Electrical Issues

[MtB]

58 minutes ago, alan_fincher said:

Presumably because the SOC is actually considerably better than the Smartgauge seems to want to tell me?  I must admit I have never really trusted the SG, which seems to show the batteries depleting far faster than I would have expected actual loads I am running.

 

Maybe yours is wrongly calibrated too then. One of mine understates the SOC straight from the box. Merlin went through a patch of sending them out wrong. Mine is about two years old I'd guess. When did you buy yours?

[nicknorman]

1 hour ago, badgerbag said:

From the OP.

Thanks for all the input. To answer the questions:

The engine is an FR2, with a huge pulley on the front end of the crankshaft. The boat is 20+ years old so I'm sure any issues relating to pulley ratios would have been sorted before now.

The engine does need to be buzzed a bit before the charge light goes out, but once out it stays out, and as the light goes out and one can see the needles on the volt meters flick up to 14v (ish).

The alternator output readings were taken from the Smartgauge, with a coat thrown over the solar panel, and have been the same in the 4 years that we have had the boat.

 

If I need to give these batteries an equalisation charge can I use a car type battery charger connected to a shore line? And if so do I have to disconnect the batteries first, as we used to do when we had to charge car batteries periodically during the winter, or is it sufficient to isolate them at the switch?

 

Can anyone explain the issue with the Smartgauge? I must admit that I bought it under the impression that it was going to tell me when the batteries were charged, to avoid running the engine unnessarily. 

 

Am I right in thinking that if, for example, in the morning before starting the engine  the Smartgauge is showing say, 50% capacity on the batteries but 13V on the voltmeter, the the solar is providing something like 0.9V

 

Many thanks

 

Yes you can use a car type battery charger connected to shore power for an equalise. However you need to use the correct type of charger - a “dumb” one, ie an unregulated one. With that sort of charger, the voltage can rise quite high once the current demand diminishes (batteries approaching fully charged). If you use a “smart” charger it will regulate the voltage and then go to float, ie reduce the voltage significantly once it thinks the batteries are charged.

 

As to the smartgauge, it isn’t particularly good at determining when the batteries are fully charged. It will be reasonably close but if it overreads by say 5% that means you might be routinely stopping charging when the SoC is 95% and that will lead to the accumulation of sulphation. Amongst the problems is the fact that “fully charged” isn’t defined and neither can absolutely “fully charged” be realisticall achieved. During charging, the state of charge increases at an ever decreasing rate - ie it takes longer and longer to add those last little bits of charge. To put it technically, 100% SoC is only asymptotically approached, never actually achieved.

 

This means that one has to compromise and consider “fully charged” to actually be something slightly less than 100%. But where the compromise is set is up to you and there isn’t much consensus. Generally it is determined by measuring the charge current, which gradually tails off as the batteries approach fully charged. The “tail current” is expressed as a percentage of the batteries’ capacity. Some people say 4%, some 2% but really, if you want to properly fully charge your batteries it should be more like 1% or less. So 1% of you 220AH batteries would be 2.2A. But be warned, going from say 4% to say 1% will take several or even many hours.

 

Unfortunately lead acid batteries take a very long time to fully charge and if you don’t do so regularly, they lose capacity due to sulphation. 

[alan_fincher]

3 minutes ago, Mike the Boilerman said:

When did you buy yours?

28th March 2017

[MtB]

2 minutes ago, alan_fincher said:

28th March 2017

 

Towards the end of the dodgy period, probably.

 

Someone from Merlin pitched up on here and took note of the problems and got future production fixed, it appears. No action was taken to contact existing owners of all the dodgy gauges sold though.

 

Ok just checked. User "Merlin Equipment Ltd" joined here on 15th November 2017. So yours is well within the dodgy period.

[Detling]

The Smartgauge also cannot tell you SOC immediatly you stop charging due to the surface charge which will take a bit of load to discharge, also if you have solar you are effectively charging until dark even if only a few millamps.

