rechargeable battery lifetime calculation

Thread Starter

jeevi

Joined Jun 17, 2013
4
I am using a rechargeable NiMH battery (300mAh,4.8V) to supply the WSN mote. The battery gets an average energy of 300J per day from a solar cell. Assuming that the mote consumes 0.163928mAh per day. Can anyone please say me the life of the mote and how to calculate it?
 

bountyhunter

Joined Sep 7, 2009
2,512
The Watt is defined as a Joule-per-second. I think you need more info to calculate the problem.

The battery: 300mAh,4.8V is about 1.5 Watt-hour.
 

crutschow

Joined Mar 14, 2008
34,280
I am using a rechargeable NiMH battery (300mAh,4.8V) to supply the WSN mote. The battery gets an average energy of 300J per day from a solar cell. Assuming that the mote consumes 0.163928mAh per day. Can anyone please say me the life of the mote and how to calculate it?
300mAh at 4.8V is 0.3Ah x 4.8V = 1.44Wh. 300J is 300 Watt-sec or 300/60 = 5 Wh. Thus the battery is fully charged each day.

0.163928mAh per day is a very small current (0.163928mAh / 24 = 6.8μA. Should it be 0.163928Ah per day which would give 6.8mA? That would give a daily energy consumption of .164Ah * 4.8V = .787Wh. On that basis the battery would last 1.44 / .787 = 1.8 days without charging.
 

Thread Starter

jeevi

Joined Jun 17, 2013
4
both mote and WSN mote are same...
at very low duty cycle ratio, there is possibility of such reduced current consumption.

If not consider that to be 46.117mAh per day, and help me..
thanks crutschow,
can u please, say the procedure to calculate lifetime with recharging the battery..
 
Last edited:

Kermit2

Joined Feb 5, 2010
4,162
http://en.wikipedia.org/wiki/Wireless_sensor_network

NiMH battery chemistry is not going to provide a very long useful recharge life for the units(several months before degradation lowers capacity below useful limits).

If your power requirements can be lowered even more than what you have now, a super capacitor may be able to supply the load during dark periods and it would have a much much better recharge lifetime (multiple years)than the NiMH batteries.
 
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