In article ,
Joe Aurelio wrote:
In article ,
(Eric Behr) wrote:

I'd like to make an external high capacity pack for my T90A
for emergencies, long special events etc. The manual isn't
[...]
On mine, when the batteries are fully charged the T90 indicates Hi-V
and does not transmit. I assume that it is in self protect mode at that
time.

Hmm, I've never ever seen that. Mine just says CHG_F and happily
transmits (unless the wall-wart is plugged in).

The manual says not to transmit with the charger plugged in (IIRC).

With the small wall-wart charger, yes. But it is less clear in
case of the "drop-in" rapid charger, and under the cigarette
lighter adapter CP-19 heading it explicitely says "the BP-217
can be charged while you are operating", so I'm assuming there
is no general prohibition on transmitting while external power
is plugged in. That's what made me consider a self-made pack.

If I were building a battery pack, I think I would keep it at or under
11 volts for recharging or 8.2 volts for operating. (8.2 is what I see
on turn on whrn the battery has been fully charged.)

I suppose it's better to play it safe, but 9.6V is well within
the stated maximum. Still, a lower voltage might work just as
well (given enough current), because the manual also says that
"power supply range is 5.5 - 11.5 V", and then that "maximum
output power is 5W regardless of P/S voltage". So they must be
using some intermediate power conditioning circuit. If that is
the case, maybe I'll start with a 6V pack to be on the safe side
and see what happens.

Thanks for the comments de KC9DUX.

--
Eric Behr | NIU Mathematical Sciences | (815) 753 6727
| http://www.math.niu.edu/~behr/ | fax: 753 1112