Lithium Polymer (LiPo) Batteries
Lithium polymer batteries or lithium-ion polymer batteries, often abbreviated to Li-Poly, Li-Po, or simply LiPo, are rechargeable lithium batteries featuring electrolytes in the form of polymer gel with graphic anode and cathode in the form of a Lithium Cobalt Oxide (LiCoO2) or some similar material.
Lithium polymer batteries are usually flat batteries, without rigid casing. This allows them to be rather lightweight and are often used in handheld devices, remote-controlled toys, and drones, in some electric vehicles, etc.
Nominal voltage, cutoff voltage, maximum charging voltage, discharge current, and other features depend on the exact chemistry type and the battery's intended use.
While large, deep-cycle Lithium Iron Phosphate (LiFePO4) batteries often have a maximum continuous discharge current around 1C, some high-discharge LiPo batteries feature a maximum discharge current of 100C or even more.
Because of such strong discharge currents, in order to keep the cells balanced, smaller LiPo batteries may have both discharging and charging wires, allowing the battery charger to analyze, balance, monitor, and in the end, charge individual cells, prolonging the battery's operating lifetime.
Lithium polymer batteries mostly differ according to their capacity, discharge current, and the number of cells connected in series:
- Lithium LiPo 2S Battery, with a nominal voltage usually around 7.2-7.4 volts,
- Lithium LiPo 3S Battery, with a nominal voltage usually around 10.8-11.1 volts,
- Lithium LiPo 4S Battery, with a nominal voltage usually around 14.4-14.8 volts,
- Lithium LiPo 5S Battery, with a nominal voltage usually around 18-18.5 volts,
- Lithium LiPo 6S Battery, with a nominal voltage usually around 21.6-22.2 volts,
- Lithium LiPo 7S Battery, with a nominal voltage usually around 25.2-25.9 volts,
- Lithium LiPo 8S Battery, with a nominal voltage usually around 28.8-29.6 volts, etc.
High-power tools and vehicles use lithium polymer batteries with even more cells connected in series and hence, higher voltages.
Note: while lithium 8S battery has a nominal voltage of 28.8-29.6 volts, 8 (eight) cell Lithium Iron Phosphate (LiFePO4) battery has a nominal voltage of "only" 25.6 volts. This voltage difference of 3.2-4 volts doesn't seem much, but if those two batteries are being discharged with 100 Amps, the power difference will be 320-400 watts. Designers of high-end devices, tools, and even vehicles often need just a few more volts/amps to be "the best"...
How to Charge LiPo Batteries?
Although LiPo batteries are able to provide currents up to 50-100+C, the best practice is to charge them with currents in the 0.5-1.0C range or as recommended by the battery manufacturer.
In order to keep them in perfect working order, LiPo Balance Chargers are recommended - they feature JST-XH ports for 2S, 3S, 4S, etc. batteries allowing them to charge the battery and balance each cell individually.
For example, Genini Lipo Balance Charger (Amazon link, link opens in the new window) features 5 (five) different JST-XH ports intended for charging 2S, 3S, 4S, 5S, and 6S Lipo Batteries.
Note: Amazon link opens in the new window, feel free to check it for the most up-to-date offers and prices.
With the advancements in electronics, such battery chargers are not even expensive.
Note: Even when charging them with professional Lipo balance chargers which protect the batteries from overcurrent, overheat and overvoltage, lithium polymer batteries should not be recharged unattended, not even when being stored in special fireproof charging bags. Also, it is a good practice to break in new Lipo batteries using a good balance charger/discharger, by charging and discharging the battery for the first few times down to 25%, 50%, and 75% DoD - even gradually than that! Just my 2c ...
Here is the list of our latest lithium polymer batteries reviews and recommendations, ordered according to the date added or updated:
Zeee SDL-9545180 is a relatively large and heavy 4S LiPo battery intended for heavy-duty use - the battery features metal plates on 5 sides for additional protection, a large 9000mAh capacity, and a maximum discharge current of 100C!
Zeee SDL-9545180 is intended for RC cars, trucks, tanks, and similar vehicles, but it can be used for large RC planes, robots, electric vehicles, and other applications that require such batteries.
Ovonic 5S 18.5V 100C 1300mAh Lipo Battery is a very popular 5S Lipo battery with a very high discharge rate, suitable even for professional FPV competitions, for powering RC quadcopters and other multirotors, for RC helicopters, RC airplanes, and similar.
Ovonic 5S 18.5V 100C 1300mAh Lipo Battery is able to provide plenty of power for a very short time, but like all other Lipo batteries, it should be charged with typical 0.5-1.0C charging currents.
HOOVO 3S 11.1V 50C 5200mAh Lipo Battery is a lightweight lithium polymer rechargeable battery featuring Tracxas discharge plug, and being able to provide plenty of power for various RC toys and hobby projects including RC cars, trucks, airplanes, helicopters, FPV, drones, etc.
Like all other Lipo batteries, HOOVO 3S 11.1V 50C 5200mAh Lipo Battery should also be charged using professional balance chargers with few first charging/discharging cycles being done at home, in controlled conditions, gradually increasing Depth of Discharge (DoD%).
Ovonic 2S 7.4V 5200mAh 50C Lipo Battery is a reliable and affordable, high-capacity lithium-polymer battery with a hard case, intended for RC toys and similar applications that require lightweight energy sources being able to provide plenty of energy and power.
Ovonic 2S 7.4V 5200mAh 50C Lipo Battery features standard Deans T plug and JST-XH plug, ensuring firm connection when being both discharged and charged.
Zeee SDL-9543125 is a very popular 2S 7.4V 50C 5200 mAh lithium polymer battery, often used in 1/8 and 1/10 RC cars and trucks, but also other RC toys like RC airplanes, RC helicopters, RC boats, drones, etc.
Zeee SDL-9543125 2S 7.4V 50C 5200mAh Lipo Battery features a 2S1P configuration and comes with a Deans T connector/plug and JST-XH plug. Although it is a Lipo battery, Zeee SDL-9543125 features a hard case for increased protection.