Newbie Question about battery Equalization

[badwolf]

Hi people I am new to this whole solar thing, I did a DIY installation in my shed mainly because i was interested in getting into the solar energy.

So my system is has follows, 680watts of solar panels, Victron 100/30 charger, Victron Battery balancer, Victron e112 energy monitor, Victron batter Monitor/Shunt, The batteries was new flooded wet lead acid, 2x 12volt 120Ah batteries wired in series to give 24 volts.

Well all was going well the system was charging the batteries up to the float point with no issues, however i noticed that system was not performing fully no where near fully, draw from batteries is 60watts an hour and i noticed the volts was dropping to 24.4 volts which is my shut off point so it does not damage the lead acid batteries, it was doing this in the space of about 7 hours, So i double checked the installation to make sure i had not made a mistake, no i had not, so next i checked the gravity of the batteries when they was fully charged and the readings was quite low around 12.10 some cells was a little higher other a little lower but not by much, so i have spent the last 2 days equalizing the batteries through the Victron solar charger and i have they have increased to about 12.50 to 12.60, and i have been watching to make sure the batteries do not get anywhere near 100F, here is my question i have already been doing this for 2 days during the day is it safe to keep doing this until all the cells are equal and have the correct gravity???

(i have not been using the system at all while i have been doing this) i leave the batteries to rest overnight and the gravity reading is either the same as the night before or maybe just a bit higher in some cells. Sorry for the long post but i have tried to give has much detail as i can

Thank You

Martin

 

[sunshine_eggo]

Hi people I am new to this whole solar thing, I did a DIY installation in my shed mainly because i was interested in getting into the solar energy.

So my system is has follows, 680watts of solar panels, Victron 100/30 charger, Victron Battery balancer, Victron e112 energy monitor, Victron batter Monitor/Shunt, The batteries was new flooded wet lead acid, 2x 12volt 120Ah batteries wired in series to give 24 volts.

Well all was going well the system was charging the batteries up to the float point with no issues, however i noticed that system was not performing fully no where near fully, draw from batteries is 60watts an hour and i noticed the volts was dropping to 24.4 volts which is my shut off point so it does not damage the lead acid batteries, it was doing this in the space of about 7 hours, So i double checked the installation to make sure i had not made a mistake, no i had not, so next i checked the gravity of the batteries when they was fully charged and the readings was quite low around 12.10 some cells was a little higher other a little lower but not by much, so i have spent the last 2 days equalizing the batteries through the Victron solar charger and i have they have increased to about 12.50 to 12.60, and i have been watching to make sure the batteries do not get anywhere near 100F, here is my question i have already been doing this for 2 days during the day is it safe to keep doing this until all the cells are equal and have the correct gravity???

(i have not been using the system at all while i have been doing this) i leave the batteries to rest overnight and the gravity reading is either the same as the night before or maybe just a bit higher in some cells. Sorry for the long post but i have tried to give has much detail as i can

Thank You

Martin

SG range is 1.XXX, 1.265 is a typical full charge SG value, but some manufacturers can vary significantly.

12.2V is not a reliable cut-off under load. 12.1-12.2V is about 50% SoC if the batteries have been sitting completely unusued for 10-24 hours. Even a small load can pull them down. If you want a reliable shut off, get a battery monitor and find the voltage that corresponds to 50% SoC for your situation and use that as a shut off.

With 120Ah of batteries, your base charge rate should be 12A. If you're regularly charging at significantly more, you may be damaging the batteries. Ensure your charge current is within the recommended range.

If all your SG are good and within 0.03 of each other, I suspect the only problem here is your chosen shut off point after a period of undercharging/overutilization in the land of the reluctant sun.

 

[badwolf]

SG range is 1.XXX, 1.265 is a typical full charge SG value, but some manufacturers can vary significantly.

12.2V is not a reliable cut-off under load. 12.1-12.2V is about 50% SoC if the batteries have been sitting completely unusued for 10-24 hours. Even a small load can pull them down. If you want a reliable shut off, get a battery monitor and find the voltage that corresponds to 50% SoC for your situation and use that as a shut off.

