First Post - ROLLS AGM S6-275

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  • jtbuildsjtbuilds Registered Users Posts: 19 ✭✭
    edited June 2016 #32

    The date code on both Rolls batteries show   K154104  H  5N  ...Oct 7 2015

    I charged the batteries again. It took 25min at 51amps for the charger to reach full 15.1 charge voltage @ 64F today. 

    After 1 1/2 hours on the charger the temperatures on the sides of the batteries where all within 0.5 degrees.


    Next I used the Pronautic set to AGM Profile #2 to charge a brand new Northstar NSB-AGM27 that is 91AH.

    http://buy.northstarbattery.com/p/nsb-agm-27m-battery

    The charger was disconnected when the outputw as 0.5A.

    Five minutes after disconnecting the charger the Northstar voltage was 13.2V

    A hour after the charger was disconnected the voltage was 12.86V.

    The LED light bar was connected (nothing else connected to the batteries) and the voltage dropped to 12.22V.
    1 hour later the voltage was 12.19V
    2 hours later the voltage was 12.08V
    3 hours later the voltage was 11.89V - the light bar was disconnected

    The Nothstar has been charged twice. Essentially it is not formed as much as the Rolls that have been charged 14 times

    The Rolls are being charge at 15.2V bulk while at the same temperature the Northstar is 14.5V bulk...that is a big difference.

    Mystifying how the same load can draw 250Ah down to 50% in the same time that 91Ah is drawn down to 40%.
  • zonebluezoneblue Solar Expert Posts: 1,218 ✭✭✭✭
    Im not sure that im following your situation exactly, but AGM capacity anxiety is common.  While AGMs are well suited to RV applications (although lithium is rapidly taking over), the trick to sanity there is a) knowing that youve fully charged them regularly, and b) employing some kind of coulomb counting based state of charge monitoring.

    Fixed absorb times are difficult to work with, can over charge or undercharge. A charger with true end amps will help a lot there. You dont want to under charge them because you create a spiral of reducing capacity each time you do it. You dont want to overcharge them because youll wear out the catylyst and pop the vents releasing gas that can not be replaced, causing the battery to fail early.

    A battery monitor like the victron/bogart's or the one built into the midnite classics will help give a reasonable estimate of SOC, but perhaps mroe usefully it also allows you to monitor in real time what is going into and out of the battery, thus allowing you to trace unusual loads.

    Over time you will learn how your particular batterys rest voltage maps to SOC, but for now it sounds like you need better information before worrying too much.


    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


  • jtbuildsjtbuilds Registered Users Posts: 19 ✭✭
    zoneblue said:
    Im not sure that im following your situation exactly, but AGM capacity anxiety is common.  While AGMs are well suited to RV applications (although lithium is rapidly taking over), the trick to sanity there is a) knowing that youve fully charged them regularly, and b) employing some kind of coulomb counting based state of charge monitoring.

    Fixed absorb times are difficult to work with, can over charge or undercharge. A charger with true end amps will help a lot there. You dont want to under charge them because you create a spiral of reducing capacity each time you do it. You dont want to overcharge them because youll wear out the catylyst and pop the vents releasing gas that can not be replaced, causing the battery to fail early.

    A battery monitor like the victron/bogart's or the one built into the midnite classics will help give a reasonable estimate of SOC, but perhaps mroe usefully it also allows you to monitor in real time what is going into and out of the battery, thus allowing you to trace unusual loads.

    Over time you will learn how your particular batterys rest voltage maps to SOC, but for now it sounds like you need better information before worrying too much.


    Thank You Zoneblue

    I have 2 - 6V S6-275 Rolls in series that are suppose to have 250Ah. I only seem to be getting 36Ah.

    The charger is left to run each time until the output is .0.5A . I don't know if this is what you would call a charger with true end amps?

    I have a battery monitor. It was going to be installed along with the rest of the system....instead the time has be diverted to problem solving the Rolls batteries.

    I have everything on a bench so as a final double check today I'll rig up the battery monitor and give things a go.

