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Battery problem

May 6, 2010
392
1984 Oday 39 79 Milwaukee
On our new boat, our Balmar SG200 goes goes from 100% soc to less than 75% soc over the course of a few days with no electrical loads. When I run the engine (or plug in to shore power) it takes about 45 minutes to get to the mid 80% range, then suddenly it will go to 100%. Our boat is on a mooring with no solar, and when we are on the boat overnight the house loads (we have all LED lighting and no refrigeration or heavy consumers) will draw it down slightly, but then by the next day it will drop quickly to low 80s. Some background information follows:

One of the projects on our new boat was complete re-wiring of the engine harness, new engine instrument panel, new AC/DC panels, new charger, batteries, ELCI, external voltage regulator, ACR, etc. The alternator is an older Balmar 91-75 rebuilt to 90amp. The boat came with a Balmar BRS-II regulator that was only allowing <14 volts output. During our delivery we motored the majority of the 3 days. After that the engine was run for an hour or two for a couple of days on the weekend. The new regulator is a Balmar ARS-5, programmed using the charging specs from my battery manufacturer. When I monitor the output it reports that it is doing exactly what it is programmed to do. Along with all of that I installed an SG200 battery gauge. The boat has a house bank of two group 31 batteries, and a group 27 reserve battery. When we bought the boat it was 400 miles away, and I made many weekend trips over the winter preparing it so sail home. I installed the batteries early this year, they had a full charge, but were not used until April when the boat was launched. The boat spent two weeks in the water prior to our delivery, and during this time the ProMariner charger was left on, because I wanted the bilge pump to be able to run as much as necessary since I was not there to monitor the boat. I programmed the charger for the house bank prior to using it. I plan to take a refractometer to the boat today to check the cells in both batteries as I am not sure what else could be causing this?
 
Oct 22, 2014
10,209
CAL 35 Cruiser Portland OR, moored EVERETT WA
goes from 100% soc to less than 75% soc over the course of a few days with no electrical loads
The drop from 100% to 75% would cause me to question the "no electrical loads". You may have a load the is not evident... e.g.wired to battery Bilge pump etc... What leads you to believe there is no load on the system during the period of apparent discharge? Have you monitored the meter for voltage / amp load or just SOC?

then suddenly it will go to 100%
If you are charging the batteries it is sometimes possible for the meeter to believe it has reached a 100% state of charge bit it is only a surface charge on the plates. Once the plates have rested the surface charge disapates and the tru state of charge is shown. I note in in the Balmer manual the the Meter is constantly learning the SOC of your batteries. It improves it's ability over time and usage.
then by the next day it will drop quickly to low 80s
Not sure why the drop unless you have a load on the battery the is not understood.

I like the idea of exploring the cells with your refractometer. You might isolate the main batteries and see if they are equalized. One bad battery could be drawing down a good one.

Let us know what you discover.
 
Nov 7, 2011
2,510
Catalina 30 Mk II Barnegat, NJ
I noticed the same type SOC numbers when I first installed my SG200 in the spring before launch. It was either under 80 or at 100 SOC. I chalked it up to being a slow learner since it was not seeing actual use and the surface charge was tricking into thinking it was at 100%.

After a few weeks of being in the water and learning my sailing (usage) and charging routine the accuracy improved.

As @jssailem mentioned, try monitoring your amperage use with the SG200, noting it is real-time usage displayed. It won’t read your bilge pump amp draw unless it is running.

And double check that all negative wires go to your negative busbar, that none have snuck onto the battery post except for the main cable to the SG200 shunt.

Good Luck!
 
May 6, 2010
392
1984 Oday 39 79 Milwaukee
Gauge shows no loads, and nothing is connected to batteries except the SG200 shunt, and the battery temp monitor for the voltage regulator. The SG200 reports 100% SOH, 12.7v, --.- time remaining, and 70% SOC. When I left the boat Sunday SOC was 84%. I checked all cells in both batteries with a refractometer and all were 1.25 +/- .01. This seems low for batteries less than half a year old and not used for half of that time, but I don't know what "normal" would be.