With 120Ah of batteries, your base charge rate should be 12A. If you're regularly charging at significantly more, you may be damaging the batteries. Ensure your charge current is within the recommended range.

If all your SG are good and within 0.03 of each other, I suspect the only problem here is your chosen shut off point after a period of undercharging/overutilization in the land of the reluctant sun.

Thank you for the information, I do have a battery monitor its the Victron shunt, and no the SG is not quite up to 1.265 highest cell is 1.260 but other cells are only read SG 1.250 and 2 of the cells as low as SG 1.240, yes seams like the sun has forgotten the UK this year lol,

One again thank you


Martin

 

[sunshine_eggo]

Thank you for the information, I do have a battery monitor its the Victron shunt, and no the SG is not quite up to 1.265 highest cell is 1.260 but other cells are only read SG 1.250 and 2 of the cells as low as SG 1.240, yes seams like the sun has forgotten the UK this year lol,

One again thank you


Martin

I missed the shunt in the initial post. I would use that to correlate a cut off voltage with the battery monitor's state of charge.

Please include battery monitor settings for review.
Please include MPPT settings for review.

The E112 is an AC energy monitor. How are you using it?

1.250 is the minimum acceptable in typical cases. Below that, even at full voltage, degradation can occur.

Equalization should only be done after the batteries have completed a full charge cycle and have been at float for two hours. It can be difficult to properly equalize batteries on solar alone.

Just in case you're not aware, checking SG when at full charge should also be done about 2 hours after float. You should also intake and expel the electrolyte 3 times before checking a reading on the 4th intake. The electrolyte can get stratified, and the intake/expelling can help improve the accuracy of the reading.

I would not resume use until you can get all cells above 1.250 OR they simply refuse to rise anymore. If there are cells that refuse to rise above 1.250, that battery is likely to fail sooner rather than later.

Again, my numbers are general for what is typical. If you have battery datasheets

 

[badwolf]

I missed the shunt in the initial post. I would use that to correlate a cut off voltage with the battery monitor's state of charge.

Please include battery monitor settings for review.
Please include MPPT settings for review.

The E112 is an AC energy monitor. How are you using it?

1.250 is the minimum acceptable in typical cases. Below that, even at full voltage, degradation can occur.

Equalization should only be done after the batteries have completed a full charge cycle and have been at float for two hours. It can be difficult to properly equalize batteries on solar alone.

Just in case you're not aware, checking SG when at full charge should also be done about 2 hours after float. You should also intake and expel the electrolyte 3 times before checking a reading on the 4th intake. The electrolyte can get stratified, and the intake/expelling can help improve the accuracy of the reading.

I would not resume use until you can get all cells above 1.250 OR they simply refuse to rise anymore. If there are cells that refuse to rise above 1.250, that battery is likely to fail sooner rather than later.

Again, my numbers are general for what is typical. If you have battery datasheets

The e112 is on the output of the ac side of the inverter, and yes i only been doing Equalization after full charge and they have been floating for at least 3 hours, and no i stopped using the batteries since i found the SG was low on the batteries.

I just done the SG test for this evening taken 2 hours after last Equalization,
Battery 1, cell one = 1.260, cell 2 =1.270, cell 3 = 1.260, cell 4 = 1.270, cell 5 = 1.250, cell 6 = 1.260
Battery 2, cell one = 1.250, cell 2 =1.260, cell 3 = 1.250, cell 4 = 1.260, cell 5 = 1.250, cell 6 = 1.250

So they have recovered quite a way i will continue tomorrow. (Sadly i only have a basic lead acid battery charger that does not have the option for Equalization thus is why i am having to do it this way)

For the shunt and charger settings see attached Pics most of the settings are factory settings.