    Take Care
    John

  • BB.BB. Super Moderators, Administrators Posts: 31,911 admin
    From what you have posted, I do not see you doing anything wrong (especially in terms of under charging).

    The batteries are ending the charge with high voltage and low current. Whether automatically terminating or you stopping at low amps (down to 0.1% or below 2.5 amps), it does not explain your poor bank performance (unless you took the batteries to dead and sat for 1+ weeks uncharged, or the batteries were delivered dead to you).

    One question, that you may have missed of mine (or I missed your answer), what is the voltage of each 6 volt battery during loads+ charging. Are the voltages very close or are they >>0.01 volts different.

    Looking to understand if you have one failing battery or two failing batteries.

    At least, one failing battery would be easier to attribute to mfg/not your problem.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jtbuildsjtbuilds Registered Users Posts: 19 ✭✭
    BB. said:
    From what you have posted, I do not see you doing anything wrong (especially in terms of under charging).

    The batteries are ending the charge with high voltage and low current. Whether automatically terminating or you stopping at low amps (down to 0.1% or below 2.5 amps), it does not explain your poor bank performance (unless you took the batteries to dead and sat for 1+ weeks uncharged, or the batteries were delivered dead to you).

    One question, that you may have missed of mine (or I missed your answer), what is the voltage of each 6 volt battery during loads+ charging. Are the voltages very close or are they >>0.01 volts different.

    Looking to understand if you have one failing battery or two failing batteries.

    At least, one failing battery would be easier to attribute to mfg/not your problem.

    -Bill

    Thanks for the reminder Bill.....after you asked I checked.....then forgot to post the results.

    I don't remember what the number are but every time I've checked (4-5 times now) the voltage on both batteries is identical to .01V.

    I've had the capacity issue since day 1. First trip out I got my ear burned off by the dear wife after spending $$$ on the Rolls only to have them last less time than the Group 27 that was there before......it gets worse my other ear keeps getting smacked because I have to run the generator (Honda 3000is) 2 times day and last trip had to make a special trip out to buy more gas. Before the generator only ran once a day or every 2nd day.

    If I did do something to the batteries then I sure like to know so I don't screw up again...my ears are very sore.

    The only thing I can think of now is that I've been assuming 50% capacity is 12.1V. Do you know what it should be?

    Thanks
    John

     


     
     



  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    is that 12.1 V been measured at rest or under load?  There is a big difference...


     
    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
  • jtbuildsjtbuilds Registered Users Posts: 19 ✭✭
    edited June 2016 #38
    is that 12.1 V been measured at rest or under load?  There is a big difference...


    The 12.1V has been measured under load but the loads varied from 1 amp to 12 amps.  I've considered the 1amp ghost load that the trailer draws to be resting.

    This is the test I did on Friday...after going down to 12.09V an hour later it returned to 12.32V

    Yesterday we charged the batteries (using the temp sensor) for 6 hours @ 15.2V bulk and 14.1 float.  Five minutes after disconnecting the charger the voltage was 13.0V
     7:15AM this morning the resting voltage was 12.82V.
    The 12amp light bar was connected (nothing else connected to the batteries) and the voltage dropped to 12.33V.
    1 hour later the voltage was 12.32V
    2 hours later the voltage was 12.25V
    3 hours later the voltage was 12.16V
    3 1/2 hours later the voltage was 12.09V - the light bar was disconnected
    4 1/2 hours later with no load on the batteries the voltage was 12.32V

    Today the ambient is temp is 74F.

     The batteries where fully charged at 14.8V bulk & 13.8V float. The charger finished charging and went into standby mode.

    Battery monitor was set up and then turned the light bar on.

    The monitor shows load from the light bar at 11.9 amps and the battery temp at 71F.

     After 3 1/2 hours with the light bar connected the monitor alarm set at 12.1V went off.

    The S6-275AGM 20 hour rate is 12.5amp to 10.5V

     http://www.rolls-battery.com/pdf/s6-275agm.pdf
  • BB.BB. Super Moderators, Administrators Posts: 31,911 admin
    Under 10+ amp load, your battery voltage can fall to ~11.5 volts.

