Balmar SG-200 Battery Monitor

[noelex 77]

Originally Posted by john61ct

All the rest do Ah-counting only

Pico do not agree. From the manual:

“PICO’s algorithm for calculating state-of-charge (SOC) is not a simple Ah-
counter.
It is constantly monitoring battery current, voltage and temperature. These
data are compared to the internal battery model and its parameters are
constantly being adjusted so that the model fits to the actual data.
The algorithm needs some time to adjust the parameters (learning phase)
and it will improve accuracy during the first few cycles.”

[john61ct]

Originally Posted by noelex 77

The algorithm needs some time to adjust the parameters (learning phase) and it will improve accuracy during the first few cycles.”

And as their firmware is improved the reality of the devices' accuracy wrt SoC will I am sure improve.

As that one piece is a very small part of its overall functionality, I am sure it will remain a great choice for many owners in the meantime.

[rgleason]

I am considering asking for this thread to be closed. This discussion is no longer focused on facts about the meter, but seems to have become a diatribe about what is wrong about gauges, including the SG200, and individual opinions, preferences and complaints. I am afraid I am also guilty of this.

As our technology and batteries change, we get more demanding about precision and knowledge. I am willing to wait and see how this works out. In particular, I hope that the bluetooth app will give us a broader window into battery operation. I expect that the next version of this gauge will be different and those differences will become clearer in time.

I do hope we can keep this thread open and useful. And above all, lets be nice and respectful to each other, even though we may have differences in opinion and may have made private judgements which should remain private. I find this group discussion is a high level, and I do learn from everyone. Let's just try to maintain that environment so we can keep the thread open. Thanks.

[sailinglegend]

Originally Posted by rgleason

I am considering asking for this thread to be closed. ....lets be nice and respectful to each other, even though we may have differences in opinion and may have made private judgements which should remain private...

Closing this thread will unfortunately not solve the problem we are seeing here. It will just happen again on the next thread. As the first poster of this important thread please do keep up the pressure to try and steer posters 'nicely' in the right direction.

[sailah]

Or not quote posters who have muddied the waters with bad information. Appreciated by those of us who have used the forum tools to not see these posts.

I'm very much interested in practical, real experience from others who actually have the SG200 as I do. When a thread turns into 40 pages of endless bickering, I tune out. And it's not helpful for those who are looking at one of these to wade through this goliath thread.

The SNR is off the charts. Wheat<->chaff

[Maine Sail]

Originally Posted by sailah

Or not quote posters who have muddied the waters with bad information. Appreciated by those of us who have used the forum tools to not see these posts.

I know one forum member who is posting a lot less here due to what you are referencing...

[TheOffice]

Originally Posted by Maine Sail

I know one forum member who is posting a lot less here due to what you are referencing...

And we are all the worse off because of your reduced presence.

[Delfin]

Originally Posted by sailah

Or not quote posters who have muddied the waters with bad information. Appreciated by those of us who have used the forum tools to not see these posts.

I'm very much interested in practical, real experience from others who actually have the SG200 as I do. When a thread turns into 40 pages of endless bickering, I tune out. And it's not helpful for those who are looking at one of these to wade through this goliath thread.

The SNR is off the charts. Wheat<->chaff

FWIW, I have the SG200 monitoring my LFP bank and the SmartGuage monitoring the LA starter bank. I believe Balmar has determined that the SG200 may not be accurate with larger banks and higher voltages, and that is what I have experienced with my 24 vdc 600 Ah LFP bank. The SoC seems sometimes accurate and sometimes not. SoH has never been higher than 92%, which I think is wrong based on the age of the bank and deep draw downs, with voltages even under load staying above 25 volts.

For example, we're at the dock in Ketchikan right now and I fully charged the LFP bank yesterday on the way in. The SG200 read 100% SoC on termination and 24 hours later the bank is resting without load at 27.2 volts, which indicates a fully charged battery, at least according to Lithionics. However, the SG200 reads SoC of 93%, which must be wrong. The bank isn't going to lose 7% of capacity sitting without load for a day, and if it did, the resting OCV wouldn't be 27.2.

I'm hopeful that the bugs in the device I've experienced will be ironed out and I'm impressed with Balmar's clear determination to get it right. That said, the device seems to work just fine in many installations based on user comments, so perhaps we're an edge case.

[lateral]

Originally Posted by Maine Sail

I know one forum member who is posting a lot less here due to what you are referencing...

Hi Rod,
Guilty of posting aspersions on the products accuracy, because thats a fact in my case.
Perhaps this forum was not the place to expect a answer though.

Seeing you are present, so to speak, a couple of questions, please.
It may help others with similars problems.

*Why is it necessary to set the taper current at less than 100% and then charge past "charge termination"? Somewhat counter intuitive?
As Moonduster on SA said, "If you're thinking that you're going to resolve "full" to within 2-3% of capacity, you need to rethink the problem."
Is this the thinking for this, to optimise the accuracy where it it can be
defined? <90%?

