rechargeable battery lifetime calculation

Discussion in 'General Electronics Chat' started by jeevi, Aug 1, 2013.

  1. jeevi

    Thread Starter New Member

    Jun 17, 2013
    4
    0
    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?
     
  2. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    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.
     
  3. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    What is a "mote"?
    What is a "WSN mote"?
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,093
    3,031
    Are you sure it's not 0.163929? :p
     
  5. crutschow

    Expert

    Mar 14, 2008
    12,991
    3,226
    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.
     
  6. jeevi

    Thread Starter New Member

    Jun 17, 2013
    4
    0
    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: Aug 2, 2013
  7. wayneh

    Expert

    Sep 9, 2010
    12,093
    3,031
    Are you asking about how many lifetime recharge cycles you can expect?
     
  8. #12

    Expert

    Nov 30, 2010
    16,257
    6,757
    Same as what? Same as each other? That doesn't tell me anything.
     
  9. jeevi

    Thread Starter New Member

    Jun 17, 2013
    4
    0
    yes the possible recharge cycles
     
  10. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,772
    931
    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.
     
  11. jeevi

    Thread Starter New Member

    Jun 17, 2013
    4
    0
    fine, i'll check that option too
     
Loading...