On Sun, May 9, 2010 at 4:24 PM, Bob Burns W9RXR <[email protected]> wrote:
> Duracell alkaline AA cells are rated at 1.5 volts and around 2800 mAH > (is this number correct?) sounds a bit high to me - that's the spec for the energizer AA lithium. Alkaline batteries don't like high current draws. I think alkalines are a losing proposition. I either can't find my notes or failed to take any, but IIRC an 8 pack of energizer AA lithium will run a T2-301 at default power (5W) beaconing once a minute for at least 24 hours. A 4 pack of CR123A cells (3V lithium camera battery) will go over 12 hours (12 was the duration of the test, batteries were not dead at the end of the test). It depends on how long and how frequently you want to operate. If this is for ballooning or emergency use, e.g. SAR (note: I am not an SAR person), for example, I think lithium batteries would be better. They are zero maintenance, high capacity, cold-tolerant, and have a long shelf life. Rechargeables, on the other hand, require regular maintenance - they don't like to sit around discharged, so you need to charge them occasionally even if you aren't using them. I vaguely recall some discussion here about the minimum voltage for the T2-301. I do recall seeing a 7808 regulator when I opened up the one that landed in the river, so there's a minimum of 8.6V for reliable operation. The actual lower limit may be higher than that. -Jason kg4wsv
