Tony Gag Jr.

My Feedback: (124)

I have a few questions about Li-Po packs. How do I know how much of a drain I am putting on the pack? Also, how do I check the voltage of the pack? Does somebody sell equipment to check that stuff? The setup I am using is a MP Jet AC 28/7-35D Outrunner Brushless Motor with a 9X6 prop, Jeti Advance Plus 18 Amp Brushless Controller and Electrifly 3-cell 1200mah packs. Is this setup OK?

Thanks,
Tony Gagliardi Jr.

Red Scholefield

My Feedback: (9)

Yes there are at least two devices on the market that do this, look for wattmeter. Astro Flite offers one and I've seen others advertised here on RCU. Invaluable tool for the electric flyer.

Glacier Girl

My Feedback: (4)

Tony,
First off invest in either an Astro or Watt meter, Will tell you pack volts, how many amps you're pulling with the set up, among other things. A good charger such as the Astro 109, has a display that shows what was put back into the pack when charging, thus how much you used.
Couldn't find specs on motor in calc programs I use, sorry. Was it a recommended set up?
BJ

Tony Gag Jr.

My Feedback: (124)

BJ,
The setup is recommended by Hobby Lobby. The instructions for the motor says it works great with a 9X6 prop and a 3-cell Li-Po pack. Hobby Lobby recommends Thunder Power packs but I went with the Electrifly packs because I like the circuit protection they have and my LHS carries them.

Thanks,
Tony

artman102

My Feedback: (1)

Remember, if your LI-po battery gets hot, do not put it in the freezer to cool off. If you forget it overnight it will be TOAST.

Matt Kirsch

My Feedback: (21)

Um, that's not true. Cold actually PRESERVES the battery packs. They won't produce good power when cold, but they don't degrade as quickly. Thaw out the battery pack to room temperature by letting it acclimate naturally, and the battery will be fine.

If you put the pack in the freezer because it got hot, then pulled it out and discovered it was toast, it was the fact that you got it HOT that destroyed the pack, not freezing it.

You shouldn't be getting the pack that hot in the first place. If you're getting it that hot, you're using it too hard, drawing too many Amps. This is where a Whattmeter will help. At least you'll know how many Amps the setup is drawing. You can compare that to the specs to make sure you're not drawing too many Amps and damaging the system.

Replacing the ThunderPower packs with Electiflys? Make sure the Electriflys are rated to handle the Amps you're expecting to draw. If the capacities and C ratings are the same, you're okay. Smaller capacity and/or lower C rating? Be careful.

Tony Gag Jr.

My Feedback: (124)

Thanks for all the help. I found out the Electrifly packs are not good enough for my setup. I guess that is why they were getting so hot. I just ordered two Thunder Power packs. I have another question. What is the difference between "C" rating and Amps? It might sound like a stupid question but all this electric stuff is all very new to me!

Thanks again,
Tony Gagliardi Jr.

Matt Kirsch

My Feedback: (21)

C rating times the capacity of the pack will tell you how many Amps the pack can handle. When you see "10C" for example, it means, "ten times the Capacity of the pack."

Why don't they just tell you how many Amps the pack can handle? Manufacturers make several different sizes of cells based on the same design, so rather than rating each cell individually, they rate them all together. It's easier to remember that a particular line of cells is "10C capable" instead of remembering, "The 170mAh cell is capable of 1.7A, the 340mAh cell is capable of 3.40A, the 640mAh cell is capable of 6.4A, the 1080mAh cell is capable of 10.8A, the 1520mAh cell is capable of 15.2A, the 2150mAh cell is capable of 21.5A, the 3200mAh cell is capable of 32A...."

Tony Gag Jr.

My Feedback: (124)

Matt,
Thanks a bunch for the help. Now I understand why the Electrifly was not good enough for my application. It is a 1200mah pack rated at 8C. So it is capable of 9.6A. The Thunder Power pack is 10-12C at 1320mah so it is capable of 13-15A. So that makes the Thunder Power a much better pack. You learn something new everyday! Thanks again Matt!!!!!!!!!

Tony Gag Jr.