Balmar SG-200 Battery Monitor

[john61ct]

I've had great results in three installs.

They are **less** accurate when the system is active, while the bank is not at least briefly at rest.

But still overall **more** accurate than the Ah-counting units I've used, difference is, those do not improve their accuracy in quiescent conditions.

For lead only though, and no ammeter functionality.

3-8% accuracy is about as good as **any** SoC meter gets IME.

Which begs the question, "how can you tell"? Especially in the ranges.

CC discharge load testing is the only way.

[witzgall]

All, I am in Australia right now, and having arrived yesterday quite jetlagged. I hope to address all of the concerns here, but for now, here are some of the issues we are aware of and are working on currently:

1. We have several related issues that affect the SoH. The fix of these should help with some of the complaints here, for example SoH pegged at 100%, or flip flopping between two different values, where one looks accurate and the other not.
2. SoC that is dropping from 100% to 90ish % when the batteries are full, and no significant draw. This is seen mostly in the Lead acid chemistries.
3. With high (Over .3C ) discharge, the SoC drops to 0 well before the battery is exhausted.
4. With high (Over .3c) Charge, the SoC spikes to 100% well before the battery is fully charged.

Keep the feedback coming!

Chris

[witzgall]

One point, if the power is pulled from the SG200, all learning is NOT lost. To save wear and tear on the non-volatile memory, data is written every few minutes. At most a few minutes of learning is lost. The SoH will show dashes, and will be reset during the next charge-discharge cycle.

Chris

[missourisailor]

Originally Posted by Kenomac

Actually, my dissapointment was with the Smartgauge not living up to the hype and the associated zealot behavior surrounding it. I found it to be nothing more than a cheap $10 ammeter. I spent the entire summer 2017 trying to get the thing to work, but despite this, I almost pulled the trigger and purchased the new (and improved) model Balmar SG200 instead of the Mastervolt system I ultimately bought. I’m so glad I went with the Mastervolt after reading reactions to the Balmar SG 200.

No issues at all with the Mastervolt.

Thanks Ken
We must have different SmartGauges because mine doesn't measure Amp's.
No way that it can.

[missourisailor]

Originally Posted by a64pilot

So how many besides Ken have had their original Smart Gauge be inaccurate?

With my SmartGauge, it is dead on when compared to FireFlies SOC vs Voltage graph.

[missourisailor]

Originally Posted by lateral

How do you get accurate readings with the original if you are most always charging?
I though resting was required?

I've asked the same question and the best answer that I've gotten is that the SmartGauge is not just measuring voltage but it is also sending a high frequency signal through the batteries to measure "whatever" it is trying to measure. And this result is added to the calculation.


I know it sounds like smoke and mirrors, but it does seem to work, because the only time I don't have a charge source "charging", is at anchor at night.

[Kenomac]

Originally Posted by missourisailor

Thanks Ken
We must have different SmartGauges because mine doesn't measure Amp's.
No way that it can.

My post should have read “voltmeter” which is what I meant... not ammeter.

[rgleason]

Thanks, good to know.

Originally Posted by witzgall

One point, if the power is pulled from the SG200, all learning is NOT lost. To save wear and tear on the non-volatile memory, data is written every few minutes. At most a few minutes of learning is lost. The SoH will show dashes, and will be reset during the next charge-discharge cycle.

Chris

[a64pilot]

Originally Posted by lateral

How do you get accurate readings with the original if you are most always charging?
I though resting was required?

I only really use it to determine SOC first thing in the morning. I don’t use it to determine when charging should cease as it’s known to be unreliable during charging.
However sometimes at night I’ll look at it if we are watching a long movie or something to sort of get an idea of what we are doing to the bank.

In the morning before Solar starts I’ll look at it and if it says my SOC is 80% and my amp counter battery monitor says we used 130 ish amps we are fine. However if my SOC is down to 75% then I have lost some capacity, and it may be time to equalize.
Now what will really mess with people is if they don’t get the bank to fully charged, then they will use x amps overnight which say may be 10% of the banks capacity and they wake up and the SG says their banks SOC is 70% cause it really is, they don’t want to believe the SG, they want to believe that they were fully charged cause their fancy high dollar Solar controller couldn’t have gone to float too early. It’s not possible, it’s a fancy high dollar controller, so therefore the Smart Gauge is wrong, when it’s not.

The fact that your controller goes into float by noon, does not mean your bank is fully charged. It takes on average roughly 6 hours to fully charge a bank, if your have had 5 to 6 hours of significant Solar by Noon, then in fact you may be fully charged, but it you have only had three hours of good Solar, your not fully charged.

Assuming lead acid of course Lithium is a whole different animal.

