LiON battery discharge

i want to know i am using LIon battery in my device, its a communication device it draw 300mA cont current. battery i am using for backup power. if somebody removes the device from power battery provide the essential power, if its remain out of power for 4 days battery will ultimately die, thats my problem how to stop it from dieing when removed from power.

Simply fit a battery protection board on the battery (or bank of batteries), they are freely available at VERY low cost, and can be sourced for varying numbers of batteries. They prevent over-charging (and resultant fires), prevent over-discharge (and ruining the batteries, plus (if you have batteries in series monitor the individual battery voltages.

Or, assuming the power outage isn't going to be for longer extended periods?, simply stick more batteries in parallel to maintain the power until it returns - if one battery lasts 4 days, then 2 would last 8 days etc.

Four days at 300mA is 32AH which is a VERY big battery. Are you sure about your figures?

Mike.

Pommie said:

Four days at 300mA is 32AH which is a VERY big battery. Are you sure about your figures?

Mike.

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its will not run on battery continuosly its just for backup and i am not using 32AH battery, i am asking which battery i should use.

ejazbeyond said:

its will not run on battery continuosly its just for backup and i am not using 32AH battery, i am asking which battery i should use.

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You said in your first post that it takes 300mA and the battery will go flat after 4 days! Has this changed or did I misunderstand?

Mike.

ejazbeyond said:

its will not run on battery continuosly its just for backup and i am not using 32AH battery, i am asking which battery i should use.

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If not for four days, then how much backup time do you need?

If not 300mA, then how much current does it draw? If it draws power in pulses, then you need to state what the profile of the pulses are.