Lithium-Polymer (LiPo) batteries dominate the RC hobby. In like 98% of the cases, if you have a drone or RC airplane, or RC car, it is powered by a LiPo battery. The reasons are simple: they are high current capable, fast to charge, and have relatively high energy density.
LiPo is, however, not the only battery technology that we can use. Lithium-Ion (Li-Ion) technology has an even bigger energy density but comes with a price.
‘ve made me an endurance Li-Ion battery pack for my 7 inch endurance quadcopter. With good quality Sony 18650 VTC6 it is possible to get 20A constant current which is enough for an airplane or endurance quadcopter. Works just fine and with reasoable speed of 40-50 km/h I’m getting more than 15 minutes of real flight. Not hover. Flight. And at the end, it still has some juice inside. Not bad, not bad at all.
18650 Lithium-Ion batteries are the workhorse of modern consumer (and not only consumer) technology. If you have anything that is battery operated and there is a “Li-Ion” mark anywhere on it, probably it is powered by 18650 Li-Ion battery. Laptop batteries, cordless drills, cordless tools, e-cigarettes. All of them (probably) have 18650 cells inside.
In this video, I will just go with the basics of 18650 cells. Dimensions, protected / not protected difference, weight and so on. Expect more in the future!
Here is another of my tutorial YouTube videos. This time, I talk a little about parallel LiPo charging: why to do it, how to do it and
why it might be dangerous when you do it wrong:
My RunCam HD died after 5 months in a drawer. Reason: battery destroyed. It had enough energy for approx. 2 seconds of operation. So I had a choice: buy original battery from RunCam for $9.99 plus shipment, or fix it DIY style. I’ve choces the second option.
Luckily for us, RunCam used generic 803035 LiPo 1S, 3,7V battery that can be purchased in specialized stores. I’ve paid around $6 for mine, but if you look hard enough, you should find something even cheaper. Also, luckily (or not) there is a battery plug: 2 pin JST 1.25mm.
This topic was eluding me for some time now. It’s time fix the problem and finally present a short tutorial how to connect 90A APM Power Meter for flight controller boards like Naza32, SP Racing F3 or any other running Cleanflight / Betaflight / INAV software and equipped with Current Meter ADC input.
I will not show where to connect APM Power Meter to flight controller, since this differs from board to board. Some boards have dedicated pins, on some boards PWM input pins are used for Current Meter ADC. You have to refer FC documentation and / or flight controller software documentation.
Continue reading “How to connect APM Power Meter to Cleanflight and INAV” »
LiPo batteries that run RC hobby are potentially dangerous devices. When not handled properly they can ignite or even explode. And they do not live forever. Even the best battery, no matter how taken care off, loses capacity, swells and has to be disposed. When we combine both facts we face a problem: how to dispose old LiPo batteries if they can catch fire? It’s extremely hard to find a place that accepts them for utilization. Throwing out with garbage is not a good idea. Disposing with popular alkaline batteries might sound as a good idea, but it is not either. So, how to utilize old LiPos? This is quite easy…
Continue reading “How to dispose / utilize LiPo batteries” »
LiPo battery, as the heaviest single element of any racer quadcopter, is mostly the first one to fell off during crash. Or displace in high-g maneuvers. Or simple fell off in flight. Like on this picture below I’ve found on Reddit. Grrrr… for sure this is something I would like not to see personally again. And I’ve seen it on my first build based on X525 frame.
So, solid and strong battery mount is a must. Battery strap for sure. Even few in case of heavier ones. But battery strap is not enough. LiPo can always slip out. To prohibit that, I’ve been using velcro strips and it worked fine. But velcro has a few drawbacks: it is not very strong connection, allows some movement, and looses strength after some time. Few weeks ago I’ve discovered something that is way way better than regular velcro: 3M SJ3550 Dual Lock Reclosable Fastener. Continue reading “The best way to mount LiPo on a drone: 3M Dual Lock” »
It is still too early to decide if new Turnigy Graphene are worth the money, but after 3 flying weekends with them I do have some thoughts about them already.
One of the values that describe LiPo batteries used in RC crafts is so called C rating. For example: 3S 1300mAh 45-90C. Or 3S 5000mAh 25-30C. Or 4S 1300mAh 65-95C. S is simple, it tells the voltage. mAh or Ah tell capacity.
But what about C rate? According to Wikipedia is can be described as:
The C-rate is a measure of the rate at which a battery is being discharged. It is defined as the discharge current divided by the theoretical current draw under which the battery would deliver its nominal rated capacity in one hour. A 1C discharge rate would deliver the battery’s rated capacity in 1 hour. A 2C discharge rate means it will discharge twice as fast (30 minutes). A 1C discharge rate on a 1.6 Ah battery means a discharge current of 1.6 A. A 2C rate would mean a discharge current of 3.2 A.
So, if we take a look at Turnigy Nano-tech 3S 1300mAh 45-90C we will know that:
Neat, yeah? Almost 60A constant current! That gives 15A per motor. And that a lot on 250 or smaller quad. So, I should be fine! Continue reading “Battery C rate: do I need a lot of it?” »