Imalent        
Results 1 to 5 of 5

Thread: battery pack for LED Christmas lights designed for car battery 12v nominal

  1. #1

    Default battery pack for LED Christmas lights designed for car battery 12v nominal

    So 10 NiMh in parallel would give 12V. Wondering if the string would be manufactured with some circuitry in the cigar lighter plug to knock down the actual 14.2v to a true 12v input, or if the string expects 14v.

    10 Lithium would give a higher voltage, so wondering if that might be bad for the LEDs if they want a true 12v.

    This brand uses 5mm LEDs said to draw 0.01 Amps for a 20 light string on 22 AWG wire, lit length 9.5 feet. You can connect up to 30 in series.

    Where can I find a battery holder configured to do 10 in parallel?

  2. #2

    Default Re: battery pack for LED Christmas lights designed for car battery 12v nominal

    LFP, like A123 at nominal 3.2V works perfectly at 4S and treated well yields over 5000 cycles.

    The LI chemistries at nominal 3.6-3.7Vpc might be a bit too high at 4S, definitely too low at 3S will need experimenting.

    LTO use 5S, maybe 6S, way to go for charging in sub-zero, other LI must be pre-warmed first.

    Paralleling (do before series'ing) just gives higher Ah capacity, nothing to do with voltage.

  3. #3
    Flashaholic*
    Join Date
    Jun 2014
    Location
    Canada
    Posts
    3,923

    Default Re: battery pack for LED Christmas lights designed for car battery 12v nominal

    The string doesn't really care whether you supply 12v or 14v. It likely has a resistor on it to limit current, or perhaps depends on the resistance of the wire. Probably wired up so there's five sections in parallel, each with four LEDs. It will be a bit brighter with 14v than it is with 12v.

    5mm LEDs can generally take at least 20mA of current. So, if this thing is only drawing 10mA per LED, there's plenty of room for extra voltage to boost up the current.
    Last edited by WalkIntoTheLight; 11-30-2020 at 01:13 PM.

  4. #4
    Flashaholic* orbital's Avatar
    Join Date
    Feb 2007
    Location
    Great Lakes
    Posts
    2,680

    Default Re: battery pack for LED Christmas lights designed for car battery 12v nominal

    +

    If you want to skip charging all those NiMH over & over, a 15Amp 12V DC power supply for $15 or less (from A..zon or ebay)https://www.ebay.com/itm/DC-
    You just need to make your our AC power cord.

    Having more Amps (like 15) is better than not
    Last edited by orbital; 11-30-2020 at 07:54 PM. Reason: add

  5. #5

    Default Re: battery pack for LED Christmas lights designed for car battery 12v nominal

    [QUOTE=john61ct;5428271
    Paralleling (do before series'ing) just gives higher Ah capacity, nothing to do with voltage.[/QUOTE]

    DOH !

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •