> FWIW - we purchased about a hundred of those cheap 400W inverters
> last year - we go inside and grab the regulated 150Vdc for use in one
> of our pipeline transmitters.  Same deal as with lots of other stuff
> - we can't purchase and assemble a 150 Vdc 4 Amp dc-dc inverter for
> anything close to $25.
>

MANY years ago, a local company (Cuesta Systems) made power inverters for,
I think, the Osborne computer. They generated +/-150VDC. I bought these to
use in another product. I bridged the output of this across the series
capacitors after the rectifier in a switchable 120/240V power supply (not
universal input). This power supply powered the system. The inverter
powered the system when AC went away. We charged a 12V SLA battery from
the +5V and -12V with a linear regulator setting the float charge voltage.
We also sensed the battery current. When it indicated the battery was
being discharged instead of charged, we shut down the charger.

Harold


-- 
FCC Rules Updated Daily at http://www.hallikainen.com - Advertising
opportunities available!
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist