[aprssig] backup pwr systems

[A.J. Farmer (AJ3U)]

Just some food for thought, if you have the battery hooked up to a
load while you are charging it, this prevents even a "smart" charger
from properly determining the state of the battery and that is why it
boils over the battery.  It is not a problem with the charger - the
charger is designed to charge a battery under little or no load.

The best way to set things up is to isolate the battery from the load
and run the load from a power supply directly.  The smart charger
connected 24x7 to the battery under no load will charge and maintain
the battery properly.  When the power fails, either manually switch
the load over to the battery or use some type of automatic transfer
switch if you need unattended operation.

Another solution is to use a solar charge controller and connect a
power supply to the voltage input where you would normally connect the
solar panels.

-- 
A.J. Farmer, AJ3U
http://www.aj3u.com

On 12/9/06, Charles Doughtie <n5exy at yahoo.com> wrote:
>
> FWIW I had two "smart" chargers (different brands)
> fail and boil two relatively new deep cycle batteries
> dry. Even the smart ones need to be monitored a bit.
> 73 de Charlie, N5EXY
> South Suburban Greater Hutto
>
> --- Dale Blanchard <wa7ixk at earthlink.net> wrote:
>
> > Chris Rose wrote:
> > > Leaving a battery constantly plugged in to a
> > charger will cook and kill the battery.  I have
> > ruined more than one.  I don't suggest that course
> > of action.  Having a battery available to connect to
> > when mains go down is a better way to go.  Some
> > circuits are available to show how to do this.  Some
> > simple and some quite elaborate depending on how
> > many raidos or scanners you have to take care of.