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Scooter Saga: Revisited; Batteries and Charger

Discussion in 'Electronic Basics' started by mea305, Jan 10, 2007.

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  1. mea305

    mea305 Guest

    I addressed this issue yesterday, but I lacked the appropriate
    nomenclature for others to give me their input. My question was --
    because I had some additional batteries installed onto my scooter (in a
    parallel configuration, ensuring that the 12 VDC requirement was met
    and not exceeded), I attempted to charge the unit yesterday. I did so
    with the following unit:

    ==> Universal Power Group Charger, Model Number 24BC5000TF-1; Input:
    100-240V AC, 50/60Hz 4.0A; Output: 24V DC, 5A MAX

    A respondent informed me that either one of the two situations
    developed: either I blew the rectifier or a fuse. However, upon
    inspecting the unit, I do not see a fuse.

    My "initial quesion" was whether I could use a standard type battery
    charger; my father-in-law has one that is on wheels, is able to charge
    just about anything from 6 to 12 V DC, and it has a dial on the front
    indicating a various number of levels.

    My battery nomenclature is as follows: "Universal Battery:"
    Non-Spillable, lead-acid battery
    Voltage Regulation: Standby Use: 13.6 - 13.8 V; Cyclic Use: 14.5-14.9 V
    The manufacture number, or model number for this battery is UB121120

    Would it be appropriate to use the standard "auto" charger? And, if
    there is no external fuse on the aforementioned charger, would it be
    contained inside the unit?

    Thanks,

    Mark
     
  2. chuck

    chuck Guest

    If this charger is indeed 24v, it should only be used with TWO 12 volt
    batteries in series. I thought you were connecting two 6 volt batteries
    to make 12 volts for a 12 volt motor.

    I am also confused by the input current rating of 4.0 amps. At 120
    volts, you would have 480 watts "going in" and 120 watts "going out",
    meaning that the charger is dissipating the difference (360 watts). It
    should get too hot to touch in a matter of minutes based on that.
    Certainly not if you have two 12 volt batteries connected in series to
    provide 24 volts. To use the "auto" charger in that case, the batteries
    would have to be disconnected from the scooter. You could connect any
    number of 12 volt batteries in parallel (plus-to-plus, etc.) and charge
    them simultaneously.

    Mark, at first we had information that you are using two 6 volt
    batteries to run a 12 volt motor, but now we learn that the batteries
    are 12 volts each and the charger is 24 volts. I think that with
    confusion of this magnitude, it would not help to provide further
    suggestions here. It would be much better if you could find someone near
    you who could look things over in person and give you a more informed
    opinion.


    Chuck
     
  3. mea305

    mea305 Guest

    Perhaps I am the one who is confusing everyone here -- and I apologize.
    Yes, I am using 6 batteries; they are connected as per the
    configuration sent to me, in a parallel set. Each of the batteries is a
    12 VDC; I was able to get the recharger through a 'contact' who was
    nice to me -- it's a 24 volt DC recharger, and I have been using it for
    the two battery configuration for some time. The only reason I decided
    to ask the questions that led me to the 6 battery installation was to
    help with the time factor with recharging.

    Yesterday, I was 'thinking' to myself, and I came to the conclusion
    that the 'system' remains a 12 VDC configuration, as the scooter
    initally required two (2) of the batteries in a parallel configuration
    to operate. Therefore, I merely hooked up the charger; but it didn't
    work, and I heard a rather 'distinctive click' before it no longer
    operated.

    My question at this point was whether I could use a standard 'auto'
    battery charger; my father-in-law has one, the kind the rolls on
    wheels; it is a 12 VDC recharger, but it also can charge the 6 V
    batteries (if needed) and it has a dial on the front that can be
    adjusted according to the user's needs. Is it appropriate to use this
    type of recharger on these type of batteries?

    Actually, the situation is 'sort of mute' now, as my motor "fell off"
    this morning. The welding that was used to connect the motor to the
    chasis had corroded; so I am going to have to get that fixed.

    The 'only' reason I wanted more 'time' with respect to charging is
    because in order to retrieve the newspaper in the AM, I have to
    navigate a rather long (well, about 1/4 mile) driveway that is on an
    incline -- I am not sure of the %, but it's not much.

    Does this clear it up, or did I make it worse?
     
  4. ehsjr

    ehsjr Guest

    That is the wrong charger for your setup. The charger
    expects to "see" a 24 volt battery, but was connected
    to a 12 volt setup. Consequently, too much current was
    drawn, and something inside failed. You could possibly
    repair the charger, but it is not suitable for you, unless
    you reconfigure the batteries for charging and then
    reconfigure for use, every time. Not practical.
    No. That kind of charger has no charging management circuit
    for SLA's. You might "get away with it" using that charger,
    but it could easily cook your batteries.
    Perhaps.

    What you need is a proper charger for your setup,
    designed for SLA charging at the charge rate you
    need and capable of supplying the charging current
    required.

    In your original post a while back, you gave these
    specs for the battery charging requirements:
    "Standby Use":
    Voltage Regulation: 13.5 - 13.8V; Initial current: 1.8A

    "Cyclic Use":
    Voltage Rrgulation: 14.5 -14.9V; Initial Current: 3.6A

    Since you now have two batteries in parallel, the current
    requirements double to 3.6 and 7.2 amps, respectively.
    The voltage requirements remain the same.

    All of the above assumes that you are using the same
    batteries that were mentioned in your initial post.

    As Chuck mentioned in his reply, you will probably
    need to find someone knowledgeable who can look
    at your setup to verify what is needed. Sounds like
    a great project for an electronics/amateur radio
    club at the local high school or Boy Scouts or ?

    Ed
     
  5. Rich Grise

    Rich Grise Guest

    It sounds like you popped the charger's protection circuit trying to
    charge 12V batteries with a 24V charger. If all that happened was that you
    heard a click, you might only need to reset the breaker; but you still
    can't use it to charge 12V batteries - theoretically, you could charge two
    12V batteries in series (for 24V), but unless the batteries are exactly
    the same age, from the same manufacturer, the same production lot, and
    have seen exactly the same usage and are in exactly the same state of
    discharge, this can be risky.
    As long as they're 12V batteries, then probably, but be sure to read the
    instruction manual first. Depending on the amp-hour capacity of the
    batteries, and the charger's algorithm, you could wind up trying to
    overcharge them, which can hurt them.

    But if the charger is "smart" enough (and you are ;-) ) then you could
    probably do it.

    Of course, read the manual. :)

    ....
    Pretty much, but I wish you'd learn to bottom-post.

    Good Luck!
    Rich
     
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