Assessing The Condition Of A Leisure Battery Bank (Part2!)

[alan_fincher]

OK, this could be real anorak stuff, but fired on by Mike the Boilerman's query in another thread, and knowing Chalice's batteries were "under-performing" by the end of last summer, I intend to try and work out what state the bank is in, and how many batteries need replacement.

 

The bank is made up of 3 x 110Ah unsealed lead acid batteries, as follows.

 

Multicell Brand (Fitted May 2008 - one of a pair the other of which failed prematurely)

Numax (Also fitted May 2008, when for various reasons not all batteries were from same manufacturer)

Albion (Fitted March 2011, to replace the failed Multicell)

 

The Numax and Albion batteries actually appear to be of identcal type, other than the labelling. The Multicell one seems less substantial in every respect, including a case that flexes rather too easily, and carrying handles I'm not confident of.

So two of the batteries nearly 5 years old, and not that strenuously maintained, the other just over 2 years old, so you might realistically expect that to be better than the others.

The engine has not been run for some weeks, and the batteries were brought home yesterday, having been connected together up until then.

Voltages before any investigation are

 

Multicell 12.48V
Numax 12.47V

Albion 12.49V

All cells had electrolyte at a reaonable level, and SGs were:

 

Multicell: 1.280 (5 cells) & 1.300 (one cell - why?)
Numax: 1.280 (5 cells) & 1.225 (one cell - so this battery already looks suspect despite an initial voltage as near as damn it the same as the others)
Albion: 1.280 (all cells)>

So two of these batteries look OK from an SG viewpoint, which might indicate "fully charged", but the actual terminal voltage, if it can be relied on, seems more consistent with about 75% state of charge.

I'm now, before trying any further measurement running the first of the batteries, (Multicell), through a load to give (initially) about 3 amps, to see how well it lasts, but early indications are that, despite healthy readings, it hasn't got a lot of capacity.

 

The tests continue.......

[Naughty Cal]

We have come to the conclusion that when our batteries start to become less reliable we are just going to change them (2x105's). There seems to be little point in trying to coax the last remaining life out of them when new batteries dont cost the earth.

[magnetman]

i've got nackered batteries, they are 2 year old Rolls surette 4000 series 6v cells, i'm considering a warranty claim as they did cost the earth

[alan_fincher]

We have come to the conclusion that when our batteries start to become less reliable we are just going to change them (2x105's). There seems to be little point in trying to coax the last remaining life out of them when new batteries dont cost the earth.

Yes, I'm not about to be a cheapskate, and any indication that any battery is shot, then it will get swapped out. I'm pleased to ave got 5 yeras out of some without flogging myself to death looking after them, particularly as they just sit there slowly self-discharging!

 

But as we have operated one battery for only 2 years alongside others that are nearly three years older, it ought to be the case that that battery at least is good for further use. If it ain't though, it will go.

 

Plus I have finally bought myself a smart, (but not overly expensive!) multi-stage charger, so I need some partially run down batteries to try it out on!

[nicknorman]

A good place to start will be after fully charging the batteries! The trouble is that some chargers seem to go to float mode pretty quickly, well before the bats are really fully charged. It might be best to keep an eye on the voltage of your new charger. If it does seem to be going to float too soon you could try a dumb charger that will just keep a high-ish voltage until you disconnect it. This will in effect be a bit of an equalisation charge. If it gases a bit, no matter you can top up if necessary.

 

There is no point in trying to check capacity until the bats are full!

 

We have Albion 110AH wet cell leisure bats. I find that they can take a high voltage, around 15v without much gassing (although ours are new).

I am glad to see that as a concession to your secret desires, you have a battery with a Hudson boat on the label!

http://www.bayswatertrading.co.uk/popup.aspx?src=/images/Product/large/VB-001.jpg

Edited April 16, 2013 by nicknorman

[bizzard]

Just noticed that MtB has not responded to all this advise, perhaps he's bought a new battery. Or perhaps he is unable to respond, lying prostrate in a soggy field somewhere around Reading all covered in sulphuric acid needing help and the area may need combing to find him.

