How to Determine Lipo Battery Charger
Lithium polymer (LiPo) batteries are the battery of choice for remote control enthusiasts. LiPo batteries are slim, lightweight and produce three times the voltage of nickel-based batteries. However, LiPo batteries are expensive compared to nickel-based batteries, so you need to ensure they are charged using the manufacturer's instructions, as this prolongs the battery life. What's more, checking that your LiPo battery is correctly charged ensures you keep your battery in good condition. Determining the LiPo battery charger is best achieved using a digital multimeter to measure the voltage and milliampere hours.
Charge your LiPo battery according to the manufacturer's instructions. Always use a charger designed specifically for charging LiPo batteries: They contain circuit protections to ensure the battery isn't overcharged, as overcharging may result in your LiPo battery exploding or catching fire. Remove your LiPo battery from the charger once charged.
Read the label on the LiPo battery to determine its output voltage and mAh rating, if fully charged. A single cell LiPo battery produces a maximum of 4.2 volts but averages 3.7 volts during the discharge cycle. The mAh rating for a single cell is 1,320 mAh, or 1.32 amperes, which remains static during the discharge cycle. If you have a LiPo battery pack, the output is a multiple of the above numbers, depending on whether the pack is wired in series or parallel. For example, if your pack contains three LiPo cells wired in series the average voltage is 11.1 volts and 3,960 mAh, but if wired in parallel the voltage remains at 3.7 volts and produces 1,320 mAh.
Set your multimeter to measure voltage and set it to read an output range between approximately 20 percent more and 20 percent less than the output voltage on the battery. For example, if the battery says 3.7 volts, set the meter in the range of 3 to 4.5 volts.
Use the sensors on the ends of the two wires from the multimeter to touch the terminals of the LiPo battery. One wire is red, meaning positive, and the other black, meaning negative. Put the sensor on the end of the red wire onto the positive terminal of the LiPo battery: it's clearly labeled "+." Put the sensor on the end of the black wire onto the negative terminal of the battery labeled "-."
Check the voltage output on the digital multimeter display. Using a single cell, it measures between 3.7 and 4.2 volts, if the battery is fully charged and in good condition. Using the example of a single cell, a measurement below 3.6 volts indicates either the battery isn't fully charged or it cannot retain a full charge. Try charging your battery again if the figure is below the output rating on the battery label, and then test it using the multimeter. If it's still below the figure on the battery label, you need to consider purchasing a replacement.
Reset your multimeter to measure mAh. Set the output range between 20 percent above and 20 percent below the reading on the battery label.
Place the sensors on the LiPo battery terminals as before. Read the digital display on the multimeter. It reads between 1,300 and 1,350 mAh for a single LiPo cell that's fully charged and in good condition. Using the example of a single cell, a measurement below 1,250 mAh indicates either the battery isn't fully charged, or it cannot produce the correct mAh. Try charging your battery again and then test it using the multimeter. If it's still below the figure on the battery label, you need to consider purchasing a replacement.