Smartgauge

[NB Alnwick]

Maybe, but out of interest are there any of the happy Smartgauge users out there, who had a decent panel voltmeter and ammeter before getting the Smartguage?

 

cheers,

Pete.

 

I've still got the ammeter it is useful as it provides an instant indication of how the alternator is charging (or not) but the voltmeter went to make way for the Smartgauge - the latter being capable of doing the same job and more.

 

I havnt got one But I do have a dog..........

 

A dog is no substitute for a tank full of diesel . . .

[Proper Job]

...........

A dog is no substitute for a tank full of diesel . . .

Two threads at once touché

 

He'll not give up you know

[Gibbo]

Maybe, but out of interest are there any of the happy Smartgauge users out there, who had a decent panel voltmeter and ammeter before getting the Smartguage?

 

Does Lionheart No 2 count?

[mrsmelly]

I've still got the ammeter it is useful as it provides an instant indication of how the alternator is charging (or not) but the voltmeter went to make way for the Smartgauge - the latter being capable of doing the same job and more.

 

 

 

A dog is no substitute for a tank full of diesel . . .

My dog is she is only six months old but soon be big enough to tow the boat, wont need diesel............

[RLWP]

My dog is she is only six months old but soon be big enough to tow the boat, wont need diesel............

 

Hey that would be really useful if you ever ran out of diese...

 

Oh

 

Richard

[NB Alnwick]

Hey that would be really useful if you ever ran out of diese...

 

Oh

 

Richard

 

[Gunna Do]

Glad to hear that someone else has had this problem with error EO3! If you check back through the forum you will see that I had similar probs after fitting solar. I was also getting 'overcharge' warnings from my (Beta)engine panel.The only solution that I could come up with was to fit covers to the panels when the engine is running. Obviously when using the motor, plenty of charge is forthcoming. It did come up one more time when moored, loads of sun and full batts so I turned on a couple of lamps. I now have plans to power the fridge from solar when plenty of power is available.

[smileypete]

Does Lionheart No 2 count?

As you're the designer of Smartgauge, I'm afraid not.

 

 

Talking of panel voltmeters, some nice ones on Ebay these days, I'm tempted to get one (clicky)

 

 

 

BTW did you hear back from Bill Darden about his battery voltage/temperature table?

 

I tried it out on a fully charged 12V gel batt, cooling it from 20°C to 6°C. The voltage dropped by ~0.025V

 

I then warmed it back up to 20°C, and... the voltage rose by 0.025V.

 

cheers,

Pete.

[Gibbo]

 

BTW did you hear back from Bill Darden about his battery voltage/temperature table?

 

 

I forgot. I'll do it tomorrow.

 

 

I tried it out on a fully charged 12V gel batt, cooling it from 20°C to 6°C. The voltage dropped by ~0.025V

 

I then warmed it back up to 20°C, and... the voltage rose by 0.025V.

 

 

I thought you'd have given up on this game by now realising it's fruitless

 

But here goes........

 

There will be a measurable temp co with gel batteries (as there will with Elecsols) because they use a lower specific gravity. Temp co is related to SG.

 

Try the same thing with a wet cell (after reading the rest below).

 

Further, a major problem you have is that the capacity changes with temperature. So a battery at (say) 90% SoC is no longer at 90% SoC if you change the temperature. Thus the terminal voltage will change if you simply change the temperature without adjusting the SoC to match the changed capacity.

 

I know you won't want/like to accept this so here's a reference....

 

http://www.batteryweb.com/manuals/techman.pdf

 

From that reference:-

 

 

Actual capacity is a function of ambient temperature and rate of discharge. At 68°F (20°C) rated capacity is 100%. The capacity increases slowly above this temperature and decreases as the temperature falls.

 

 

And this is what you've actually measured because the terminal voltage change purely due to temperature change at less than 100% SoC is the other way round!. Yes, the terminal voltage goes up with decreasing temperature not down. But at 100% it doesn't move.

 

In a normal wet cell at 100% SoC temp coefficient is zero. I know you won't want/like to accept this either so here's yet another reference confirming same....

