LV2424 equalize charge voltage

Scott Martinez

New Member
I'm not seeing a thread on this, but need to equalize my lead acid 24v bank monthly. Will the DC connection on the PIP be able to handle 32.4 volts from shore power, or a better MPPT charge controller, or should I take it off line?
 

Scott Martinez

New Member
Possibly. I'm trying to figure out what, if anything I should do next with this system, or if I should eventually scrap and go with grid tie inverters with limiters for each leg. My goal is to have batteries for backup, but have been toying with letting them be drawn off of during good sunny weather. I am not drawing enough during the day to get maximum use from my panels with my nightly load exceeding battery capacity pretty easily. I can see how the solar hobby can be addicting (expensive) trying to tweak and configure.
 

snoobler

Solar Honey Badger
You're not kidding about expensive. I just bought another 10kW of panels from Santan because... solar.

Are you sure you need to equalize your batteries? Does the specific gravity indicate you should do so?
 

Scott Martinez

New Member
You're not kidding about expensive. I just bought another 10kW of panels from Santan because... solar.

Are you sure you need to equalize your batteries? Does the specific gravity indicate you should do so?
Probably not. It's just the manufactures recommendation it be done monthly. 8 Trojan T105's for 24 volts...
 

snoobler

Solar Honey Badger
Actually, Trojan has more specific criteria for equalization based on SG. I have 8X T-1275 for 48V.



I. Specific Gravity Test (Flooded batteries only)

  1. Do not add water at this time.
  2. Fill and drain the hydrometer 2 to 4 times before pulling out a sample.
  3. There should be enough sample electrolyte in the hydrometer to completely support the float.
  4. Take a reading, record it, and return the electrolyte back to the cell.
  5. To check another cell, repeat the 3 steps above.
  6. Check all cells in the battery.
  7. Replace the vent caps and wipe off any electrolyte that might have been spilled.
  8. Correct the readings to 80º F (26.6º C):
    • Add 0.004 to readings for every 10º F (5.6º C) above 80º F (26.6º C)
    • Subtract 0.004 for every 10º (5.6º C) below 80º F (26.6º C)
  9. Compare the readings.
  10. Check the state of charge using Table 1 below.
The readings should be at or above the factory specification of 1.277 +/- 0.007. If any specific gravity readings register low, then follow the steps below.

  1. Check and record voltage level(s).
  2. Put battery(s) on a complete charge.
  3. Take specific gravity readings again.
If any specific gravity readings still register low then follow the steps below.

  1. Check voltage level(s).
  2. Perform equalization charge. Refer to the Equalizing section for the proper procedure.
  3. Take specific gravity readings again."

AND:


If you want to get the most out of your batteries, you really need to study both of those resources and develop a maintenance plan.
 

Scott Martinez

New Member
Actually, Trojan has more specific criteria for equalization based on SG. I have 8X T-1275 for 48V.



I. Specific Gravity Test (Flooded batteries only)

  1. Do not add water at this time.
  2. Fill and drain the hydrometer 2 to 4 times before pulling out a sample.
  3. There should be enough sample electrolyte in the hydrometer to completely support the float.
  4. Take a reading, record it, and return the electrolyte back to the cell.
  5. To check another cell, repeat the 3 steps above.
  6. Check all cells in the battery.
  7. Replace the vent caps and wipe off any electrolyte that might have been spilled.
  8. Correct the readings to 80º F (26.6º C):
    • Add 0.004 to readings for every 10º F (5.6º C) above 80º F (26.6º C)
    • Subtract 0.004 for every 10º (5.6º C) below 80º F (26.6º C)
  9. Compare the readings.
  10. Check the state of charge using Table 1 below.
The readings should be at or above the factory specification of 1.277 +/- 0.007. If any specific gravity readings register low, then follow the steps below.

  1. Check and record voltage level(s).
  2. Put battery(s) on a complete charge.
  3. Take specific gravity readings again.
If any specific gravity readings still register low then follow the steps below.

  1. Check voltage level(s).
  2. Perform equalization charge. Refer to the Equalizing section for the proper procedure.
  3. Take specific gravity readings again."

AND:


If you want to get the most out of your batteries, you really need to study both of those resources and develop a maintenance plan.
Thank you for digging this up. I'm frustrated with myself trying to understand all there is to know about batteries. I think what I've learned is that I have more panels (1600w) then I can use most days unless I load the inverter, while I don't have enough battery (450Ah) to get nowhere through the night to supply that load. I think I'll treat the batteries as a UPS, and run the PIP 2424 to do Solar/Util/Bat in the future, and start planning my next move.
 

snoobler

Solar Honey Badger
If you're flattening your batteries, you're going to kill them in a year. If you're cutting off after about 225Ah, then you'll get several years with proper maintenance.

"UPS mode" is probably better. If there are times of day where you can use their power to offset higher costs and charge them when power is cheaper, that makes sense too. You just shouldn't discharge them below 50% in any situation but an emergency.
 

Scott Martinez

New Member
If you're flattening your batteries, you're going to kill them in a year. If you're cutting off after about 225Ah, then you'll get several years with proper maintenance.

"UPS mode" is probably better. If there are times of day where you can use their power to offset higher costs and charge them when power is cheaper, that makes sense too. You just shouldn't discharge them below 50% in any situation but an emergency.
When I realized that 21v was super bad, I bumped that to 23.7, but that only is realistically a few hours with a load of 700 watts. I am thinking about getting a transfer switch so I can at least get more watts from the panels without running extension cords everywhere, and top the batteries off daily. (load/battery/util). That seems to be the best use of what I built.
 
Top