New L16 Batteries but not installed yet.

System
System Posts: 2,511 admin
in Advanced Solar Electric Technical Forum #1
I have had my 16, 415 AH, L16HC, US Batteries for six weeks but have not had the time to finish the complete installation of the system. Do I need to get these bad boys on a charger to keep 'em up or are they OK for another month?
· Share on Twitter

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #2
    Re: New L16 Batteries but not installed yet.

    Your best bet would be to measure the specific gravity and/or voltage (and temperature) with an accurate voltmeter.

    If they are 75% or below state of charge--you need to charge them right away. If the are above ~90%--they probably are OK for now.

    It probably would not be a bad idea to recharge them every month or two.

    Does the Mfg. have any information on how often to charge if they are in storage?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: New L16 Batteries but not installed yet.

    yes, put them on some kind of charger to keep them up. it doesn't have to be a real big charger for temporary, but something just to lightly charge or even float it to help stop any problems due to sulphation from setting in. if you can bring them to full charge that would be a plus.
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #4
    Re: New L16 Batteries but not installed yet.

    The Fluke meter reads 6.18V on just about all of them. There were a few 6.14V, and this is at 40 degrees.
    My interconnect cables are being made this week, I should have 'em on Friday.
    I have a little old car battery charger that puts out 12V at 1 amp. Would that work to keep 'em charged up if I have 8 of them hooked up in a string? Or should I charge them individually? If so, about how long should I keep the charger on?
    · Share on Twitter
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #5
    Re: New L16 Batteries but not installed yet.

    2 in series, to create 12V should do it, and on the 12V car charger, 24 Hours should have them bubbling away, and then on the the next pair. Get them all charged up, and ready for your new system. You have your wrenches all taped up right ? Don't want a wrench to short out those big baby's !
    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 ,

    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #6
    Re: New L16 Batteries but not installed yet.

    -5mV per cell per degree C temperature offset from 20C:

    -5mV * 3 cells * (40C-20C) = -0.300 mV offset

    6.14 volts * 2 = 12.32 volts

    Use this state of charge chart (scroll way down) for 12 volt batteries, we find that 12.32 volts converted to 20C is:

    12.32V + 0.300V = 12.62 volts => ~70% state of charge
    6.18V*2 + 0.300V = 12.66 volts => ~73% state of charge

    Not good, your batteries are probably sulfating at that charge level (remember, this is an estimate of state of charge--you need a proper hydrometer for more accurate measurements).

    We probably don't know what their level of charge was when they were put into storage.

    You should get them on a charger right away... 1 amp is a trickle charge for one battery of those size--You will need roughly 20-40 amp charger (per battery) for proper charging (or per pair of batteries if connected as 12 volts, two in series if using a 12 volt charger).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #7
    Re: New L16 Batteries but not installed yet.

    How long on the charger depends on the size of the charger...

    415 amp*hours / 40 amps = ~10 hours for full charge
    415 amp*hours / 1 amp = ~415 hours for full charge

    You are down 30%, so:

    10H * 30 % + 2-4 hours for finishing charge = ~5-7 hours to charge (40 amp charger)
    415H * 30 % = ~ 120+ hours (1 amp charger)

    Couple of things, you need a charger with a Deep Cycle and/or Equalize setting... And you need ~5-13% of your battery (bank) AH capacity for the charger. For equalization, you need to get the batteries up to ~15 - 15.5 volts

    If 48 volt bank (2 strings of 8 batteries in series), you would have:

    415AH*2=830AH
    830AH*5%=~46 amp minimum charger
    830AH*13%=~108 amp maximum charger

    And, assuming you need to purchase a backup 120/240 VAC battery charger--make sure you get one with a remote battery temperature sensor--much more accurate charge voltage set points (both for your AC charger and your Solar Charger--assuming you are getting one of those too).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #8
    Re: New L16 Batteries but not installed yet.

    So basically what I need to do is get the XW6048 installed with the grid as back-up and mash the equalize button ASAP.
    · Share on Twitter
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #9
    Re: New L16 Batteries but not installed yet.

    i don't see the need to eq asap, but get them charged up with a standard charge as you don't want sulphation to lessen the lifespan of your batteries. a trickle charge into your batteries will only serve to maintain its current charge level which being low will allow the sulphation to start taking place in about 25% of each battery.
    · Share on Twitter
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #10
    Re: New L16 Batteries but not installed yet.
    -5mV per cell per degree C temperature offset from 20C:
    Oh, Nooooo, Mr. Bill!! :roll:

    That temp comp formula generally applies to correcting absorb- and float target voltages. Also, the reference is usually 25 C, but it does vary from mfr to mfr.

    Here are links to temperature compensated SOC vs. voltage charts:

    http://jgdarden.com/batteryfaq/carfaq4.htm#soc
    http://jgdarden.com/batteryfaq/carfaq4.htm#mf_soc
    http://www.trojanbattery.com/BatteryMaintenance/Testing.aspx (requires correcting electrolyte SG for temperature)

    HTH,
    Jim / crewzer
    · Share on Twitter

Categories