It is possible to use mobile phone lithium batteries to DIY batteries. Multiple batteries can be connected in parallel and then connected in series, like two strings. The maximum voltage is 8.4V, as shown in the picture. .
Use 6 batteries. 7.4V battery composed of batteries, so DIY batteries need to pay attention to:
1. The capacity of each parallel battery should be as close as possible; 2. It is better to add an equalizer to avoid a certain group of voltages.I would like to give you 4 suggestions:
Firstly, cell phone lithium batteries do not support high current discharge because they are lithium-ion batteries , not to mention that 3800mAh must be a false label, if you want to discharge with high current with such a large capacity, the battery will swell, and you can't have cake and eat itr too. It is recommended to purchase a regular 18650 battery, which should last a while, but ultimately it is recommended to purchase nickel-metal hydride, which is cheap and can discharge at high currents (18650). but for safety or performance reasons, I suggest you buy a special battery. The high-power model aircraft motor consumes a lot of current and cannot afford to damage it. Plus, model airplanes aren't just for hours of playing. If you really want to play, playing with oil is pretty good.
Second, if you want your own DIY charger, I suggest you go to the official website of Maxim or Linear to find chips dedicated to charging lithium batteries and solder a board yourself . I've had lithium batteries explode when. I charged them myself, so be careful and carry a 3A protection card. HeThere is no problem charging together in series, but this requires protective plates between the batteries.
Third, the nickel-metal hydride battery charger should not be used to charge lithium batteries, because the charging methods are different, so do not connect it, otherwise it will shorten the service life of the lithium battery. you don't connect the protection board, then you just risk the flowers.
Fourth, I have played with model airplanes before, but not anymore Haha, it is important to pay attention to safety. Cheapness and convenience are both fish and cake, unless you have certain abilities and knowledge. So I can't explain it completely clearly, so if you don't understand, don't hesitate to ask. I'm an electronics student and I like tinkering with little things. Hehe~~~~~