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

David Madden dhm at mersenne.com
Sat Oct 29 10:49:58 EDT 2011

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, and 
switching over to it when the main power goes out.  I've been thinking 
about it for a long (LONG!) time, and would like to have it exercise the 
battery occasionally too (run off battery for a while, then recharge, 
even though the regular power is still on).

Perhaps it's time to collaborate on a project like that?  Who's in?

I need: 120VAC input (I guess an off-board transformer / wall wart would 
be OK too, if it was cheap), 12V battery maintenance, 12VDC and 3.3/5VDC 
output, and seamless power switchover.  Max current out of the 12VDC is 
probably a couple of amps (I have some old smoke detectors, a PIR motion 
detector, and some security-system buzzers that need to be powered.)

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