Bitcraze Forums

Yeah definitely need to be careful. I have a pretty conservative voltage alarm ( <= 3.4v ) set up on my Devo, and use a proper lipo charger to charge. Do you know what the internal resistance of the stock battery is? I have a lipo charger that claims to measure internal resistance, though I have not done my own test to check its accuracy. On that charger, it says the stock battery is about 300 mOhms (though, I've run that battery into the ground so I expect it would be lower brand new). The 20C 300mah battery reads in at about 120 mOhms (flown through maybe 10 cycles by now), and the 45C 300mah battery is about 80mOhms (basically new - 1 or 2 flights). I definitely see these differences reflected in the effective voltage sag under load, which explains the difference in performance.

Mechanically, they're all good. The 20C are a little bit thicker and a little bit narrower than the stock battery. The 45C are a little bit longer than the stock battery but otherwise the same. Both fit between the headers and I haven't had any problems with them falling out while flying using the friction method (the foam pad + battery holder deck) but I'm going to add some Velcro or dual-lock to be safe.

I'm not sure the internal resistance of the stock battery but 300mOhm sounds a bit much, would have expected 150-200mOhm but as I haven't tested it accurately I can't tell if it is correct or not. Which charger do you have? Do you know what method the charger use to measure it?

I picked up a 6-pack of Tattu 380mah 3.7V 1.4Wh lipos and they're working great. Size is a bit longer than the stock battery for the CF2, but they work great, give a couple extra minutes of flight time.

Hi guys,

So how long can CF fly with 380mAh or 500mAh battery? Do we need to get a more powerful motors for that?

Thanks!

SlouchyCat wrote:Hi guys,

So how long can CF fly with 380mAh or 500mAh battery? Do we need to get a more powerful motors for that?

Thanks!

Hey @SlouchyCat

I'm getting about 9-10 minutes with the 380mah batteries.

Hey hittstick!

Thanks for the fast reply~ Thats impressive! Have you tried with LPS or just manual fly to get 9 mins flight time?

Thanks!

SlouchyCat wrote:Hey hittstick!

Thanks for the fast reply~ Thats impressive! Have you tried with LPS or just manual fly to get 9 mins flight time?

Thanks!

Manual flight only.

Hey hittstick!

Okay understood. I will buy the Lipo and try with LPS~

SlouchyCat wrote:Hey hittstick!

Okay understood. I will buy the Lipo and try with LPS~

You can find them on amazon, I got a pack of 6 for less than 10 dollars US.

Hey hittstick,
How much does each of those Tattu batteries weigh?