Best way to resurrect under-watered batteries?

PorkChopsMmm
PorkChopsMmm Solar Expert Posts: 189 ✭✭✭✭✭
We had a newborn and had some other issues come up recently and have not checked my 8 GC2 batteries in a long time for water usage. We had some really bad energy retention recently and so I went out and opened up the batteries -- I could see the top of all of the plates! :cry:

I added distilled water and have EQ'ed a few times since then, but power retention, e.g. after EQ'ing and with small loads the voltage drops quickly. Any suggestions on what to do now? EQ for a full day? I foresee a battery bank replacement in my future.

We live offgrid and the battery bank is in near full-time use, even if a generator is feeding the inverter, so it is hard to pull them out of service for long periods of time. Thanks in advance.

Comments

  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Best way to resurrect under-watered batteries?

    what do you get the SG's up to? Doesn't sound too good though...
     
    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
  • PorkChopsMmm
    PorkChopsMmm Solar Expert Posts: 189 ✭✭✭✭✭
    Re: Best way to resurrect under-watered batteries?

    I couldn't even measure the SG before I added the water -- not enough liquid and I didn't want to try and jam the instrument in the batteries. I haven't measured it since adding the water -- I can tell they are still holding a poor charge just by watching the voltage dropping with a small load (e.g. 140 watts), etc. I am going to try and EQ them all night and try to take the SG when I am done and have let them rest a bit. Yeah, I don't think it sounds good.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Best way to resurrect under-watered batteries?

    once the plates expose it losses immediately some of its capacity and if left long enough and deep enough i would consider them soon to be toast. plate exposure is a definite no no. it sounds like you will need a new battery bank. sorry.
  • PorkChopsMmm
    PorkChopsMmm Solar Expert Posts: 189 ✭✭✭✭✭
    Re: Best way to resurrect under-watered batteries?

    Any chance I could drain the batteries and refill with new electrolyte? Or are the plates toasted and so the new electrolyte won't help?
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Best way to resurrect under-watered batteries?

    I concur with Niel, probably dunners... How much water did you add and how much of the plates was exposed?

    I would not leave then to EQ alone , best to be there in case of thermal runaway... you can possibly give yourself a bit of time to search out a new set, but ??
     
    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: 33,613 admin
    Re: Best way to resurrect under-watered batteries?

    It is oxidation of the plates and drying out that damaged them. There is probably not much that you can do to "recover" the plates. And the batteries probably have a higher chance of "ugly" failures (hot spots, plate connection failures, cell shorts, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PorkChopsMmm
    PorkChopsMmm Solar Expert Posts: 189 ✭✭✭✭✭
    Re: Best way to resurrect under-watered batteries?

    I guess my goal is to get me to Spring, if possible. I was going to double the size of our battery bank (to 16) anyway and buy all new batteries at that time. Looks like my timeline just got moved up :( This is hard to swallow, 8 batteries are ~$750. I think I could swing the new batteries but a) I want to buy all of my batteries at once and b) this is the darkest time of year and I don't know if my 3500 watt Champion generator can keep up with all of the charging of 16 batteries without any assistance from the sun.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Best way to resurrect under-watered batteries?

    check the SG's. You may have different charge states and can , maybe, get one half your bank running. maybe.
     
    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
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Best way to resurrect under-watered batteries?
    this is the darkest time of year and I don't know if my 3500 watt Champion generator can keep up with all of the charging of 16 batteries without any assistance from the sun.

    Sorry to hear about your batteries... With 16 batteries you will have twice as many to maintain... twice as many dollars to replace if there is another lapse in maintenance. Have you thought about a single string of L-16 batteries?

    I don't see the problem with charging 16 GC batteries with a 3500 watt generator... what am I missing?

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Best way to resurrect under-watered batteries?
    and I don't know if my 3500 watt Champion generator can keep up with all of the charging of 16 batteries without any assistance from the sun.

