Balmar SG-200 Battery Monitor

[sailah]

Went out to boat today and checked gauge. SoC charge dropped to 76% overnight with no loads and no bilge pump running as i switched those off. Still seeing the 0.3A draw. Goes away occasionally as i watched it.

The house bank was 12.6V, the start was 12.9 so i suspect ACR was still closed. My house bus was methodically done recently so only draw it could be is ACR. I need to parallel both banks with my battery switch and drain them both below 12.75V so the ACR opens. That should isolate things.

Weird the SoC dropped so much but i figure it's still learning.

[lateral]

Dunno why Taper current default in manual is 2-4%C? that is a pretty big range.
Are they trying to keep everyone happy that user has achieved the "holy grail" of
"100%"
I set mine at 1%C. (4.5A) Probably too low.
4%C is 16A+ for me. That is not close to 100% SOC.
6A would be ok. ie 1.4%C deducting 44A for 90% SOH.
So far this unit is extremely user friendly.
Roll on the BT app!!

[Delfin]

Originally Posted by lateral

Dunno why Taper current default in manual is 2-4%C? that is a pretty big range.
Are they trying to keep everyone happy that user has achieved the "holy grail" of
"100%"
I set mine at 1%C. (4.5A) Probably too low.
4%C is 16A+ for me. That is not close to 100% SOC.
6A would be ok.

In speaking with Balmar, I believe you should set this value for what you think is "100%" full. For my 600 amp bank, that is 20 amps, which is 3.4%, and 27.8 vdc for the charge voltage. When the acceptance rate (for me) drops to <20 amps AND the voltage is above 27.8 volts, the SoC should read 100%.

[missourisailor]

Question for Witzgall,


I have a 12vdc system consisting of 6ea Firefies, in two separate boxes.
All 6 are hooked up in parallel with the positive feed connected on batt 1 in one box and the negative feed on batt 6 in the other box.


I understand that the SG200 shunt should be connected at or as close to the neg. feed post as possible. But getting the positive sense lead to the positive feed post will require some length to be added to the lead.


Will it degrade the SC200 performance if I just connect it to batt 4's positive post?

[sailah]

At boat today, no weird 0.3A draw. Put on every load i could, 20A draw. Got voltages down beliw ACR and then shut everything off, 0.0A. So i think that load is just electrons going between house and start.


Everything normal, ran into dock and had on shore power.

Need to do a deep cycle but i keep having to do projects so i keep connecting to shore power.

[lateral]

Same.

[witzgall]

The voltage is a value used for both SoH and SoH calculations. If you connect the positive lead on Batt 4, you would be getting a mid-pack voltage, which may be different over time then the end pack voltage. The draw is milliamps, how far would the total run for to the proper place be?

Chris

Originally Posted by missourisailor

Question for Witzgall,


I have a 12vdc system consisting of 6ea Firefies, in two separate boxes.
All 6 are hooked up in parallel with the positive feed connected on batt 1 in one box and the negative feed on batt 6 in the other box.


I understand that the SG200 shunt should be connected at or as close to the neg. feed post as possible. But getting the positive sense lead to the positive feed post will require some length to be added to the lead.


Will it degrade the SC200 performance if I just connect it to batt 4's positive post?

[rgleason]

For those who are techically inclined, here is some reading.

A Closer Look at State of Charge (SOC) and State of Health (SOH)Estimation Techniques for Batteries Martin Murnane Solar PV Systems, Analog Devices, Inc.Adel Ghazel Chief Technology Officer, EBSYS Technology Inc./WEVIOO Group

https://pdfs.semanticscholar.org/964c/93c82bf2ee272c6491b3cb85a06529e935d2.pdf

and

Estimation of State-of-Charge and State-of-Health for Lithium-Ion Degraded Battery Considering Side Reactions

1. Yizhao Gao,
2. Xi Zhangz,
3. Jun Yang and
4. Bangjun Guo

Estimation of State-of-Charge and State-of-Health for Lithium-Ion Degraded Battery Considering Side Reactions




Is it possible that the SG200 is using the the first paper?

[missourisailor]

Originally Posted by witzgall

..... The draw is milliamps, how far would the total run for to the proper place be?

Chris

From the neg feed post to the pos feed post, pushing about 8 feet (cable length).

[Bleemus]

I wish I could provide feedback on the SG200 but the one I ordered from Rod got stolen by a porch pirate.

I still use and love the original SG though. I have more confidence in it than just about any piece of gear I own.

Cheers,
Keth

[lateral]

Originally Posted by Delfin

In speaking with Balmar, I believe you should set this value for what you think is "100%" full. For my 600 amp bank, that is 20 amps, which is 3.4%, and 27.8 vdc for the charge voltage. When the acceptance rate (for me) drops to <20 amps AND the voltage is above 27.8 volts, the SoC should read 100%.

As I see it, the only way to know YOUR batteries are 100% SOC is by a capacity test at different levels of taper current.
https://marinehowto.com/winter-batte...aracteristics/
As Rod iterates here manufactures shy away from 0.5-1.5% statement which I think is closer to 100% SOC because of the potential for over charging.
<1.5% gives me a higher rested voltage after 24hrs. There is a definite discernible difference from 1 to 1.5%. Gauge default was 2%.

