Merlin Smartgauge specifications and accuracy

[Paul C]

Whether there is one faulty Smartgauge, or 1000, isn't the point. Without at least a basic understanding of how batteries behave, the hypothetical "dummy" boater is expected to put their trust into a device without any means of cross-checking its readings are sensible or otherwise. Something of an over-reliance.

 

 

I'll still go along with rather than jumping in with a £150 device, buy a £10 device (a cheap multimeter) and spend a bit of time learning about what readings to expect, when. By this point a basic "power audit" (which shouldn't be scary, but could go something like "If I have a big mains fridge, a big mains freezer, loads of halogen lights, 2 laptops and watch telly all night I'll use quite a lot of power; I'm going to need to recharge for some amount of time") Then as knowledge improves, buy a £25 device (a clamp ammeter) and make some readings. Then the power audit can be refined to "Now I know my laptop consumes 6.4A during charging and 3.2A when its battery is charged; I know my inverter draws 1.5A with no loads; I know what power my lights consume; I know that when my engine first starts, charge is 50A but this drops to 25A and after 6 hours its 3A" etc etc Without the power audit we're still quantifying "quite a lot" and "long time" etc etc

 

Eventually the power audit is quite accurate, and the boater may think "maybe I'm running my engine too little/too much"; "my breadknife is nagging for a microwave, could it work?"; "my breadknife is nagging to use a hair dryer"......ok maybe I've gone too far now.

[WotEver]

Sorry Paul, but you're giving the 'average newbie' way more credit for wanting to understand leccy matters than they generally demonstrate on this Forum.

 

In Mike's thread where he was explaining where he simply doesn't have the time to charge his bank (the thread you linked to a while back) one poster stated words to the effect of "What a lot of numbers. I run the engine till the box says 12.4. When it drops to 12.3 I run it again" (I paraphrase). Do you really REALLY think she wants to go through the exercises you outlined? She wouldn't even want s SmartGauge. She's happy to hammer her batteries and replace them when they're dead. I suggest to you that she's not unique, and she is the type of boater for whom SmartGauge was designed.

[Paul C]

Hope springs eternal.

[smileypete]

From the evidence I'd say yes!

 

Anyway, where have you been, you seem to have been in hibernation since October?

I was very busy at work until the end of the year, plus my mother was terminally ill with leukaemia and sadly passed away at the end of November.

 

Since then I've found I'm not so motivated to reply about technical problems, though it's good to see there are quite a few people who are still willing to help!

 

By the way I found that the latest Google Voice keyboard is fairly good for replying to posts on the smartphone, it's by no means perfect but is around 80% of the way there. Though it keeps trying to call me pizza instead of Pete!

 

cheers, pizza pizza Pete.

[nicknorman]

I was very busy at work until the end of the year, plus my mother was terminally ill with leukaemia and sadly passed away at the end of November.

Since then I've found I'm not so motivated to reply about technical problems, though it's good to see there are quite a few people who are still willing to help!

By the way I found that the latest Google Voice keyboard is fairly good for replying to posts on the smartphone, it's by no means perfect but is around 80% of the way there. Though it keeps trying to call me pizza instead of Pete!

cheers, pizza pizza Pete.

Sorry to hear about your mum. Mine is 92 and still going strong but I know it's just a matter of time.

[WotEver]

I was very busy at work until the end of the year, plus my mother was terminally ill with leukaemia and sadly passed away at the end of November. .

Sorry to hear that, Pete. My mum finally gave up the struggle on New Years Eve. Funeral this coming Tuesday. I feel your pain.

 

As a contrast, I find this forum a welcome distraction.

 

Don't be a stranger.

 

Tony

[George94]

Exactly what I was thinking.

 

EDit.

Edited January 15, 2016 by George94

[Tom and Bex]

We have been living off grid for over a year now and would not be without our Smartgauge. We also have a digital volt meter and shunt based ammeter (less than £10 from China) and although I can make a good guess at soc using those it is so much easier to just glance at one gauge.

 

I like to think I have a pretty good grasp of batteries and boat electrics (thanks in part to this forum) but just like the ease of one simple "fuel" gauge as well as being very simple for my wife to understand if she needs to charge the batteries or can carry on watching a bit more tv with no worries.

 

As to doing a power audit that everyone seems to love talking about on here, I just really can't be bothered. I have the knowledge and equipment to do one but it would be fairly meaningless as our usage can vary massively. I would guess that very very few boaters even on this forum have ever done a power audit. Sometimes our batteries have been down to 35% in the morning, and others only down to 95%. Also we run our washing machine via inverter in the summer. How does a meaningful power audit take account of such varied usage?

 

Finally Smartgauge is pretty good at telling me our cheapest of cheap wet leisure batteries are currently knackered. The soc is far lower in the morning now for similar usage pattern than it was 12 months ago! And yes we do tend to equalise at 16v for a couple of hours about once a month.

