New configuration for 24v setup

[Simonbr]

I’ve just upgraded my system to 24v. I changed the charge configuration by multiplying the current settings by 2. Just wondering if the SOC is also the same? I was using 12.8 down to about 12.1 for my SOC, do I also just multiply for 24v? 24.2v to 25.6v?

Also are there any other settings I should be changing? I’ve changed my wizbang jr max amp to 10% or the battery aH for charging. Changed the wizbang jr aH to 420aH, I seen rebulk was at 8 not sure if that should be higher.

Anything else I’m forgetting?

[ClassicCrazy]

I’ve just upgraded my system to 24v. I changed the charge configuration by multiplying the current settings by 2. Just wondering if the SOC is also the same? I was using 12.8 down to about 12.1 for my SOC, do I also just multiply for 24v? 24.2v to 25.6v?

Also are there any other settings I should be changing? I’ve changed my wizbang jr max amp to 10% or the battery aH for charging. Changed the wizbang jr aH to 420aH, I seen rebulk was at 8 not sure if that should be higher.

Anything else I’m forgetting?

What kind of batteries do you have - that is what makes the difference for the charging voltage setpoints.
The SOC capacity is based on the ah capacity of your batteries.  Two batteries in series is the same AH capacity as one.
The SOC efficiency % is based on the kind of batteries you have.
From what information you have provided it is hard to give any suggestions.

Larry

[Simonbr]

Oh y’a forgot to mention that. I have 4x6v 420aH lead acid batteries connected in series.

[ClassicCrazy]

Oh y’a forgot to mention that. I have 4x6v 420aH lead acid batteries connected in series.

Your Whizbang ah will be 420 ah . You didn't say if they are flooded or sealed agm/ gel type batteries.
For flooded Trojan recommends 2.45v per cell x 12 = 29.4v absorb . But not sure what manufacturer you have.
Here is the Trojan info https://www.solar-electric.com/lib/wind-sun/Trojan-userguide.pdf
Different settings for AGM or Gel
Also depends if you are going to use your whizbang to set ending amps then that would be around 4 hours absorb time and 5 a for ending amps for the flooded.
Really depends on your usuage and you would need to confirm using specific gravity if flooded.
Somewhere in the battery specs it will say the temp compensation which will be most likely around -3mv ( classic will multply that out automatically for amount of cells).
If you look at East Penn Deka then you will see it is a bit different from Trojan
https://www.eastpennmanufacturing.com/wp-content/uploads/Renewable-Energy-Charging-Parameters-1913.pdf
Vic usually says that flooded lead acid efficiency is around 88  but some use something a bit higher like maybe 92 % . You have to observe and tweak it to match your system .
Look here for a lot of info
http://www.midniteftp.com/support/kb/faq.php?cid=1
Also not sure what controller you are using but lots of info tutorials here
https://www.youtube.com/user/MidNiteSolar/videos

Larry

[Simonbr]

They are flooded lead acid batteries. I have interstate l16 batteries, there is no data for them but most say they are manufactured by us batteries. Link to data sheet below.I currently have my absorption to 29v and float to 27.6v, staying in the mid range. I’ve set the absorption time to 4 hours and ending amps to 9.5a which falls between the 2 to 3% of 420aH.


As for the t-comp I have it currently set at -5.0mV, what would you suggest for my setup knowing a little more about batteries now?



https://www.usbattery.com/wp-content/uploads/2019/11/usb_L16xc_data_sheet_11_2019.2.pdf

[ClassicCrazy]

They are flooded lead acid batteries. I have interstate l16 batteries, there is no data for them but most say they are manufactured by us batteries. Link to data sheet below.I currently have my absorption to 29v and float to 27.6v, staying in the mid range. I’ve set the absorption time to 4 hours and ending amps to 9.5a which falls between the 2 to 3% of 420aH.


As for the t-comp I have it currently set at -5.0mV, what would you suggest for my setup knowing a little more about batteries now?



https://www.usbattery.com/wp-content/uploads/2019/11/usb_L16xc_data_sheet_11_2019.2.pdf

Look at the life cycles per dod  depth of discharge graph
You will see how much longer the batteries last  if you only take 20% out of them compared to 50%

Your link seems to say -3mv per cell and not -5 although they left out a zero - maybe misprint ?