    Then rebound to 12.0 to 12.1 volt no load.

    And be at roughly 50% capacity.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jtbuildsjtbuilds Registered Users Posts: 19 ✭✭

    This became even more puzzling....this morning I took the batteries to be test.

    They put 400amp load on each battery for 2 seconds then put 100amps on for 10 seconds.

    Both batteries tested good.

    The needle on the battery tester was on the low side of the range for being good so I don't know if that means anything.
     

  • BB.BB. Super Moderators, Administrators Posts: 31,911 admin
    It does take several dozen cycles +/- (deeper than 75% state of charge) to full form plates.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jtbuildsjtbuilds Registered Users Posts: 19 ✭✭
    BB. said:
    It does take several dozen cycles +/- (deeper than 75% state of charge) to full form plates.

    -Bill
    Thank You Bill

    The last thing I want to do is return the batteries but I need batteries that last longer than 3 1/2 hours with a 12 amp load.

    As the plates form do you see the capacity going from 3 1/2 hours at 12amps to being close to the 20 hours at 12.5 amps that the batteries are rated for?

    Take Care
      John
     

  • BB.BB. Super Moderators, Administrators Posts: 31,911 admin
    No, not really.

    Probably talking about a ~20% increase in capacity.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • zonebluezoneblue Solar Expert Posts: 1,218 ✭✭✭✭
    edited June 2016 #44
    Ive got lost with your units and methods. We generally here measure loads in watts and watt hours per day. A 1A load running at 12V is quite a different thing to a 1A load running at 15V.

    In order to rely in any meaningful way on rest voltage the batterys have to sit for around 4-6 hours with no loads. Then you can get a reasonable idea of their SOC from the tables.

    For the charger, yes if its holding 14.8 at 25*C, for several hours then goes to float at 0.5A, that ought to be charged.
    Now that you have the battery monitor in place you can see exactly how many watts are leaving the battery. Multiply the load watts by the number of hours and thats the amount of Wh youve drawn down. You dont really want to routinely draw down more than one quarter of the battery's nominal capacity. Load tests are tricky to do and kinda destructive, so you need pretty controlled conditions to do it.
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


  • jtbuildsjtbuilds Registered Users Posts: 19 ✭✭
    edited July 2016 #45
    The wrap up to this was that I sent the batteries back to the dealer.

    Rolls - Surrette AGM are Full River AGM with a red case. Knowing that  would have saved $50/battery.
     
    Before sending the batteries back I called another battery dealer. They have a 25amp constant current test machine and they offer to test the batteries for free. The Rolls dealer never offered to test the batteries.

    After tying with 2 different chargers (one a pulse charger) they could not get the batteries to come up to full charge.
    The 25 amps down to 10.5 volts test results where:
    First test  - 475 minute
    Second test  - 478minutes
    The batteries tested 90%.

    After the batteries where tested I sent them back to the Rolls dealer. They tested the batteries with a light then a heater and said the batteries tested great.  I asked what the amperage and the finishing voltage was. The dealer said "We are not going to send you a Excel spread sheet".

    I got a full refund and bought a 6V open cell batteries from the dealer that tested the batteries for free.
  • Marc KurthMarc Kurth Solar Expert Posts: 854 ✭✭✭✭
    jtbuilds said:
    The wrap up to this was that I sent the batteries back to the dealer.

    Rolls - Surrette AGM are Full River AGM with a red case. Knowing that  would have saved $50/battery.......................................................................................
     
    After the batteries where tested I sent them back to the Rolls dealer. They tested the batteries with a light then a heater and said the batteries tested great.  I asked what the amperage and the finishing voltage was. The dealer said "We are not going to send you a Excel spread sheet".

    I got a full refund and bought a 6V open cell batteries from the dealer that tested the batteries for free.

    Rolls/Surrette is generally known as a higher end product for their FLA's. Their AGM's in a blue case do test to meet their spec's.

    I am surprised that you couldn't get some real technical help. Is your dealer listed as an Authorized dealer/distributor?


    I always have more questions than answers. That's the nature of life.
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