How long will it last?
Work out a node's runtime from its battery, idle draw, how often it transmits and any solar top-up.
ESTIMATED RUNTIME1.9 days
AVERAGE DRAW37.4 mA
PER DAY897 mAh
TRANSMITTING12 s/h
USABLE CAPACITY1,700 mAh
Assumes 85% of rated capacity is usable. Cold weather and ageing cells cut runtime further; real devices vary with firmware settings.
/ HOW IT WORKS
01
Average current
Idle draw runs all the time. Transmit draw only runs for the seconds each hour you are on air, which is packets per hour times airtime per packet.
02
Usable capacity
We count 85% of the rated capacity. Cells sag in the cold and lose capacity with age, so plan a margin for winter.
03
Stretch it
Turn off GPS on fixed nodes, send positions less often and use a faster preset. On a solar node, the panel only has to beat the daily draw.
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