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battery monitoring


destinyjon

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Seems to me that most boat batts suffer or die from persistent undercharging, to which Smartgauge is at least a partial solution.

 

So I feel the need for a highly accurate SoC reading is overstated, though it will help to reassure the less technical peeps. :)

 

Horses for courses though, if you've paid the Mastervolt/Victron tax to run a hi power inverter then an extra £160 isn't a big deal.

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Seems to me that most boat batts suffer or die from persistent undercharging, to which Smartgauge is at least a partial solution.

 

So I feel the need for a highly accurate SoC reading is overstated, though it will help to reassure the less technical peeps. :)

 

Horses for courses though, if you've paid the Mastervolt/Victron tax to run a hi power inverter then an extra £160 isn't a big deal.

The trouble is that the smartgauge in all the cases I have seen leads to under charging. By under charging sulphate is left on the plate and hardens and the cycle of under charging repeats itself and more sulphate is left on the plate. So the cry goes out equalisation needed, the very act of equalisation shortens the battery's life.

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The trouble is that the smartgauge in all the cases I have seen leads to under charging. By under charging sulphate is left on the plate and hardens and the cycle of under charging repeats itself and more sulphate is left on the plate. So the cry goes out equalisation needed, the very act of equalisation shortens the battery's life.

 

It is still a better guide than anything else for the electrically challenged. Many folk have no monitoring at all, and usually suffer from undercharging. At least those with a Smartgauge have a better idea, and certainly an idea when to start charging again.

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The SmartGauge is not designed to tell you when to stop charging. I believe that's a far more relevant fact than how good it is at it. (Whatever you decide "fully charged" actually is.)

 

As it happens it's not actually that bad (Nick's example is around 2% out for instance) but an ammeter is recommended to determine the tail current to suit your own preference of "full". You can then decide 4%, 2%, 1% or whatever.

 

Tony

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The SmartGauge is not designed to tell you when to stop charging. I believe that's a far more relevant fact than how good it is at it. (Whatever you decide "fully charged" actually is.)

 

As it happens it's not actually that bad (Nick's example is around 2% out for instance) but an ammeter is recommended to determine the tail current to suit your own preference of "full". You can then decide 4%, 2%, 1% or whatever.

 

Tony

Think you have misread Nick's experiment,it was stopped when the Amps going into the battery were nominally 2.77% of capacity, how do you compute that to being 2% or so of SoC?

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Bloody 'ell, cost us £45 each for crap seats. Mind you, Jeff was paying!

our seats were ok at the end we were chatting to one of the ushers and he moved us to two empty seats in a much better place, the original seats wernt bad but if you dont ask you dont get

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The trouble is that the smartgauge in all the cases I have seen leads to under charging. By under charging sulphate is left on the plate and hardens and the cycle of under charging repeats itself and more sulphate is left on the plate. So the cry goes out equalisation needed, the very act of equalisation shortens the battery's life.

 

Yeah the benefits of recharging at exactly 50% can be easily outweighed by gradual capacity loss.

 

But I reckon most Smartguage users are part time boaters, probably with little real interest in batts/electrics, and would gladly trade some batt life in return for keeping things simple as poss - and why not. smile.png

Edited by smileypete
  • Greenie 1
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Yeah the benefits of recharging at exactly 50% can be easily outweighed by gradual capacity loss.

 

But I reckon most Smartguage users are part time boaters, probably with little real interest in batts/electrics, and would gladly trade some batt life in return for keeping things simple as poss - and why not. :)

Don't think that is correct everyone I have seen has been aboard a liveaboard. As it happens I am going to look at another one tomorrow, with charging problems, yep a liveaboard.

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The trouble is that the smartgauge in all the cases I have seen leads to under charging. By under charging sulphate is left on the plate and hardens and the cycle of under charging repeats itself and more sulphate is left on the plate. So the cry goes out equalisation needed, the very act of equalisation shortens the battery's life.

 

 

It is still a better guide than anything else for the electrically challenged. Many folk have no monitoring at all, and usually suffer from undercharging. At least those with a Smartgauge have a better idea, and certainly an idea when to start charging again.

 

 

And therein is the nub of the argument. Which is more likely to hasted the demise of a battery on a boat owned by the man on the bus, and Amp hour counter (with or without slight refinements) or a Smartguage?

