Re: Charging A Lead Acid Battery

On Tue, 12 Feb 2008 01:30:43 GMT, ehsjr <ehsjr@xxxxxxxxxxxxxxxx> wrote:

:Dave.H wrote:
:> How would I go about building a charger for a lead acid battery.
:> Jaycar Electronics sells a 5 amp hour 6 volt SLA battery for use in
:> flashlight lanterns, but as far as I can tell they don't sell the
:> charger.
:>
:> Battery
:> http://www.jaycar.com.au/productResults.asp?FORM=KEYWORD
:> (CAT. NO. SB2498)
:>
:> Thanks
:
:
:Very simple charger:
:
: -----
: +9 ------Vin|LM317|Vout---+
: ----- |
: Adj [2.5R]
: | | 1N400x
: +----------+---->|---+
: | +
: [Batt]
: |
: Gnd --------------------------------+
:
:You need a 9 or 12 volt wall wart capable of
:at least 500 mA, an LM317 chip, a heat sink for
:the chip, and 2 5 ohm, 1 watt (at least) resistors
:in parallel to make the 2.5 ohm resistance, and
:a 1N400x diode. Charge for 12-14 hours.
:
:Ed


While that might work, it is a constant current source more appropriate to
charging Ni-Cd or Ni-Mh cells, not a lead acid battery.

LA battery is best charged with a constant voltage source or better still, a
regulated 2 or 3 stage charger.

Read Jaycar's own reference *** on SLA batteries.
http://www.jaycar.com.au/images_uploaded/slabatts.pdf
.