# New Alarm and LiFePo4 battery

Discussion in 'General Electronics Chat' started by logicrules, Apr 30, 2011.

1. ### logicrules Thread Starter Member

May 3, 2009
16
0
Hi.
I am using a 12.8V, 1500ma, LiFePo4 battery pack to power my tricycle alarm system. It draws 8.5ma at idle, and 38-48ma when activated.
My estimate on how long I may run this is about 30 days before recharge but my knowledge is limited.
First I dont know how long the charge will remain at maximum or how much the discharge will affect the battery to the point of being useless. I do not have a means of continuously testing the charge at this time.
From what I understand of LiFePo4 batteries I should be recharge every month, at the current rate of discharge, and the occasional activation, in order to get the maximum use of the pack.
Any help will be appreciated, and possibly save me some money.

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2. ### designnut Member

Apr 21, 2011
33
1
2500 / 8.5 = 176 hours /24 = 7.3 days If you run it around the clock.
The batteries often don't live up to nameplate and age markedly in a year.

3. ### logicrules Thread Starter Member

May 3, 2009
16
0
Boy did you lose me there. "2500 / 8.5 = 176 hours /24 = 7.3 days If you run it around the clock."
Of cource it has to run round the clock but 2500? How does 2500 fit into this equation?
This is 8.5ma+ on a 1500ma battery that should take the charge a while to dissipate.