Thank You

Martin

 

[sunshine_eggo]

Yep. Drive to at least 1.260 and then make sure you:

1) get to float as often as possible.
2) equalize as needed. Either on a schedule or by monitoring SG. Best done manually when conditions are favorable. Automatic gets skipped if conditions are unfavorable.

Since you're charging on solar, charged voltage should be 0.2V below absorption to ensure you don't get false sync. I would also change the efficiency to 95%.

 

[badwolf]

Yep. Drive to at least 1.260 and then make sure you:

1) get to float as often as possible.
2) equalize as needed. Either on a schedule or by monitoring SG. Best done manually when conditions are favorable. Automatic gets skipped if conditions are unfavorable.

Since you're charging on solar, charged voltage should be 0.2V below absorption to ensure you don't get false sync. I would also change the efficiency to 95%.

Thank you, I have altered the shunt setting to what you said, After i have completed all the Equalizations do you think i should reset the SOC on the shunt ??

Thank you

Martin

 

[badwolf]

Yep. Drive to at least 1.260 and then make sure you:

1) get to float as often as possible.
2) equalize as needed. Either on a schedule or by monitoring SG. Best done manually when conditions are favorable. Automatic gets skipped if conditions are unfavorable.

Since you're charging on solar, charged voltage should be 0.2V below absorption to ensure you don't get false sync. I would also change the efficiency to 95%.

Here is todays gravity readings,

Battery 1, cell one = 1.285, cell 2 =1.290, cell 3 = 1.280, cell 4 = 1.290, cell 5 = 1.275, cell 6 = 1.280
Battery 2, cell one = 1.270, cell 2 =1.275, cell 3 = 1.270, cell 4 = 1.275, cell 5 = 1.270, cell 6 = 1.270

These readings taken 3 hours after last Equalization,
Question do i try another day at trying Equalization?? Clearly they are still rising or will i damage the batteries?

Thank you

Martin

 

[sunshine_eggo]

Unless the manufacturer specifies otherwise, 1.265 is typically regarded as full (IIRC, Trojan is a little higher at 1.278).

I would say you're good. Pick a few of the lowest cells and monitor them every 2-4 weeks. When any drop below 1.250, or the range is > 0.03, equalize.

 

[badwolf]

Unless the manufacturer specifies otherwise, 1.265 is typically regarded as full (IIRC, Trojan is a little higher at 1.278).

I would say you're good. Pick a few of the lowest cells and monitor them every 2-4 weeks. When any drop below 1.250, or the range is > 0.03, equalize.

Thank you sunshine_eggo for all your help you have provided in getting this issue hopefully sorted now, I do not know what the gravity should be because i can find very little info about them, they are SolarFlex batteries, but clearly they have been probably stood for a while, i just hope the 10 days i used them did not totally break them i guess time will tell after a couple of cycles, i even charged them fully before i first used them, well we all have to learn some way or another...

Thank You

Martin

 

[sunshine_eggo]

Thank you sunshine_eggo for all your help you have provided in getting this issue hopefully sorted now, I do not know what the gravity should be because i can find very little info about them, they are SolarFlex batteries, but clearly they have been probably stood for a while, i just hope the 10 days i used them did not totally break them i guess time will tell after a couple of cycles, i even charged them fully before i first used them, well we all have to learn some way or another...

Thank You

Martin

1.265 is pretty safe across the board for most things except forklift batteries, which tend to run higher concentrations. 1.250 is a good target to ensure all cells are achieving a minimum SG to minimize degradation.

Unfortunately, you're learning the lesson that flooded lead acid (FLA) batteries are finicky about maintenance. The good news is that with proper maintenance, properly sized FLA batteries can last 10+ years before their lost capacity drives replacement.

There's a saying about FLA... FLA batteries don't die. They are murdered. Regular maintenance prevents murder.

Given that the cells have recovered to healthy SG levels, that's a good sign. If you are able to regularly attain full charge (daily preferred), and they maintain a healthy SG without the need for EQ cycles no more often than 30 days, that's an even better sign.

