TS, one of a group of hunters, was looking for a better, more durable means to power the portable electronic devices that he likes to use during his frequent hunting sorties in remote regions of Alabama. His electronic devices are powered by rechargeable AA and AAA batteries, and include a 3-watt xenon LED flashlight, a set of Midland 16 mile radios with NOAA alert, an iPod with speaker dock, and a Kodak Easyshare digital camera. Traditionally, when the batteries in one device run out of power, batteries from one device are switched to another, and recharging must wait until he has returned to his automobile or an AC power outlet. During prolonged hunting sorties, the loss of power due to discharged batteries is inconvenient. The battery charger he uses is a fast charger by Energizer that can recharge four batteries in 15 minutes, and is stored in his motorvehicle for days at a time while he is hunting.
TS approached Powerenz and asked if we could design a custom portable power system that would allow him to recharge his AA and AAA batteries as needed in the field for prolonged periods of time. He needed a unit that would:
a. utilize solar energy for fuel,
b. be stored and carried in a durable bag that could be carried by a handle, shoulder strap, as a fanny pack, or attached to any MOLLE-compatible backpack or vest,
c. be light-weight for long hauls,
d. be charged by DC or AC power when available,
e. produce AC power for his fast AA/AAA battery charger,
f. provide durable, long-term independence from the power grid, and
g. be silent.
A portable solar panel-battery system was assembled that included the following components:
a. reliable, 12-volt, 7.5 amp-hour, sealed lead acid AGM battery,
b. 10-watt flexible, rollable solar panel that remained outside the bag,
c. 7-amp solar charge controller,
d. 160-watt DC-AC power inverter for the AC-powered battery charger,
e. 12-volt female DC socket for a DC-powered device,
f. proper fusing and wiring, and
g. MOLLE-compatible deployment pack in digital woodland camouflage.
The power system could deliver a maximum of 90 watts of power to the DC port and inverter, and was wired and fused accordingly. If the power draw of the portable electronic device was 60 watts, the battery would last approximately 1.3 hours before it needed to be recharged, longer if the power draw was less. If the power draw exceeded 90 watts, a 7.5-amp ATC fuse would blow and would need to be replaced. In good sunlight, it would take 9-10 hours for the solar panel to recharge the battery. The power system weighs approximately 8 pounds, and the solar panel weighs an additional 1.8 pounds.
The portable solar power system powers up the AA/AAA battery charger silently and repeatedly while on the go. When not in use, the portable system is stored with the remainder of the hunting gear, and trickle-charged using an AC-powered battery charger until it is needed again.