[Col_T]

2 hours ago, Detling said:

The Smartgauge also cannot tell you SOC immediatly you stop charging due to the surface charge which will take a bit of load to discharge

I have heard it said, on this very forum, that surface charge is just part of the charge in the battery - it may be used more quickly than charge that has to come from deep within the cells, but it's charge none the less. So, two things:-

 

• is this actually correct - can't think why it shouldn't be, but I have a lot to learn;
• if this is correct, all that will happen is that Smartgauge SoC will fall rapidly while the surface charge is 'burned off'?

 

[nb Innisfree]

I'm sure Gibbo would have taken surface charge into account when he designed the SG. 

[Richard10002]

45 minutes ago, nb Innisfree said:

I'm sure Gibbo would have taken surface charge into account when he designed the SG. 

Somebody here said that Gibbo said to them, something like, “Smartgauge isn’t accurate when discharging until it gets below 80% - and why would anybody care?”

 

The manual says that it isn’t accurate at all when charging. It doesn’t say this until near the end of the manual.

[Alan de Enfield]

3 hours ago, Detling said:

The Smartgauge also cannot tell you SOC immediatly you stop charging due to the surface charge which will take a bit of load to discharge, also if you have solar you are effectively charging until dark even if only a few millamps.

 

8 minutes ago, Richard10002 said:

Somebody here said that Gibbo said to them, something like, “Smartgauge isn’t accurate when discharging until it gets below 80% - and why would anybody care?”

 

The manual says that it isn’t accurate at all when charging. It doesn’t say this until near the end of the manual.

 

Smart Gauge : A bit like shiny new fishing lures - they catch more fishermen than they do fish.

 

 

[TheBiscuits]

1 hour ago, Alan de Enfield said:

Smart Gauge : A bit like shiny new fishing lures - they catch more fishermen than they do fish.

... and the odd boilerman ...

[rusty69]

11 minutes ago, TheBiscuits said:

... and the odd boilerman ...

He's not that odd! 

[WotEver]

3 hours ago, Richard10002 said:

The manual says that it isn’t accurate at all when charging

No it doesn’t. 

[Alan de Enfield]

[mrsmelly]

You need a voltmeter and an amp meter or better still a bm2 or similar. Watch the charging ampage which starts high and gradually drops as the voltage rises. Forget the stoopid bit at the end which supposedly show a you percentage charge as it will always or near as damn always be incorrect. When voltage is 14.4 and amps going in down to about 2 amps ish for about an hour then yer charged. I sometimes switch off at 14.3 because it's all a trade off between fuel use age and engine wear and noise versus battery replacement cost. Forget the not so smart gauge. I am not an electrical expert just a bloke who's lived aboard eight boats for a long time and this way works.

[Richard10002]

1 hour ago, WotEver said:

No it doesn’t. 

It obviously doesn’t use those exact words, but that is what it implies. Recalling a bit more, I think it says it can be 10% wrong... seems fairly inaccurate to me, and I’d guess it could have been responsible for more than a few people sulphating their batteries prematurely.

[WotEver]

56 minutes ago, Richard10002 said:

It obviously doesn’t use those exact words, but that is what it implies.

Not really, no. It doesn’t imply that it ‘... isn’t accurate at all while charging.’  What it actually says (in part) is:

 

During charging, SmartGauge only shows the calculated charge status as does an amp hours counter however SmartGauge, because it operates on a different principle, calculates a charge status that is much more accurate. For this reason, it is possible that, during the charge cycle, the charge status displayed may not be totally accurate. It will be within 10% of the actual battery charge status.

[MtB]

15 minutes ago, WotEver said:

During charging, SmartGauge only shows the calculated charge status as does an amp hours counter however SmartGauge, because it operates on a different principle, calculates a charge status that is much more accurate. For this reason, it is possible that, during the charge cycle, the charge status displayed may not be totally accurate. It will be within 10% of the actual battery charge status.

 

It missed out a crucially important piece of information.

 

"This only applies when the instrument has been correctly calibrated."

