Deep Cycle Battery Testing and Recovery Plan

AlanRTAlanRT Solar Expert Posts: 57 ✭✭✭✭
Can anyone point me to a step-by-step on how to test, evaluate and recover an existing stack of batteries?

We've inherited a 48 volt system with 32 US Battery L16HCs in various states of age and abuse. We want to recharge/test/EQ the entire group to sort out which ones are worth keeping and which ones should be tossed.

Based on stuff I found out on the net, I've gotten this far in developing a test and recovery plan:

1. Mark each battery in a corner with a permanent marker - Group One: 1-1, 1-2, 1-3, 1-4,...1-8. Group Two: 2-1, 2-2, 2-3,...2-8, etc

2. Disconnect the batteries from the inverters and charge controllers.

4. Check each battery with a digital voltmeter and write the values on the tops of each battery. If a battery reads less than 5.25 volts, mark these batteries "Dead" and remove them.

5. Check each battery cell with a hydrometer and write the values near the cap of each cell. If the difference between the highest cell and lowest cell is more than .050 (50 points) , mark these batteries "Dead" and remove them.

6. Reconnect the remaining batteries and interchange their locations in the following configuration (if possible):
-[x-4]-[x-3]-[x-2]-[x-1]-[x-8]-[x-7]-[x-6]-[x-5]-
6. Make sure all battery connections are tight, and the battery cells have adequate water

7. Reconnect the batteries to the inverters and charge controllers

8. Start the generator and run a recharge cycle until all batteries are full.

9. Run an equalization cycle for three hours.

10. Disconnect the batteries from the inverters and charge controllers and leave them disconnected overnight.

11. Check each battery again with a digital voltmeter and write the values on the tops of each battery.

12. Check each battery cell again with a hydrometer and write the values near the cap of each cell.

13. Reconnect the inverters. Leave the charge controllers disconnected.

14. Apply a load test. US Battery rates their L16 HCs at 322 AH @ 5 hr rate:
322 AH / 5 Hours = 64.4 Amps DC per hour
64.4 Amps DC @ 48 volts = 3,091 watts
3091 watts X 95 % Inverter efficiency = 3,254 watts
3,254 watts @ 240 volts = 13.6 Amps
Running a 240 volt AC load for 2.5 hours @ 13.6 amps per each stack of 8 batteries = 161 AH DC (50% discharge or 322 AH).
15. Check each battery again with a digital voltmeter and write the values on the tops of each battery. If a battery reads less than 6.1 volts after load testing, mark these batteries "Dead" and remove them.

In absence of another/better test plan, what do you think? I'd welcome anything less complicated.

Comments

  • RCinFLARCinFLA Solar Expert Posts: 1,280 ✭✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    Only thing I would do differently is do them one series string at a time. Match estimated battery condition for eight in the string.

    I have had some success on slightly sulfated batteries by charging them fully then discharge them by about 20% DOD. Then give them a strong recharge rate, about 30% A-Hr current. (also a reason to do one string at a time)
  • AlanRTAlanRT Solar Expert Posts: 57 ✭✭✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan
    Only thing I would do differently is do them one series string at a time.
    Good advice. Thanks.
  • RCinFLARCinFLA Solar Expert Posts: 1,280 ✭✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    One other thing, hope not too late.

    Do not add water to a battery that is not fully charged.

    When battery is partially discharged and you add water, the top plate section that is submersed in primarily water is subjected to a super fast recharge from current supplied by battery section below that is in the normal acid level electrolyte. This can damage the plate or separator at the top section of the battery.

