The (old) battery storage question

MarkCMarkC Posts: 173Solar Expert ✭✭✭
After searching deep cycle battery storage questions, it seems my dilemma is a little different.
I can "store" 4 deep cycle batteries (12V, ~150 ahrs) as spares for my golf cart  in a vented box inside my "solar shed".  Connections are set up to parallel these "spares" with my in-situ cart batteries.  The combined energy is enough to run certain ceiling fans, lights and a TV during the night in an emergency use case - and all is set up to do so quickly if an emergency (hurricane) happens by.   I bought the "spares" over a year ago (maybe 2) thinking it must be close to time of failure of the golf cart set (almost 6 years of torture by my Grandkids).  I recently put  the "spares" in operation and trying to:
1.  Decide when to buy a new "spare" set - would like to have them available IF the second set ever fails - not easy to get (good) new ones at this remote cabin.
2.  Decide on how best to maintain them in a South Texas (hot) shed.  Note that I've managed to use ventilation and reflective insulation board to essentially keep the interior of the shed approx same as outside - but still gets to 100 +oF a few days every summer.  No freeze problems!
3.  Bite the bullet and consider Li tech batteries at some point - $$$'s?

Any suggestions appreciated.  







3850 watts - 14 - 275SW SolarWorld Panels, 4000 TL-US SMA Sunny Boy Grid tied inverter.  2760 Watts - 8 - 345XL Solar World Panels, 3000 TL-US SMA Sunny Boy GT inverter.   3000 watts SMA/SPS power.  PV "switchable" to MidNite Classic 250ks based charging of Golf cart + spare battery array of 8 - 155 AH 12V Trojans with an  APC SMT3000 - 48 volt DC=>120 Volt AC inverter for emergency off-grid.   Also, "PriUPS" backup generator with APC SURT6000/SURT003  => 192 volt DC/240 volt split phase AC inverter.  

Comments

  • mike95490mike95490 Posts: 7,790Solar Expert ✭✭✭✭
    Seems like there is nothing wrong with the FLA golf cart batteries.   Just replace them, and in another 5 years, maybe the Li batteries will be practical.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Dave AngeliniDave Angelini Posts: 3,886Solar Expert ✭✭✭✭
    If it has worked keep using the golf batteries.  You will have to figure a better way to keep that shed cooler or the value of long life with Li-ion will be negated. Even your flooded batteries do not like 100F and are not going to last as long as they could.

    Many li-ion batteries monitor with their electronics the temperatures they are charged at and log this for warranty.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • EstragonEstragon Posts: 2,607Registered Users ✭✭✭✭
    > @MarkC said:
    ...
    > 1.  Decide when to buy a new "spare" set - would like to have them available IF the second set ever fails - not easy to get (good) new ones at this remote cabin.

    6yrs is pretty good for used/abused batteries. The second set WILL fail, the question is how (sudden death or slow loss of capacity), and when.

    > 2.  Decide on how best to maintain them in a South Texas (hot) shed.  Note that I've managed to use ventilation and reflective insulation board to essentially keep the interior of the shed approx same as outside - but still gets to 100 +oF a few days every summer.  No freeze problems!

    I'd dig a hole in the shed deep enough to moderate the temp of the "stored" batteries, and charge them every 3mos or so. Put the reflective board on top (but well above battery posts!).

    > 3.  Bite the bullet and consider Li tech batteries at some point - $$$'s?

    Maybe if the power to weight ratio would give you a hot-rod golf cart, otherwise I don't really see the point :smile:
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • softdownsoftdown Posts: 1,840Solar Expert ✭✭✭✭
    I'd expect about two years at those temperatures. Have a basement? Basements tend to be much cooler.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • MarkCMarkC Posts: 173Solar Expert ✭✭✭
    Good point about the temperatures affecting the LI tech batteries.  My Leaf's battery temperature runs about 85-95 oF normally in summer when kept in the garage overnight and not parked in the sun during the day. 

    The one good thing is that the shed has a silver galvalume roof and often gets quite cool by morning (emissive cooling?).  The averaged temps during the summer are likely to be more like 85-90 oF.  I also have 4 "trickle" chargers - batteryMinder Plus that claim "desulphating" action.  Should I keep those on each battery continuously or for a few days every month or so?  In the "spare" set kept in storage, I discharged them (lightly) with my 48 VDC system every few months and recharged them with my 15 amp auto style to periodically mix the electrolyte.  They seem to be holding up OK in the cart, but its only been a few months.




    3850 watts - 14 - 275SW SolarWorld Panels, 4000 TL-US SMA Sunny Boy Grid tied inverter.  2760 Watts - 8 - 345XL Solar World Panels, 3000 TL-US SMA Sunny Boy GT inverter.   3000 watts SMA/SPS power.  PV "switchable" to MidNite Classic 250ks based charging of Golf cart + spare battery array of 8 - 155 AH 12V Trojans with an  APC SMT3000 - 48 volt DC=>120 Volt AC inverter for emergency off-grid.   Also, "PriUPS" backup generator with APC SURT6000/SURT003  => 192 volt DC/240 volt split phase AC inverter.  
  • softdownsoftdown Posts: 1,840Solar Expert ✭✭✭✭
    MarkC said:
    Good point about the temperatures affecting the LI tech batteries.  My Leaf's battery temperature runs about 85-95 oF normally in summer when kept in the garage overnight and not parked in the sun during the day. 

    The one good thing is that the shed has a silver galvalume roof and often gets quite cool by morning (emissive cooling?).  The averaged temps during the summer are likely to be more like 85-90 oF.  I also have 4 "trickle" chargers - batteryMinder Plus that claim "desulphating" action.  Should I keep those on each battery continuously or for a few days every month or so?  In the "spare" set kept in storage, I discharged them (lightly) with my 48 VDC system every few months and recharged them with my 15 amp auto style to periodically mix the electrolyte.  They seem to be holding up OK in the cart, but its only been a few months.




