# Charging at 2 or 3C, great electric tip

May 27, 2011 No Comments

Here is another good tip that comes from my friend Albert Tejera who own www.TMEnet.com. Albert is an enthusiastic flyer and just an all-around good guy. This tip for all you guys who fly electrics which is a lot of people. Remember never go more than 1C unless the battery manufacturer recommends it.

## How do I charge at 2C and 3C etc ?

One question that seems to puzzle a lot of our customers is what do they have to do to charge their new pack at 2C or more. As Lithium battery technology advances, battery manufacturers are now claiming that you can safely charge Lithium packs at higher rates in order to get a faster charge. In theory charging at 1C takes a discharged pack a little over an hour to charge. At 2C it would take about 1/2 hour and at 3C would take about 1/3 hour. So the question is usually, how do you tell the charger to charge at the higher rate?

The problem arises because the charger cannot possibly know the mAh rating of the battery. When charging at 1C, you have to tell it what to charge at by setting the charge rate to be the same number as the mAh rate. So therefore when charging at 2C you will need to multiply the battery capacity times 2 in order to set the charge rate to 2C. This goes the same for 3C, 4C or whatever they set as a maximum. So if you have a 3, mAh pack and you want to charge at 3C you would multiply 3,000 by 3 to get a charge rate of 9,000 mAh or 9 Amps! Now at this point you may find that your charger doesn’t make it to 9,000 mAh and you wonder what to do? Well the bad news is you will not be able to charge that fast with the charger that you presently have. The good news is that in this case 9,000 mAh is the recommended maximum so that anything less will work just fine. The only problem is that you will not be able to charge as quickly as you might have had you been able to charge at that 9,000 mAh rate.

### About the author

West Coast senior editor About me: I’ve been involved with RC aircraft since high school and have flown just about everything. I started my RC career with scratch-building, but now like many pilots I rely on ARFs to get me in the air. My main focus is on pylon racing, aerobats, combat and scale warbirds.
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