A few more Cellpro 4s questions...

[NogaroHeli]

I STFA and haven't come up with the answers (maybe I missed them?)- anywho, I've noticed that when charging with my Cellpro 4s on the 1C setting it often charges much lower than 1C. For example my 3s TP extreme 2200 is charging right now at 1.2A, the battery and charger are both at room temperature. Why would this be?

Second, what has everyone agreed upon as far as hooking a battery up to the Cellpro charger immediately after flight? I know in the manual it says you can do that without harm to the battery but I'm still a bit uncomfortable with that. What do the freaks think?

Thanks in advance!

[Pinecone]

Maybe the pack is far enough out of balance it is slow charging first.

[NogaroHeli]

Hmmm, but why would it be that far out of balance it if gets balanced charged every time?

[JokerGuy]

I'm new, very new, but I thought 1.2a is normal for 1C. My 3 FP EVO25s charge at this rate on my CellPro 4s.

It does start off much lower rate than that, balancing up I guess, and charges much lower than that at the end of the cycle again.

Like I said, I'm very new.:lol:

[zagiman]

It starts out low in the begining while it figures out the capacity of the battery that was just plugged in. It is also determining the condition of the battery. Then it will up the amps. During the charge it is always checking to see how the battery is taking the current charge and adjusts accordingly. I've had it sit around .70 amps for 5 minutes or so and then increase the amps more. I've even seen it drop the amps during the charge and then back up again. I've noticed this more as the pack gets closer to it's end of life. Also, it starts to balance when the battery reaches 90% full (that single beep that you hear). It starts to drop the amps as the cells get closer to 4.2V.

My understanding is that the Cellpro will not charge more than what the cells can handle. Things that can effect how many amps a battery can handle while being charged are: age, damage in a crash, to much pulled out, etc.

Most of my batteries when new would be charged around 2 amps. Now that I have several cycles on them, the average charge amp is around 1.5 to 1.75.

This is my understanding of 1C:
1C is 10% of the number of amp hour (Ah) capacity of the battery. So for example: if your battery has a 2170mAh capacity, it has a 2.17Ah capacity. 1C for this battery is 2.17 amps.

[kamtsa]

This is my understanding of 1C:
1C is 10% of the number of amp hour (Ah) capacity of the battery. So for example: if your battery has a 2170mAh capacity, it has a 2.17Ah capacity. 1C for this battery is 2.17 amps.

You meant 100%, right? (since 2170ma = 2.17A).

Kam

[carlo_the_wonder_frog]

The reason its gets a lower amperage rate is because it is getting near the end of its charge, as it gets closer to the end you will see the amps drop even lower, this is all normal.

[Pinecone]

That too. Lipos are charged with a Constant Current/Constant Voltage cycle. At the beginning they charge at a given amp rate. When the charking voltage hits 4.2 volts per cell, the voltage stays there and the charge current drops until the pack is charged.

As for balancing, even if you balance charge every time, the pack may be out of balance slightly when discharged (cell discharge at different rates) or during the charge (cells charge at a different rate). And that is why you should balance charge every time.

[zagiman]

You meant 100%, right? (since 2170ma = 2.17A).

Kam

mAh = milli-Amp hours
Ah = Amp hours

Okay, I made a mistake in my first response. Made it more complicated than it is.

1C = mAh / 1000

[Ginvent]

my really old TP packs charge at 3amps on 1.4c. your packs are getting tired. I would sudgest 1.4c and see where that takes you. if it still at less then 2 amps your batteries are getting old as the cellpro will never charge your packs at a rate they cant handle