 

I do not see how anyone can claim it will be the Amp hour counter any more than I can see where anyone has said a Smartguage will PREVENT sulphation.

 

The only advantage of the Amp hour counters that I can see is that they also provide an ammeter and voltmeter which will allow someone with an ideal about charging to control their charging better that either gauge - if they are so minded to. This means we are not comparing like with like.

 

When we get batteries that will not lose capacity and have a constant recharge efficiency in all conditions and for life then the Ah counter will be the best, until then we must put up with the Smartguage that is not perfect for the job but is better than anything else in the consumer market.

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When we get batteries that will not lose capacity and have a constant recharge efficiency in all conditions and for life then the Ah counter will be the best, until then we must put up with the Smartguage that is not perfect for the job but is better than anything else in the consumer market.

What a neat summation :)

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And therein is the nub of the argument. Which is more likely to hasted the demise of a battery on a boat owned by the man on the bus, and Amp hour counter (with or without slight refinements) or a Smartguage?

 

I do not see how anyone can claim it will be the Amp hour counter any more than I can see where anyone has said a Smartguage will PREVENT sulphation.

 

The only advantage of the Amp hour counters that I can see is that they also provide an ammeter and voltmeter which will allow someone with an ideal about charging to control their charging better that either gauge - if they are so minded to. This means we are not comparing like with like.

 

When we get batteries that will not lose capacity and have a constant recharge efficiency in all conditions and for life then the Ah counter will be the best, until then we must put up with the Smartguage that is not perfect for the job but is better than anything else in the consumer market.

There is nothing that will easily read the state of charge while charging. Except something that reads current (amps) into the battery and thus make the tail current available and allow charging down to 1% tail current of capacity. At least by doing that there is a reasonable chance of a full charge.

 

The smartgauge even in the recent test published on here did not get to that level before reaching 100%. Whilst the MS gauge being tested along side it got to 94% SoC. From the tail current declared in the test I believe the MS gauge was almost spot on.

 

I have just come from a boat with a smartgauge. The owner relies totally on the gauge and has been told he only needs to charge to 90% on the gauge. Now the gauge has an accuracy while charging of 10% so he could be charging to 81% or 99% or something in between. But let's say it is 90% that means all the sulphate is not removed and that will harden and the smartgauge takes the batteries to only have 90% of their actual capacity. The result is the 90% charge becomes 90% of 90% (81% of capacity) and the sulphating increases. So it goes on and battery life is shorten because of sulphating caused by bad charging regimes.

 

I am not sure but am starting to believe it would be better for the batteries and the overall costings if users were told to recharge at an on load of voltage X and to charge until a tail current of say 1% of capacity is reached.

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And therein is the nub of the argument. Which is more likely to hasted the demise of a battery on a boat owned by the man on the bus, and Amp hour counter (with or without slight refinements) or a Smartguage?

 

I do not see how anyone can claim it will be the Amp hour counter any more than I can see where anyone has said a Smartguage will PREVENT sulphation.

 

The only advantage of the Amp hour counters that I can see is that they also provide an ammeter and voltmeter which will allow someone with an ideal about charging to control their charging better that either gauge - if they are so minded to. This means we are not comparing like with like.

 

When we get batteries that will not lose capacity and have a constant recharge efficiency in all conditions and for life then the Ah counter will be the best, until then we must put up with the Smartguage that is not perfect for the job but is better than anything else in the consumer market.

 

Agreed.

 

Edit to add quote.

 

I was agreeing with Tony Brooks, not Graham.m.

Edited by Loafer
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And therein is the nub of the argument. Which is more likely to hasted the demise of a battery on a boat owned by the man on the bus, and Amp hour counter (with or without slight refinements) or a Smartguage?

 

I do not see how anyone can claim it will be the Amp hour counter any more than I can see where anyone has said a Smartguage will PREVENT sulphation.

 

The only advantage of the Amp hour counters that I can see is that they also provide an ammeter and voltmeter which will allow someone with an ideal about charging to control their charging better that either gauge - if they are so minded to. This means we are not comparing like with like.

 

When we get batteries that will not lose capacity and have a constant recharge efficiency in all conditions and for life then the Ah counter will be the best, until then we must put up with the Smartguage that is not perfect for the job but is better than anything else in the consumer market.

