New SLA Batteries requiring charging

Discussion in 'General Electronics Chat' started by finn, Apr 3, 2014.

  1. finn

    Thread Starter New Member

    Apr 3, 2014
    I work for a company which purchased many new sla batteries varying in size from 12V 5ah to 12V 86ah, I would like some advise on how I can charge them and maintain them before they go bad. These batteries at the moment are just sitting on a wooden shelf. Please any advise would be appreciated.
  2. crutschow


    Mar 14, 2008
    SLA batteries need a trickle charge to prevent sulfation and damage to the plates. I would purchase a small trickle charger for each battery to maintain their charge when sitting for more than a few weeks. Such small chargers are used to maintain motorcycle batteries, for example.
  3. finn

    Thread Starter New Member

    Apr 3, 2014
    Thank you, however my company has 3000-4000 batteries sitting on the shelf any suggestions? lol
  4. wmodavis

    Well-Known Member

    Oct 23, 2010
    I would suggest they do not keep so many in stock unless absolutely necessary because as cruts says they will die if not kept properly charged. And that might be more expensive to throw out bad batteries than trickle charging them! Think $.
  5. tracecom

    AAC Fanatic!

    Apr 16, 2010
    Get a new purchasing manager? :)
  6. wmodavis

    Well-Known Member

    Oct 23, 2010
    Become a hero. Provide them clear concise information as to the hazard (waste of batteries and money) of not providing a maintenance charging system for the SLA batteries kept in stock for more than a minimum period of time. A starting place to become knowledgeable about SLAs (and other battery types) is here (
    Last edited: Apr 3, 2014
  7. wayneh


    Sep 9, 2010

    Batteries are a perishable asset, like produce in the grocery store. It's not prudent to have so many dollars tied up in wasting inventory. You could probably offer an estimate of the cost, for example 4000 batteries x 0.5% loss per day x $100 per battery = $2000 per day. Of course you'll need the proper figures to back up your advice.
  8. ian field

    Distinguished Member

    Oct 27, 2012
    Tell your firm to buy and store the SLA batteries; "dry charged" but not prepared for use. AFAIK the batteries can be supplied vacuum packed with an ampule of electrolyte for each cell - just don't fill the cells until ready to use them.
  9. k7elp60

    Active Member

    Nov 4, 2008
    I used to work for a company that had the same problem. It is possible to charge about 20 or more at a time if you have some adjustable bench power supplies that will provide about 5A of current.
    For more info or for more help please send me a PM
  10. inwo

    Well-Known Member

    Nov 7, 2013
    The equipment to keep the batteries charged seems trivial and low cost, compared to battery cost.

    1250ma 3 stage automatic battery maintainers are less than $5 each.
    I only had to buy 10 or 20 to get that price.

    The hard part is labor and space. Even doing a 100 at a time the logistics would be a killer.

    I don't believe keeping fresh sla batteries in storage for a year is a problem.

    I had some 12V 18AH for 2 years without voltage dropping to point for worry.

    Repeating above suggestion.
    If they are on the shelf for over a few months it's an inventory problem.
  11. crutschow


    Mar 14, 2008
    Even though the voltage may not have significantly dropped, the battery still could be sulfating and suffering damage.
  12. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    I've float charged multiple 12v SLAs from a single 13.8v regulated supply and a 5W series resistor for each battery.

    5W 0.47 ohms sounds about right, but 5W 1 ohm would work also.
  13. elec_mech

    Senior Member

    Nov 12, 2008
    Before going off to charge thousands of batteries, we need more information.

    How long do you plan to keep said batteries? If you just got them and plan to sell them all in two months, no worries. They should come charged from your supplier and, if memory serves, you only need to charge them once every three months if you plan to keep them for awhile. Don't hold me to that time frame, it's been several years. But ultimately, ask your battery supplier how often you should charge them.

    Also note most SLA batteries are only good (reliably) for three years if properly maintained - whether or not they are used. So if you don't foresee selling all your batteries off in a year or so, :eek:. Battery suppliers, at least the one I talked to, try very hard to not have batteries sitting on their shelves for long periods. This eliminates the reliably concern as well as the charging issue. Again, I strongly urge you to contact your battery supplier as they'll be happy to give you more info on shelf life, charging, etc.