    If you have the 3500/4000 Champion, that is the one I have. It will run a DLS-27-40 (40amp) 24v ok, but it is really pushing it and if my fridge starts with ANY other small loads on it will stall the generator. If you have the 3000/3500 I would only expect the generator to run the charger by itself and no other loads. But I still love it for the price, it's pretty quiet, and it is really good on fuel consumption even compared to the inverter generators (when at 50%+ load).
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • SolInvictus
    SolInvictus Solar Expert Posts: 138
    Re: Best way to resurrect under-watered batteries?

    If your batteries are in a cold place, the electrolyte is at risk for freezing, expanding and splitting the cases. You should check the density.

    The portion of the plates that was exposed to air is done storing electricity. If you charge these batteries over and over again for months, they may regain a small fraction of the charge they used to store. It will not be worth the effort, and you need them to store electricity now. It is likely time to replace them.

    Do not give the old batteries away. Look for a good scrap value because lead has become valuable which will help minimize the cost of the new ones.
  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Best way to resurrect under-watered batteries?

    Unfortunately, a hard lesson learned. :cry:
    The others are correct. The batteries are finished.
    Reminds me of something I once read: "Most batteries don't die, they are murdered".
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    Re: Best way to resurrect under-watered batteries?

    Exposed plate sulfide quickly depending on their discharge state.

    When you add water it is like putting a deeply discharged smaller battery in parallel with a charged larger battery. The lower part of the plates will recharge the previous top exposed part of plates at a high current rate potentially damaging the previously exposed plate area due to excessive recharge current density. Pure water is like the electrolyte in a fully discharged battery meaning there lots of free water molecules used during recharging and little sulfuric acid that inhibits recharge.

    Pour water in slowly (good to do anytime water is added). You may hear some crackling which is not a good thing. Slower adding of water should reduce crackling as it give some time for electrolyte to remix to a lower concentration of pure water at top of battery.

    Be careful using an SG bulb when water is low as the hose may damage the plates separator top inducing current leakage or shorts later on.
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Best way to resurrect under-watered batteries?
    RCinFLA wrote: »
    When you add water it is like putting a deeply discharged smaller battery in parallel with a charged larger battery. The lower part of the plates will recharge the previous top exposed part of plates at a high current rate potentially damaging the previously exposed plate area due to excessive recharge current density. Pure water is like the electrolyte in a fully discharged battery meaning there lots of free water molecules used during recharging and little sulfuric acid that inhibits recharge.

    :D Very nice explanation, RCinFLA. Those currents between the tops and bottoms of the plates also flow when a battery is stratified... adding water to exposed plates is the ultimate stratification.

    :confused: Makes me wonder if PorkChopsMmm should pour the electrolyte out of his batteries, dilute it, and then pour it back in.

    Carrying that thought to the extreme: During routine maintenance, when I add water to the batteries (long before the plates are exposed), should I suck out a few ounces of electrolyte (with the hydrometer), mix it with a few ounces of water, and then pour it back into the battery?

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Best way to resurrect under-watered batteries?

    I wish you had posted sooner before you did to much to them. How low was the electrolyte on the plates ?? What was the SG level the last time you checked it ?? Eq voltage now is adding insult to injury, I'd keep them just above gassing ( 57.2 - 57.6 ) for as long ( 12-18 hrs at a time ) as you can and see if there is any rise in the SG's, watch the temperatures. You need to open a cap and verify that you have gassing.

    Since you are using them it's going to be hard to tell if your seeing any success with them. The exposed portion is pretty much gone, I don't know the age of them, but if you had 80% capacity and now you only have 50% you don't have much unless you can get whats still useable working. There are some chemical treatments, but usually they produce a limited success long term.

    This is a process, without knowing what your seeing from them it's hard to tell you what to do.
  • PorkChopsMmm
    PorkChopsMmm Solar Expert Posts: 189 ✭✭✭✭✭
    Re: Best way to resurrect under-watered batteries?

    I was in a rush but when I added the water I honestly couldn't see any liquid in the batteries !

    I bought 8 new ones. Life is good again and lesson learned. Thanks guys.