I think perhaps the advocates of the smartgauge need to think about what they say, for example that it will tell people how long they should charge there batteries for. In the recent experiment reported on here two gauges were tested, unfortunately without a master reference. In that test, stopped when the smartgauge reached 100% with a tail current of 12/13 amps. The other gauge the MS was reading 94% SoC, now with a tail current of 4 amps or less in this case I might have agreed the batteries were at 100%. However, with a tail current of 12/13 amps I believe the MS at 94% was nearer perfect on the mark.

 

But neither is the perfect answer.

 

I have just returned from a boat with charging problems. They had been told to charge to 90% on their smartgauge. Now as when charging the smartgauge has an accuracy of +/-10% that 90% could have actually been 81% or 99% or something in between. No matter which the batteries are being under charge, thus allowing a buildup of sulphate. So the battery is charged to 90%, the sulphate hardens and the smartgauge learns the new capacity (90% of the original). Then charged to 90% (81% of original) and more sulphate is laid down and hardens the sgauge learns that capacity. The it is charged to 90% of the 81% of original capacity to 73% of the original capacity and so on and quite rapidly there is a sulphated battery. Now it does not matter at what percentage of SoC you start unless the batteries are fully charged sulphation will start and grow and that to me is a major problem with the smartgauge.

 

The Ah meter type have at least the ability to read tail current and voltsge accurately and tell you when that current has ceased to drop and the battery is fully charged.

 

I am coming the the conclusion that people should be told to charge their batteries at voltage X and to charge the until the tail current is down to 1% of capacity. This is a job an Ah meter can do with accuracy. To buy separate meter with the level of accuracy needed from my research will cost more than Ahgauge.

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I am coming the the conclusion that people should be told to charge their batteries at voltage X and to charge the until the tail current is down to 1% of capacity. This is a job an Ah meter can do with accuracy. To buy separate meter with the level of accuracy needed from my research will cost more than Ahgauge.

 

This may seem like splitting hairs but an Ah Counter can not read amps, that is what an ammeter does even though both those and a voltmeter may be built into the same case.

 

I do not think anyone has suggested that ideally tail current would be used to decide when to stop charging but what on an ammeter tells you when to start charging? Come to that what on an Ah counter tells you when to start charging apart from the voltmeter PLUS the boater following a reading procedure that stands the chance of getting the correct reading. Even taking the Ah taken from a battery is going to be only a roughindication because as far as I know there is no simple meter that gives the actual capacity.

 

The complete ammeter/voltmeter/Ah counter unit requires additional knowledge to be useful, a Smartguage does not.

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They had been told to charge to 90% on their smartgauge.

By whom?

 

Certainly not by the manufacturer, nor by the designer. Nor by anyone who understands the subject. Whoever gave that advice is ignorant of either the SmartGauge, battery charging in general, or both.

 

The SmartGauge manual (and if they've lost theirs it's freely downloadable) states (in part)

Not charging to 100% charge state is one of the most common reasons for premature battery failure. Not charging to 100% (or occasionally well in excess of 100%) causes sulfation of the plates which is the main cause of early battery death.

It also suggests ways to ensure that you do charge to 100% and specifically states that you should not rely on the 100% SmartGauge reading when charging.

 

Commonly offered advice for those boaters who have only a SmartGauge and no ammeter is to charge until SmartGauge reads 100% and then keep going for an hour. This is not ideal, and the cost of the possibly wasted fuel in doing so could easily cover the cost of an ammeter.

 

Tony

 

Edited for tryping

 

We've said a lot of things all along!

Yet it appears that we have to keep repeating them :( Edited by WotEver
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By whom?

 

 

I have not the foggiest and did not enquire. I do know the boater is unlikely to have installed the gauge themselves. I have a niggle it was installed when other electrical work was done on the boat, but can't be sure where he got it from, but he had firmly got it and was carrying it out. Hopefully I have changed his mind.

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This may seem like splitting hairs but an Ah Counter can not read amps, that is what an ammeter does even though both those and a voltmeter may be built into the same case.

