SmartGauge v. Mastershunt

[bizzard]

Mythical wizard which the lady of the lake imprisoned.

[bottle]

 

So it looks to me that SmG can indeed give a false sense of security?

 

The main determinant of battery life being proper charging, not recharging at some mythical figure?

 

Well yes and no but not necessarily in that order.

 

I only ever charged to 95% SOC and very rarely went to 100%. It was only in the last eighteen months that with solar that they got to 100%SOC.

 

So it was not the Smartgauge, it was me that was at fault.

 

I will now be using 'tail current' as a guide because in the last six years I have learnt a lot.

 

The Smartgauge is still useful for the other crew member, for whom it was specifically designed.

[Loafer]

 

Well yes and no but not necessarily in that order.

 

I only ever charged to 95% SOC and very rarely went to 100%. It was only in the last eighteen months that with solar that they got to 100%SOC.

 

So it was not the Smartgauge, it was me that was at fault.

 

I will now be using 'tail current' as a guide because in the last six years I have learnt a lot.

 

The Smartgauge is still useful for the other crew member, for whom it was specifically designed.

 

The tail current is the only way of determining a 100% charge.

 

The Smartgauge is the only way to tell the 'other half' when to fire up the genny, to START the charge (if, for example, the 'first half' is away for a while).

 

Where's the argument? What's not to like? It works, dunnit?

 

 

 

I must add though, thanks to the discussions on this topic (on several threads), I have learned a little bit more than I knew a year ago.

 

All of it has come from a few forum members here, where none of them begin with 'G'.

 

These threads are far more interesting to me than the political bo!!ocks that seems to take up most of the bandwidth available.

 

So a point each for all the moderators, all contributors on this subject, except Mr G, whoever he is. He gets zero points.

 

 

I wish to thank the forum moderators for allowing all this to continue. The only people reading these threads now, must surely be those boring old electrical sparkheads like us, so I don't see any harm. There's no swearing, character defamation, insults, or indeed any other forum rule-breaking, other than the occasional outburst of righteous indignation.

 

Vive la Smartgauge stuff.

 

I wish I had more to contribute, but I don't have a Smartgauge. But I DO wear the scarf.

[George94]

 

The tail current is the only way of determining a 100% charge.

 

The Smartgauge is the only way to tell the 'other half' when to fire up the genny, to START the charge (if, for example, the 'first half' is away for a while).

 

Where's the argument? What's not to like? It works, dunnit?

 

 

 

I must add though, thanks to the discussions on this topic (on several threads), I have learned a little bit more than I knew a year ago.

 

All of it has come from a few forum members here, where none of them begin with 'G'.

 

 

Oh dear. I am going to have to try a lot harder.

[FadeToScarlet]

Another limit is that the test was not of a sufficient duration to see how Ah counter types cope with an ever reducing battery capacity

Well, I can tell you that my Victron BMV yesterday was happily telling me that the batteries were at 99% charge, with only a 0.4A discharge.

 

The voltage was 11.8v.

 

(yes, the batteries are knackered, I'm just eking them out until payday to get some Trojans to replace them!)

[Loafer]

 

Oh dear. I am going to have to try a lot harder.

 

George, I'm terribly sorry old chap. (If you're not old, I'm sorry about that too!)

 

Mistake noted. Any other 'G's out there?

[cuthound]

The tail current is the only way of determining a 100% charge.

 

The Smartgauge is the only way to tell the 'other half' when to fire up the genny, to START the charge (if, for example, the 'first half' is away for a while).

 

Where's the argument? What's not to like? It works, dunnit?

 

 

 

I must add though, thanks to the discussions on this topic (on several threads), I have learned a little bit more than I knew a year ago.

 

All of it has come from a few forum members here, where none of them begin with 'G'.

 

These threads are far more interesting to me than the political bo!!ocks that seems to take up most of the bandwidth available.

 

So a point each for all the moderators, all contributors on this subject, except Mr G, whoever he is. He gets zero points.

 

 

I wish to thank the forum moderators for allowing all this to continue. The only people reading these threads now, must surely be those boring old electrical sparkheads like us, so I don't see any harm. There's no swearing, character defamation, insults, or indeed any other forum rule-breaking, other than the occasional outburst of righteous indignation.

 

Vive la Smartgauge stuff.

 

I wish I had more to contribute, but I don't have a Smartgauge. But I DO wear the scarf.

Specific gravity is another reliable method of ensuring a battery is fully charged. N

However neither tail current of sg is perfect. Tail current can be affected by short circuits within cells and sg can be affected by sulphstion and stratification.

[Loafer]

Specific gravity is another reliable method of ensuring a battery is fully charged. N

However neither tail current of sg is perfect. Tail current can be affected by short circuits within cells and sg can be affected by sulphstion and stratification.

