Balmar SG-200 Battery Monitor

[rgleason]

Thanks for the post, its good to keep it current.

Add to this MaineSail - who tested the SG-200 and gave it a good review - has said that over 90% of Battery Monitors are incorrectly installed and incorrectly programmed, so the SG-200 is never going to work properly for a large % of users.

There are a lot of serial jumps and opinions here leading to a conclusion that may not be that accurate. 90% Mainesail (all battery moniters) to SG-200 specifically. That does not wash IMHO.


With all the problems we are facing about "facts", lets not muddy the water.

[Mike Crothers]

I am confident I have installed the SG200 correctly. I do not use my alternator to charge my starter battery (charged with a solar panel).



The negative cable from the house batteries goes directly to the SG200 Shunt. Nothing else connects to the input side of the shunt or to the negative terminals of the batteries with the exception of a temperature prop for both the Magnum Charger and one for the Balmar Regulator.



I do not see any way house power is bypassing the SG200 Shunt.



I do understand the solar panels that are connected to the house batteries provide a lot of small incremental charges that the SG200 will have a hard time accounting for. I also have found it best to turn off the solar panels at night and not turn them back on until I have charged the batteries with the generator or engine/alternator so as to avoid confusing the Magnum or Balmar as to the current state of the batteries.

[Stu Jackson]

Originally Posted by rgleason

Thanks for the post, its good to keep it current.


There are a lot of serial jumps and opinions here leading to a conclusion that may not be that accurate. 90% Mainesail (all battery moniters) to SG-200 specifically. That does not wash IMHO.


With all the problems we are facing about "facts", lets not muddy the water.

rg,


Thnx for that dose of sanity.

For the record, Maine Sail did NOT say the coulomb counters do not work. This quote is wrong.

Add to this Maine Sail - who tested the SG-200 and gave it a good review - has said that over 90% of Battery Monitors are incorrectly installed and incorrectly programmed, so the SG-200 is never going to work properly for a large % of users.

What he DID say was that altogether too many skippers either neglect to program them AT ALL or do it incorrectly.

That is why he wrote his "How to Program a Battery Monitor" and why I wrote my "Gotcha" article. Both of us, independently, realized that the instruction manuals, while quite correct in "engineer-speak" were woefully inadequate in explaining the details of the "Why" behind the functions and features. Add to that the clarity offered by many on this and other boating forums about the use of "trailing amps at absorption voltage" and the picture became much clearer. Also once we all got over that stupid "battery fuel gauge" nonsense.

After all this, it is rather simple:

--- a coulomb counter works if the skipper bothers to spend the time to learn how it works and programs it properly.

--- The SG has its use for those who don't like to program equipment. But, it has its limitations and one of its major drawbacks is that it doesn't work well when there is charging present. So, if you have solar, it MAY be an issue for you.

Those who only think they "need" SOH may want to do more research and homework on battery systems, given there seems to be so much angst about it.

I prefer to know what's going back in, because what's coming out is always linear (Amps times time). My energy budgets are always spot on, 'cuz it's that simple. It's what goes back in, with inefficiencies, etc., that make a coulomb counter so useful in the real world.

Your boat, your choice.

[sailinglegend]

Originally Posted by Stu Jackson

For the record, Maine Sail did NOT say the coulomb counters do not work. This quote is wrong.

Originally Posted by sailinglegend

....
Add to this MaineSail - who tested the SG-200 and gave it a good review - has said that over 90% of Battery Monitors are incorrectly installed and incorrectly programmed, so the SG-200 is never going to work properly for a large % of users.

I never said they didn't work ....MaineSail actually said in "How to Program a Battery Monitor":

"To sum it up in simple terms we have yet to come across a properly installed and properly calibrated Ah counter. I know this sounds shockingly surprising, but when you fully understand and comprehend how these devices work, and how a battery ages, it becomes a lot clearer as to why such craziness can be stated."

This is far worse than the older quote of his where he said around/about 90% are incorrectly installed or programmed.....

[Stu Jackson]

Originally Posted by sailinglegend

I never said they didn't work ....MaineSail actually said in "How to Program a Battery Monitor":

"To sum it up in simple terms we have yet to come across a properly installed and properly calibrated Ah counter. I know this sounds shockingly surprising, but when you fully understand and comprehend how these devices work, and how a battery ages, it becomes a lot clearer as to why such craziness can be stated."

This is far worse than the older quote of his where he said around/about 90% are incorrectly installed or programmed.....

I have a lot of respect for MS, but he hasn't seen mine!


Seriously, I knew him "when he was just getting started" and he's a great guy and has contributed more than any gaggle of folks on any subject.



Many of us have implemented what he's written.


With great success.


