The 7 Best LiPo Chargers
Pros And Cons Of LiPo Batteries
This allows them to provide a higher specific energy for their size, making them very useful in applications where excess weight can be detrimental.
Lithium Polymer batteries, referred to as LiPo for short, are becoming increasingly popular in consumer electronics. Unlike many other types batteries, which use a liquid electrolyte, LiPo batteries use a polymer electrolyte. This allows them to provide a higher specific energy for their size, making them very useful in applications where excess weight can be detrimental. They are especially gaining traction in the radio controlled vehicle and mobile device industries where people desire long run times in a compact and lightweight form.
LiPo batteries offer a number of benefits over other battery types. LiPo batteries are significantly lighter in weight than other types. A standard 3.7-volt, single-cell LiPo battery weighs roughly three grams. They can also be made into practically any shape or size. These factors make them extremely popular in radio-controlled vehicles, especially flying models like drones where even a few grams of additional weight can result in slower speeds and a shorter flight duration.
Despite being lightweight and compact, LiPos are actually capable of very high capacities and discharge rates, meaning they pack more punch than other battery types. In fact, they offer about four times the energy density of NiMH or NiCd batteries. Their power-to-weight ratio is impressive to say the least.
Unfortunately, LiPo batteries require special care to keep them in good shape. They must be properly stored, charged, and discharged. And even if they are meticulously cared for, they tend to have a shorter lifespan than competing battery types. The average LiPo can only be recharged roughly 500 times before needing to be replaced, whereas NiMH batteries often allow for 1,000 charge cycles. Of course, there are LiPo batteries that offer a higher number of charge cycles, though they tend to be costly. Another major drawback of LiPo batteries is their sensitive makeup. It is possible for them to catch fire if punctured or charged improperly.
What To Consider When Buying A LiPo Charger
First and foremost, it is important to ensure the charger is compatible with your battery. Somewhere on your LiPo should be a number with an S behind it. Such as, 2S or 4S. This number represents the number of cells contained within. As you may have deduced, 2S means your battery has two cells. On some older batteries you may see a figure like 2S2P. This means your battery actually has a total of four cells, two wired in series and two wired in parallel. Lower cost chargers may only be able to support batteries with two or three cells, whereas higher end models can often support the full range from one to six cells.
This allows you to save some time when recharging your battery, but it comes at a cost.
Many higher end chargers have the ability to balance charge multiple batteries simultaneously. Balance charging refers to the process of checking the voltages of each individual cell when charging to ensure they are all at the same level. This is a very important factor to keeping LiPos in good working order. Almost all models have the ability to perform balance charging, but if you want to charge multiple LiPos at the same time, it is worth checking to see if the unit you are considering supports that.
Some models have a fast charge feature. This allows you to save some time when recharging your battery, but it comes at a cost. When set to fast charge, most chargers skip the balancing step and instead just look at total battery voltage, which could potentially damage the cells by overcharging them. They will also generally stop slightly below the battery's maximum capacity to prevent overcharging of a particular cell. This means that while fast charging will get your drone back in the air faster, it won't stay there as long. Plus, you are taking a gamble on potentially shortening the lifespan of you battery.
On a LiPo, the maximum charging current is rated in Cs. Unfortunately, manufacturers have added some confusion to the mix by making users specify a charger's output in amps. To convert these values, you must multiply the battery's capacity by its C rating. For example, if you have a 4400mAh battery with a 2C rating, you could potentially set your charger as high as 8.8 amps (4.4aH x 2 = 8.8A). However, charging your battery at 1C will keep it more stable and help ensure the longest possible lifespan, so in this scenario, it is still best to just set the charger to 4.4 amps. For these reasons, we consider the fast charge feature to be more of a marketing gimmick and it shouldn't factor into your purchase decision.
Properly Storing You LiPo Batteries
The majority of issues people have with LiPos is a direct result of improper storage. Unlike with more traditional battery forms, you can't just use a LiPo until it dies and then toss it in a draw until you need it again. LiPo batteries are considered fully charged at 4.2 volts per cell and dead at 3.0 volts per cell. This means your devices will only discharge your battery to roughly 3.0 volts per cell. But, when a LiPo sits for a long time without being used, it will naturally discharge itself. LiPos that drop below the 3.0 volt threshold often will never hold a charge again.
In the same right, you can't fully charge a LiPo and then not use it.
In the same right, you can't fully charge a LiPo and then not use it. This can be just as harmful. In fact, it is possible for a LiPo to be damaged in as little as one week if left sitting fully charged. You should store your LiPo batteries at a 40 to 50 percent charge. This isn't as difficult as it sounds though. The majority of chargers have a storage mode that automatically charges or discharges your battery's cells to this level.
After you have put your LiPo in the charger and achieved the correct charge level by using the storage function, you should place it in a fireproof container until you plan on using it again. This is because they have the potential to combust during storage. While it doesn't happen often, it is possible. If you follow these simple storage tips, you can expect a long time of safe operation from your charger and your batteries.