Tony,
It actually uses five of these batteries. I am guessing they are in series
to produce 5V (okay 6V) needed for the SIMMs at 250mAh. If the point of the
Sure. In otehr words the battey pack (all 5 in series) can provide 250mA
for an hour. Given the currnet taken to support all thsoe SIMMs and the
refresh circuitryand which must be running, it could well only last a
coupoel of hours
battery is just for use during system swap/maintenance
1-2 hours is plenty
of time. Especially considering that once it is out of the system you can
connect it again to the big battery.
Sure.
As Tothwolf said it may just be that they are not manufacturing them any
more for use. Or that the 250mAh batteries just don't last long enough for
newer applications. I think what I may end up doing is trying to see how
well the batteries charge up as it stands. If I can get a few minutes out of
them I am good. If not I am considering swapping them out for either 300 mAh
or 400 mAh batteries and just having a longer charge time (but also longer
"backup time").
I don't know how complciate dthe circuit is, but it might be possible to
incresae the charging current (often these batteries are just trickele
chargeed at 'C/10' -- that is 25mA for a 250mA battery). Maybe just
chaning one reissotr could increase the chragign current to 40mA for the
more modern battery. It would then take the same time to charge but
would, of course, power the board for longer.
-tony