 

I do not think anyone has suggested that ideally tail current would be used to decide when to stop charging but what on an ammeter tells you when to start charging? Come to that what on an Ah counter tells you when to start charging apart from the voltmeter PLUS the boater following a reading procedure that stands the chance of getting the correct reading. Even taking the Ah taken from a battery is going to be only a roughindication because as far as I know there is no simple meter that gives the actual capacity.

 

The complete ammeter/voltmeter/Ah counter unit requires additional knowledge to be useful, a Smartguage does not.

Don't think you read my post fully. I said boater told to start charging at voltage X and stop at tail current Y.

 

Both those facilities are easily available on an Ah gauge.

 

The smartgauge does not tell the boater when to stop charging and I understand that the designer suggested other ways to determine the end of charge.

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I think perhaps the advocates of the smartgauge need to think about what they say, for example that it will tell people how long they should charge there batteries for. In the recent experiment reported on here two gauges were tested, unfortunately without a master reference. In that test, stopped when the smartgauge reached 100% with a tail current of 12/13 amps. The other gauge the MS was reading 94% SoC, now with a tail current of 4 amps or less in this case I might have agreed the batteries were at 100%. However, with a tail current of 12/13 amps I believe the MS at 94% was nearer perfect on the mark.

But neither is the perfect answer.

I have just returned from a boat with charging problems. They had been told to charge to 90% on their smartgauge. Now as when charging the smartgauge has an accuracy of +/-10% that 90% could have actually been 81% or 99% or something in between. No matter which the batteries are being under charge, thus allowing a buildup of sulphate. So the battery is charged to 90%, the sulphate hardens and the smartgauge learns the new capacity (90% of the original). Then charged to 90% (81% of original) and more sulphate is laid down and hardens the sgauge learns that capacity. The it is charged to 90% of the 81% of original capacity to 73% of the original capacity and so on and quite rapidly there is a sulphated battery. Now it does not matter at what percentage of SoC you start unless the batteries are fully charged sulphation will start and grow and that to me is a major problem with the smartgauge.

No you are wrong on several counts. First that during my test the tail current was down to below 3% when the SG got to 100%. Some people (including Victron) recommend 4% as the fully charged criteria. There is no right answer, it is a compromise, and you have no information to make a judgement on what the compromise actually is in terms of genny running time vs sulphation. It may well be that 2.6% causes no significant sulphation.

 

If you bear in mind that during the final stages of charging a good proportion of the current goes to gassing, not much goes to adding charge to the battery, and that the current is tapering off, the additional % of AH that could be added by continuing to 1% is not much, maybe 1% of capacity or 2% max. Therefore the AH gauge was way out at 94% and the SG was much closer at perhaps 1 or 2% out.

 

Secondly you have repeated the error you made sometime ago which is to say that if you charge to 90% twice you end up at 81% etc. This is as incorrect as saying that 2+2 = 3 and by repeating it, your argument loses credibility. If you charge to 90% and then recharge to 90% you are at 90%. Over time you may lose some capacity but it certainly won't be 10% each time.

 

The key point is hat if you recharge to 90% you don't instantly get 10% of sulphation, which is what you are saying.

 

Anyway it is a little academic because no-one is suggesting that you routinely charge to 90% without having, say weekly, a charge to 100% and a bit more in order to dissipate any accumulated sulphation.

Edited by nicknorman
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Just noticed this post appear...

 

Think you have misread Nick's experiment,it was stopped when the Amps going into the battery were nominally 2.77% of capacity, how do you compute that to being 2% or so of SoC?

Nope, I have misread nothing. I believe you have misinterpreted the results though. According to many authorities, 3% or even 4% tail current IS 100%.

 

Tony

The key point is hat if you recharge to 90% you don't instantly get 10% of sulphation, which is what you are saying.

Yes, that is key. The 10% figure is out by more than a factor of 10.

 

Tony

Edited by WotEver
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I love the idea of a Smartgauge. I have NO doubts about its accuracy in determining SoC, which is what it was designed to do.

 

If I had enough spare drinking vouchers, I'd have one tomorrow.

 

(PS: Personally, I agree, all of the time, with Nicknorman and Wotever, and a couple of other good chaps, when it comes to electric stuff. I have learned much from these guys over the last 'x' months or so. I DEFINITELY don't bother trying to decipher any other rubbish, from aged, hard-wired opinionated gets. Bloody auto-correct.)

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