On a go-forward basis, monitor the weakest cells every 2-4 weeks, all cells in 90 days, and if everything looks good, go to a monthly spot check with all cells checked every 3-6 months. The more reliable/consistent they show themselves to be the less frequently they can be maintained with an upper limit of monthly spot checks and full checks every 6 months.

Actually... I can't believe I haven't linked these yet. While they are for different brands, they are a very good resource even if their exact numbers differ:

Rolls Battery User Manual [Flooded, AGM & OPzV Gel] | Rolls Battery

www.rollsbattery.com

Trojan Battery | Battery Maintenance

The key to achieving optimum performance and long battery life is to follow a regular care and maintenance program. Read our tips for high performance battery maintenance.

www.trojanbattery.com

While you will see small differences between them, they are representative of two manufacturers with good reputations (Rolls especially) and how they recommend their batteries be maintained. Most of the recommendations I have made have been from my interpretation or slight modification of these resources.

 

[badwolf]

1.265 is pretty safe across the board for most things except forklift batteries, which tend to run higher concentrations. 1.250 is a good target to ensure all cells are achieving a minimum SG to minimize degradation.

Unfortunately, you're learning the lesson that flooded lead acid (FLA) batteries are finicky about maintenance. The good news is that with proper maintenance, properly sized FLA batteries can last 10+ years before their lost capacity drives replacement.

There's a saying about FLA... FLA batteries don't die. They are murdered. Regular maintenance prevents murder.

Given that the cells have recovered to healthy SG levels, that's a good sign. If you are able to regularly attain full charge (daily preferred), and they maintain a healthy SG without the need for EQ cycles no more often than 30 days, that's an even better sign.

On a go-forward basis, monitor the weakest cells every 2-4 weeks, all cells in 90 days, and if everything looks good, go to a monthly spot check with all cells checked every 3-6 months. The more reliable/consistent they show themselves to be the less frequently they can be maintained with an upper limit of monthly spot checks and full checks every 6 months.

Actually... I can't believe I haven't linked these yet. While they are for different brands, they are a very good resource even if their exact numbers differ:

Rolls Battery User Manual [Flooded, AGM & OPzV Gel] | Rolls Battery

www.rollsbattery.com

Trojan Battery | Battery Maintenance

The key to achieving optimum performance and long battery life is to follow a regular care and maintenance program. Read our tips for high performance battery maintenance.

www.trojanbattery.com

While you will see small differences between them, they are representative of two manufacturers with good reputations (Rolls especially) and how they recommend their batteries be maintained. Most of the recommendations I have made have been from my interpretation or slight modification of these resources.

Thanks for the links very interesting, and yes i will be doing regular maintenance for sure, and i will have to alter my loads depending on how things go over the upcoming winter months, its just a learning curve and understanding what the system can do and keeping things realistic.

Once again thank you

Martin

 

[badwolf]

1.265 is pretty safe across the board for most things except forklift batteries, which tend to run higher concentrations. 1.250 is a good target to ensure all cells are achieving a minimum SG to minimize degradation.

Unfortunately, you're learning the lesson that flooded lead acid (FLA) batteries are finicky about maintenance. The good news is that with proper maintenance, properly sized FLA batteries can last 10+ years before their lost capacity drives replacement.

There's a saying about FLA... FLA batteries don't die. They are murdered. Regular maintenance prevents murder.

Given that the cells have recovered to healthy SG levels, that's a good sign. If you are able to regularly attain full charge (daily preferred), and they maintain a healthy SG without the need for EQ cycles no more often than 30 days, that's an even better sign.

On a go-forward basis, monitor the weakest cells every 2-4 weeks, all cells in 90 days, and if everything looks good, go to a monthly spot check with all cells checked every 3-6 months. The more reliable/consistent they show themselves to be the less frequently they can be maintained with an upper limit of monthly spot checks and full checks every 6 months.