"Battery temperature adjustment: reduce the voltage by 0.028 Volts per cell for every 10°F above 80°F, increase by the same
amount for temperatures below 80°F."

sometime when you discharge batteries by a good amount - then you can check the specific gravity of electrolyte to see if when the classic says it gets to ending amps - the SG is showing full as shown in your manufacturers data. New batteries need some cycles to break them in to working at their full capacity.
Larry

[Vic]

They are flooded lead acid batteries. I have interstate l16 batteries, there is no data for them but most say they are manufactured by us batteries. Link to data sheet below.I currently have my absorption to 29v and float to 27.6v, staying in the mid range. I’ve set the absorption time to 4 hours and ending amps to 9.5a which falls between the 2 to 3% of 420aH.


As for the t-comp I have it currently set at -5.0mV, what would you suggest for my setup knowing a little more about batteries now?



https://www.usbattery.com/wp-content/uploads/2019/11/usb_L16xc_data_sheet_11_2019.2.pdf

Your link seems to say -3mv per cell and not -5 although they left out a zero - maybe misprint ?

"Battery temperature adjustment: reduce the voltage by 0.028 Volts per cell for every 10°F above 80°F, increase by the same
amount for temperatures below 80°F."

sometime when you discharge batteries by a good amount - then you can check the specific gravity of electrolyte to see if when the classic says it gets to ending amps - the SG is showing full as shown in your manufacturers data. New batteries need some cycles to break them in to working at their full capacity.
Larry

The one gotcha in the USBattery data on Temp Comp, is that they use a temp range, of 10 degrees, and the other one, is that they are using degrees F,  so, IMO,  0.028 V per ten degrees F range is 5 mV per degree C, for a Classic,  -5 mV/C, should do the trick.

Simon,  I think that your Float V is a bit high, and, also think that your EA setting is too high.  But, unfortunately, the proper EA setting for Flooded Lead Acid (FLA) batteries seems to vary, depending on the Depth Of Discharge (DOD), in the previous discharge.

BTW,  my FLA batteries, have a nominal Charge Efficiency, that is a bit less than 80%,  but this number also varies, depending on the DOD  --    lightly-cycled FLA batteries tend to have lower charge efficiency.

Flooded batteries, are generally, very forgiving.  But follow Larry's advice:  measuring SGs is THE Gold Standard for confirming charge voltage, time, and EQ necessity/effectiveness for your batteries, as they are being charged and used.

IMO,   Vic

[ClassicCrazy]

Thanks Vic - I was wondering about that temp compensation and didn't notice the 10 vs 5 degree difference !

Larry

[Simonbr]

They are flooded lead acid batteries. I have interstate l16 batteries, there is no data for them but most say they are manufactured by us batteries. Link to data sheet below.I currently have my absorption to 29v and float to 27.6v, staying in the mid range. I’ve set the absorption time to 4 hours and ending amps to 9.5a which falls between the 2 to 3% of 420aH.


As for the t-comp I have it currently set at -5.0mV, what would you suggest for my setup knowing a little more about batteries now?



https://www.usbattery.com/wp-content/uploads/2019/11/usb_L16xc_data_sheet_11_2019.2.pdf

Your link seems to say -3mv per cell and not -5 although they left out a zero - maybe misprint ?

"Battery temperature adjustment: reduce the voltage by 0.028 Volts per cell for every 10°F above 80°F, increase by the same
amount for temperatures below 80°F."

sometime when you discharge batteries by a good amount - then you can check the specific gravity of electrolyte to see if when the classic says it gets to ending amps - the SG is showing full as shown in your manufacturers data. New batteries need some cycles to break them in to working at their full capacity.
Larry

The one gotcha in the USBattery data on Temp Comp, is that they use a temp range, of 10 degrees, and the other one, is that they are using degrees F,  so, IMO,  0.028 V per ten degrees F range is 5 mV per degree C, for a Classic,  -5 mV/C, should do the trick.

Simon,  I think that your Float V is a bit high, and, also think that your EA setting is too high.  But, unfortunately, the proper EA setting for Flooded Lead Acid (FLA) batteries seems to vary, depending on the Depth Of Discharge (DOD), in the previous discharge.

BTW,  my FLA batteries, have a nominal Charge Efficiency, that is a bit less than 80%,  but this number also varies, depending on the DOD  --    lightly-cycled FLA batteries tend to have lower charge efficiency.

Flooded batteries, are generally, very forgiving.  But follow Larry's advice:  measuring SGs is THE Gold Standard for confirming charge voltage, time, and EQ necessity/effectiveness for your batteries, as they are being charged and used.

IMO,   Vic

I’ve just completed a full charge to float today and verified the SG. The classic is showing 99% but SG is only at about 1.23 so I imagine I need to adjust things.

What would you suggest for float V and end amp? Is the 4 hours long enough? Maybe it’s reaching the time before the end amps. Is there a way to know if the time ran out before the end amps were reached?

I also noticed that for my absorption voltage there was very slight battery bubbles and some smell, would you suggest I lower that too? I was using 14.4 back when only doing 12v with 2x 6v batteries, so I might return to 28.8v

[Vic]

Hi Simon,

I forget, if these are new-ish batteries  ...  if so,  it can take about 15 -50 cycles, for the batts to settle-in,  kind of a break-in.

Did you regularly take SG readings, before going to 24 V?  You could have had some deficit-charging, previously.

Are you using a known-good, Hydrometer, or Refractometer?

To me, a Sulfur aroma during Abosrb (and EQ) means that the batts really needed that charge, and if the aroma still exists at the end of Absorb (or EQ), it means to me, that the battery needs more charging.

The desired length of Absorb, varies, with the DOD of the battery, in the previous discharge.  SO, it is really a variable length.

The FLA batts here need an EA of about 1.3% of 20 hour Capacity.  One way to tell a good starting place for EA, is, to set a long Absorb time, like about 6 hours, and watch the Wb Amps into the battery (on the MNGP, or Local App).  When the Wb amps stop diminishing,  this about the right setting for EA.  However, if you have fairly large loads, that are cycling on/off ( line an A/C), this will change the Wb amps, somewhat  --  this is caused by the change in the voltage drop in the cable, and circuit breaker between the Classic and the battery.

Nothing needs to be perfect, with FLAs.  Would suggest a longer Absorb, or two, to see if you can get the SGs up.  About how often do you EQ your batts?  If you have a 20, or so point variation in SGs, after measuring each cell,  you probably need ot EQ, after a full-ish charge.

I would use the recommended Vfloat, from US B,  it seemed that you were above that value.

More later,   Vic

[Simonbr]

Hi Simon,

I forget, if these are new-ish batteries  ...  if so,  it can take about 15 -50 cycles, for the batts to settle-in,  kind of a break-in.

Did you regularly take SG readings, before going to 24 V?  You could have had some deficit-charging, previously.

Are you using a known-good, Hydrometer, or Refractometer?

To me, a Sulfur aroma during Abosrb (and EQ) means that the batts really needed that charge, and if the aroma still exists at the end of Absorb (or EQ), it means to me, that the battery needs more charging.

The desired length of Absorb, varies, with the DOD of the battery, in the previous discharge.  SO, it is really a variable length.

The FLA batts here need an EA of about 1.3% of 20 hour Capacity.  One way to tell a good starting place for EA, is, to set a long Absorb time, like about 6 hours, and watch the Wb Amps into the battery (on the MNGP, or Local App).  When the Wb amps stop diminishing,  this about the right setting for EA.  However, if you have fairly large loads, that are cycling on/off ( line an A/C), this will change the Wb amps, somewhat  --  this is caused by the change in the voltage drop in the cable, and circuit breaker between the Classic and the battery.

Nothing needs to be perfect, with FLAs.  Would suggest a longer Absorb, or two, to see if you can get the SGs up.  About how often do you EQ your batts?  If you have a 20, or so point variation in SGs, after measuring each cell,  you probably need ot EQ, after a full-ish charge.

I would use the recommended Vfloat, from US B,  it seemed that you were above that value.

More later,   Vic

Hello Vic, I will try to give you all the info, I hope I don't forget any information.

Last year I purchased 2x of the Interstate 6v 420aH batteries and used an Epever 40a SCC then changed to the Midnite Classic 150. I always has a hard time getting the SG up to the correct level. I only use the system from May to October, so at the end of the season I returned the batteries to the store so they could test the batteries and was told they had only needed about 1 hour extra charge time to get up to the correct SG. The solar tech at the store let me know to increase the absorption time and that should do the trick.

I already had the idea to move up to 24v instead of 12v so this year I purchased 2 more of the same batteries and a new inverter charger (Aims 24v 3k). Before moving the batteries to the camp I made sure I charged them both at home to the 1.27-1.28 level.

So to answer your first question, last year I was in a deficit and tried to get them higher but didn't know as much as I know now. I have both a refractometer and hydrometer but I usually always use the Refractometer as i find more accurate. Its the same one I used just 2 months ago to confirm the charge at home.

I do have a DC fridge that cycles on and off so this might affect the EA as you mentionned.

What do you think I should do at this point? Here are my thoughts with settings;

-Configure Absorption to 28.8v
-Configure float to  26.1v
-Configure EA to 5.5a
-Configure Abs time to 5 hours
-Configure EQ 29.8v
-Check the SG of all cells today and if they are off from each other, perform an EQ tomorrow to get them all equal.