As I don't have the stomach for capacity tests vs taper current I am going to up
my charge termination to 1.5%C and see how the gauge deals with it and follow up with the minor adjustments per p32 of manual.

The other thing that is the definition of a cycle. Should your
shore charger/solar be on a timer if you are not using your boat much over winter to better define "cycle".
Or am I overthinking this? Happy to stop.

[Delfin]

Originally Posted by lateral

As I see it, the only way to know YOUR batteries are 100% SOC is by a capacity test at different levels of taper current.
https://marinehowto.com/winter-batte...aracteristics/
As Rod iterates here manufactures shy away from 0.5-1.5% statement which I think is closer to 100% SOC because of the potential for over charging.
<1.5% gives me a higher rested voltage after 24hrs. There is a definite discernible difference from 1 to 1.5%. Gauge default was 2%.

As I don't have the stomach for capacity tests vs taper current I am going to up
my charge termination to 1.5%C and see how the gauge deals with it and follow up with the minor adjustments per p32 of manual.

The other thing that is the definition of a cycle. Should your
shore charger/solar be on a timer if you are not using your boat much over winter to better define "cycle".
Or am I overthinking this? Happy to stop.

You first have to understand the capacity of the bank before the percentage of charge means anything much in absolute terms. I did a draw down on a 600 hour bank of around 580 amps without getting to 24 vdc, so the 600 amp nominal capacity is what I use. I totalize the Ah consumed via a Link20, so if I take out 300 Ah and the SG200 reads 50%, I can assume it is accurate. Mine is still learning, as I have only done relatively shallow discharges, then partial recharges since I brain wiped it. I expect by next week I'll have enough cycles on a >50% discharge and 100% charge cycles to measure accuracy.

[john61ct]

Note that a "lower" endAmps definition of 100% leads to a **higher** SoC, closer to the battery maker specification of Full.

As the bank ages, it takes longer to actually get there, or with a "too high" defintion (lower endAmps spec) can become downright impossible.

But, as discussed above my understanding was that the SG200 with its automatic adjustment of SoH capacity, measures "from the bottom", so that the owner is expected to just get used to seeing 94%, then 87% etc as the "Full SoC" point, as SoH capacity gets reduced by the bank's wear and aging?

Or am I mistaken about that, and the adjustment being discussed now is a workaround, allowing SoC measurement "from the too", so like all other meters, display of SoC 100% can mean "as high as I want the bank to get" and be adjusted as SoH declines?

[lateral]

Originally Posted by Delfin

You first have to understand the capacity of the bank before the percentage of charge means anything much in absolute terms. I did a draw down on a 600 hour bank of around 580 amps without getting to 24 vdc, so the 600 amp nominal capacity is what I use. I totalize the Ah consumed via a Link20, so if I take out 300 Ah and the SG200 reads 50%, I can assume it is accurate. Mine is still learning, as I have only done relatively shallow discharges, then partial recharges since I brain wiped it. I expect by next week I'll have enough cycles on a >50% discharge and 100% charge cycles to measure accuracy.

My factory capacity was 464Ahrs.
The SG200 sayes 90% SOH.
So I have lost approx 2.5% capacity per year as they are 4yr's old.
I have PSOC'd for the last 4yrs with a sprinkle of equalisations. (1/yr)
I think I've done well!

I am too lazy to do a draw down test. I bought the SG200 for that.
BUT, I had to question the taper current recommended by Balmar because
Rod (& others) have stated different in unrelated tests.
That they (Balmar) have set their SW for the 2-4% taper current is feasible.
To get the charge termination "+" right.
3.4% is way off 100% soc , for my setup. IMHO as stated earlier.
(That imaginary number, 100%).

If Rod sayes its accurate, that good enough for me. Little point in my half-ass testing. I suppose bank specific testing has merit for calibration.
I would be curious to know if he altered the "advanced " settings ie taper current, Perkuerts etc in his tests.
Can't see him letting that past the radar without comment.

[lateral]

Originally Posted by john61ct

Note that a "lower" endAmps definition of 100% leads to a **higher** SoC, closer to the battery maker specification of Full.

As the bank ages, it takes longer to actually get there, or with a "too high" defintion (lower endAmps spec) can become downright impossible.

But, as discussed above my understanding was that the SG200 with its automatic adjustment of SoH capacity, measures "from the bottom", so that the owner is expected to just get used to seeing 94%, then 87% etc as the "Full SoC" point, as SoH capacity gets reduced by the bank's wear and aging?

Or am I mistaken about that, and the adjustment being discussed now is a workaround, allowing SoC measurement "from the too", so like all other meters, display of SoC 100% can mean "as high as I want the bank to get" and be adjusted as SoH declines?

I think the last paragraph is accurate. You decide what 100% soc is and charge termination "+" point.
That charge termination is confusing as it has no control of the charger.
If you charge to inputted taper current, gauge will always show 100%.
Even if it isn't technically 100%.
SOH will continue downward of course.
How I understand it. At this pt.