Linheart, Dean, and Mike,
Thanks Linheart,
I am glad to hear that we can get 3 charges from a light weight (<16 lbs) MC battery. This looks like a good option for my small park flying. Your generator idea sounds like the ultimate solution for the park without power. It may be a little overkill for one, but will be great when there are several elec. CL flyers at the same site. Perfect for the electric CL contest of the future! The new ones are as quiet as our planes. :-)
Thank you Dean.
The car battery option is attractive because it is automatically charged, and most of the time it travels with us. In my case I walk to one park, and the other park requires the car to be parked out of my view, farther away than I trust my batteries and chargers to be safe. ... BTW: How many charges do you get before you reach your 30% cut off point?
Thanks Mike,
I don't think I will ever be as dedicated as you guys. If I can get in 8 CL flights in one session I will be VERY happy. I usually fly my R/C 3D elec. plane 3 or 4 times between CL flights, so it makes for a full morning. If I go flying all day with my larger R/C planes I go to our club CL/RC field which has AC power. There I can fly elec. all day.
Linhart was right, he said someone would come up with the #s! Thanks :-) For my 4 charge needs, I get: 55.44 x 4 = 222 watt hrs used for 4 flights, 222/.6 = 370 total watt hours needed, with reserves, 370/12V = 31 AMP/hr battery required.
The ideal would be an AGM 12V battery. They charge faster, can be used in any position, and are very safe. Serendipitously I just read a long article on batteries in one of my sailing magazines. Below is an excerpt from one of the tables they had. This really shows what you were talking about Re discharging the 12V less than 100%. Like you, they said to keep the battery fully charged, and when stored for the winter, keep it on trickle if possible. They also said DON'T use a regular auto charger. I use my Trinitron charger, and it seems to do fine.
Discharge No of Cycles
5% 10,000
20% 2,800
50% 1,050
80% 550
100% 360
If anyone out there reading this wants a battery, you may find what you need at this excellent web site:
http://ebatteriestogo.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=EBTG&Product_Code=D5745-ABIf you have any questions, just call the Ph number in the upper left on their site. The guy is a battery expert who was very helpful. They have a sale on now with free shipping. I ordered two of the batteries shown on the page address above. Using Mike's #s these should meet my needs and give me flexibility, and at 15 lbs, not break my arm carrying it when I walk to the park. :-) At $33.95 ea. with free shipping, for an AGM battery it should work for our needs.
Thanks again for all your complete answers. It has helped me, and I hope it helps others getting into elec. CL flying.