Just two questions I have,
1. I don't like how high the US Battery EQ is on their sheet, when I was doing 12V people where saying 15v was high. Do you think my 29.8v is good and still at a safe level?
2. Is there a way to know what ended the absorption, if it was the EA or the timer? I'm not always close to my SCC so its hard to tell once I get to it.

[Vic]

Hi Simon, thanks for all the additional info.

Little time, right now, but:
'
If you can get the Classic on My Midnite, the MN web site, that allows the Classic to report-in about every five minutes,  you can see when the Classic beging Absorb, and when it ends,  AND you can also see the Wb current, from each report during Absorb (as well as all other times).  The time resolution, is usually better than +/- ten minutes.

You can also get the amount of time that the CC has been in Float, in the Charge>Time>More page on the MNGP,  for the total Absorb time,  BUT, you need to know what time the CC went to Absorb  ...

More Later,  Vic

[Simonbr]

Hi Simon, thanks for all the additional info.

Little time, right now, but:
'
If you can get the Classic on My Midnite, the MN web site, that allows the Classic to report-in about every five minutes,  you can see when the Classic beging Absorb, and when it ends,  AND you can also see the Wb current, from each report during Absorb (as well as all other times).  The time resolution, is usually better than +/- ten minutes.

You can also get the amount of time that the CC has been in Float, in the Charge>Time>More page on the MNGP,  for the total Absorb time,  BUT, you need to know what time the CC went to Absorb  ...

More Later,  Vic

Thank you for this I will configure the networking to log. What do you think about the other info on voltages and EA?

[Vic]

Hi Simon, thanks for all the additional info.

Little time, right now, but:
'
If you can get the Classic on My Midnite, the MN web site, that allows the Classic to report-in about every five minutes,  you can see when the Classic beging Absorb, and when it ends,  AND you can also see the Wb current, from each report during Absorb (as well as all other times).  The time resolution, is usually better than +/- ten minutes.

You can also get the amount of time that the CC has been in Float, in the Charge>Time>More page on the MNGP,  for the total Absorb time,  BUT, you need to know what time the CC went to Absorb  ...

More Later,  Vic

Thank you for this I will configure the networking to log. What do you think about the other info on voltages and EA?

Hi Simon.  Regarding EA:

"The FLA batts here need an EA of about 1.3% of 20 hour Capacity.  One way to tell a good starting place for EA, is, to set a long Absorb time, like about 6 hours, and watch the Wb Amps into the battery (on the MNGP, or Local App).  When the Wb amps stop diminishing,  this about the right setting for EA.  However, if you have fairly large loads, that are cycling on/off ( line an A/C), this will change the Wb amps, somewhat  --  this is caused by the change in the voltage drop in the cable, and circuit breaker between the Classic and the battery".

IMO, 29,8 Veq,  is FAR too low, it the battery bank really needs an EQ.  I would say 30.5 minimum.  But, a good way to determine Veq, is to take SG readings on a couple of your Pilot Cells (usually chosen from the cells that customarily have a bit lower SG readings than the rest.  Check 1-2 of them every 30-ish minutes, to see if their SGs are still rising.  If they are not, then this usually means that further EQ (at that Veq) will yield no improvement in SGs.  If you still see more variation in SGs, when each cell is measured,  then, IMO, raise the Veq 1/2 V, or so, depending on the amount of the variation in SGs.

My favorite FLA maunfacturer  --  Surrette  --  recommends a minimum Veq, for 24 V FLAs, of 31 V, the last time I checked. (although, they recommend a Vabs of 30 V).  These high numbers, are probably due the finding that many FLA users, kill their batts, from chronic under-charging   ...

Five hours of Absorb, is a long time.  If your batts really need this much Absorb time, then perhaps do not raise the Vabs, too much from where you are.  But, just watch the Wb amps into the battery, and when it no longer diminishes for 10 - 20 minutes, then you should be done, at least for that day.  That intermittent load on the system, might cause the Wb current to vary a bit on its own.

Back to work, here.  There is an Android Phone App, on this site, written by a chap named, Graham,  that could be very useful for you to use to watch your Classic charge the batts.  Will look for that link, Vic

[ClassicCrazy]

Vic was mentioning the other monitoring apps
If you have Android look for Midnite Classic Monitoring app in the playstore.
https://play.google.com/store/search?q=classic%20monitoring%20app&c=apps
If you have more tech skills and want to do more look here
https://github.com/ClassicDIY
Larry