Battery absorb time issues.

Shawn-H
Shawn-H Solar Expert Posts: 107 ✭✭
in Solar Beginners Corner #1
I just replaced/upgraded my batteries to 2 strings Surrette Battery - 6 Volts, 375 Amp-Hours http://www.solar-electric.com/batteries-meters-accessories/batteries/suprdecyba/6voltbatteries1/suba6vo350am.html on a 24v off grid sys. If I use the (T*c20/80) to find the absorb time It gives me 3.9375 hours. This 4 hour mark seems a bit long to me. is this a good charge time? or do you think i should change it?
100% Off-grid in the White Mountains of Arizona. 36 Kyocera 265w mounted on four DPW 9 module pole top mounts, midnite solar combiners, breakers, & lightning arresters, 1 midnight solar classic 150, & 3 classic 150 lights, 3 x 1574 AH GB Industries forklift batteries total of 4722 AH @24v. Feeding a Outback power systems FW500 with 2 x VFX 3624, with the x240. 2 Honda EU3000is gensets with the 240 combiner and control box running LP, and 1 Honda EU2000is Gas. 
System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground  cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
Vag woodstove for heat.
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  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    #2
    Shawn
    What cc are you using. One way you might check the absorb time is to watch and time the absorb. When the amps goes to their lowest point and stays their for about a half hour, check how long this took and compare it to your settings. Then check the sg and see where you are at. My battery will go below 1% on the return amps before it is even close. Some may get there at about 2% of amp hour capasity going to the battery. My opinion is find the bottom and hold for 1/2 hour. If I am wrong I am hoping others will comment.

    Good luck
    gww
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,654 admin
    #3
    2-6 hours is typical... 2 hours if not deeply cycled. 6 hours if very deeply cycled. As a starting point, 4 hours is fine.

    Logging your temperature corrected specific gravity (per cell) and per battery voltages, etc. and see how they look.

    If you have to add water to a cell once every two months--You are probably fine. If you have to add water every month or less--Probably too much charging (too long of absorb time, too high of absorb voltage).

    Especially during winter (short sun hours, poor weather), you probably need keep your absorb voltage on the high side.

    As always, find the current documentation from the battery mfg. for their recommendations--And adjust to your needs based on the above (SG, voltage, water usage).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Shawn-H
    Shawn-H Solar Expert Posts: 107 ✭✭
    #4
    gww1 wrote: »
    Shawn
    What cc are you using. One way you might check the absorb time is to watch and time the absorb. When the amps goes to their lowest point and stays their for about a half hour, check how long this took and compare it to your settings. Then check the sg and see where you are at. My battery will go below 1% on the return amps before it is even close. Some may get there at about 2% of amp hour capasity going to the battery. My opinion is find the bottom and hold for 1/2 hour. If I am wrong I am hoping others will comment.

    Good luck
    gww



    thank you I'm using 3 x Midnight solar classic 150 Maxed out and dilled bk. im I have them set to give 80amps to the bank but could have them give 181amps. the c20 is 75amps.
    100% Off-grid in the White Mountains of Arizona. 36 Kyocera 265w mounted on four DPW 9 module pole top mounts, midnite solar combiners, breakers, & lightning arresters, 1 midnight solar classic 150, & 3 classic 150 lights, 3 x 1574 AH GB Industries forklift batteries total of 4722 AH @24v. Feeding a Outback power systems FW500 with 2 x VFX 3624, with the x240. 2 Honda EU3000is gensets with the 240 combiner and control box running LP, and 1 Honda EU2000is Gas. 
    System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground  cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
    Vag woodstove for heat.
    Follow our journey at
    https://www.facebook.com/ShawnpHarvey
    · Share on Twitter
  • Shawn-H
    Shawn-H Solar Expert Posts: 107 ✭✭
    #5
    BB. wrote: »
    2-6 hours is typical... 2 hours if not deeply cycled. 6 hours if very deeply cycled. As a starting point, 4 hours is fine.

    Logging your temperature corrected specific gravity (per cell) and per battery voltages, etc. and see how they look.

    If you have to add water to a cell once every two months--You are probably fine. If you have to add water every month or less--Probably too much charging (too long of absorb time, too high of absorb voltage).

    Especially during winter (short sun hours, poor weather), you probably need keep your absorb voltage on the high side.

    As always, find the current documentation from the battery mfg. for their recommendations--And adjust to your needs based on the above (SG, voltage, water usage).

    -Bill
    thank you. you told me to do what i have done. i guess i just needed to hear others tell me i was doing right.... lol.
    100% Off-grid in the White Mountains of Arizona. 36 Kyocera 265w mounted on four DPW 9 module pole top mounts, midnite solar combiners, breakers, & lightning arresters, 1 midnight solar classic 150, & 3 classic 150 lights, 3 x 1574 AH GB Industries forklift batteries total of 4722 AH @24v. Feeding a Outback power systems FW500 with 2 x VFX 3624, with the x240. 2 Honda EU3000is gensets with the 240 combiner and control box running LP, and 1 Honda EU2000is Gas. 
    System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground  cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
    Vag woodstove for heat.
    Follow our journey at
    https://www.facebook.com/ShawnpHarvey
    · Share on Twitter
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #6
    Doesn't look like you have a/any WhizBang jr's on your system.. They solve your question by allowing you to see exactly what went into the battery not just what went out of the Classic.... get one, cheap at twice the price..http://www.midnitesolar.com/productPhoto.php?product_ID=519&productCatName=Software&productCat_ID=5&sortOrder=1&act=p
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • Shawn-H
    Shawn-H Solar Expert Posts: 107 ✭✭
    #7
    westbranch wrote: »
    Doesn't look like you have a/any WhizBang jr's on your system.. They solve your question by allowing you to see exactly what went into the battery not just what went out of the Classic.... get one, cheap at twice the price..http://www.midnitesolar.com/productPhoto.php?product_ID=519&productCatName=Software&productCat_ID=5&sortOrder=1&act=p
    lol thank you. and you are right. I'm waiting on it in the mail as we speak.
    100% Off-grid in the White Mountains of Arizona. 36 Kyocera 265w mounted on four DPW 9 module pole top mounts, midnite solar combiners, breakers, & lightning arresters, 1 midnight solar classic 150, & 3 classic 150 lights, 3 x 1574 AH GB Industries forklift batteries total of 4722 AH @24v. Feeding a Outback power systems FW500 with 2 x VFX 3624, with the x240. 2 Honda EU3000is gensets with the 240 combiner and control box running LP, and 1 Honda EU2000is Gas. 
    System #2 is a off grid water system @ 1590w (6 Kyocera 265's) on a 6 module DPW top of pole mount. Feeding a Granfas deep well pump and pump controller at 580 feet. 2 x 2800 gallon above ground poly storage tanks, and 1 x 1200 gallon underground  cistern and a Granfas 24v booster pump feeding a 90 gallon carbon fiber pressure tank.
    Vag woodstove for heat.
    Follow our journey at
    https://www.facebook.com/ShawnpHarvey
    · Share on Twitter
  • Alaska Man
    Alaska Man Solar Expert Posts: 252 ✭✭
    #8
    Think I'll get one just for giggles..........
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