 

And some weren't, as any fule kno. 

[Richard10002]

3 hours ago, WotEver said:

Not really, no. It doesn’t imply that it ‘... isn’t accurate at all while charging.’  What it actually says (in part) is:

 

 

 

 

Whilst saying that it is way more accurate than an amp hour counter, (NASA BM2), he is also saying that, because it can be out by 10%, dont rely on it as it’s the main cause of early Battery death. I’ll quote the most important part of the instruction/advice, which doesn’t appear until page 23 of 29 of the small print manual:

 

“For this reason it may not be wise to place too much faith in the charge status during charging. SmartGauge will certainly give a very good indication (certainly better than an amp hours counter – and certainly better than a volt meter [which will tell you nothing more than that the batteries are charging]) but it could be that SmartGauge shows the charge status to have reached (as a worst case example) 100% when in actual fact the batteries have only reached 90%.

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.

Therefore, as when using any form of charge status meter, if using an intelligent charger, do not shut the charger down when charge status meter indicates 100% charge status. Instead, rely upon the charger, which can reach a much more accurate measurement of when the batteries are actually fully charged.”

 

The fact that it is more accurate than something that is completely inaccurate, doesn’t make it accurate. The writer doesn’t give the above warning because he believes the monitor to be accurate.... he gives it because he knows it is not accurate.

 

Why do you defend it so.... it does a good job of guiding you to charge your batteries. It also helps to calculate capacity remaining if used in conjunction with an amp hours counter.... but it does not tell you when your batteries are full, such that you can stop charging.

[Tony Brooks]

To add;

 

On no account even think about running a three way (gas, 12V & mains) fridge on 12v and also 240V AC you WILL wreck your new batteries.

 

You say SMALL fridge. Be wary of any that do not have a proper compressor, if its a Peltier solid state cooler it will be very electricity hungry and again may well wreck your battery.

 

Be aware than the cheaper an inverter is the more unreliable it will tend to be and more to the point will use more electricity just working itself than a brand name one.

 

12v car chargers work fine for phone I find although you may have to pay if your phone maker insists on using proprietor connectors and charger. Ditto powering/charging a lap top or tablet.

[WotEver]

8 hours ago, Richard10002 said:

Why do you defend it so.

I don’t. I simply correct lies such as “the manual states it isn’t accurate at all during charging”. Stick to the facts and I won’t feel the need to correct anything. 

 

Smartgauge is easily the most accurate SoC display on the market when using your batteries. It will show you when to start charging, or at the very least stop discharging. Knowing this will maximise your battery life. How many folk post on here saying “My inverter keeps cutting out on low voltage...”? If they had a SmartGauge they would never have got to that stage where the batteries are now ruined. 

 

When charging, it’s best not to rely on any gauge from whatever manufacturer to indicate 100%, but rather to use an ammeter or hydrometer. If you do rely on the SmartGauge to tell you when you’re at 100% you might either undercharge your batteries or waste diesel, neither of which is a good idea. Should you ignore that advice then as soon as you start using your batteries then SmartGauge will resync, and you’ll either see that the batts weren’t at 100% (because it read high), or that they are at 100% (because it was either accurate or read low). Generally it’s within 5%, from limited observation. 

[MtB]

42 minutes ago, WotEver said:

I don’t. I simply correct lies such as “the manual states it isn’t accurate at all during charging”. Stick to the facts and I won’t feel the need to correct anything. 

 

 

So which bit of “the manual states it isn’t accurate at all during charging” is wrong, given Richards copy N paste from the manual in post 43, which seems to say exactly this?

 

I suppose it could be read that it might be right, but don't rely on it. 

[Tony Brooks]

I think that we all accept its not so accurate while charging BUT it is more accurate than any other consumer device in the hands of an average boater. If the other devices are set up and installed by someone with the knowledge to keep then accurate then that user would not need anything more than a voltmeter and ammeter so we really are talking about a typical boater.

