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Battery Power. 5V at 2A and 9/12v at 2A 15000mAh $50 — Parallax Forums

Battery Power. 5V at 2A and 9/12v at 2A 15000mAh $50

tonyp12tonyp12 Posts: 1,951
edited 2013-12-29 16:08 in General Discussion
Could be useful for that mixed 5v and 12v battery operated project.
http://www.newegg.com/Product/Product.aspx?Item=0SC-000Y-00056&clickid=zW0XZ6UEXXEcwqzSOqRcSR1LUkTwg7RUeUzIy40&iradid=95978&ircid=2106&irpid=10147&nm_mc=AFC-IR&cm_mmc=AFC-IR-_-na-_-na-_-na
will not charge devices with input currents lower than 40mAh, I guess you must have a minimum draw of 40mA (hrs?)

Comments

  • TubularTubular Posts: 4,703
    edited 2013-12-28 12:22
    Nice find, Tony, especially the 12v output.

    Could that be 4A total at 5v available? Good for running portable neopixel projects if it is
  • ercoerco Posts: 20,256
    edited 2013-12-28 12:41
    Good find, nice capacity battery.That flat form factor might make a nice robot chassis. Slap some motors, wheels, sensors and a controller on it and call it a day.
  • Mark_TMark_T Posts: 1,981
    edited 2013-12-28 12:45
    40mA is current, 40mAh is charge.

    I presume it auto-switches-off when the charging current drops to 40mA to prevent it discharging
    itself endlessly when left unattended.

    The battery is 15Ah, not 15000mAh, thats what innumerate marketoids call it to make it sound
    larger than the competition!

    So about 55Wh, the same as a laptop battery pack basically. 2A at 12V will drain it in about 90
    minutes I'd guess, allowing for losses and the marketroids lying...

    It claims to not charge faster than 1.2A at 12V, so 5 or more hours to fully recharge it looks.


    Ah yes, the marketroids are lying through their teeth again:
    Adopt top-rated Li-Polymer Battery cells, which are more stable and safe than Li-ion battery, such as both iPad and iPhone use the safer Li-polymer battery

    Shame they don't just produce the electronics and allow you to plug in a LiFePO4 cell of your choice (!)
  • CuriousOneCuriousOne Posts: 931
    edited 2013-12-28 23:20
    I have assembled such device by myself, using LT1370 as adjustable step-up converter and LT1185 as CC/CV lithium charger. Using 10x Sanyo 2000mAh 18650s (BGmicro has them for cheap).
  • RDL2004RDL2004 Posts: 2,554
    edited 2013-12-29 11:47
    The battery is 15Ah, not 15000mAh, thats what innumerate marketoids call it to make it sound
    larger than the competition!

    Okay, I read that twice and counted the zeroes carefully. What is the difference? Does 1 A per hour not equal 1000 mA per hour?
  • Mark_TMark_T Posts: 1,981
    edited 2013-12-29 15:00
    Its "innumerate" to say 15000mAh if you know SI. In SI you either use scientific notation (1.5 x 10^4), or
    the prefixes with numeric values in the range 0.1 to 100 wherever possible and sensible (exceptions
    being like having a column in a table with the prefix given in the column header).

    The point being to have a canonical representation for a particular value (avoiding the craziness of
    having 0.047uf / 47nF / 47000pF all being in common use for the same value, 47nF).

    Would you say 15000mm instead of 15m? Would you say 13000 hours instead of 18 months?

    There is also the innumeracy of quoting excess digits of precision when you say 15000mAh instead of
    15Ah (the error bar will be perhaps 10%, not 0.01% as implied by the latter)

    Here I use numeracy in an open-ended way (which is how literacy is used - there's a large scale of literacy)

    A school science course that didn't teach the above about SI and number precision is a poor course...
  • RDL2004RDL2004 Posts: 2,554
    edited 2013-12-29 16:08
    Ah, I see. You were just referring to the way it was presented and not the actual numerical amount.
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