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Nov 7, 2011
2,510
Catalina 30 Mk II Barnegat, NJ
Not sure if you mean when charging with the motor or with the battery charger.

I stopped using the battery charger for a week so I could draw down the batteries a bit and see what the alt would put out. It was down to about 55% when I ran the motor to read the amp output. I then plugged in the Sterling ProCharge Ultra. It got up to 70% in a few hours but it took 2 or 3 days for it to bring the batteries up to 100%.
If you on a mooring and relying on the motor to charge the batteries that could take quite a while to get it up to 100%.
 
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Feb 5, 2004
3,934
Tartan 3800 Westport, MA
it took 2 or 3 days for it to bring the batteries up to 100%.
How were you determining 100%, by the meter? It shouldn't take 2 to 3 days, even with a relatively low output charger, once you've gotten past most of the bulk and absorption phase. If 100% SOC is defined as I =< 2% C (20), then it should only be an hour so from the .1C point.

You really have to know the battery manufacturer's recommended absorption voltage and max bilk current.

Sounds to me like the OP's batteries may be sulfated. You can get brand new sulfated batteries, if they aren't fresh and haven't been stored properly. They will appear to charge fast, and they will discharge even faster.
 
May 6, 2010
392
1984 Oday 39 79 Milwaukee
You really have to know the battery manufacturer's recommended absorption voltage and max bilk current.
I have the specs, and have my voltage regulator programmed accordingly.
From East Penn:
Float 13.5V
Absorb 14.55V
Bulk 14.85V
Equalize 15.75V

They don't list a specific gravity though.
 
Feb 5, 2004
3,934
Tartan 3800 Westport, MA
There's something odd about the spec you cite, which is there's typically not a voltage spec for bulk. What model is the battery?
 
May 6, 2010
392
1984 Oday 39 79 Milwaukee
There's something odd about the spec you cite, which is there's typically not a voltage spec for bulk. What model is the battery?
SLI31MDC. Bulk is one of the parameters to program with the Balmar regulator.
 
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Feb 5, 2004
3,934
Tartan 3800 Westport, MA
Interesting. I will look at the Balmar manual, but at this moment I have no idea what a bulk voltage parameter might mean.
 
Nov 2, 2017
9
Delphia 37 Bayfield
From everything I’ve read online, conversations with Balmar support and Balmar product managers the SG-200 needs a firmware update in certain situations before the results can have much of any creditability. Typically the issues are around SOH which you haven’t reported much on - my guess is both your SOH and SOC are ping ponging around (one drives the other and vice versa to my limited understanding). It’s an identified known issue bouncing between two SOH values, lower being the truth I’m told.

To update the firmware you will need the yet to be release Bluetooth adapter ($~65.00 I think) which hopefully is out in a few weeks. I’m a little miffed at the product being over hyped/marketed/talked up but in all honestly I’m most upset at cutting a 2”+ hole to mount this thing should it prove to be a complete dud.

$65 is cheap in boat dollars so I’m committed now as my nav station install was in the wood panel and no undoing that one.
 
Feb 5, 2004
3,934
Tartan 3800 Westport, MA
O.K., I was able to find the Balmar regulator manual, but not a data sheet for the batteries you have. They seem to be made my East Penn, but labeled Duracell - is that correct? Duracell provides no data sheet, and East Penn doesn't list that model number. I've looked at what I think is the equivalent battery from East Penn.

Recommended absorption voltage is 14.4 to 14.7V. The bulk voltage you mention is the regulator's target voltage during bulk mode (I had never seen this). East Penn recommends a bulk target voltage of 80% to 90% of the "full charge voltage," which I interpret to be the absorption voltage. So, your bulk voltage should be lower, not higher, than the absorption voltage, if I read this correctly.