Maybe he just hasn't seen the fruits of his labors, 'cuz his customers are there because they can't DIY. That's why they come to him, so that's what he sees.



Ya think???

[lateral]

I consider my installation to be technically correct.
For my setup, with mostly day sailing and only occasional deep discharge the sg200 has no value other than a V & A display.

The first firmware release was most accurate for SOC & SOH.
Since latest update SOC is only approx accurate from <60% and SOH sits on 100%
on 5.5yro FLA's. Programming for capacity and taper current per manual.
Basically staying in as backup voltage and current display. Installed Feb 2018.
It will be first to go if I need more instrument space.
No longer a sponsor of this forum? I guess the game must have changed.

[sailinglegend]

Originally Posted by Stu Jackson

--- The SG has its use for those who don't like to program equipment. But, it has its limitations and one of its major drawbacks is that it doesn't work well when there is charging present. So, if you have solar, it MAY be an issue for you.

Thanks for your feedback Stu but I have one further comment on your quote above.

Balmar admit it can't accurately measure the SoC when charging but it does estimate it - like any Ah counting device does - and it will be within 10%. This is much better than any Ah counter that is not properly programmed or installed - which I repeat is over 90% of Ah counters on boats. This is why the Smartgauge was developed in the first place.

[sailinglegend]

Originally Posted by lateral

I consider my installation to be technically correct....
.....
Since latest update SOC is only approx accurate from <60% and SOH sits on 100%
......Installed Feb 2018.

If you followed the Rev A or Rev B installation manual then you will have installed the shunt incorrectly. The circuit diagram was corrected in Rev C in 2019.

See the differences below where the negative cable from the auxiliary or starter battery should go through the shunt to measure the charge current when charging the house battery. Some people can't get their head around why this also doesn't measure the charge current into the Starter battery. (I have an email from Balmar asking me this.)

Manual Rev A & B

wiring.png Views: 140 Size: 112.0 KB ID: 235190" style="margin: 2px" />

Manual Rev C - 2019

wiring.jpg Views: 122 Size: 151.3 KB ID: 235191" style="margin: 2px" />

[lateral]

Originally Posted by sailinglegend

If you followed the Rev A or Rev B installation manual then you will have installed the shunt incorrectly. The circuit diagram was corrected in Rev C in 2019.

See the differences below where the negative cable from the auxiliary or starter battery should go through the shunt to measure the charge current when charging the house battery. Some people can't get their head around why this also doesn't measure the charge current into the Starter battery. (I have an email from Balmar asking me this.)

Manual Rev A & B

Attachment 235190

Manual Rev C - 2019

Attachment 235191

Sorry can't follow you. I have not connected any of aux connections as I'm not interested in monitoring the start battery.
I think it was stated "optional" in manual and my start battery has its own
multimetering. (Not balmar) What that has to do with the SOC/SOH of HOUSE bank I can't imagine. Manual is long gone, poor excuse for, it was.

[sailinglegend]

Originally Posted by lateral

Sorry can't follow you. I have not connected any of aux connections as I'm not interested in monitoring the start battery....

Thanks for your response - it seems you may not have wired the shunt correctly for the SG200 to be able to 'see' the charging amps going into the service battery. When the service bank is being charged it should be obvious because the voltage will rise and amps going into the service bank should also be seen by the SG200. If no amps from the alternator are seen this will give meaningless results on the SG200.

This lack of amps being counted on Battery Monitors is the biggest installation problem I see. Let me explain why:

With a battery monitor installed that has the shunt in the negative cable the shunt becomes the new negative post for the service bank and this should be connected to a new busbar to take all the load negative cables. So the starter battery common negative that connects the starter negative to the house bank negatives must also be connected to this shunt bus bar. This error is probably one of the major causes of battery monitors not reading the alternator charging amps going through the service battery.

So without an Ah counter with a shunt when split charging VSRs or diodes charge both banks together this supplies positive volts to the starter bank and the service bank. The alternator positive goes to the starter battery positive post and the alternator negative is the engine block which goes to the starter battery negative post. Now try and follow the negative return path to the alternator when charging the service battery. This will be via the service battery negative stud and then, via the common negative cable joining the service battery and the starter battery negative stud, which is usually wired to the engine block and hence to the negative of the alternator. All installations must have this common negative to allow the alternator to charge both the starter and the service batteries.

With an Ah counting battery monitor and the SG200, the direct connection to the negative post must be moved to the other side of the shunt - marked cable - which effectively becomes the new service bank negative post to which all negative loads must be connected. Now any amps from the service bank negative back to the alternator will show up on the amp counter.

Moving the starter battery common negative to the other side of the shunt always confuses people because they think the shunt will then also be monitoring the charge current going into the starter battery. This is impossible because current can only flow one way - from the starter battery to the engine block and from the service battery shunt to the starter battery negative - to the engine block.

This needs a diagram - or pencil one out yourself to see why it works.

[witzgall]

Yes, we had an incorrect drawing in the first manual - it was corrected a few months after the initial release. However, the grounds shown incorrectly do not exist on the majority of installations, as they typically would only be needed in an isolated ground system.

What can throw things off quite a bit is if there are ground cables connected to any of the batteries in the house bank that go directly to the negative posts of any other battery - start, genset - whatever. This can have the unintended effect of incorrect current counting, and also really mess with the measurements the SG200 makes to determine the State of Health.

Sailinglegend, can you share a photo of your SG200 installation, so that other cans see how you have it installed? It may serve as a good teaching point.

Also as a request, you are mentioning the "SG" in previous posts, referring to the original (NOT SG200) Smart Gauge. By just using those initials, it can easily confuse any reader who may think you are making comments about the SG200. Best to keep the discussion of that product out of this one? An example above is where you talk about the SG not being good at SoC when a charge source is applied. It would be easy to think you were writing about the SG200, which does quite well at counting up the SoC as charge current flows.

Chris

Originally Posted by sailinglegend

If you followed the Rev A or Rev B installation manual then you will have installed the shunt incorrectly. The circuit diagram was corrected in Rev C in 2019.

See the differences below where the negative cable from the auxiliary or starter battery should go through the shunt to measure the charge current when charging the house battery. Some people can't get their head around why this also doesn't measure the charge current into the Starter battery. (I have an email from Balmar asking me this.)

Manual Rev A & B

Attachment 235190

Manual Rev C - 2019

Attachment 235191

[sailinglegend]

Originally Posted by witzgall

Yes, we had an incorrect drawing in the first manual - it was corrected a few months after the initial release. However, the grounds shown incorrectly do not exist on the majority of installations, as they typically would only be needed in an isolated ground system.

Thanks for coming back after 6 months!!!!

It was the first and second manual that was incorrect!

I think your above quote about my posting is totally incorrect. And do you believe that your clients know what an isolated ground system is? I think you need to explain why my posting was incorrect. I received an email from you that clearly showed you had no idea what I was talking about.

Originally Posted by witzgall

What can throw things off quite a bit is if there are ground cables connected to any of the batteries in the house bank that go directly to the negative posts of any other battery - start, genset - whatever. This can have the unintended effect of incorrect current counting, and also really mess with the measurements the SG200 makes to determine the State of Health.

This is exactly what I was talking about - the house bank negative not going through the shunt.

Originally Posted by witzgall

Sailinglegend, can you share a photo of your SG200 installation, so that other cans see how you have it installed? It may serve as a good teaching point.

I don't have an SG 200 I have the SmartGauge (SG). I am just very concerned that a company like Balmar, that I have always respected, can be making so many mistakes on the SG200.

Originally Posted by witzgall

.....where you talk about the SG not being good at SoC when a charge source is applied. It would be easy to think you were writing about the SG200, which does quite well at counting up the SoC as charge current flows....

Sorry about the confusion - so can you please answer the obvious question - if the SG200 'does well' at counting up the SoC as charge current flows does that mean it is using the amp count to modify the SmartGauge part of the SG200. If that is the case then the 90% or more (your product tester MaineSail's estimate) of shunts that are incorrectly installed or incorrectly programmed means the SG200 will not work for most of your clients.

These are serious questions that Balmar needs to get its head around - or explain in detail why I am wrong.

[newhaul]

My question is is the sg200 any better than the cheap one I installed ?
The only difference I can see is the option for Bluetooth monitoring.
https://www.amazon.com/dp/B07FGFFHC6...ing=UTF8&psc=1

[lateral]

For clarification:
I am only talking about my configuration. Non isolated ground, house/emergency combine/engine switches (3) and ACR to start bat. One of Rods iterations that appealed. All charge sources go to House.
Aux +ve shunt to start battery not connected. -ve start batttery is thru shunt.
Its been the same since install three years ago;Only changes to SOC/SOH readings have been on FW update.
I do struggle with what the start battery -ve thru shunt will do to SG200 processing; Probably minimal as battery gets little use. Unless it is measuring the SOH of start battery, which is 10yrs old. Haha!
I concede my boat use of the device is sub-optimal for best results.
Too busy to do a diagram, but will in future for next owner/poor sucker that inherits
my sound, but flawed, with proof of service, but not perfect, endeavours.

[rgleason]

Sailinglegend for someone writing as you do, I was truly amazed to learn that you don't have an SG200!!!

That one late revelation might have been made clearer earlier. Apologies if it was. because I have not read the whole thread.

Nevertheless strong writing against balmar, without havkng or using using the device does not help credence.