 

Sorry for long post but just wanted to give my experience of usefulness of Smartgauge in real life off grid liveaboard use. And to give thanks to the regular electrical experts whose advice and answers I know I can trust!

 

Tom

[WotEver]

Sorry for long post but just wanted to give my experience of usefulness of Smartgauge in real life off grid liveaboard use. And to give thanks to the regular electrical experts whose advice and answers I know I can trust!

 

Tom

No need to apologise, Tom. That was a well written post describing exactly the scenario for which SmartGauge was designed, as used in a real-world environment.

 

Tony

 

Edit 'cos I called Tom Tim

Edited January 16, 2016 by WotEver

[George94]

No need to apologise, Tom. That was a well written post describing exactly the scenario for which SmartGauge was designed, as used in a real-world environment.

 

Tony

 

Edit 'cos I called Tom Tim

 

Just don't call him Tom Tom. That's something else entirely.

[WotEver]

Lol

[sjc]

As seems to be the case recently, most posts are just contributors arguing between themselves, leaving the OP to seek an answer elsewhere as the wide variety of answers tells them nothing !

 

As mentioned earlier in this thread there is no perfect method of measuring SoC, so how on earth can anyone claim 1% accuracy ? Unless you have accurate, calibrated equipment to compare against you cannot possibly claim anything !

 

That said, I considered buying a smartgauge but never did, it seems to me to be a very simple tool for the non technical boater. If you want more this equipment isn't for you, live with ( without ) it !

 

I have no problems with the smartgauge principle, I can only assume the algorithm measures the rate of change of terminal voltage, very simplistic, but probably gives a good enough indicator without getting down and dirty every few days. A very ingenius idea but probably mis-understood by people expecting too much for very little.

 

As with any equipment, it is impossible to fit and forget, the user has to apply common sense in all situations and whenever any gauge alerts you, the first thing to do is to suspect the gauge and do a sanity check. Those of you talking about fault finding on your degree courses take note !

 

The un-calibrated smartgauges out there, do they really need their voltage reading calibrated, in this day and age, a voltage reading is the easiest thing in the world, no calibration required, smells like BS to me...

 

Personally I would like to know my remaining Ah capacity, rather than just having 60% of some unknown capacity, but that's just me. If it was truly for the non technical boater that be the icing on the cake.

 

If at any time you want to know your true battery capacity try the following, I have no connection with them, and cannot claim to know any accuracy levels :-

 

http://www.actmeters.co.uk/battery-testing/chrome-ibt

 

That should stoke the fire somewhat...

[WotEver]

As seems to be the case recently, most posts are just contributors arguing between themselves, leaving the OP to seek an answer elsewhere as the wide variety of answers tells them nothing.

This sentence makes no sense whatsoever. The OP was Nick providing a link to the SmartGauge specs.

 

What answers do you think the OP has been left to seek elsewhere?

 

Tony

[WotEver]

The un-calibrated smartgauges out there, do they really need their voltage reading calibrated?

Here we go again... WHICH uncalibrated Smartgauges? Where are they? Who has them?

 

I keep reading on here about a supposed batch of uncalibrated Smartgauges - I even referred to their apparent existence in one post - but NOBODY has been able, so far, to point to a single one other than the very obviously faulty one that Tommy had.

 

If there are 'a number' of them, where are they? All I see is satisfied users who have confirmed the accuracy of their own gauge by observation and/or testing.

 

Tony

 

As for your 1% query you have obviously not read the specs linked to in the OP.

[smileypete]

We have been living off grid for over a year now and would not be without our Smartgauge. We also have a digital volt meter and shunt based ammeter (less than £10 from China)

 

Which ammeter did you buy in the end? A web link to the model would be a great help.

 

For batteries in daily off-grid use, a good long charge at least weekly can be a great help to keep them in good condition, but that's not always practical - though solar can be a great help when available.

 

Seems to me most batteries are killed by persistent undercharging, and then subsequent capacity loss and over discharging, as surely as night follows day. This is something that Smartgauge can largely help with, though it's not a panacea.

 

cheers, Pete.

smpt

Edited January 17, 2016 by smileypete

[smileypete]

. (duplicate)

Edited January 17, 2016 by smileypete

[George94]

Which ammeter did you buy in the end? A web link to the model would be a great help.

 

For batteries in daily off-grid use, a good long charge at least weekly can be a great help to keep them in good condition, but that's not always practical - though solar can be a great help when available.

 

Seems to me most batteries are killed by persistent undercharging, and then subsequent capacity loss and over discharging, as surely as night follows day. This is something that Smartgauge can largely help with, though it's not a panacea.

 

cheers, Pete.

smpt

 

Indeed, it doesn't actually charge your batteries for you. But it tells you that you need to do it, and whether you have done enough.

 

Some people seem to be expecting a Smartgauge to be a solution to the fact that they aren't doing enough charging. It's not a solution; it's only a guide.