    Discharge the plates looks for sulfuric acid, recharge the plates looks for water.
  • blackswan555blackswan555 Solar Expert Posts: 246 ✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    1. Mark each battery in a corner with a permanent marker - Group One: 1-1, 1-2, 1-3, 1-4,...1-8. Group Two: 2-1, 2-2, 2-3,...2-8, etc

    Yes mark them, but I would just go 1 > 32, Then I make a spreadsheet type doc, with 1 > 32 down the side, and columns wide enough to note SG`s & temps in,

    2. Disconnect the batteries from the inverters and charge controllers.

    Nope going to need them in a min,

    4. Check each battery with a digital voltmeter and write the values on the tops of each battery. If a battery reads less than 5.25 volts, mark these batteries "Dead" and remove them.

    not a good indication, a few cells will be lower than others at this point,

    5. Check each battery cell with a hydrometer and write the values near the cap of each cell. If the difference between the highest cell and lowest cell is more than .050 (50 points) , mark these batteries "Dead" and remove them.

    Check and record each cell, SG`s could be all over the place, not a good indicator of a bad cell at this point,

    6. Reconnect the remaining batteries and interchange their locations in the following configuration (if possible):
    -[x-4]-[x-3]-[x-2]-[x-1]-[x-8]-[x-7]-[x-6]-[x-5]-

    wouldn't change them at the mo,

    6. Make sure all battery connections are tight, and the battery cells have adequate water

    Yes

    7. Reconnect the batteries to the inverters and charge controllers


    8. Start the generator and run a recharge cycle until all batteries are full.

    Yes, I give them around an 8 hr, top of the bulk voltage charge,
    If you need to water, at the end of this is a good time,

    9. Run an equalization cycle for three hours.

    Run EQ, but until it is done not by the clock, See below

    Record SG`s and cell temp `s at start of EQ then every hour after, It is not particularly the number you are looking at but what each cell is doing in relation to each other in that string, continue EQ`ing and measuring every hour until all cells are stable in relation to each other.
    Keep and eye on your bat temps and shut down and allow to rest if they get to 45c (temp compensation does not work on most EQ settings) this can take anywhere from 3 to 16 hours,
    Comparing the SG`s and the patterns for each cell afterwards, look for any cells that are out of the ordinary,also have a visual check to see if any of them are "dirty`r" than the others, also have a cross check of the temp`s, you should be able to see any faulty cells resonably easily.

    For very badly sulfated FLA`s you can also do a corrective EQ, Charge at a low current ( 5 %) at high voltage, but that takes even longer.

    Have a good one
    Tim

    Some good info on here http://www.rollsbattery.com/content/troubleshooting-0
  • AlanRTAlanRT Solar Expert Posts: 57 ✭✭✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    Great. This is the kind of feedback I'm looking for.

    Hopefully, this thread can summarize a plan for others in the same situation. Couldn't find this in one place combing through the other threads.
  • PhotowhitPhotowhit Solar Expert Posts: 5,075 ✭✭✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    If they are old and sitting...

    I'd agree with blackswan, but check for low cells first!, exposed plates would create problems, I would add enought water to cover the plates with a bit extra. Be sure to fill all cells before equalizing, the equalizing will mix the liquid and boil off some hydrogen.

    I would do this one string at a time.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • blackswan555blackswan555 Solar Expert Posts: 246 ✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan
    Photowhit wrote: »
    If they are old and sitting...

    I'd agree with blackswan, but check for low cells first!, exposed plates would create problems, I would add enought water to cover the plates with a bit extra. Be sure to fill all cells before equalizing, the equalizing will mix the liquid and boil off some hydrogen.

    I would do this one string at a time.

    ???

    Question 6 ?

    6. Make sure all battery connections are tight, and the battery cells have adequate water

    Yes


    Just to clarify, Check water at this point, add if very low, If not wait until end of absorb and start of EQ to do levels, (Question8 8)

    have a good one
    Tim
  • wespowespo Registered Users Posts: 20
    Re: Deep Cycle Battery Testing and Recovery Plan

    Great info here.

    Is there any way to do this on a set of VRLA sealed batteries???