 

http://books.google.co.uk/books?id=q58IX4BM7-0C&pg=SA1-PA27&lpg=SA1-PA27&dq=lead+acid+battery+temperature+coefficient&source=bl&ots=lP_mkcJe7t&sig=r_6zOUwwN7PGVugIyuWAWwMAeN4&hl=en&ei=lhiRTPnALN-N4gbu9bXsDQ&sa=X&oi=book_result&ct=result&resnum=9&ved=0CEUQ6AEwCDgK#v=onepage&q=lead%20acid%20battery%20temperature%20coefficient&f=false

 

See 1/27 to 1/29

 

I have now produced 3 references confirming this plus the results of my own (proper) tests. I get the feeling I could produce another 100 and you still wouldn't accept it.

Edited September 15, 2010 by Gibbo

[Top cat]

going back to my original question, given our usage pattern of moving on every day and not hammering the batteries in the evening is a smartgauge going to tell me anything useful ?

 

terry

[Pretty Funked Up]

I have those guages Smiley Pete, amps and volts sep. guages.

For accuracy you need to power them independently from the boat bank, otherwise they do exactly what the say on they tin I like 'em

 

edit: mine are on a switched feed from a seperate 10Ah 12v cell.

Edited September 15, 2010 by Pretty Funked Up

[alan_fincher]

going back to my original question, given our usage pattern of moving on every day and not hammering the batteries in the evening is a smartgauge going to tell me anything useful ?

 

terry

My [personal view, (sorry Gibbo!), is that if you never have to charge batteries other than by moving, and you are not trashing them regularly, then it's quite possibly a luxury.

 

It would be for us as non live-aboards, who pile on the miles, but it becomes more marginal if you need to keep levels up on days of no or minimal miles covered.

 

I don't know your circumstances, but if you live-aboard, and spend days iced in unable to move, I'd then be surprised if it were not sometimes useful.

 

Am I being fair to the product ? I think so. There are some people, like us, for whom I have doubts of it's benefits, but I'm not rubbishing the idea for the many people I can see it can help.

 

p.s. Chris W always used to say something like "You can't possibly be charging your batteries enough - I'm sure you are killing them", but whenever I have chosen to use that £3 SmartGauge substitute, (a battery hydrometer), it has always told me that he is wrong, given our usage and charging patterns. And I only have a 70 amp alternator, (one). And I don't have an external alternator controller. Even then he was still wrong, (for our boat, and usage of it).

[Timleech]

 

p.s. Chris W always used to say something like "You can't possibly be charging your batteries enough - I'm sure you are killing them", but whenever I have chosen to use that £3 SmartGauge substitute, (a battery hydrometer), it has always told me that he is wrong, given our usage and charging patterns. And I only have a 70 amp alternator, (one). And I don't have an external alternator controller. Even then he was still wrong, (for our boat, and usage of it).

 

Chris W was never wrong, surely you knew that?

 

Tim

[mudslide]

p.s. Chris W always used to say something like "You can't possibly be charging your batteries enough - I'm sure you are killing them", but whenever I have chosen to use that £3 SmartGauge substitute, (a battery hydrometer), it has always told me that he is wrong, given our usage and charging patterns. And I only have a 70 amp alternator, (one). And I don't have an external alternator controller. Even then he was still wrong, (for our boat, and usage of it).

Ok got to put my twopenneth worth in !!

I'm now the proud owner of 'new' batteries - I've got my 3 quid hydrometer (recently) which did a grand job of showing up the faults in my old setup.

I'm going to use it to check all the cells of the new bank for future reference . I've got a Victron monitor which is good for measuring amps in/out and volts but for measuring true SOC using the hydrometer it would appear that I have to disconnect everything , leave it for at least 2 hours , then isolate each battery (if i want to check voltage) and take it's SG readings - seems to me that a smatgauge would make it a helluva lot easier . I want one but I've blown the budget on batteries - should've contacted Vince sooner - should've bought that hydrometer sooner

Edited September 15, 2010 by mudslide

[Denis R]

going back to my original question, given our usage pattern of moving on every day and not hammering the batteries in the evening is a smartgauge going to tell me anything useful ?

 

Well it will tell you your actual state of charge, but if you're convinced your cruising/charging regime is working for you, don't bother. If battery life is an issue for you, yes, fit one.