* My SOC is doing what Delfin's is doing. ie Falling off a cliff with NO load.
12.7V 73% (TC set at 1.5%C)
*After a reset, (unintentional) my SOH is stuck on 100% for 4yro batteries.
* Do I need a complete reset or firmware flash, or keep increasing TC?

(464Ahr FLA's, Mark Grasser SCO, Pronautic 1250P)
CV=14.8V, TC=1.5%C, Peukerts default
SG200 =12.7V, Fluke=12.6V
I purchased from you.

Thanks

[ayates]

First comparison SoC between Victron coulomb counting and the SG200. Victron shows 65% and the SG200 shows 45%. Given the battery bank is three years old, it would make sense that the SG200 would show lower value, as it is supposed to show reality rather than ideality.

Though there is something interesting in the displays, as the charger control shows a 52A charge current, yet the Victon CCGX only shows the 6A house current draw. I can't explain that at this point...


Allan.

[CatNewBee]

Originally Posted by ayates

First comparison SoC between Victron coulomb counting and the SG200. Victron shows 65% and the SG200 shows 45%. Given the battery bank is three years old, it would make sense that the SG200 would show lower value, as it is supposed to show reality rather than ideality.

Though there is something interesting in the displays, as the charger control shows a 52A charge current, yet the Victon CCGX only shows the 6A house current draw. I can't explain that at this point...


Allan.

I would say, you contradict yourself in your findings.
If the battery is old and cannot accept that amount of energy any more and the SG smarts it out, I would expect the SG showing the battery is full while the Victron is showing the missed capacity, the value of the SG cannot be explained your way, even if the battery has lost 20%, the SOC must show 100% when the battery cannot accept more charges and is full, SOC does not mean capacity, a battery of 20Ah can be at 100% SOC as well as a 1000Ah battery, it is a relative figure to the capability of charge acceptance.

The current goes directly to your loads, so it is normal, that the current produced differs from the current going into the battery, it can even become negative if you draw more current than your charger provides. The summ of all currents is always 0 in a installation. So the battery is currently charged with the remaining 44A at the moment if your installation is correct, Or you have unmonitored loads that bypass the loads shunt (e. G. inverter directly connected to the battery poles)

Sorry, actually you burn 58A, the 6A are negative on your display, 6A go to the house and 52A to an unmonitored load.

[transmitterdan]

Originally Posted by ayates

Though there is something interesting in the displays, as the charger control shows a 52A charge current, yet the Victon CCGX only shows the 6A house current draw. I can't explain that at this point...


Allan.

Maybe it means exactly what it says. The house loads are 6.2A and the batteries are accepting 46.6A because they are below 50%.

[Maine Sail]

Originally Posted by lateral

Hi Rod,


* My SOC is doing what Delfin's is doing. ie Falling off a cliff with NO load.
12.7V 73% (TC set at 1.5%C)

See #2 in post #527

[ayates]

Originally Posted by CatNewBee

I would say, you contradict yourself in your findings.
If the battery is old and cannot accept that amount of energy any more and the SG smarts it out, I would expect the SG showing the battery is full while the Victron is showing the missed capacity, the value of the SG cannot be explained your way, even if the battery has lost 20%, the SOC must show 100% when the battery cannot accept more charges and is full, SOC does not mean capacity, a battery of 20Ah can be at 100% SOC as well as a 1000Ah battery, it is a relative figure to the capability of charge acceptance.

Not sure about this...

The battery bank is rated at 740 AH, and that was entered into both the Victron and SG units.

Victron says the State of Charge is 66%, which would indicate there are 488 AH remaining (740 * 0.66). The Victron only knows the bank capacity as 740 AH.

The SG says the State of Charge is 45%. I don't have the State of Health figure from the SG, i.e. what the SG thinks the 740 really is, but one can safely assume it is less than 740. So if we arbitrarily pick 600 AH as the bank's current capacity, then 600 * 0.45 = 270 AH remaining.

So I guess the fact that the SG is reporting a lower State of Charge does not imply it is more accurate, but it is fine for it to be lower. If the SG was reporting a higher number, then that would be an issue.


Allan.

[ayates]

Originally Posted by CatNewBee

ISorry, actually you burn 58A, the 6A are negative on your display, 6A go to the house and 52A to an unmonitored load.

Originally Posted by transmitterdan

Maybe it means exactly what it says. The house loads are 6.2A and the batteries are accepting 46.6A because they are below 50%.

I actually think the Victron CCGX has a bug in its calculations. I recall seeing uncomprehendable numbers before wrt the "DC Power" (house load). It only has a shunt which tells it the net current to the battery bank, and it uses telemetry from the battery charger(s) to calculate the DC load. i.e. Charger current - current to battery = DC load.

Looking at this second photo from the end of the charge cycle, the numbers make sense. Charger supplying 33A, 10A into the battery and 23A (337W/14.7V) to the house.

I think in the first photo somehow the Victron has messed up its calculations. Assuming my cabling is correct that is; and there is definitely no possible way the house is drawing 52A, as the 6A figure is confirmed by my house ammeter lower on the panel.


Allan.