Charging lithium batteries.

Discussion in 'General Electronics Chat' started by ian field, Nov 9, 2013.

  1. ian field

    Thread Starter AAC Fanatic!

    Oct 27, 2012
    My question is along similar lines to one or other existing threads, but I'd rather not hijack someone else's thread - so here goes;

    I've been using Vapourlites e-cigarettes, and found them somewhat less than reliable (not entirely their fault) If you're not very careful when refilling the cartomiser, the fluid can run into the battery tube and wreck the vacuum detector. In the short term I've been bodging them by wiring in a pushbutton to replace it, its integrated with the lithium battery charge cut-off chip so can't be removed altogether, its a minute assembly and I got a solder whisker while rewiring one, that damaged some of the USB charging adaptors.

    When I opened one of the damaged adaptors, apart from the circuitry for a bi-colour charge LED, all it had to regulate charge current was a 5R series resistor.

    I'm guessing this is done because its cheaper than a constant current regulator, but I'd welcome comments on the merits of just using a resistor, or whether constant current would be better or worse?

  2. MrChips


    Oct 2, 2009
    There's a new word for me "bodge" similar to "botch".
    Is that commonly used down under?
  3. bountyhunter

    Well-Known Member

    Sep 7, 2009
    You can't charge Li with constant current. The charge current MUST be terminated based on cell voltage. Overcharging/overdischarging Li batteries can cause fires.
  4. ian field

    Thread Starter AAC Fanatic!

    Oct 27, 2012
    I made that clear enough in my original post when I explained that the pressure sensor assembly had to be retained because it also contained the end of charge cut-off chip.