Balmar SG-200 Battery Monitor

[rgleason]

@ Chris Witzgall
When is Balmar going to introduce a new external regulator design that:
1. Has easier programming.
2. Connects to the SG200 Battery Monitor to take advantage of current sensing and use SOC for protecting LFP, in particular.
3. Improves charging efficiency.
4. Perhaps has canbus connections for BMS.
5. Extends the SG200 Bluetooth interface to include the alternator.

[Be Free]

Originally Posted by rgleason

MaineSail information about use of SG200 to increase accuracy of SOG and SOH
https://www.cruisersforum.com/forums...ml#post2780484

BTW I asked Chris W. from Balmar about using two shunts in series and he advised it would just cause a small drop in voltage and would not be a problem.

See https://www.cruisersforum.com/forums...-a-211193.html
Also Mainesail advises about use of the BMV-712 shunt.

Mainesail at cruisers forum is Rod at Marine How To.


Sorry, this was intended for another forum where Mainsail is not so well known.

[Peeew]

I am generally happy with my SG200. But an issue seems to come up occasionally. When my batteries are about 50-70% SOC and I draw a large momentary load the voltage will drop for a second or two and the SG200 will show a silly low state of charge (2-8%) from then forward until the batteries receive a fairly long charge. During this low SOC showing the voltage will still show numbers appropriate for the 50-70% state. House bank is 5 firefly 12 volt 116 ea amphours.
I realize that the short lived low voltage is likely triggering this but the voltage profile should help it figure out that the SOC is not correct. Any suggestions?

[Mike Crothers]

I have three 4D gel batteries for 550Ahrs that are 26months old and have died. I was hoping the sg200 would warn me prior to failure but the SOH stayed at 89% for months until overnight the batteries dropped to 10.4 V

We cruise full time and the balmar alternator keeps the batteries charged but the last two months we have been on a mooring and have used the Honda generator with a magnum charger to keep the batteries between 50 and 80percent charge.

I am now shopping for new batterie s and I have upgraded the sg200 software and I am hoping for better results next time but I would warn others not to have too high an expectation of the sg200.

[Peeew]

If your batteries show a sudden drop to 10.4v it might be one dead, shorted cell in one battery. It might be worth figuring which battery it is and separating it from the rest. It might be that you can use the others until you replace the set.

[Mike Crothers]

Thanks for your comment. I had hoped the same thing but wheb we test each of the batteries individually by 30min discharge followed by a 15 minute recharge, all three behaved the same. No smoking gun.

[Peeew]

This might be obvious so excuse me if it is. But you tested each battery while disconnected from the rest?

[rgleason]

Is it possible your Honda did them in?

[newhaul]

Originally Posted by rgleason

Is it possible your Honda did them in?

No the problem was PSOC death

[Mike Crothers]

PSOC partial state of charge. Guilty as charged. Cruising life does not make easy to get batteries above 80% other than going into a marina at$100 plus a night. Maybe new batteries every two years is the cheaper option?

[newhaul]

Originally Posted by Mike Crothers

PSOC partial state of charge. Guilty as charged. Cruising life does not make easy to get batteries above 80% other than going into a marina at$100 plus a night. Maybe new batteries every two years is the cheaper option?

Ok if you want to stay with lead I would recommend you get 4 gc2 ( 6 volt golf cart) batteries that will give you 440ah or 220 usable ah vs your current 550 ah 4d gels with 275ah usable
The cost will be significantly less and the per unit weight is half .
Then I would say we see about getting you a couple hundred watts of solar . Charge with generator early in the day and let the solar do the long tail.
Your other option would be lifepo4 . ( diy is comparable to the cost of your gels. )

[Mike Crothers]

The batteries are located under my bed so I don't feel safe with Lead Acid due to sulfuric acid and hydrogen.



My post is more concerned with why the SG200 by Balmar did not predict the end of life of my batteries. The SG200 consistently had SOH as 89% until the night they went flat.

[bcboomer]

Take a look at Fireflys. They tolerate a PSOC better than any other lead batteries.

[newhaul]

Originally Posted by bcboomer

Take a look at Fireflys. They tolerate a PSOC better than any other lead batteries.

Yes but they will still die from it in a few years .
For the cost of them I would definitely go LFPs I personally built a 250ah bank all in wiring bms and even a 300amp shunt battery monitor under 600 usd.


This chart Adelie put time into should help you a lot

[sailinglegend]

This thread is going off topic. I have posted the below on another thread and have been encouraged to re-post here. (Re: Battery Monitor Comparison - Victron BMV712 vs Balmar SG200)

We need to keep this thread active in the hope that Balmar's product manager witzgall will post with some updates.

6 months ago he said they had identified some common installation faults that were causing problems. Some of these came from their own badly written Rev A and Rev B manuals where they showed a diagram with the common neutral between the service and the starter battery not going through the shunt. That meant when the alternator was charging the service battery that did not show on the Ah count. In a personal email to witzgall he didn't understand what I was talking about!!!!!

The original Smartgauge from Merlin that Balmar also sold worked because it was impossible to install it incorrectly. As soon as you add a shunt and try to count Ah to get the State of Health reading then any loads or charging sources not going through the shunt will make the SoH meaningless. If they also use the Ah count to try and make the State of Charge more accurate then that will be meaningless too.

Merlin were criticized for not including a shunt with their original Smartgauge because they knew it would cause the problems that the SG-200 is now having.

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.