[dorkbotpdx-blabber] Looking for a cheap 12v SLA charger/UPS solution

[Aaron Burt]

On Sat, Oct 29, 2011 at 07:49:58AM -0700, David Madden wrote:
> On 10/29/11 3:01 AM, Russell Senior wrote:
> >You don't want to overcharge.  You want the charger to go into float
> >mode when the battery is fully charged.
> 
> I also need a little circuit for keeping a 12V backup battery happy,
<snip>

That's been a back-burner project for me, too.  There are off-the-shelf
"intelligent" chargers for motorcycle batteries (Battery Tender et al.) but
I'd like something cheaper, that can be incorporated in existing designs,
and that can be adjusted for different battery capacities.

Check out Battery University for some info on what SLA batteries like.  A
decent charger can be built with a transformer and 1-2 linear regulators,
there are designs all over the net.

I'm thinking of hacking on a 12V switching wall-wart to see if I can tweak
the voltage regulation or run it in current-regulation mode.  Yes, I know
(some of) the risks. :)