[alan_fincher]

 

I am glad to see that as a concession to your secret desires, you have a battery with a Hudson boat on the label!

http://www.bayswatertrading.co.uk/popup.aspx?src=/images/Product/large/VB-001.jpg

Yes, this was a bit of a shock to me when I took it out of the boat.

 

I don't think it is a real Hudson battery, as there doesn't appear to be a false rivet in sight!

 

On the subject of "how charged were the batteries on removal, shouldn't an SG in most cells of 1.28 actually equate to "quite well"?

 

I've been working on other things since, so have not investigated further, though.

[nicknorman]

Yes, this was a bit of a shock to me when I took it out of the boat.

 

A likely story - I almost believe you (not!)

 

1.28 = Pretty well charged as you say, but not fully so and I suspect they could do with an equalisation charge if you have not done that recently.

[alan_fincher]

1.28 = Pretty well charged as you say, but not fully so and I suspect they could do with an equalisation charge if you have not done that recently.

 

Equilisation charge!

 

I have an A127 alternator that charges the batteries when the boat goes anywhere, (which it hasn't much lately!).

 

That has been it, until yesterday - if the engine hasn't been doing the charging then nowt else has been available, (for the whole life of the batteries).

 

I have been out most of the day, but have spent a bit of time running a fairly mild load on the first two of the batteries, (the 5 year old ones).

 

I'm fairly confident without doing much more that they are completely knackered, (that seems to be the most appropriate technical term I can come up with!), but as I want to see the new charger in action, I will try and see if it does anything significant with them at all.

 

Given their age, and how treated, I'm surprised they have hung on this long, so I'm not expecting a lot, frankly.

[smileypete]

So two of these batteries look OK from an SG viewpoint, which might indicate "fully charged", but the actual terminal voltage, if it can be relied on, seems more consistent with about 75% state of charge.

 

I'm now, before trying any further measurement running the first of the batteries, (Multicell), through a load to give (initially) about 3 amps, to see how well it lasts, but early indications are that, despite healthy readings, it hasn't got a lot of capacity.

 

The tests continue.......

I wouldn't rule out the possibility the hydrometer may not be as accurate as you hope it is, which could screw over all your theories and tests, BTTDTGTTS The difference between 1.230 and 1.280 isn't that much in mass terms... The cheap refractometers seem to be better for doing an absolute check of SG.

 

Might be good to give the batts a FULL charge, adjust the acid levels to where they were when supplied, then do a capacity test at about C/20.

 

If they test out poorly then try some EQ charging and see if that improves the SGs at end of charge, and gives a better discharge test.

 

(ETA: I did suggest a way of using digital scales to check the hydrometer but had second thoughts and edited it out - sorry!)

 

cheers, Pete.

~smpt~

Edited April 16, 2013 by smileypete

[magnetman]

I just received a refractometer today and it is quite accurat. I had thought about using scales but you'd need either very accurate scales or quite a lot of acid. the refractometer only needs a drop of liquid on the prism.

[Naughty Cal]

Yes, I'm not about to be a cheapskate, and any indication that any battery is shot, then it will get swapped out. I'm pleased to ave got 5 yeras out of some without flogging myself to death looking after them, particularly as they just sit there slowly self-discharging!

 

But as we have operated one battery for only 2 years alongside others that are nearly three years older, it ought to be the case that that battery at least is good for further use. If it ain't though, it will go.

 

Plus I have finally bought myself a smart, (but not overly expensive!) multi-stage charger, so I need some partially run down batteries to try it out on!

If it has been linked to two older (and seemingly knackered) batteries though it will have been dragged down by the older batteries and wont have been getting a full charge so chances are thats pretty knackered as well. It isnt such a great idea to mix and match batteries.

 

Personally I would start afresh. You know that you have a fresh reliable bank of batteries that way which ought to last you for the foreseeable future as the last lot did.

 

We get fed up of seeing people at our marina struggling along with knackered batteries that are well past their best when for not a lot of money you could easily replace them. One boat we cruise with was having to fire up his two 200hp diesel engines to start the diesel heating in a morning, madness!!!!

[alan_fincher]

If it has been linked to two older (and seemingly knackered) batteries though it will have been dragged down by the older batteries and wont have been getting a full charge so chances are thats pretty knackered as well. It isnt such a great idea to mix and match batteries.

