Balmar SG-200 Battery Monitor

[newhaul]

Originally Posted by JmanC

Looks to me that tying to figure out were 20% is (the lowest you should go) and knowing where 50% is (putting back to storage levels), based on charge voltage is too hard without a full charge then discharge half ah. How else? I was just hoping the SG200 would give a rough idea and make storage easy.

for lifepo4.
good point to use is 3.25 which is about 45% or a multimeter reading of 13.0 volts on the bank when at rest ( about 4 hours with no charge or load. )
no need to be perfect just close . Check bank voltage monthly for peace of mind.

[john61ct]

Well if you'd been using the device on an ongoing basis over time and felt its SoC reading were accurate, then of course just take its word.

As I said accuracy in just what the SoC is just before isolating for storage is not important.

If you were only going to check on them occasionally then I'd say 3.2Vpc.

If more frequently, then 3.1 would be fine.

Just come up with a plan that ensures keeping them well above 3.0.

Simpler is more reliable than complex.

[newhaul]

Originally Posted by john61ct

Well if you'd been using the device on an ongoing basis over time and felt its SoC reading were accurate, then of course just take its word.

As I said accuracy in just what the SoC is just before isolating for storage is not important.

If you were only going to check on them occasionally then I'd say 3.2Vpc.

If more frequently, then 3.1 would be fine.

Just come up with a plan that ensures keeping them well above 3.0.

Simpler is more reliable than complex.

your welcome

[witzgall]

Allan,

Thanks for the feedback. We are looking into both n2k connectivity and allowing relay control.

Chris

For the last item, you can set an alert to give you a screen notification when charging is compete, or at any SoC you wish. Same with Needs charging.

Originally Posted by ayates

Existing features I like:

• Bright very readable display.
• Secondary display capability. I have one display in the engine room, and plan to place a second display in the deck house.
• Nice simple main screen. One big number people that people can focus on is the key.
• Accuracy (I assume).
• State-of-health. This will be extremely interesting to see.

Features I wish it had:

• Logging capability. I have a requirement to log electrical system performance/usage over a two month period each year. I then review and make changes/enhancements for the next season. This could be the discussed NMEA gateway, as there are NMEA loggers available.
• Programmable relay outputs. Ideally I would like two outputs: one that says batteries need charging, and one that says charging is complete (i.e. the generator can be turned off). These would tie into simple LEDs that the crew can follow.

Allan.

[sailinglegend]

Originally Posted by john61ct

Only if the batteries are completely isolated can you estimate self-discharge. No BM will be able to measure that......

This is another very confusing comment of yours.

Of course the SG-200 and the Merlin SG are measuring the effect of any self discharge, they are just not displaying its value.

A shunt based Battery Monitor cannot measure the effect of this this self-discharge, which is just one of the reasons they become so inaccurate as the batteries age and the self-discharge increases. This increase can be due to over zealous use of an hydrometer and the impurities added by not storing it properly or not making sure it its clean and dry before use.

[witzgall]

The SG200 does indeed measure self discharge, as part of Active Impedance Compensation. This process which corrects for measurement errors that are inherent in any shunt based monitoring system, also will account for self discharge, as it does not rely on Coulomb counting alone.

Chris

Originally Posted by sailinglegend

This is another very confusing comment of yours.

Of course the SG-200 and the Merlin SG are measuring the effect of any self discharge, they are just not displaying its value.

A shunt based Battery Monitor cannot measure the effect of this this self-discharge, which is just one of the reasons they become so inaccurate as the batteries age and the self-discharge increases. This increase can be due to over zealous use of an hydrometer and the impurities added by not storing it properly or not making sure it its clean and dry before use.

[john61ct]

In context, my statement was that self-discharge - that of the batteries alone, **isolated from everything** including the BM - cannot be measured by any BM, selbstverständlich.

The AIC calculation of the SG-200 only works if it continues to be hooked up, if it's powered down, its learning history is lost, and the loss off just a few Ah gets lost in the noise.

A very precise CC load test may well pick it up I suppose, but in reality not worth the trouble, given the simple goal with lead of keeping SoC as high as possible.