Actually... I can't believe I haven't linked these yet. While they are for different brands, they are a very good resource even if their exact numbers differ:

Rolls Battery User Manual [Flooded, AGM & OPzV Gel] | Rolls Battery

www.rollsbattery.com

Trojan Battery | Battery Maintenance

The key to achieving optimum performance and long battery life is to follow a regular care and maintenance program. Read our tips for high performance battery maintenance.

www.trojanbattery.com

While you will see small differences between them, they are representative of two manufacturers with good reputations (Rolls especially) and how they recommend their batteries be maintained. Most of the recommendations I have made have been from my interpretation or slight modification of these resources.

sunshine_eggo: after reading them documentations you posted i also noticed that there is a break in period for these lead acid batteries anything upto 90 days, so maybe that is another thing my batteries are doing?? because they was brand new when i got the just about 2 weeks ago, So i am going to keep the loads very light on the batteries for a few months let them have some use but also make sure they reach float everyday at least for the break in period. I will check fluid levels weekly and do a gravity test every 2 weeks, just so i have a record of how they are performing.

Thank You

Martin

 

[sunshine_eggo]

could be, but new batteries should generally not need equalization right out of the box.

Break in is typically in the first 50-100 cycles.

I would use them normally ensuring they stay within voltage and current limits.

 

[badwolf]

could be, but new batteries should generally not need equalization right out of the box.

Break in is typically in the first 50-100 cycles.

I would use them normally ensuring they stay within voltage and current limits.

Well its been just over a week and i just did a SG test and they are all back down to around 1.220 we had a full day of sun and they have been floating for the past 4 hours, I have made sure the batteries have reached float charge every day.

I tested the car battery just to be sure and that says 1.273 so its not the meter.

most odd!!!!

Thank you

Martin

 

[sunshine_eggo]

Well its been just over a week and i just did a SG test and they are all back down to around 1.220 we had a full day of sun and they have been floating for the past 4 hours, I have made sure the batteries have reached float charge every day.

I've lost track of where we are.

Confirm the charger is set to FIXED absorption period with a 4 hour duration. Default is adaptive, and that can cause problems in some situations. It's under the EXPERT settings.

 

[badwolf]

I've lost track of where we are.

Confirm the charger is set to FIXED absorption period with a 4 hour duration. Default is adaptive, and that can cause problems in some situations. It's under the EXPERT sett

 

[badwolf]

I've lost track of where we are.

Confirm the charger is set to FIXED absorption period with a 4 hour duration. Default is adaptive, and that can cause problems in some situations. It's under the EXPERT settings.

my absorption is set to 5 hours but it don't do that amount of time, its goes to floating after about 3 hours sometimes less on a sunny day. should it be doing that?? or should it do the full 5 hour absorption as what i had set??

Thank You

Martin

 

[badwolf]

I've lost track of where we are.

Confirm the charger is set to FIXED absorption period with a 4 hour duration. Default is adaptive, and that can cause problems in some situations. It's under the EXPERT settings.

picture from my settings

 

[sunshine_eggo]

Disable your tail current.

 

[badwolf]

Ah yes now I see that Was stopping the charge and going over to float before the 5 hours was up... Thank you.. I will give it a week or 2 and see if that helps.....

Thank you

Martin

 

[sunshine_eggo]

Are your MPPT and Shunt in a VE.Smart network?

 

[badwolf]

Are your MPPT and Shunt in a VE.Smart network?

Yes do i need to take them out???

 

[sunshine_eggo]

Yes do i need to take them out???

No. That typically yields the best results as it uses shunt voltage and current data for charging purposes, which are more accurate and meaningful than the MPPT measured/reported values.

Also worth the shunt voltage measurement with a separate meter.

 

[badwolf]

No. That typically yields the best results as it uses shunt voltage and current data for charging purposes, which are more accurate and meaningful than the MPPT measured/reported values.

Also worth the shunt voltage measurement with a separate meter.

Volt meter says 26.1 and the shunt in the software says 25.9, At least it got the full absorption hours today

Thank you

Martin