I recommend that you try equalizing the batteries. The equalization charge may knock some of the sulfates off the plates, and maybe return some capacity.

You might also try a load test on them, to see what they are really doing, regardless of the smart gauge.

See this:
Renewable Energy Charging Parameters
 
May 6, 2010
392
1984 Oday 39 79 Milwaukee
As @marty9876 reports, I also had what I thought was an anomaly with the SOH where it was reporting 90% for a few weeks, then after installing the battery temp monitor, it went to 100% and has remained there.
 
May 6, 2010
392
1984 Oday 39 79 Milwaukee
Recommended absorption voltage is 14.4 to 14.7V. The bulk voltage you mention is the regulator's target voltage during bulk mode (I had never seen this). East Penn recommends a bulk target voltage of 80% to 90% of the "full charge voltage," which I interpret to be the absorption voltage. So, your bulk voltage should be lower, not higher, than the absorption voltage, if I read this correctly.
I thought this was odd as well, but those are the numbers provided by East Penn's technical support department for the model number I provided - which is in fact labeled Duracell.

Edit: I followed up with East Penn today, the Deka equivalent battery is DC31DT, the Duracell version is made by them for Batteries Plus to the same specifications. They confirmed that the numbers quoted above for bulk and absorption are correct.
 
Last edited:
Feb 5, 2004
3,934
Tartan 3800 Westport, MA
They confirmed that the numbers quoted above for bulk and absorption are correct.
Seems very strange to me. It contradicts other guidance they have out there, and is weird. What will the Balmar regulator do in this case? It might just switch to the absorption phase once the voltage reaches the absorption set point.
 
May 6, 2010
392
1984 Oday 39 79 Milwaukee
Seems very strange to me. It contradicts other guidance they have out there, and is weird. What will the Balmar regulator do in this case? It might just switch to the absorption phase once the voltage reaches the absorption set point.
I don't believe it switches to absorption until the bulk voltage set point has been achieved.
 
May 6, 2010
392
1984 Oday 39 79 Milwaukee
Yesterday I connected to shore power and fully charged the house bank. When we left the boat Saturday, bank was at 100% according to the gauge. Arriving at the boat yesterday it was at 63% (no loads during this time). After charging for a couple hours the gauge jumped from the low 80s to 100% in a few minutes as has been typical. I checked the SG in several cells and they were all around 1.25. I put the charger in equalization mode for 4 hours and noted very little if any change in SG across the cells so halted the process. Today the gauge reports 100% SOC and 90% SOH (still on shorepower). We plan to sail for a few hours today so we'll see if there is any change in the rapid depletion of the charge we've been experiencing.
 

Maine Sail

Moderator
Feb 6, 1998
11,037
Canadian Sailcraft 36T Casco Bay, ME
Yesterday I connected to shore power and fully charged the house bank. When we left the boat Saturday, bank was at 100% according to the gauge. Arriving at the boat yesterday it was at 63% (no loads during this time). After charging for a couple hours the gauge jumped from the low 80s to 100% in a few minutes as has been typical. I checked the SG in several cells and they were all around 1.25. I put the charger in equalization mode for 4 hours and noted very little if any change in SG across the cells so halted the process. Today the gauge reports 100% SOC and 90% SOH (still on shorepower). We plan to sail for a few hours today so we'll see if there is any change in the rapid depletion of the charge we've been experiencing.
Once the BT dongle/app is done & shipping there will be a future update to the shunt that will fix this issue. We have been testing the app/dongle here for a while now, and working through typical Beta stage tweaks, and it is coming along nicely. Unfortunately Balmar lost their app developer mid stream, and then scrapped all his teams work, and had to start over from scratch.
 
May 6, 2010
392
1984 Oday 39 79 Milwaukee
Once the BT dongle/app is done & shipping there will be a future update to the shunt that will fix this issue.
So I'm unclear as to whether my batteries are indeed discharging as rapidly as stated or if the problem all lies with the gauge? Or a combination of both?