I'm wondering if I have the formula down correct..

Scanner with a plug in 1000 mah charger. 4 2300 mah batteries. 4 *
2300 = 9200 mah. 9200 (total mah of batteries) / 1000 (mah rate of
charger) = 9.2. So 9.2 hours? Am I using the correct formula?

Thanks.

Evan
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i would doubt that the size of the charger capability has anything to do
with actual charge time.
the scanner should have an internal constant current charge circuit, the PSU
is just a supply to the scanner.

i would expect the charge current to be about 50mA to the batteries, so go
from there (you are correct with your formula)
capacity/charge current=hours needed)

it is quite common for the chargers in scanners to never fully charge NiMh
batteries, (i assume that's what you have.)
it won't harm the scanner, nor the batteries as such, but don't let anything
get too hot, particularly the cells.
if they do, life will be severely restricted.

use an external charger.

mike

"Evan Platt" wrote in message
...
I'm wondering if I have the formula down correct..

Scanner with a plug in 1000 mah charger. 4 2300 mah batteries. 4 *
2300 = 9200 mah. 9200 (total mah of batteries) / 1000 (mah rate of
charger) = 9.2. So 9.2 hours? Am I using the correct formula?

Thanks.

Evan
--
To reply, remove TheObvious from my e-mail address.



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Just leave it in charge overnight. When you get up in
the morning it's reday for a full day's use.


"Evan Platt" wrote in message
...
I'm wondering if I have the formula down correct..

Scanner with a plug in 1000 mah charger. 4 2300 mah batteries. 4 *
2300 = 9200 mah. 9200 (total mah of batteries) / 1000 (mah rate of
charger) = 9.2. So 9.2 hours? Am I using the correct formula?

Thanks.

Evan
--
To reply, remove TheObvious from my e-mail address.

Not quite. A simple estimate of charge time for a completely discharged
battery is:

Charge Time = Battery Capacity / Charge Current

The current rating of the charger is (probably) NOT the charge current--that
is controlled by whatever circuit feeds the batteries. All the batteries
are charged with the same current (they are connected in series in the
scanner), so you do not have to multiply the capacity by the number of
batteries. The charge current with the batteries in the scanner is not
likely to be terribly high (100 mA), so it is quicker to charge high
capacity batteries with a smart charger that uses a high current initially,
then switches to a lower current when the charge is complete. Also remember
that the batteries aren't generally fully disharged, so the charge time to
replenish them is less than the calculated time. The suggestion made in
another reply to charge overnight is a good one.


"Evan Platt" wrote in message
...
I'm wondering if I have the formula down correct..

Scanner with a plug in 1000 mah charger. 4 2300 mah batteries. 4 *
2300 = 9200 mah. 9200 (total mah of batteries) / 1000 (mah rate of
charger) = 9.2. So 9.2 hours? Am I using the correct formula?

Thanks.

Evan

I'm wondering if I have the formula down correct..

Scanner with a plug in 1000 mah charger. 4 2300 mah batteries. 4 *
2300 = 9200 mah. 9200 (total mah of batteries) / 1000 (mah rate of
charger) = 9.2. So 9.2 hours? Am I using the correct formula?


Batteries are usually in series. The current is the same in a series
circuit. If the charger is a constant current charger (which I would be
surprised if it was) the charger would be putting out 1000 ma and it would
take just 1 X 2300 devided by 1000 for a total of 2.3 hours . Then you have
to allow for about a 10% overcharge time as slightly more power is put back
in the battery than taken out. BTW I am asuming the charger is rated for
1000 mA and not 1000 mAh.

repeat mail again.

mike

"Evan Platt" wrote in message
...
I'm wondering if I have the formula down correct..

Scanner with a plug in 1000 mah charger. 4 2300 mah batteries. 4 *
2300 = 9200 mah. 9200 (total mah of batteries) / 1000 (mah rate of
charger) = 9.2. So 9.2 hours? Am I using the correct formula?

Thanks.

Evan
--
To reply, remove TheObvious from my e-mail address.



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Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
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On 25 Oct 2004 07:32:45 -0700, (Arghh!) said in
rec.radio.scanner:

Since all scanners that take 'AA' rechargeable batteries are designed
to safley charge 700ma nicads in about 11-14 hours. There is an
internal circuit in the scanner that drops the charger's current down
to about 60-80 milliamps or so.

From the Pro-95 manual:

"Battery Charge Current.......... 150 mA"

Safe for 1500 mAh cells and above - *IF* you limit the charge to 16
hours or a fast temperature rise, whichever comes first.