Dear Herbert:
Referenced pack looks good.
A K2 12 V x 10 amp LiFePO4 battery is +/- 151mm long, 65mm wide, and 98mm high.
Depending on how you stacked them, 2 of the referenced HobbyKing packs wired in parallel could be +/- 150mm long x 52mm wide x 140mm high with a good 1/2" of room on the side to "store" the extra wiring. If you can manage the additional 1-5/8" height, you are now sporting almost 17 amps per battery well.
(Note to self...reminded again engineers usually know what they are talking about.)
On Tuesday, October 16, 2012 9:44:32 AM UTC-4, wrote:
On Monday, October 15, 2012 7:13:11 PM UTC-5, (unknown) wrote:
Yes J7, you are correct. However the flat rectangular cells offered by HobbyKing and are lower amperage cells and not suitable to soaring amperage requirements unless you combined multiple packs in parallel. This is too complicated for my likes.
My interest is having only four cells wired in series providing 10, 12, or better yet 15 amps such as these examples.
RAS moderators and et al please note. In no way am I endorsing the following products or trying to sell them. Information is for reference only.
http://www.ebay.com/itm/4PCS-12V-LiF...e m33752e1ec6
http://www.ebay.com/itm/4PCS-12V-LiF...e m33753e0bb2
http://www.ebay.com/itm/4PCS-12V-LiF...e m337698b7ad
The 10 amp and 12 amp cells should fit in existing battery wells. The 15 amps cells will probably require battery well modification.
LiFePO4 cells certainly are the "now" technology and in my opinion offer the best performance and longevity for the buck today.
Got juice?
On Monday, October 15, 2012 1:25:53 PM UTC-4, wrote:
On Monday, October 15, 2012 9:49:11 AM UTC-5, (unknown) wrote:
My RC friends who use LiFePO4 swear by them. They handle high amperage drain and can be charged at higher amperage than other battery technology. They are not as popular in RC as they are heavier and larger than equal LiPo amperage. These differences are not a concern for sailplane use.
And of most importance, LiFePO4 cells do not have the explosion/fire risk of LiPo cells if charged incorrectly. FWIW,all LiPo cells I've seen are flat and thin and rectangular. All the LiFePO4 I've seen are cylindrical.
Absolutely, Lipo cells require balance maintenance. I cannot confirm but have read LiFePO4 cells are self balancing when connected in series and do not require an on board balance circuit or an external balancing plug..Please do your own due diligence.
Other than K2, all the LiFePO4 packs I've seen were home made packs using cylindrical cells taken from DeWalt tool power packs. It is my understanding the DeWalt cells are actually A123 brand LiFePO4 cells.
This is an outstanding battery and charger forum. http://www.rcgroups.com/batteries-and-chargers-129/
Safe flights.
There are tons of non-cylindrical LiFePo4 batteries here
http://www.hobbyking.com/hobbyking/store/index.rc
They make cells of all types of cell numbers and capacities. I tried them in the past for RC use and they were not very reliable then(2-3 years ago).
The prices are modest since they sell the naked cells with balance charge plug and power leads. You need your own charger but they can also be had at Hobbyking. Note that they have a warehouse in the USA.
Dear Unknown,
Here is the battery I just ordered with the intent to replace my 10Ah NiMH battery dedicated to the transponder. It is ready for usage, no soldering except for the fuse and the plug.
http://www.hobbyking.com/hobbyking/s...dproduct=20645
This is a 8400mAh 4S cell with a 30C discharge rate, you can fry your eggs on the discharge of that thing (over 200A).