As mentioned on my last 2 activations my 4.2 aH SLA battery has had it, despite a full charge the night before lucky to get a half hour of activating out of it...
So purchased a Zippy 4200 30C series LifePO4 battery. Old SLA and new battery
I decided to go with LifePO4 as supposedly safer than LIPO batteries, plus they have a better lifetime charge/discharge cycle, and will maintain a constant output.
The weight is a bit heavier than LIPO, but at 550 g instead of the 1.3 Kg SLA I'm not complaining!
Voltage out is around 13-14 v so the FT817 is happy. Also got a "Watts Up" meter to monitor the voltage. Shows the FT817 draws around 0.36 A just on receive!...On full 5W out draws around 1.95 A, so should get a few hours on a charge.
Got a Turnigy 8150 charger to balance charge it, took around an hour to bring up to full charge, each of the full cells to 3.6 V, for 14.4 V charge.
Found I can just fit the battery, meter, radio and log book in my Kathmandu case, neat.