Why Do I Need All Of This Power??
In short, more power (watts) traditionally equals more current at higher volts, resulting in a faster charge time.
Realistically if you are looking for a solution to charge the Sky remote AA's every few months the iChargers features and power rating are probably well over the top for your needs. But if batteries and chargers are a common part of your entertainment or even your professional arena, then we have something that may interest you!
Whether it is hobby radio control vehicles, portable electronics or even power tools, a good computerised charger with adequate power is a must.
In short, more power (watts) traditionally equals more current at higher volts, resulting in a faster charge time. We do not recommend charging any battery that doesn't have set manufacturer charge rating higher than 1C or 1 x time the capacity at more than 1C. I.e. 2000 mah battery should be charged at 2000 mah or 2amps, unless specified by the battery manufacturer.
If you are new to battery terminology and need an over view of the ratings and what the values mean, we have a really good resource that should bring you up to speed. Located here.
As always we strongly recommend you read through and understand ALL safety tips located here. Battery chemistry, in particular Lithium batteries are made from volatile substances and can catch on fire and cause harm if all care is not taken.
So what is the power and why do I need so much of it?
Say you wanted to charge a 6 cell (6S) 4000 mah Lipo battery pack at 1c or 1 times the rating. This Lipo battery pack is made up of 6 cells that have a nominal voltage of 3.7 volts each, maximum voltage of 4.2 volts each (when fully charged) and minimum voltage of no less than 3 volts each (when discharged). This means that this battery pack has a 22.2 nominal voltage and is 27.6 volts fully charged. At 1C charge rate (1 x capacity) we would need to feed 4000 mah or 4amps into this battery. Nearing its full charge voltage of 27.6 volts, at 4amps this example would require 110 watts. Worked out by multiplying Amps by Voltas (W = A x V). This does not factor any energy loss in leads, wiring, circuitry, heat etc. Energy loss usually equates to 10-20% and sometimes worst depending on what equipment, charger, wiring etc. you are using.
Based on this simple example you can see how many watts are required to charge this pack at 1C or in an hour. Other chargers may have a current rating that can be 10 amps or 20 amps. But they don't always tell you what the output wattage of the charger is rated at. What you will find is that you won't be able to charge a large pack like this at 1C on your conventional charger.
Say this example battery had a manufacturer specified charge C rate of 2C (charge 2 x capacity). Based on the equation mentioned earlier in this example we would require 220 watts. If your charger (and power supply) does not have adequate power to provide this, you would never be able to charge at actual "2C" and you would be sitting there waiting for much longer than you'd expect for the charge cycle to complete.
Here is another example… Parallel Charging is becoming more popular amongst RC enthusiast these days. Mainly as it provides the option of balance charging all your (same cell) battery packs in one go. Negating the need of plugging and unplugging and setting and resetting. All the packs are charged together and ready to go.
**Please note that there are some strict safety guidelines that need to be adhered to. These can be found here
Ok… On with another example, say you had an RC car that used 7.4 volt Lipo batteries. You had two x 2S (7.4 volt) lipo with a capacity of 3000, one x 2S (7.4 volt) lipo with a capacity of 4000. When in parallel, these 3 batteries would have a nominal voltage of 7.4 volts, a fully charged voltage of 8.4 volts and a total capacity of 10,000 mah. (Capacity is always added together in parallel wiring). If you wanted to charge this "battery pack" at 1C you would need to feed it 10 amps. Reaching its full charge voltage the total power consumption would be 84 watts, which is approximately an hour charge.
If ALL of these batteries had a manufacturer charge rating of 2C (2 x rated capacity) the current required would be 20 amps and a total power consumption of 168 watts. If your charger does not have the output power rating to supply this, the charge time would be significantly higher.
Please note; in these examples we have used Lipo battery packs of the same cell count. Although their capacity can vary (within reason), they MUST be the same cell count (voltage), otherwise you can risk damage and/or serious injury