[nb Innisfree]

Indeed, it doesn't actually charge your batteries for you. But it tells you that you need to do it, and whether you have done enough.

 

Some people seem to be expecting a Smartgauge to be a solution to the fact that they aren't doing enough charging. It's not a solution; it's only a guide.

 

Gibbo once pointed out to someone that the reason their batteries were flat was because they weren't charging them properly. The response was to the effect that they thought the Smartgauge prevented them going flat.

 

Folk can be a pain.

Edited January 17, 2016 by nb Innisfree

[Graham.m]

Here we go again... WHICH uncalibrated Smartgauges? Where are they? Who has them?

 

I keep reading on here about a supposed batch of uncalibrated Smartgauges - I even referred to their apparent existence in one post - but NOBODY has been able, so far, to point to a single one other than the very obviously faulty one that Tommy had.

 

If there are 'a number' of them, where are they? All I see is satisfied users who have confirmed the accuracy of their own gauge by observation and/or testing.

 

Tony

 

As for your 1% query you have obviously not read the specs linked to in the OP.

 

Interesting I think it was you who first mentioned them, could have been NM. Mind you it is rare for a one off to happen things like that tend to happen in batches

Gibbo once pointed out to someone that the reason their batteries were flat was because they weren't charging them properly. The response was to the effect that they thought the Smartgauge prevented them going flat.

 

Folk can be a pain.

 

Nowt so query as folk. But unless they are gently educated it is going to happen.

[WotEver]

Interesting I think it was you who first mentioned them

No, it wasn't me. I don't know why you find it interesting.

 

Tony

[smileypete]

 

Indeed, it doesn't actually charge your batteries for you. But it tells you that you need to do it, and whether you have done enough.

 

Some people seem to be expecting a Smartgauge to be a solution to the fact that they aren't doing enough charging. It's not a solution; it's only a guide.

Yeah it doesn't tell you if the charge voltage is correct for the battery type and temperature, and if a proper full charge is done.

 

Still it's a Great Leap Forward for most people and at least prevents gross undercharging, or over discharge, but won't really understand your batteries for you :-).

 

cheers, Pete.

smpt

[John V]

Just saw your post, sorry to read your news.....tough time.

 

What about a new identity, SmileyPizza sounds good

[MtB]

I'm beginning to notice some more odd behavior from my Smartgauge, other than it displaying a higher battery voltage than my selection of DVMs says the true voltage is.

 

Now the batteries are truly on their last legs I'm seeing the SG report them as low as 10% or 15% in the morning after a good beating from leaving the fridge on overnight and several hours on the lappy the previous evening and the digital radio on. Now after charging them in the morning at say 15A for an hour and a half between getting up and going to work, the SG reports them up to perhaps 30% SoC on leaving for work

 

The (possibly) odd SG behaviour I'm noticing is when I get back from work in the evening, the SG is reporting a SoC of typically 50% after leaving in the morning with it displaying 30% and leaving the fridge on all day. WHY has it gone up?!

 

Hard to believe the solar is responsible given it typically charges at 0.1a to 0.5a for a short period in the middle of the day in this light...

Edited January 17, 2016 by Mike the Boilerman

[Loafer]

It could be that the SoC readings are true, as a percentage of your actual battery capacity.

 

If you had a VERY small battery bank, those sort of readings wouldn't be too unusual, I shouldn't think. I don't have a Smartgauge by the way, but I am a supporter.

 

It could be an indication of a dying set of batteries.

 

On the other hand, I have no knowledge of how the Smartgauge responds to even a very small input, during the short days of winter, with solar panels. From what I understand of it, the only time to read a Smartgauge is when there is NO solar input.

[Graham.m]

I'm beginning to notice some more odd behavior from my Smartgauge, other than it displaying a higher battery voltage than my selection of DVMs says the true voltage is.

 

Now the batteries are truly on their last legs I'm seeing the SG report them as low as 10% or 15% in the morning after a good beating from leaving the fridge on overnight and several hours on the lappy the previous evening and the digital radio on. Now after charging them in the morning at say 15A for an hour and a half between getting up and going to work, the SG reports them up to perhaps 30% SoC on leaving for work

 

The (possibly) odd SG behaviour I'm noticing is when I get back from work in the evening, the SG is reporting a SoC of typically 50% after leaving in the morning with it displaying 30% and leaving the fridge on all day. WHY has it gone up?!

 

Hard to believe the solar is responsible given it typically charges at 0.1a to 0.5a for a short period in the middle of the day in this light...

 

Mike,

 

I guess the gauge is correctly installed Have you checked for the same voltage on both end of the cable?

 

If your solar is producing 0.5A and doing that for say 5 hours that would give about 2.5Ah

 

I wonder what the gauge say the voltage is and what your DVMs say it is at the batteries?

 

Is the fridge left on all day or is everything switched off?

Edited January 17, 2016 by Graham.m