What amps required to charge 6 300mah 2s?

[fishsticks]

I recently purchased a Hobby King Eco 6-10 200W charger and a Junsi 350 W power supply.

I am new to the hobby so bear with me.

I have a Blade nano cpx, an mcpx, and an mcpx bl.

A member of this forum posted a video of how to use an accucel 6 Hobby King charger and he uses the following formula to set the amp rate on the charger. Number of batteries * The mah of the battery * 2. So for example if I am charging 6 of my 250 mah 1S MCPX I would get [6 batteries * 250mah * 2] = 3000 mah. So I set the charger to 3 amps and it charged all six batteries in about 25 minutes. Which was great. I tried the same formula for my nano 1s batteries and it also charged them in about 25 minutes.

Is this formula a good rule of thumb? So if I want to charge all 6 of my 300mah 2s batteries I would get [6 * 300mah * 2] = 3600 mah, and set the charger to 3.6 amps?

I don't want to hurt my batteries or burn my house down so all help is appreciated. Also, if anyone can point me to a good thread that will teach me how to figure all this stuff out on my own feel free to do so.

[RedOctobyr]

Read here:

http://www.tjinguytech.com/charging-how-tos

Specifically the "Parallel charging LiPos" section.

No, that formula is a little off. For (6) 2S 300's, it would be:

6 * 300mAh = 1800mAh. Divide by 1000, to convert it to Ah. So they're 1.8Ah all-together. So a 1C charge is 1.8 Amps.

Don't involve the cell-count in the amps calculation. 1C for a 3S 2200mAh pack is 2.2A. And 1C for a 6S 2200mAh pack is still 2.2A.

Your (6) 1S 250mAh batteries are charged at 1.5A, for a 1C charge.

I'd start with 1C charges if it were me. I charge at 1C if time & patience permit, 2C if I'm in more of a hurry, and 3C when field-charging for flying continuously.

[fishsticks]

Awesome! Thanks for the advice and the link! This stuff is starting to make more sense already.

[Slyster]

Those tiny packs do NOT take well to fast charging.. your best bet is to charge 6 at a time at 1C. That way at least you are charing 6x faster than 1 packs at a time. At higher C (amps) the lipo IR is just way too high.. the charger will quit at 4.20v but then they will sag way back down to like 1/2 full.

[ahahn]

Originally Posted by Slyster

Those tiny packs do NOT take well to fast charging.. your best bet is to charge 6 at a time at 1C. That way at least you are charing 6x faster than 1 packs at a time. At higher C (amps) the lipo IR is just way too high.. the charger will quit at 4.20v but then they will sag way back down to like 1/2 full.

I certainly don't see this on my 2s300mAhr cells. I charge 3 in parallel at 3A total, equivalent to a ~3C charge. There is no sagging back, charge level stays where it is, other than the normal slight drop off to just below 4.2.

IR is always higher on small packs, but also the actual charge current is smaller, when stated as a "C" charge.

These are the standard Eflite 35C packs, which came originally with my 130X. They are also rated for 3C charging.

I have no complaints. They've been working great.