View Full Version : I Want a LiPo
Hi All,
How do you understand a Li-Po? i looked for answers with little luck to my dumb knowledge. they talk about "C" and "mAh" (i understand milli-amp hours) i have a 12V conglomeration of cells in the front of my heli powering my night lights. seams to way as much as my whole transmitter. was thinking about maybe two separate 3 cell Li-Po. but if i figure out my AMP Draw. (Yes I'm up in the 2 amp area) how do i figure out what type of LiPo i need?
thanks in advance.
kamtsa
09-19-2007, 11:35 AM
Hi All,
How do you understand a Li-Po? i looked for answers with little luck to my dumb knowledge. they talk about "C" and "mAh" (i understand milli-amp hours) i have a 12V conglomeration of cells in the front of my heli powering my night lights. seams to way as much as my whole transmitter. was thinking about maybe two separate 3 cell Li-Po. but if i figure out my AMP Draw. (Yes I'm up in the 2 amp area) how do i figure out what type of LiPo i need?
thanks in advance.
1. The 'C' units tells you the max charging and discharging rates of the battery. Let's say you get a 1200ma/hour LIPO battery with discharge rate of 8C. For this battery, 1C = 1200ma = 1.2A so you can discharge it by up to 1.2A * 8 = 9.6A. Most LIPO batteries are specified as 1C charge rate which in this case will be a max charge current of 1.2A.
2. Let's say you want to draw average current of 2A for a period of 15minutes (1/4 hour). This is 2A * 0.25h = 0.5Amp/Hour or 500mah. Add some margin (e.g. 50%) and you will get 750mah which means that you will need a battery of at least 750mah.
3. Remember, LIPO batteries are dangarous!. Follow all the instructions that comes with the battery.
4. Also, you will need a charger that supports LIPO bats and you will need a cell balancer (either within the charger or a separate unit). Chargers with internal balancer starts at about $20 and goes up to $100-$200. Make sure that the balancing connector of the battery you get matches the connector of your charger/balancer (or get an adapter).
Kam
cool! thanks Kam for brakeing it down for me. i get it now.
Thank you!!!!!! :-)
Silenus
09-20-2007, 04:47 PM
SB. Have a look at RCgroups.com in the Batteries and Chargers forum. There is a sticky with a lot of Lipo information there:
http://www.rcgroups.com/forums/showthread.php?t=209187