However read this article, it speaks to AGM batteries because I believe many people think they charge so much faster than flooded lead acid does, and maybe the do initially, which is irrelevant because with Solar your never limited by the banks ability to absorb the power in the beginning of charging, only much later on, so in the real world of Solar on a boat AGM’s theoretical faster charge rate doesn’t exist.
But anyway a lead acid battery is pretty much a lead acid battery, if your after being fully charged it’s going to take pretty much 6 hours.
You either accept that or accept that this guy is full of it and doesn’t know as much as you do, although it’s hard to argue with actual testing that is recorded and not just going on the light turned green, so I’m charged
https://marinehowto.com/how-fast-can...ry-be-charged/

[Exile]

Originally Posted by a64pilot

I only really use it to determine SOC first thing in the morning. I don’t use it to determine when charging should cease as it’s known to be unreliable during charging.
However sometimes at night I’ll look at it if we are watching a long movie or something to sort of get an idea of what we are doing to the bank.

I thought (from prior threads) that it was also unreliable when the batteries are being used/discharging? Or maybe just less so?

[a64pilot]

Originally Posted by Exile

I thought (from prior threads) that it was also unreliable when the batteries are being used/discharging? Or maybe just less so?

No. It’s only reliable when the bank is being discharged. Which isn’t really true it good at other times too, I guess the best way to say it is that it’s displayed SOC lags behind actual SOC when the bank is being charged, other than that it’s correct.
My amp counting battery monitor and my SG agree within 1% or 2%, but it’s important to note that I get to a real true 100% SOC daily and my amp counter doesn’t drift because of that, if I didn’t get to a real honest full charge it would.
I’m in a Marina with he bank in float and it’s been there for quite awhile, my SG says 99%, to me that 1% is close enough

[Exile]

Originally Posted by a64pilot

No. It’s only reliable when the bank is being discharged. Which isn’t really true it good at other times too, I guess the best way to say it is that it’s displayed SOC lags behind actual SOC when the bank is being charged, other than that it’s correct.
My amp counting battery monitor and my SG agree within 1% or 2%, but it’s important to note that I get to a real true 100% SOC daily and my amp counter doesn’t drift because of that, if I didn’t get to a real honest full charge it would.
I’m in a Marina with he bank in float and it’s been there for quite awhile, my SG says 99%, to me that 1% is close enough
Attachment 196346

What I meant to ask was whether it was reliable when the batteries are no longer being charged and discharging under load. Like when you said you were watching a movie. I recall previous reports of unreliability on both the charging & consumption sides, just not when the batteries are (more or less) at rest (like first thing in the morn, presumably). This is also of course the most reliable time to check your standard voltage meter for the same reasons.

[a64pilot]

I believe it to be accurate during discharging, when we are cruising, there is very little time we are not charging or discharging, with a BD80 compressor running a large poorly insulated spillover and an Engle set to max cold or use as a freezer, we pretty much continuously are discharging 8 to 10 amps.
I looked for Maine Sails test of it, but didn’t see it. As far as I know he is the only one to actually test the thing, by that I mean under controlled conditions with calibrated instrumentation etc.

Nothing is perfect, but I believe that as an instrument to use or tell you your banks SOC fist thing in the morning, it’s tough to beat the original Smart Gauge.
Now anything can be poorly or incorrectly installed or mis programmed and not work as intended. Mine got “wonky” there for awhile. What was the indicator was it’s voltage reading was low, I tracked that to corrosion on the supplied fuses and holders, cleaned them and the voltage readings came back to being correct and very quickly so was the SOC.
But voltage and SOC read way low when there was a high resistance connection, so it would appear that the SG is susceptible to poor connections, but isn’t everything?

Found it after a brief search
https://marinehowto.com/smartgauge-b...nitoring-unit/

[Exile]

OK, your real world experience is most helpful and promotes confidence in the product. Yeah, lots of stuff corrodes but higher quality marine products use materials that withstand it much better than others. Supposedly that's what at least partly justifies the higher prices. But overall, I'd be OK with the SG too if it was only skewed during charging but was reasonably accurate the rest of the time. In fact, until/unless the SG-200 gets better sorted, the original SG -- used in conjunction with my Victron BMV -- would be my preference (as you have pointed out).

[a64pilot]

What I was trying to say is that if you have an amp counter, and the original Smart Gauge, then if your lead acid chemistry you have I believe enough to take care of your bank.
I don’t know enough about LFP to comment, SOC determination would I think be difficult.

It could be argued effectively that if you have a chart of voltage under load vs SOC, then with a good voltmeter that’s all you need.
Lifeline publishes such a chart. That will tell you SOC under discharge and tailing amps at absorption voltage will tell you full charge.

However much has been said about having an energy budget. In my opinion an amp counter is pretty much necessary to develop such a budget, cause without one, your guessing.

I don’t know anything at all about this SG200, but would suspicion that a lot of the issues come from incorrect programming, and I’d guess maybe some of that is the fault of a manual that has faults, makes assumptions, and maybe leaves important data out.

For instance I’m sure my B&G Zeus is likely the Cats meow, but whoever wrote that manual, I’d like to send to an effective communications class.