Battery Power

On Monday, September 24, 2012 11:45:03 AM UTC-4, Cookie wrote:
Actually it is not 10 hours worth....its about 4 hours worth.



The "rated" 9 AH is rated at .05C or 450 ma.



If you run at 800 ma, that's about .1C.....so you don't get half the time,

you get way less than half...........



Also they rate the batteries as "dead" at 10.5 volts, but for glider

equipment, once you get down to 11.5 or so, stuff doesn't work well.



Actually anything under 12 volts means time to recharge.....below 10.5

volts and battery damage can occur.



For an 800 ma draw, the proper battery would be 16 AH.....this in theory

would last 20 hours, and leave you at 10.5 volts.....probably 10 hours to

stay above 11.5...



Cookie











At 03:30 24 September 2012, Mike the Strike wrote:

The 9A.h batteries I use would have a rated capacity of about 8A.h at a

current of 0.8A - that's about ten hours' worth. Dropping the

temperature

to freezing will drop that to about 7 to 8 hours - still more than you're

getting.



Also remember that the current drawn by some devices may increase as the

voltage drops. I'd suggest checking your current draw at a range of

battery voltages.



If your charger's ok, it sounds like your battery isn't.



Mike



Cookie nailed it. Also, that is all for a new battery. The numbers all go sour as the battery gets old and abused. Deep discharge is the worst offender over time. Keep 'em charged boys! (Yes even in off-seasons).

-Jim