    I've tried a "soft EQ" with a bit of success.
  • blackswan555blackswan555 Solar Expert Posts: 246 ✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    Do not take your VRLA`s up to EQ voltage !! they may go bang !! note from niel-they do not go bang, but will vent excess charges without water being able to be replaced.
    But what I have seen by some manufacturers is a " maintainence charge" A long (14ish hrs) charge at absorb, Which makes sense to me, (make sure all cells are full to brim)
    I only use FLA`s so please check with your manufacturer first, I would also recommend having a temp sensor installed,

    Have a good one
    Tim
  • westbranchwestbranch Solar Expert Posts: 5,180 ✭✭✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    look in this string...

    http://forum.solar-electric.com/showthread.php?t=4624

    for a long entry on the second page by PETERD , there is some Absolyte specific info and compare that with the specs for your ??? specific batteries

    Eric
     
    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
  • wespowespo Registered Users Posts: 20
    Re: Deep Cycle Battery Testing and Recovery Plan

    Thanks for the thread link.
    The thread talks about watering the cells, but my specific battery's "lid" is welded shut.
    I managed to open a corner and saw what looked to be clear plastic circular covers/valves. I have not tried to remove these, but fear that if I do, that may destroy the battery completely...any experience here..???....

    These batteries have one of those "magic eyes"...at one time was green, now is black...and has been for many months. I read on the Delco site that the "eye" will show green if good SOC, dark if lower SOC and whitish/bright if low electrolyte. Has anyone seen this whitish, low electrolyte stage??

    Apologies for hijacking the thread...I will continue in my previous posts.

    Bill
  • westbranchwestbranch Solar Expert Posts: 5,180 ✭✭✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    Bill, sorry I don't know anything about those Delco's...

    but I do remember a thread about them probably within the last year here, something about that 'eye' rings a bell... there are only 12 hits for 'Delco eye', you may find it there...

    HTH
    Eric

    ps if they (one?) are that far gone you may be successful in opening one for destructive sampling:blush:

    ej
     
    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
  • BB.BB. Super Moderators, Administrators Posts: 29,967 admin
    Re: Deep Cycle Battery Testing and Recovery Plan

    The low electrolyte for the Delco Eye is just a round plastic rod with a point that sits in the electrolyte.

    If the level is higher than the tip, light just enters the rod from the top and goes down into the electrolyte (no refection from the tip).

    If the electrolyte is lower than the the tip, The air/plastic interface cause a reflection and you see a "white ring" of light reflected back up the rod.

    Of course there is usually only one "Delco Eye" per battery--so you could have other cells low and not know there is a problem--but this is usually not likely unless there are other problems with the battery (like the "Eye" is in a shorted cell).

    Here is a PDF File on how it works from the Manufacturer of the "Delco/Magic Eye"... It seems that there 10 different specific gravity levels that can be ordered for the Green Ball--Would have to contact the battery manufacturer to know what level "green" is (bet that the if the green ball is "dark"--get the battery on a charger quickly). The ball is temperature corrected so there should be no "confusion" there.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • blackswan555blackswan555 Solar Expert Posts: 246 ✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    Alan, An important point to add about Equalizing FLA`s, The equipment I mainly use (Outback) you will have to check on yours, Temperature compensation is not active during EQ, You have to do it manually,

    It is wise to keep an eye on cell temp/ bat voltage/ charge current as you can get a thermal runaway situation where the temp rises, Which requires less voltage, If not lowered, The temp and the amps rise, which requires less voltage,
    You know the rest,

    Have a good one
    Tim
  • AlanRTAlanRT Solar Expert Posts: 57 ✭✭✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    In case anyone would like to see the starting point for these batteries, here is what my crew reported initially. No values were entered for some cells because the water was so low that they did not get a valid SG reading after they topped them off.

    baterias-westbrook.jpg

    A fundamental problem with this system is obvious from the start - too many batteries (US Battery L16s). The owner has about 3,500 watts in panels, with a backup generator.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    alan,
    i like your test procedure list that you had made out. how is the progress going on determining the battery conditions? don't forget that load testing can be done after you sort through things just to be certain they are within reason of their specs.
  • AlanRTAlanRT Solar Expert Posts: 57 ✭✭✭✭
    Re: Deep Cycle Battery Testing and Recovery Plan

    My guys only had time to take the initial readings. They're going back today to group batteries with similar characteristics and then recharge/equalize groups one at a time. I'll keep everyone posted since this may help others.
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