 

I'm going to use it to check all the cells of the new bank for future reference . I've got a Victron monitor which is good for measuring amps in/out and volts but for measuring true SOC using the hydrometer it would appear that I have to disconnect everything , leave it for at least 2 hours , then isolate each battery (if i want to check voltage) and take it's SG readings - seems to me that a smatgauge would make it a helluva lot easier .

 

Yep, I too really do have more interesting things to do on a regular basis than clearing a load of stuff out the way, lifting the battery covers and playing scientist. I'm more than happy to let the Smartgauge do it for me.

[alan_fincher]

..............but for measuring true SOC using the hydrometer it would appear that I have to disconnect everything , leave it for at least 2 hours , then isolate each battery (if i want to check voltage) and take it's SG readings - seems to me that a smatgauge would make it a helluva lot easier .

I admit that using a hydrometer is a lot of faffing about, and hardly for regular usage, particularly if your batteries are in a tricky location.

 

However I'm aware of no requirement to let them stand isolated for 2 hours to get a good enough reading.

 

Personally I'd let them settle for a bit if they had just been charged, but, other than that, I don't think you would see significant difference between a reading taken now, and one where you guarantee to have left them unused for 2 hours.

 

I agree with a voltage reading you need to, but if the hydrometer shows your cells at maximum specific gravity, I don't think voltage is going to tell you anything that adds much to your knowledge.

 

My stance is that if I check periodically with a hydrometer, (for my usage pattern), if it's always fine, then I don't need to do it that often.

 

Unless sealed, you need to be going into them to check electrolyte levels anyway, so sticking the hydrometer in too when you have each cell open really represents not a lot of extra effort......

[WotEver]

Talking of panel voltmeters, some nice ones on Ebay these days, I'm tempted to get one (clicky)

I bought 4 of those, connected all 4, and chose to use one of the three that agreed with each other. Another of those three I gave to a fellow boater, one is a spare, and the one which reads 0.1V higher than the others is rattling around in the boot of my car.

 

Tony

[Gibbo]

To take an SG reading you don't need to let them stand. In fact, letting them stand after a charge will make the reading less accurate because the electrolyte settles. To get a proper SG reading you should actually shake them up to stir the electrolyte. Problem is, shaking them up disturbs the sediment at the bottom which stops them working as well.

 

An SG reading will tell you, quite accurately, the state of charge as compared to 100% when the batteries were new. It won't tell you the state of charge as compared to what they are capable of now.

 

A battery that is down to 90% state of health (capacity wise - due to normal ageing), will show a 50% SG reading when it is at 50% of its "as new" capacity. Which will be at 55.5% of its actual capacity. And as you have no way of knowing what the state of health is, the SG reading just gives you a number and you don't know what the state of charge is from it.

 

Also, there are many battery conditions where the SG reading shows a healthy state of charge but in actual fact the batteries go flat shortly afterwards.

 

SG is good as a diagnostic tool for fault finding. For getting an indication of state of charge it's actually pretty poor.

 

Anyone who doubts this should get themselves a tired battery (that doesn't have a duff cell), charge it up fully, take an SG reading and work out the state of charge from it. They'll see it bears little or no resemblance to what that battery is actually capable of powering.

 

I bought 4 of those, connected all 4, and chose to use one of the three that agreed with each other. Another of those three I gave to a fellow boater, one is a spare, and the one which reads 0.1V higher than the others is rattling around in the boot of my car.

 

The photo shows a tweaker. Not that a voltmeter should ever have one but it's there so they can use wide tolerance components to reduce manufacturing costs. It could possibly be tweaked (back) into calibration.

[WotEver]

The photo shows a tweaker. Not that a voltmeter should ever have one but it's there so they can use wide tolerance components to reduce manufacturing costs. It could possibly be tweaked (back) into calibration.

Yeah, I considered that. Next time I remember I'll take my old Avo 8 to the boat (still the best calibrated voltmeter I own) and see how far out the 'all-reading-the-same' ones are. Could well be that the odd one out is actually closest

 

Tony

[smileypete]

going back to my original question, given our usage pattern of moving on every day and not hammering the batteries in the evening is a smartgauge going to tell me anything useful ?

Hi Terry,

 

The alternator charge warning lamp will tell if the alternator is charging or not.

 

However... if the lamp itself blows or becomes loose, the alternator will probably stop working.

 

So a basic car panel voltmeter, wired to the engine ignition circuit with it's own fuse, would give some reassurance.