 

Without a Smartguage we know from endless questions on the forum boaters wreck their batteries but with one the rate of wrecking  will be reduced. Add am decent ammeter and knowing how to interpret it and the rate of wrecking will be reduced again.

 

Now, I am sorry Mike your battery problems were   as far as I can see caused by a faulty Smartguage and to a large extent you not realising that ideally you should recharge every day. Even if you had a dead accurate amp hour counter you would have still wrecked your batteries by leaving them longer in a discharged state. You can't blame the Smartguage (apart from its poor calibration) but maybe you can blame the Forum for not making you aware how important daily charging is for optimum battery life. You would have a valid complaint about the calibration IF you had returned it and it came back in the same state or Merlin had refused to deal with it..

 

However inaccurate the Smartguage is during charging it is by far the most accurate battery monitor available to typical boaters and especially the technically or electrically illiterate.

 

I just wish the usual suspects would stop knocking the Smartgauge and start trying to explain to posters how to get the best out of it and what other battery monitoring compliments it very well indeed.

[alan_fincher]

10 minutes ago, Tony Brooks said:

I just wish the usual suspects would stop knocking the Smartgauge and start trying to explain to posters how to get the best out of it and what other battery monitoring compliments it very well indeed.

 

I don't know if I'm a "usual suspect" or not.

I don't know if my SG is wrongly calibrated, as I don't have access to a highly accurate voltmeter to check, although comparison to several "standard" multimeters imply it may well be inaccurate.

From what Mike says, there was quite a long period where inaccurate ones may have been supplied.

That to me implies a lot of people may be trusting what are wrong answers.

It really isn't acceptable that something that needs accurate calibration may have apparently been supplied in significant numbers without actually getting it.

I don't have a problem with the basic concept - but there does seem to have been a major problem with Merlin's quality control.

[MtB]

1 hour ago, alan_fincher said:

 

I don't know if I'm a "usual suspect" or not.

I don't know if my SG is wrongly calibrated, as I don't have access to a highly accurate voltmeter to check, although comparison to several "standard" multimeters imply it may well be inaccurate.

From what Mike says, there was quite a long period where inaccurate ones may have been supplied.

That to me implies a lot of people may be trusting what are wrong answers.

It really isn't acceptable that something that needs accurate calibration may have apparently been supplied in significant numbers without actually getting it.

I don't have a problem with the basic concept - but there does seem to have been a major problem with Merlin's quality control.

 

 

Yes ^^^this^^^

 

There are two separate complaints about Smartgauge which get conflated, and ought to be discussed independently of each other:

 

1) There was a period when Smartgauges were sold wrongly calibrated. As gets pointed out, this doesn't really matter if the SG is used only to know when the batteries are getting flat and need re-charging.

 

2) People tend use the SG to judge when the batteries are fully charged because the display still displays a state of charge during charging.  The manual tells you not to use it for this, but only buried in dozens of pages of densely packed highly technical small print.

 

My solution to this would be for the display to read say "charging" rather than displaying a steadily climbing and highly credible (yet unreliable) number. People tend to believe the big red clear number and who can blame them? 

 

The manual ought to make this clear RIGHT AT THE FRONT on the first pages people read. But it doesn't do this because it conflicts with the marketing stuff that claims it is a 'fuel gauge for batteries'. 

 

 

 

Edited August 6, 2018 by Mike the Boilerman
To correct grammar in two sentences

[Tony Brooks]

I agree on both counts and its a same Merlin did not do all they could to inform customers of potential problems and sort them. Regrettably we have seen time and time again how politicians allow makers of stuff to ride roughshod over consumers. Tumble driers and certain cars spring to mind and i would add Merlin over the Smartgauge. However we are at where we are so need to make the best of a bad job.

 

If anyone thinks their Smartgauge might be inarticulate then back to Merlin it should go and if they do not play fair then the forum should be told - plus the boating press.

 

Until Merlin modify the Smartguage along the lines Mike suggests then it is up to us to try to educate users.