Charging of domestic batteries

[cereal tiller]

7 minutes ago, WotEver said:

What would he moan about daily then?

There is always something to moan about I guess I am Intrigued re SG, really cant see that a Device that Calibrates itself can possibly be wrong.

Will know for  sure when Mel Merlin has had a chance to Investigate

Edited November 15, 2017 by cereal tiller

[WotEver]

23 minutes ago, cereal tiller said:

 I am Intrigued re SG, really cant see that a Device that Calibrates itself can possibly be wrong

It learns SoC, which is based on voltage. It has to have a reference. It has to know what the voltage is in order to learn. 

[cereal tiller]

1 minute ago, WotEver said:

It learns SoC, which is based on voltage. It has to have a reference. It has to know what the voltage is in order to learn. 

I fully understand that, cannot see how it can go "wrong"though.

[WotEver]

Just now, cereal tiller said:

I fully understand that, cannot see how it can go "wrong"though.

It can’t ‘go’ wrong. But it can be miscalibrated at the factory and be ‘made’ wrong. 

[WotEver]

Example - CD players. They have a crystal oscillator circuit running at a high frequency which is then down-sampled to 44.1kHz. Place 6 CD players alongside each other all playing the same CD and after a very short time they’ll all be at a different place on the CD because they’ll all be running at slightly different speeds. It’s not critical, so they’re not calibrated at the factory so component tolerances are permitted to play their part. Can’t have that on a piece of equipment which has to track voltage very, very accurately. 

[cereal tiller]

3 minutes ago, WotEver said:

Example - CD players. They have a crystal oscillator circuit running at a high frequency which is then down-sampled to 44.1kHz. Place 6 CD players alongside each other all playing the same CD and after a very short time they’ll all be at a different place on the CD because they’ll all be running at slightly different speeds. It’s not critical, so they’re not calibrated at the factory so component tolerances are permitted to play their part. Can’t have that on a piece of equipment which has to track voltage very, very accurately. 

Yep, got that Ok,I do recall that the SG MUST be connected Direct to Battery Terminals and would no be surprised to find that  if those Instruction are not strictly adhered to I.E. supply wiring sharing connections with other Equipment, things could go Awry?

[MtB]

27 minutes ago, cereal tiller said:

I am Intrigued re SG, really cant see that a Device that Calibrates itself can possibly be wrong.

It isn't 'self-calibrating'. It needs to be told what 12.00v and 24.00v looks like initially, at the factory.

On mine, both have been told slightly wrong. When both connected to the same battery at true terminal voltage of say 24.8v, one will read it as 24.50v and the other will see it as 25.20v. They can't both be right! And mine are both wrong. 

Nick reckons the displayed voltage is a rounded version of the voltage the software is reading and using to calculate the SoC. So if the calibration of the voltage detection stage is 0.30v out, this has a massive effect on the calculated SoC.

Edited November 15, 2017 by Mike the Boilerman

[WotEver]

22 minutes ago, cereal tiller said:

Yep, got that Ok,I do recall that the SG MUST be connected Direct to Battery Terminals and would no be surprised to find that  if those Instruction are not strictly adhered to I.E. supply wiring sharing connections with other Equipment, things could go Awry?

Most definitely. Tiny voltage drops down supply cables will throw the calculations out completely. 

[WotEver]

4 minutes ago, Mike the Boilerman said:

Yes. On mine, when both connected to the same battery at true terminal voltage of say 24.8v, one will display 24.50v and the other will display 25.20v. Nick reckons the displayed voltage is a rounded version of the voltage the software is using to calculate the SoC. So if the calibration of the voltage detection stage is 0.30v out, this has a massive effect on the calculated SoC.

Yes, the resolution used internally by SmartGauge is unknown but is certainly much higher than the 1.5 decimal place resolution of the display. Mostly, SmartGauge watches trends, especially subtle ones.  So if it’s at the end of a length of cable that drops 0.01V when the Pump is on then it believes it’s seen a voltage droop at the battery due to a much heavier load. That’s why it matters where it’s connected. 

[MtB]

Just now, WotEver said:

Yes, the resolution used internally by SmartGauge is unknown but is certainly much higher than the 1.5 decimal place resolution of the display. Mostly, SmartGauge watches trends, especially subtle ones.  So if it’s at the end of a length of cable that drops 0.01V when the Pump is on then it believes it’s seen a voltage droop at the battery due to a much heavier load. That’s why it matters where it’s connected. 

 

I fully appreciate that. And this is why it is so important to connect them directly to the battery terminals. 

And I wouldn't be surprised if the volt drop allong say the pump cable on a lot of boats is closer to 1.00v than 0.01v!

[WotEver]

Just now, Mike the Boilerman said:

I fully appreciate that. And this is why it is so important to connect them directly to the battery terminals. 

