LibrePilot Forum

General Category => General Discussion => Topic started by: Parris on May 31, 2016, 12:48:21 am

Title: Battery purchase .
Post by: Parris on May 31, 2016, 12:48:21 am
I found these batteries on Gearbest . Myself , I bought 5 . Couldn't beat the price .

http://www.gearbest.com/multi-rotor-parts/pp_176500.html?wid=2
Title: Re: Battery purchase .
Post by: Sid on June 01, 2016, 03:31:59 am
We usually use high c rating batteries like 40c and above. 25c is way too weak for a quad with four hungry motors. Maybe for
a small foamy airplane but again 3000mah would make it very heavy for any application.
Title: Re: Battery purchase .
Post by: Mateusz on June 01, 2016, 12:52:58 pm
The C rating of the battery is related to how much current it can deliver. For 1000mAh 25C you approximately get 25A of burst current

If your copter drains more current than battery is able to deliver, then you put stress on your batteries.
In such condition battery will puff, because of oxidation process that also increases battery internal resistance further decreasing it's C rating and making situation even worst.

Draining too much current is like shorting the battery. It won't last long. Puffed/degraded batteries are dangerous to use, since they over-heat due to high internal resistance and building up pressure make them likely to explode and start a fire. So it's not only less power and slower charging but also risky and short living battery. Of course higher C batteries are more expensive.

When you buy battery usually C ratings are provided for charging and discharging. For discharging two values can be provided lower continuous and higher burst. If one discharge C value is provided its usually burst. Usually reported rating on the battery is higher than what battery can deliver in reality, even in high quality LiPos.