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Old Sep 14, 2012, 03:30 PM
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Hi:

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Quote:
Originally Posted by Eddie500 View Post
Hello, I want to charge a single 6s1p battery pack and am unsure of some of the charge options in the software. Charger is a powerlab 8.
The batteries are Turnigy 5000Mah, 6s1p, 2c charge, 20c discharge.

http://www.hobbyking.com/hobbyking/s...dProduct=16207



Charge Amps: , Am I better off setting it to 2c? Or should I set it to 10 amps?
It all depends on your comfort level with charging. the AUTO C, 2C, 3C modes are convenient, but it takes them a while to ramp up because the unit has to be conservative so it's safe. So a lot of people would rather set the charge rate manually. For the battery you listed above, a 2C charge would be 10A. If you know how to calculate a 2C rate based on the pack capacity, you will ultimately be more happy with the results doing it that way. If you just want the easiest, most convenient approach, use AUTO modes.

C/? Termination: What is this exactly, what should I set this to?
The default presets usually use C/20 or C/10. In this simple formula, "C" is the battery pack capacity. So, when a LiPo charges, it starts out with CC (Constant Current) mode. In CC mode, the unit regulates the current at the set charge rate. After the cells reach approx 90% charge, the unit switches to CV (Constant Voltage) mode. In CV, the unit regulates the voltage to make sure it never exceeds 4.2V per cell (or whatever you have the per cell termination voltage set). It will maintain this voltage regulation as the current falls off further and further. When the termination C/? is reached, the charge is complete. So, if you had termination at C/20 on your 5000 mAh battery pack, and you had set the charge rate to 10A, it would stop at 10A/20 = 0.5A (or 500 mA). This is a simplified answer, but it will give you the idea of how the charge process works and how the charge gets terminated.

Cold Weather: It is 70-85 degrees in my charging area. Do I need to set this? It defaults to 50F. Should I set this to none or leave it at 50F? If it never drops below 70 deg F, I'd either turn this feature off, or set it to 32 deg F. Sounds like you'll never need it. It is bad to charge a LiPo to 4.2v (100%) when ambient temperatures drop below 50 deg F. It does permanent damage to the cells.

Discharge Voltage: I read where you should not discharge a Lipo below 3.65V. Why does it default to 3.30V? Should I change this? You should follow your battery manufacturer's recommendations on this. I am told that a log of newer LiPo cells should not be taken as low as the defaults. In our experience, it doesn't hurt the batteries we've owned, but we are not the experts on battery chemistry, only battery charging. That's why we allow access to 100 or so adjustable parameters in the PL8 open architecture presets. Therefore, trust what the battery manufacturer tells you.

I just got these batteries new. Is there any reason to discharge them before I charge them? I'll let others chime in here and I'm sure you'll hear a lot of different opinions if they do. I think the most common sense answer is, break them in by charging them up at 1C the first couple times, and simply discharging them in the model, but don't go crazy. Just fly, nice, gentle circuits with new packs the first few flights. But again, I'm not the expert on matters of battery break in; just passing along what makes the most since to me from various things I hear.


Here is an optional question if someone has the time to help me out.
This is a parallel charging question. I want to charge 4 batteries in parallel using a board.
Here is my power supply.
http://www.hobbyking.com/hobbyking/s...dProduct=17414
Output Power: 600w
Output Voltage: 17v
Output Current: 0-36A


When charging 4 of these 6s1p batteries using the power supply in the link. What are the best charge settings I should use?
Here's the good news. PowerLab Battery Workstations are extremely smart. They offer you Smart Power Management. Read up on that in the user guide and set your input supply current limit to just below what the power supply is spec'd. In your case, I'd set that number to say 32A. I'd set the input supply low voltage setting at 12v. Now, decide how fast you want to charge each of the packs you will be connecting to the PL8. If there will be multiple 5000 mAh packs, for example, and you want to charge each at 2C, set the preset's charge rate for 10A. Then when you charge, connect up the packs in parallel, call up the preset you set up to use, and answer the question about #P correctly. If you're charging 3 packs in parallel, the answer is "3P". The PL8 will do the rest, and if will charge the packs at the 10A each you selected for the preset, or as quickly as your PSU will allow based on the input current limit you set, without letting your PSU get damaged. Following these steps takes all of the guesswork and worry out of it, and the PL8 will do all the math for you.
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