Yeah, I know you do. I was posting more for the benefit of a new user, unfamiliar with the SmartGauge. 

[cereal tiller]

Just now, Mike the Boilerman said:

 

I fully appreciate that. And this is why it is so important to connect them directly to the battery terminals. 

As the SG learns over several Battery Charge/Discharge Cycles I cannot see that the Volts accuracy is that critical, maybe that is why it isn't?

[MtB]

1 minute ago, WotEver said:

Yeah, I know you do. I was posting more for the benefit of a new user, unfamiliar with the SmartGauge. 

 

I know you know, but I felt Mr Tiller was working around to suggesting I'd just connected mine to some convenient bit of wire nearby

[WotEver]

13 minutes ago, Mike the Boilerman said:

the displayed voltage is a rounded version of the voltage the software is reading

Not so much a rounded version as an interpolation of the measurement. SmartGauge samples the voltage many times a second which would make the display unreadable if directly output. So the interpolation of those measurements ‘slows down’ the display to give something usable. 

[cereal tiller]

Just now, Mike the Boilerman said:

 

I know you know, but I felt Mr Tiller was working around to suggesting I'd just connected mine to some convenient bit of wire nearby

As if I would!you would likely use an INconvenient bit of Wire!

[MtB]

1 minute ago, WotEver said:

Not so much a rounded version as an interpolation of the measurement. SmartGauge samples the voltage many times a second which would make the display unreadable if directly output. So the interpolation of those measurements ‘slows down’ the display to give something usable. 

 

That's what I meant, but I'd forgotten the worm....

[WotEver]

2 minutes ago, cereal tiller said:

As the SG learns over several Battery Charge/Discharge Cycles I cannot see that the Volts accuracy is that critical, maybe that is why it isn't?

But it is. 

Smartgauge learns the trends of your system to better calculate exactly what the batteries are doing, but it must do this relative to a known voltage. 

[MtB]

Just now, cereal tiller said:

As if I would!you would likely use an INconvenient bit of Wire!

 

Nothing was more inconvenient than running a continuous bit of 2.0mm2 cable from the batteries in the back cabin to the galley in the middle!

[WotEver]

1 minute ago, Mike the Boilerman said:

 

Nothing was more inconvenient than running a continuous bit of 2.0mm2 cable from the batteries in the back cabin to the galley in the middle!

You could have looped one from the other...

[MtB]

1 minute ago, WotEver said:

You could have looped one from the other...

 

Not according to page 1982 of the manual....

[cereal tiller]

1 minute ago, WotEver said:

You could have looped one from the other...

Shushhh.......

[MtB]

Or more accurately, not without cutting and joining the cable to the more distant one!

Anyway one is 15m away, the other 2m away. I only connected up the second out of curiosity before taking it to the other boat and installing it. Glad I didn't!

[MtB]

On 15/11/2017 at 19:45, Merlin Equipment Ltd said:

As suggested - here we are Gents & Ladies! If anyone thinks they have an issue with a SmartGauge it's important to us. I am sorry it has taken us so long to catch up. The SmartGauge is an absolutely fantastic product so we clearly need to address your concerns. If anyone has a unit that they believe has this problem then please call us to arrange its return. If we conclude there is a problem then we will replace it immediately free of charge. I will say that we have conducted reviews on a couple of the small number of units returned to us and found there to be no issue however we also don't doubt the experience of many customers on this forum. You know your electrics far better than us. In addition to replacing any units found to be faulty, we will also offer an "at cost" upgrade to our DataCell I or DataCell II battery monitors if you are interested. The DataCell I will monitor multiple battery banks for voltage and SoC. The DataCell II will also monitor SoH (State of Health) as well as other parameters too... (Blame Gibbo - he's still at it!)... 01202 697979

 

A picture paints a thousand words.... as someone once said...

 

 

This one is the more accurate of the two I have on this battery, but it's easier to photograph. The other one reads about 0.4v higher than the BMV702 and the Whispergen. Fluttering around 29.20v.

 

 

Edited November 17, 2017 by Mike the Boilerman
To fiddle with the details

[WotEver]

9 hours ago, Mike the Boilerman said:

This one is the more accurate of the two I have on this battery, but it's easier to photograph. The other one reads about 0.4v higher than the BMV702 and the Whispergen. Fluttering around 29.20v.

So....

 

On 15/11/2017 at 19:45, Merlin Equipment Ltd said:

If anyone has a unit that they believe has this problem then please call us to arrange its return.

 

Which we’ve been saying for months

[rusty69]

3 minutes ago, WotEver said:

So....

 

 

Which we’ve been saying for months

But Mike is on a mission to educate others, not have his replaced/fixed,which he has been saying for months.