Lithium-ion polymer batteries or polymer lithium ion or more commonly lithium polymer batteries and Lipo for short.
Thunder Power lipos are know to be top quality lipo batteries in the RC hobby world, although the price is much higher, but as they say, you get what you pay, quality batteries. I myself rather pay 70% less and purchase from Hong Kong. The longevity of your batteries depends on how hard you push them and how slowly you charge and discharge them. Charging your lipo batteries fast and draining them fast will make them wear out quicker ( sometimes as little as 10 cycles ).
The difference between capacity and voltage:
The capacity of the battery is measured in milli-amp-hours ( mAh ), and it determines how long the battery can run before it’s drained to its minimum safe voltage.
The voltage of lipo batteries is affected by how many cells are in the pack.
3-cell Lipos give out the same voltage regardless of the capacity.
An 800 mAh lipo packs have the same voltage as say a 2200 mAh packs, but the 2200 will last a lot longer if the amperage of the motor is the same. The 2200 is also a lot heavier, which is why its best to use them on bigger planes, and a 800mAh size battery is great for little planes that weigh around 10 to 20 oz such as the little 3D banchee or the Sammy 3D. So basically the mAh of the lipo battery is how long the battery will give out juice, mAh has nothing to do with voltage.
Lipos at full charge have 4.2 volts per cell, so a 3-cell Lipo will have 12.6 volts at full charge, and it will drain safely to about 9.6, maybe a little lower but you do not want to push it. Most ESCs have a LVC (Low-Voltage Cutoff) to prevent you from draining your Lipo too low. I always drain my lipo batteries at 3.6 volts per cell, so 3.6v x 3 cell battery = 10.8v
The capacity of the battery affects how much amperage it can safely deliver. Lipo packs will have an amperage rating given as a function of the capacity, usually around 20C for bigger packs or 30C to 40C for better quality packs. Most packs have the actual max amperage marked on them (See photo below)
To find the max amprage or max C rating or max C burst rating of a lipo pack, you simply take the capacity of the lipo battery and drop the ‘hours’ unit and multiply by the rating number. So a 2200mAh ( milli-amp-hours ), drop the hours unit, leaves you with 2200 milli-amps, or 2.2 amps. If the rating is 20C, the maximum current that battery can safely deliver is 20×2.2 amps, or 44 amps.
Be very careful that you understand how these units work. Running a battery at less than the rated amperage is required, and running it at much less than the rating will extend the life of the battery. The amperage that your plane will draw is determine by the battery voltage (not capacity), the specification of the motor, and the propeller you choose. The capacity does not determine the amperage you will get, but it does determine if the battery will run safely or not.
One thing i cannot say enough is to purchase a quality lipo battery charger. If you are really into this hobby and use a generic charger, you are putting your self and your home or car in danger of fire, i myself know of 4 people in the field where i fly at who have burned their cars by either not having a good charger or not knowing how lipo batteries work.
Below is a great battery charger that i use myself and have been using it for over 2 years now and i highly recommend it, its easy to use, the price is unbeatable and it will balance your battery and charger your battery with a click of a button.
IMAX B8 Lipo Charger Discharger 1 to 8 Cells