 

Personally I would start afresh. You know that you have a fresh reliable bank of batteries that way which ought to last you for the foreseeable future as the last lot did.

 

The problem with that argument is that you are completely ignoring the fact that the majority of people who seem to understand the topic well say that that is precisely what doesn't happen!

 

The vast majority say that provided old batteries in the bank are just "tired", but not actually in any way internally shorted, they simply do not have an adverse effect on other newer batteries in the bank.

 

At the end of the day you have to listen to the arguments, then make your own call who to believe.

 

You are wrong about the last lot having lasted well because they were all bought together, as one failed at less than three years, and had to be replaced. If I had taken that as a sign that I needed to scrap the other two at the same time, it would ultimately have wasted money, as the other two have given sterling service for two more years.

 

I have yet to determine the condition of the battery in the bank that is the "new" one, but even if it is scrapped now, it will still have been a sensible decision to have only put in one, rather than replace all three.

 

Also firing up even one 200hp diesel is only something that worries me when I get in the car!

[Naughty Cal]

The problem with that argument is that you are completely ignoring the fact that the majority of people who seem to understand the topic well say that that is precisely what doesn't happen!

 

The vast majority say that provided old batteries in the bank are just "tired", but not actually in any way internally shorted, they simply do not have an adverse effect on other newer batteries in the bank.

 

At the end of the day you have to listen to the arguments, then make your own call who to believe.

 

You are wrong about the last lot having lasted well because they were all bought together, as one failed at less than three years, and had to be replaced. If I had taken that as a sign that I needed to scrap the other two at the same time, it would ultimately have wasted money, as the other two have given sterling service for two more years.

 

I have yet to determine the condition of the battery in the bank that is the "new" one, but even if it is scrapped now, it will still have been a sensible decision to have only put in one, rather than replace all three.

 

Also firing up even one 200hp diesel is only something that worries me when I get in the car!

 

That very much depends on who you talk too!!

[Guest]

IIRC - el battery supremo Gibbo used to say the same as Alan....

 

A battery had to have an internal short to drag the others down....but my memory may be faulty on that.

[bizzard]

IIRC - el battery supremo Gibbo used to say the same as Alan....

 

A battery had to have an internal short to drag the others down....but my memory may be faulty on that.

I think this is right. Providing there is no internal short a dead battery will happily just sit there still providing the circuits link.

 

I haven't got this quite right. If a battery is dead it can't short, it can only break the circuit link by an internal connection having disconnected or very nearly so due to corrosion, hence the use of my severe drop test involving ''The thick bar'' to prove this.

Edited April 17, 2013 by bizzard

[MtB]

That very much depends on who you talk too!!

 

Indeed it does. English middle class people seem to have a touching faith in a cloth-capped 'mechanic' with a roll-up stuck to his bottom lip, taking everything he says as gospel truth.

 

In reality he is sometimes making it up as he goes along in order not to damage your misplaced faith in his apparently amazing depth of knowldedge, and you have no way of knowing this without doing all your own research. He is quite possibly just regurgitating something he read on here, or that his boss told him years ago, but he DOES know that when you buy a new set of batteries the problem goes way (usually) so he must be right.

 

I see this effect all the time on the world of boiler and central heating repairs and it depresses me how much utter bollux is spouted by people in the trade who ought to know their stuff, but in reality, don't. There are plenty of 'marine engineers' about like this too.

 

MtB

 

Edited to add a word so a sentence makes sense

Edited April 17, 2013 by Mike the Boilerman

[Chris Pink]

And some tradesmen think they know it all anyway and so are blind to such vagaries such as in any engineering problem there will be a range of solutions, that most people are trustworthy, and that all people, themselves included, have limitations.

[MtB]

And some tradesmen think they know it all anyway and so are blind to such vagaries such as in any engineering problem there will be a range of solutions, that most people are trustworthy, and that all people, themselves included, have limitations.

 

Totally agree. Recognising one's limitations is essential in any area of expertise, but runs counter to human nature. Plumbers can sometimes demonstrate a mixture of incompetence, over-confidence and blatant self-interest, the effects of this can be really ugly.

 

Little old ladies wasting their life savings on a new boiler when the old one was perfectly repairable, for example. If only the plumber has said "I can't fix it but I know a man who can", but no, it's so often "can't get the parts for this love, you'll have to have a new boiler".