    We don't seem to recommend constant charging. I also don't believe the de-sulphating claims to be very worthy. 

    Discharging them slightly with a 48 volt system seems like a bit of a project. 

    The board members often tend to feel that stored batteries are toast by the "time you finish coffee." I live in a cool environment and have been able to store batteries for significant periods. One must keep them charged of course. That is much easier in a cool environ.

    I still have a number of 8D's built in 2011 in service. Worth no more than scrap value to anybody else I supplement my existing bank with them. But my electrical demands are not very noteworthy. Below average in all likelihood. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • MarkCMarkC Posts: 173Solar Expert ✭✭✭
    I now do have the option of leaving the "48" volt wiring in place and use a 48 volt smart charger.  Either way, it's a 5 min job to hook them up as the wires sit next to the posts.  The more in series, the higher chance of balance issues?  Keeping them cooler is simply not an option.  It's half way through hurricane season now and forecasts are much lower chances due to El Nino - likely I'll wait until next summer to purchase the spare set.
    3850 watts - 14 - 275SW SolarWorld Panels, 4000 TL-US SMA Sunny Boy Grid tied inverter.  2760 Watts - 8 - 345XL Solar World Panels, 3000 TL-US SMA Sunny Boy GT inverter.   3000 watts SMA/SPS power.  PV "switchable" to MidNite Classic 250ks based charging of Golf cart + spare battery array of 8 - 155 AH 12V Trojans with an  APC SMT3000 - 48 volt DC=>120 Volt AC inverter for emergency off-grid.   Also, "PriUPS" backup generator with APC SURT6000/SURT003  => 192 volt DC/240 volt split phase AC inverter.  
  • EstragonEstragon Posts: 2,607Registered Users ✭✭✭✭
    More in parallel = balance issues. More in series shouldn't be a balance problem, but worth checking once in a while, and charging a battery seperately if need be IMHO.

    In higher temps, self-discharge will be higher, so charging more frequently (eg bi-weekly or monthly) at lower voltage (temp corrected, if possible) may be best. Others may disagree, but I wouldn't bother discharging beyond self-consumption. De-sulfation will likely be some sort of equalization at higher voltage and low current for some period after absorb and before float. Probably worth doing periodically.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mcgivormcgivor Posts: 2,052Solar Expert ✭✭✭✭
    Series is best for ballance, one option could be to use the 48v smart charger plugged into a timer set to come on for an hour each day.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • MarkCMarkC Posts: 173Solar Expert ✭✭✭
    It is a 50 watt "smart charger" with desulfating circuitry (Granite manufacturer).  Easy to use an appliance type timer to turn it on daily for an hour or two.

    I thought stratification was an issue with NOT discharging and bulk charging with FLAs - if left stored too long**?  Also, that minimal charge levels of .1C are needed.  These are why I "exercised" the spare set periodically.  Note that the spare set seems in great shape - time will tell!

     **However, I do hear "gassing" when charging even with the 48 volt 50 watt charger.


    3850 watts - 14 - 275SW SolarWorld Panels, 4000 TL-US SMA Sunny Boy Grid tied inverter.  2760 Watts - 8 - 345XL Solar World Panels, 3000 TL-US SMA Sunny Boy GT inverter.   3000 watts SMA/SPS power.  PV "switchable" to MidNite Classic 250ks based charging of Golf cart + spare battery array of 8 - 155 AH 12V Trojans with an  APC SMT3000 - 48 volt DC=>120 Volt AC inverter for emergency off-grid.   Also, "PriUPS" backup generator with APC SURT6000/SURT003  => 192 volt DC/240 volt split phase AC inverter.  
  • mcgivormcgivor Posts: 2,052Solar Expert ✭✭✭✭
    The 50W 48V charger on for an hour or so per day will  keep the self discharge to a minimum without overcharging, but being a smart charger that  shouldn't be a problem even if left on continually, but for the most part it would be doing nothing.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • EstragonEstragon Posts: 2,607Registered Users ✭✭✭✭
    My understanding is it's the gassing during the absorb and EQ stage of charging that mixes electrolyte and prevents stratification.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mcgivormcgivor Posts: 2,052Solar Expert ✭✭✭✭
    Yes that's true, it would probably be best to refresh charge, boost or equalize, before use after a long storage, a daily shot of energy would minimize the amount of refresh charge needed, electrolyte levels should not be depleted unnecessary in storage especially if unattended.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • MarkCMarkC Posts: 173Solar Expert ✭✭✭
    Got it - thanks for all the advice. 

    Going to watch forecasts - if things change and we get into the "cone of certainty  :s" of a hurricane this season, I'm going to buy the "spares" and set them up.  I realise this seems a little over the top, but we have actual experience in the past to our family - we spent over a week at our rural cabin while our Houston neighbors suffered without electricity for several days due to tropical storm Allison.  Luckily, they were able to use my home generator and bought a small window A/C unit for some local cooling - and to keep their refrigerator going. 
    3850 watts - 14 - 275SW SolarWorld Panels, 4000 TL-US SMA Sunny Boy Grid tied inverter.  2760 Watts - 8 - 345XL Solar World Panels, 3000 TL-US SMA Sunny Boy GT inverter.   3000 watts SMA/SPS power.  PV "switchable" to MidNite Classic 250ks based charging of Golf cart + spare battery array of 8 - 155 AH 12V Trojans with an  APC SMT3000 - 48 volt DC=>120 Volt AC inverter for emergency off-grid.   Also, "PriUPS" backup generator with APC SURT6000/SURT003  => 192 volt DC/240 volt split phase AC inverter.  
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