a few times in your posts. His pronouncement is misleading and basically incorrect.

 

 

 

 

I suspect this too. It sounds like they are probably sulphated due to poor maintenance by the previous owner.

 

Chris

[chris w]

I don't know if I can save the batteries or not. Today they registered a little over 12.5 volts after 24 hours rest. .

That's around a 90% charge based the open circuit voltage you quote above. However, that is only half the story. It could be they are fully charged but only have a low capacity due to sulphation. ie: they have become fully charged 20AH batteries instead of fully charged 110AH batteries.

 

Chris

[FORTUNATA]

I seem to recall there is a capacity test where voltage is read after cranking over the engine for a certain duration. There is also the standard squeeze bulb test. I could have removed my batteries for service ages ago but for some reason tend to like working in a set order, one thing at a time. I'm now working on the rear stern cover which, to my own way of thinking, is fundamental.

I recall when I first took on my other fibreglass boat that had a battery too but it was a mega battery. It was one huge battery, maybe a tractor battery. You could hardly lift it. I don't know anything about tractor batteries. I heard they're no good for boats. Maybe loads of CCA but not so much deep cycle suitability.

 

That's around a 90% charge based the open circuit voltage you quote above. However, that is only half the story. It could be they are fully charged but only have a low capacity due to sulphation. ie: they have become fully charged 20AH batteries instead of fully charged 110AH batteries.

 

Chris

[Nickhlx]

Surely temeperature will have an effect ? - no-one has asked at what temp the batteries are and we have had some pretty cold temps recently

 

So,

 

At 20 deg C, 10 deg C, 0 deg C and -5 deg C what should a new condition healthy flooded / wet lead acid battery after full charge settle at these sample temps ?

 

( My 17 month old bike battery is usually around 12.8 volts at 5 to 10 deg C after around 24 to 48 hours and it is supplying a few milliamps to keep the alarm alive) but I am not sure of the battery type other than it's sealed - possibly a Gel type - they cost around £75 - measured with a calibrated meter known accurate to +/- 10 mv )

 

Nick