 

 

I have those guages Smiley Pete, amps and volts sep. guages.

For accuracy you need to power them independently from the boat bank, otherwise they do exactly what the say on they tin I like 'em

 

edit: mine are on a switched feed from a seperate 10Ah 12v cell.

It looks like the one I linked to is 2 wire. If you need to get rid of the battery there are 12V to 12V converters available where the output is isolated from the input: (clicky)(clicky).

 

I also came across an ammeter that claims not to need a separate supply (clicky)

 

I'd also add a choke/inductor and capacitor to protect the converter or meter from spikes and clean up the supply.

 

 

I have now produced 3 references confirming this plus the results of my own (proper) tests. I get the feeling I could produce another 100 and you still wouldn't accept it.

Fair enough, I was just trying to see if the table in the battery FAQ was valid or not. I know about capacity but not SoC falling in lower temperatures. I may do some more testing

 

 

Yeah, I considered that. Next time I remember I'll take my old Avo 8 to the boat (still the best calibrated voltmeter I own) and see how far out the 'all-reading-the-same' ones are. Could well be that the odd one out is actually

Or maybe get a precision voltage reference chip, or even another meter (clicky)

 

cheers,

Pete.

Edited September 16, 2010 by smileypete

[NB Alnwick]

going back to my original question, given our usage pattern of moving on every day and not hammering the batteries in the evening is a smartgauge going to tell me anything useful ?

 

terry

 

The truth is that the Smartgauge is a very clever piece of kit and, provided it is properly installed as per the instructions, it will help you to prolong the life of your batteries and it will save you money. Those people that are sceptical will tell you that you don't need it and can manage without one but they are invariably people who have not installed one on their own boat.

 

It is not surprising that the biggest critics of this product are those that: have not tried it; do not understand it; or both.

[Gibbo]

Fair enough, I was just trying to see if the table in the battery FAQ was valid or not. I know about capacity but not SoC falling in lower temperatures. I may do some more testing

 

Look at this way (ignore Peukert and messy bits for this purposee). We have a battery at a certain temperature that we know from previous tests is exactly 100Ahr at that temperature. It is fully charged. It is therefore at 100% SoC. We remove 10Ahrs. It is now at 90% SoC.

 

We lower the temperature so that the battery loses some capacity and becomes an 80Ahr battery at the new temperature.

 

We have already removed 10Ahrs. That figure of 10Ahrs cannot be changed retrospectively. We have had that energy and used it. So it now has 70Ahrs remaining (the new capacity of 80Ahrs minus the 10Ahrs already used). It has therefore dropped from 90% SoC to 87.5% SoC just by dropping the temperature.

 

If you look up the capacity change with temperature you'll find that the drop in terminal voltage you measured will match the drop in SoC.

 

It is not surprising that the biggest critics of this product are those that: have not tried it; do not understand it; or both.

 

Or those who, because they dont understand how it works, have decided that it can't

[nb Innisfree]

I've had a Smartgauge installed for 12 months now but have been unable to use the percentage reading due to our domestics being under half their capacity, as we have 8 batteries this doesn't present a problem as there is enough collective capacity to give us 24 hrs usage with a reasonable recharge time. We also have a BMV shunt based monitor and with our tired batteries this is by far the most useful using the voltmeter and ammeter to indicate when to recharge and when charging is complete. Though the Smartgauge is a clever bit of kit don't go thinking it will always be the solution to all your battery problems.

Edited September 16, 2010 by nb Innisfree

[blackrose]

Maybe, but out of interest are there any of the happy Smartgauge users out there, who had a decent panel voltmeter and ammeter before getting the Smartguage?

 

cheers,

Pete.

 

Yes, I have a BEP DC monitor which showed amps in/out on my domestic bank, volts on start, domestic and BT batteries, and Amp hours remaining in figures and as % of total capacity of the domestic bank. However my intuition was that the last of these features did not seem very acurate and it often needed to be recalibrated. I bought a Smartgauge and I am very happy with it because it seems to give much more accurate amp hours information. I now have all the functions I need and can also check one monitor against the other.

Edited September 16, 2010 by blackrose

[WotEver]

Or maybe get a precision voltage reference chip, or even another meter (clicky)

Does the phrase "can't be arsed, it's close enough" work for you?

 

Tony