Babooshka
,
Monday, 9th of August 2010 04:42:17 PM
depends on the duty cycle of the flash. A good 9 volt alkaline
Babooshka
battery is about 550 mA-hr, so at 20 ma, that is about 27 hours at full
Registered User
on. If it is on 1/10th the time, that would be 270 hours.
Joined: Wednesday, 12th of May 2010, 09:08:29
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.
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Tinkle Bear
,
Tuesday, 10th of August 2010 08:14:27 AM
The last 2 are mostly right, I would simply add that in
Tinkle Bear
flashing, the device is off at least part of the time, so the expected
Registered User
lifetime is probably twice that previously given (for a 50% duty cycle on
Joined: Monday, 7th of June 2010, 04:18:22
the flashing). Obviously, however, if the device is not rated for 9V,
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then it might well burn up and not work at all. Further, even if it will
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tolerate th 9V, if it is not rated for 9V, it will likely use more power
than listed.
boo bear
,
Wednesday, 11th of August 2010 01:48:55 AM
Typical 9V = 550mAh
boo bear
550/20=27.5hrs
Registered User
You can get lithium 9Vs that are around 1.2Ah
Joined: Wednesday, 19th of May 2010, 06:16:37
1200/20=60hrs
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Sorry I missed the flashing:
Above Hrs / duty cycle % = battery life Hrs
Mugums
,
Thursday, 12th of August 2010 10:04:09 AM
A 9 v battery has a stored capacity of 625 mA-h
Mugums
(mililamp-hours). Dividing that number by the amperage will give you the
Registered User
time in hours that the battery will last.
Joined: Wednesday, 26th of May 2010, 20:15:20
Posts: 1203
So that would be about 31.25 hours of continuous use. If the circuit
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doesn't draw the full 20mA when not lit, that could make it last longer
though.