 

But as you say, most people are perfectly honourable and trustworthy, just not all, but those who aren't, play on the 'trust' thing mercilessly. This can heppen when taking advice on battery banks as well as new boilers.

 

MtB

[nicknorman]

Unless there is a shorted cell resulting in the other bats discharging into it, or excessive self-discharge, I can't see how having a reduced-capacity battery in a bank with new ones can be detrimental.

[bizzard]

We all learn something new everyday although some big heads won't admit it, they already no it all.

My cat Satchidanander got too fat and was running about like a little over inflated black balloon, and I discovered last night that if he eats too much late at night he'll be sick in the night. So he is now on a diet and not fed late at night anymore.

[alan_fincher]

That very much depends on who you talk too!!

Precisely why I said you have to make a value judgement on which expert you believe speaks from a position of knowledge, and which is potentially talking bollocks.

 

Clearly it is in the interest of the trade to convince you that you should only replace battery banks in their entirety, but nobody has yet given me any sound science as to why that statement is likely to be true. Can you offer an explanation, other than someone said so, and it actually sounds plausible until you really think it through.

 

It also seems wrong to me from a "save the planet" viewpoint to scrap perfectly serviceable batteries, and hence needlessly increase production of new ones, if it can be avoided, although I suppose it keeps people in work!

[ditchcrawler]

I just received a refractometer today and it is quite accurat. I had thought about using scales but you'd need either very accurate scales or quite a lot of acid. the refractometer only needs a drop of liquid on the prism.

Which one did you get? I used them all the time at work. If you have 100 batteries to check (emergency light supply) its a lot quicker.

 

The problem with that argument is that you are completely ignoring the fact that the majority of people who seem to understand the topic well say that that is precisely what doesn't happen!

 

The vast majority say that provided old batteries in the bank are just "tired", but not actually in any way internally shorted, they simply do not have an adverse effect on other newer batteries in the bank.

 

At the end of the day you have to listen to the arguments, then make your own call who to believe.

 

You are wrong about the last lot having lasted well because they were all bought together, as one failed at less than three years, and had to be replaced. If I had taken that as a sign that I needed to scrap the other two at the same time, it would ultimately have wasted money, as the other two have given sterling service for two more years.

 

I have yet to determine the condition of the battery in the bank that is the "new" one, but even if it is scrapped now, it will still have been a sensible decision to have only put in one, rather than replace all three.

 

Also firing up even one 200hp diesel is only something that worries me when I get in the car!

I think a lot depends on how you class knackered, to some people tied batteries that only have a small capacity are knackered. To others like you they are only knackered when they are actually bust with a shorted cell or similar.

[Naughty Cal]

Indeed it does. English middle class people seem to have a touching faith in a cloth-capped 'mechanic' with a roll-up stuck to his bottom lip, taking everything he says as gospel truth.

 

In reality he is sometimes making it up as he goes along in order not to damage your misplaced faith in his apparently amazing depth of knowldedge, and you have no way of knowing this without doing all your own research. He is quite possibly just regurgitating something he read on here, or that his boss told him years ago, but he DOES know that when you buy a new set of batteries the problem goes way (usually) so he must be right.

 

I see this effect all the time on the world of boiler and central heating repairs and it depresses me how much utter bollux is spouted by people in the trade who ought to know their stuff, but in reality, don't. There are plenty of 'marine engineers' about like this too.

 

MtB

 

Edited to add a word so a sentence makes sense

In this case we are the mechanic and we buy our batteries from a valued friend

[magnetman]

Which one did you get? I used them all the time at work. If you have 100 batteries to check (emergency light supply) its a lot quicker.

I found a DEUTZ one on ebay. Its a nice toy it has scales for battery acid, a scale to show how far below freezing you can go with the antifreeze concentration and something called 'adblue' which i understand is something to do with big trucks and exhausts an urea - not sure I'll be using that bit. Its a really good way to have a look at the batteries and I feel like a proper pirate looking through the eyeglass which is nice

 

 

eited for incomprehensibility

 

out of interest what batteries are best for emergency light supply? ie reliable ?

Edited April 17, 2013 by magnetman