 

Agreed, but specific gravity measurement is a huge faff, even if you can get to your batteries easily. AND you need a new pair of jeans nearly every time.

 

Tail current is a good method if it seen to be reducing normally, I reckon. Any obvious deviations would highlight one of your shorts, wouldn't it?

[cuthound]

Agreed, but specific gravity measurement is a huge faff, even if you can get to your batteries easily. AND you need a new pair of jeans nearly every time.

 

Tail current is a good method if it seen to be reducing normally, I reckon. Any obvious deviations would highlight one of your shorts, wouldn't it?

I agree, except for using sg readings to detect shorts on my batteries which are AGM's. I was being pedantic

[ditchcrawler]

Specific gravity is another reliable method of ensuring a battery is fully charged. N

However neither tail current of sg is perfect. Tail current can be affected by short circuits within cells and sg can be affected by sulphstion and stratification.

I can't imagine me taking a set of specific gravity readings at 5pm every day to see if the batteries are fully charged or not.

[WotEver]

I can't imagine me taking a set of specific gravity readings at 5pm every day to see if the batteries are fully charged or not.

You'd have to be pretty OCD to want to

[dmr]

When charging I find that I usually glance at the Smartgage first to see if I am fully charged, and its only when Smartgage says 100% that I look at the tail current to see how close to 100% things really are. Maybe I prefer those nice red LED numbers to the washed out boring LCD display on the current monitor!

 

Tail current is not quite a perfect indication of 100% charge as a sulphated battery will show a low tail current when its not really really fully charged, this is where specific gravity wins.

 

The Smarthgage reading during charge is just an intelligent timer and this is the one area where I think Gibbo could have done better.

I think the Smartgage should only go up to maybe 97% and should then drop into a much slower mode so that it only gets to 100% after several hours. I hope I am not giving ammunition to the Smartgage unbelievers (SGU's) here.

 

...............Dave

[Loafer]

When charging I find that I usually glance at the Smartgage first to see if I am fully charged, and its only when Smartgage says 100% that I look at the tail current to see how close to 100% things really are. Maybe I prefer those nice red LED numbers to the washed out boring LCD display on the current monitor!

 

Tail current is not quite a perfect indication of 100% charge as a sulphated battery will show a low tail current when its not really really fully charged, this is where specific gravity wins.

 

The Smarthgage reading during charge is just an intelligent timer and this is the one area where I think Gibbo could have done better.

I think the Smartgage should only go up to maybe 97% and should then drop into a much slower mode so that it only gets to 100% after several hours. I hope I am not giving ammunition to the Smartgage unbelievers (SGU's) here.

 

...............Dave

 

Yes he could, but it still doesn't claim to be particularly accurate with charging, so it's still a good instrument at doing what it claims to do. Any user can simply extend his charge if he wishes, regardless of SG saying 100%.

 

I don't have one, but isn't that 'early' 100% reading a compromise, to avoid hours of generator running? If you REALLY want a 0.5% tail current, it takes feckin AGES of genny running!

[WotEver]

Tail current is not quite a perfect indication of 100% charge as a sulphated battery will show a low tail current when its not really really fully charged, this is where specific gravity wins.

Yes and no

 

A low tail current will demonstrate that the battery in its current state is fully charged. A non-increasing SG reading will demonstrate exactly the same thing but will additionally give an indication of how sulphated the battery is. That's assuming that you have open wet batteries of course - not everyone has. However, most boaters will already be aware that their battery has lost capacity by the simple observation that it doesn't last as long as it used to (or the SoC decreases faster if you prefer).

 

If you determine that your battery has lost capacity then you could try one or more desulphation/equalising charges to see if this helps.

 

Tony

... isn't that 'early' 100% reading a compromise, to avoid hours of generator running? If you REALLY want a 0.5% tail current, it takes feckin AGES of genny running!

Yes, because as with all things electrical when running off-grid you have to make compromises.

[nicknorman]

The Smarthgage reading during charge is just an intelligent timer and this is the one area where I think Gibbo could have done better.

I think the Smartgage should only go up to maybe 97% and should then drop into a much slower mode so that it only gets to 100% after several hours. I hope I am not giving ammunition to the Smartgage unbelievers (SGU's) here.

 

Yes I agree. The shape of my graph of the SG SoC on charge is pretty much a straight line, which we know is wrong. If should follow a curve as per the MS AH counter. As you say, it surely wouldn't have been hard to make it count up in that sort of curve.

 

I certainly find it is way out mid-charge (lagging behind) but does eventually end up closing on 100% at pretty much the right time. Gibbo perhaps took the view that it wasn't really important to be able to stop charging at a precise (say) 85%, and of course if that is done anyway, the SG will re-synchronise when the discharge starts.