If the BM **is** attached, then of course its own parasitic draw (yes small in mA) would be added to the batt self-discharge.

Unless some BM were to be externally powered, but I've only seen some BMS with that feature, no BM.

[Maine Sail]

Originally Posted by john61ct

Only if the batteries are completely isolated can you estimate self-discharge. No BM will be able to measure that.

John,

You really need to be a lot more careful in your factually stated statements. If you lack actual experience I would urge you to refrain from posting on subjects or products that you have no direct experience with.

[john61ct]

given the statements above with the context restored, I'd appreciate, as always, any correction if there is an error

[marty9876]

Does anyone have experience changing the default CHARGE V or TAPER CURR values? Per support, charge voltage should be ~.2v below adsorption voltage.

Context of the question: when I first installed the SG 200 I changed the charge voltage to match my absorption voltage settings (custom programmed charging settings on all my sources). After a few light cycles my SOH came back at 100% and I felt pretty good about myself (new gel batteries this year). Then rereading the install manual and they said not to change those settings to I reset things to default\changes battery type to start over. Few shallow cycles later and SOH came back at 93%.

My logic for changing it before was the default charge voltage (14.36v for gel I think) is much higher than my setup (14.1v) so that didn’t make much sense given my charging profiles.

Granted, I got a number I didn’t like so I’m looking to change things until I get a number I like... just curious if anyone has any first hand experience changing these values.

[Delfin]

Originally Posted by marty9876

Does anyone have experience changing the default CHARGE V or TAPER CURR values? Per support, charge voltage should be ~.2v below adsorption voltage.

Context of the question: when I first installed the SG 200 I changed the charge voltage to match my absorption voltage settings (custom programmed charging settings on all my sources). After a few light cycles my SOH came back at 100% and I felt pretty good about myself (new gel batteries this year). Then rereading the install manual and they said not to change those settings to I reset things to default\changes battery type to start over. Few shallow cycles later and SOH came back at 93%.

My logic for changing it before was the default charge voltage (14.36v for gel I think) is much higher than my setup (14.1v) so that didn’t make much sense given my charging profiles.

Granted, I got a number I didn’t like so I’m looking to change things until I get a number I like... just curious if anyone has any first hand experience changing these values.

Yes, I have. For whatever reason, I can't get mine to ever register above 92% SoH. I even changed the capacity value to 500 Ah - it is actually 600 Ah - just to see if I could get it to go to 100%. After drawing down 523 Ah with capacity set at 500 Ah the SoH reads 92%, which clearly is nonsensical. Like you, I think the default values for charge current are off by being too low. I set mine higher, but it is still well below the actual absorption voltage I am using so your comment makes me think I should set it to the actual CV value and see what happens. Just FYI, but I have around 30 cycles since installation.

[lateral]

Late to party. Re self discharge.
Yes, as demonstrated by last numbers.
Zero load, zero amperes from shunt, a month later and SOC 62%. It was 100% when I left it.
I’m talking about SOC wrt to self discharge. Not loss of capacity.
SOH. Is a series of dashes. I think it is trying to tell me that I
Need to buy firefly. Haha!

[Exile]

Are you guys talking about SoH or SoC??

[lateral]

What are you guys using for tail current?
Actual, or 2-4% as in manual.

NOTE: Changing these values can completely stop the calculation of
SoH if the Charge V is set too high, or Taper Current too low, or both.

Oops! Guilty your honour.


And, what happens when you equalize?
Does it skew the SG200's values for a while?

[Delfin]

Originally Posted by lateral

Late to party. Re self discharge.
Yes, as demonstrated by last numbers.
Zero load, zero amperes from shunt, a month later and SOC 62%. It was 100% when I left it.
I’m talking about SOC wrt to self discharge. Not loss of capacity.
SOH. Is a series of dashes. I think it is trying to tell me that I
Need to buy firefly. Haha!

You can get dashes, or at least I have, with a limited number of cycles. As noted, resetting the device, or changing capacity of the bank as I have to see if I can ever get to 100% SoH will also reset SoH to dashes. They will also "pop up" after a reset and after getting some SoH value for a few cycles, then you can get dashes, then they go away as the number of cycles increases.