 

Oh to have the source code, one could make all sorts of improvements!

Edited February 6, 2016 by nicknorman

[dmr]

 

Yes he could, but it still doesn't claim to be particularly accurate with charging, so it's still a good instrument at doing what it claims to do. Any user can simply extend his charge if he wishes, regardless of SG saying 100%.

 

I don't have one, but isn't that 'early' 100% reading a compromise, to avoid hours of generator running? If you REALLY want a 0.5% tail current, it takes feckin AGES of genny running!

It is a compromise and I can see why he did it, but as the most common battery problem (as discussed on this good forum) is progressive sulphation due to constant undercharging I think my scheme would be better. it would encourage people to grasp that they are not routinely getting to 100% and so need to do a big charge every week or two.

 

..............Dave

[Col_T]

Apologies if this is going off on a tangent, but . . .

 

From what I have read on this, and other threads, sulphation can be pretty much fixed by regular equalisation charges or at least the effects can be reduced if it's detected in time. For those with open cell wet batteries, water that gets evaporated off by the equalisation charges can simply be added which is not the case for those, me being one, with sealed low maintenance batteries. This raises a question in my mind - what is the balance between shortening battery life by equalisation charges and reducing the fluid levels within the batteries and reducing battery life by not performing enough equalisation charges? Put more simply, Trojan open cell wet batteries may require a monthly equalisation charge, but wouldn't that regime severely reduce the life expectancy of sealed low maintenance batteries?

[WotEver]

Col, if a boater has shore power and regularly charges his batteries to 100% then his batteries will last a very long time and will not suffer significant Sulphation. I guess you already know that but I mention it to point out that an equalisation charge is not a replacement for regular charging to 100%. Every equalisation charge will damage the battery. They're only done because the batteries have become sulphated due to poor charging.

 

SLA wet batteries have to be equalised much more gently than open ones for reasons you understand.

 

That's a long-winded way of saying that an equalisation charge is never a 'good thing' in and of itself, rather a necessary evil to recover some lost capacity in order to counter poor charging.

 

Better batteries (like Trojan or Rolls) can withstand equalisation charges better than cheap ones, SLA wet don't like it very much, and many Gel batteries state that it shouldn't be done at all.

 

So... if your charging regime means that you regularly fail to bring your batteries close to 100% and only get them up there occasionally you'll be better off with a battery that can withstand equalisation without too much bother.

 

Does that ramble answer your question?

 

Tony

[Col_T]

Surely does, Tony, and provides the reasoning, so many thanks.

[Loafer]

Col, if a boater has shore power and regularly charges his batteries to 100% then his batteries will last a very long time and will not suffer significant Sulphation. I guess you already know that but I mention it to point out that an equalisation charge is not a replacement for regular charging to 100%. Every equalisation charge will damage the battery. They're only done because the batteries have become sulphated due to poor charging.

 

SLA wet batteries have to be equalised much more gently than open ones for reasons you understand.

 

That's a long-winded way of saying that an equalisation charge is never a 'good thing' in and of itself, rather a necessary evil to recover some lost capacity in order to counter poor charging.

 

Better batteries (like Trojan or Rolls) can withstand equalisation charges better than cheap ones, SLA wet don't like it very much, and many Gel batteries state that it shouldn't be done at all.

 

So... if your charging regime means that you regularly fail to bring your batteries close to 100% and only get them up there occasionally you'll be better off with a battery that can withstand equalisation without too much bother.

 

Does that ramble answer your question?

 

Tony

 

Sounds good to me.

[Iain_S]

Yes and no

 

A low tail current will demonstrate that the battery in its current state is fully charged. A non-increasing SG reading will demonstrate exactly the same thing but will additionally give an indication of how sulphated the battery is. (snip)

 

I thught the Smartgauge would go to 100%, no matter how sulphated the batteries are. (Mine does, anyway )

[Theo]

 

I thught the Smartgauge would go to 100%, no matter how sulphated the batteries are. (Mine does, anyway )

As does mine with my poor abused gels.

 

N

[George94]

 

I thught the Smartgauge would go to 100%, no matter how sulphated the batteries are. (Mine does, anyway )

 

It goes to 100% of current capacity. Which might well be 30% of original capacity.

[nicknorman]

I thught the Smartgauge would go to 100%, no matter how sulphated the batteries are. (Mine does, anyway:cheers: )

He meant specific gravity. I think we should have a convention whereby SG is Smartgauge and sg is specific gravity!

[Loafer]

So let me get this right. If you have a sulphated battery that has 50% capacity left, would that show on a hydrometer as 50% discharged?