RE: HELP with Li-Po Pack

RE: HELP with Li-Po Pack
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RE: HELP with Li-Po Pack - 7/21/2004 5:09:42 PM

Posts: 149
Joined: 4/9/2004
From: Clovis, CA, USA
Status: offline

My pack says to charge as 2c. So charging it at 1C would actually take less time!? See my pack specs in post #53 as it says on the label. I'd definitely like to see it take only 1 hour than 4 hours, that's for sure.

Thanks,
Nick

[/quote]

...you should charge them at 1C and they will only take 1 hour to charge. That makes it a lot easier to keep your eye on them.
[/quote]

(in reply to coomarlin)

RE: HELP with Li-Po Pack - 7/21/2004 5:34:06 PM

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Joined: 8/11/2003
From: Milwaukee, WI, USA
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Nick, it's possible that you are confusing the comment "charge as 2 cell" and charging at "2C". They are two different things. When you program that battery, you would choose Li-poly, 2 cell (7.4V), and you need to specify your peak charge current rate in amps. If you want to charge that battery of yours at a 1C rate, you would set the peak charge current to .860 amps. Then it will take 1 hour ONLY if it were fully discharged. Actually it will take less than an hour, maybe even a half hour. I'd check with the people you bought the battery to find out how high of "C" you can go with that pack. If they say 2C is ok, then just multiply the .860 times two and that will be the charge rate for THAT battery pack only.

Also please never leave a Li-poly pack charging unattended. You should be there watching it in case it ignites due to a failure in the battery or charger. Also an improperly setup battery could do that too.

Joe

quote:

ORIGINAL: Nickerz

My pack says to charge as 2c. So charging it at 1C would actually take less time!? See my pack specs in post #53 as it says on the label. I'd definitely like to see it take only 1 hour than 4 hours, that's for sure.

Thanks,
Nick

...you should charge them at 1C and they will only take 1 hour to charge. That makes it a lot easier to keep your eye on them.

(in reply to Nickerz)

RE: HELP with Li-Po Pack - 7/21/2004 6:00:00 PM

Posts: 149
Joined: 4/9/2004
From: Clovis, CA, USA
Status: offline

Thanks JoeAirPort!

You are right, I was comparing two different things. No wonder it took so long. Thanks for breaking this down too!

I charged my pack in the fire place with it closed up and a smoke alarm next to it but I know I should watch it. Now that It may take only 30 minutes to 1 hour, I'd be more likely inclined to stick around during the entire charge.

Thanks again!
Nick

quote:

ORIGINAL: JoeAirPort

Nick, it's possible that you are confusing the comment "charge as 2 cell" and charging at "2C". They are two different things. When you program that battery, you would choose Li-poly, 2 cell (7.4V), and you need to specify your peak charge current rate in amps. If you want to charge that battery of yours at a 1C rate, you would set the peak charge current to .860 amps. Then it will take 1 hour ONLY if it were fully discharged. Actually it will take less than an hour, maybe even a half hour. I'd check with the people you bought the battery to find out how high of "C" you can go with that pack. If they say 2C is ok, then just multiply the .860 times two and that will be the charge rate for THAT battery pack only.

Also please never leave a Li-poly pack charging unattended. You should be there watching it in case it ignites due to a failure in the battery or charger. Also an improperly setup battery could do that too.

Joe

quote:

ORIGINAL: Nickerz

My pack says to charge as 2c. So charging it at 1C would actually take less time!? See my pack specs in post #53 as it says on the label. I'd definitely like to see it take only 1 hour than 4 hours, that's for sure.

Thanks,
Nick

...you should charge them at 1C and they will only take 1 hour to charge. That makes it a lot easier to keep your eye on them.

(in reply to JoeAirPort)

RE: Attn: Hobbico Elite Owners - 7/21/2004 6:07:21 PM

Posts: 1001
Joined: 10/2/2002
From: Morgantown, WV, USA
Status: offline

Most LiPo manufactures suggest charging at 1C. The correct rate is easy to figure out. Take the capacity of your pack in mah and divide it by 1000. That will give you the correct amount of amps to set your charger at.

_____________________________

Windy Ridge RC Club

(in reply to Nickerz)

RE: Attn: Hobbico Elite Owners - 7/21/2004 6:25:45 PM

Posts: 6741
Joined: 8/11/2003
From: Milwaukee, WI, USA
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Nick, BTW, charging at 2C takes less time since it's twice as much charging current as 1C. But since Coomarlin said 1C is typical for most Lipo's, I'd stay at 1C (.860 amps). Also the battery's capacity will need to be programmed in as well (860). I'd double check your settings for that battery in the memory# to make sure it's 100% correct.

Joe

< Message edited by JoeAirPort -- 7/21/2004 12:30:16 PM >

(in reply to coomarlin)

RE: Attn: Hobbico Elite Owners - 7/21/2004 6:28:16 PM

Posts: 149
Joined: 4/9/2004
From: Clovis, CA, USA
Status: offline

That's what I was thinking, but at least increasing the current rate from .15 (which was the Auto Sett btw) to .86 should take less time to charge then...right?

See, if I input the battery info, then the Auto Set calculates the current rate. So I can simply increase this, thus taking less time to charge? I guess the charger is just thinking this is the safest charge rate.

Thanks,
Nick

quote:

ORIGINAL: coomarlin

Most LiPo manufactures suggest charging at 1C. The correct rate is easy to figure out. Take the capacity of your pack in mah and divide it by 1000. That will give you the correct amount of amps to set your charger at.

< Message edited by Nickerz -- 7/21/2004 10:30:15 AM >

(in reply to coomarlin)

RE: Attn: Hobbico Elite Owners - 7/21/2004 7:00:53 PM

Posts: 1001
Joined: 10/2/2002
From: Morgantown, WV, USA
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quote:

ORIGINAL: Nickerz

That's what I was thinking, but at least increasing the current rate from .15 (which was the Auto Sett btw) to .86 should take less time to charge then...right?

See, if I input the battery info, then the Auto Set calculates the current rate. So I can simply increase this, thus taking less time to charge? I guess the charger is just thinking this is the safest charge rate.

Thanks,
Nick

quote:

ORIGINAL: coomarlin

Most LiPo manufactures suggest charging at 1C. The correct rate is easy to figure out. Take the capacity of your pack in mah and divide it by 1000. That will give you the correct amount of amps to set your charger at.

Correct. Just increase the input to .85 Amps. Should take around an hour.

_____________________________

Windy Ridge RC Club

(in reply to Nickerz)

RE: Attn: Hobbico Elite Owners - 7/21/2004 7:01:32 PM

Posts: 149
Joined: 4/9/2004
From: Clovis, CA, USA
Status: offline

Okay, so now I'm getting ready to charge my 2nd Li-po pack (I bought two).

I set it up the same way but when I select the volts off the label of the pack (7.4V) it selects 2C, If I scroll down to 1C, it displays volts that are not my battery. So I don't think I charge at 1C. However, I am adjusting the current rate, which it automatically selected .15 from the Auto Start Set but I increased this to .85 (taking 860mAh / 1000 = .86).

Anyone see any problems with this setup?

Thanks,
Nicholas

PS I thought you are not suppose to discharge Li-po packs? The charger has a feature to discharge the Li-po pack???

(in reply to Nickerz)

RE: Attn: Hobbico Elite Owners - 7/21/2004 7:04:04 PM

Posts: 149
Joined: 4/9/2004
From: Clovis, CA, USA
Status: offline

Thanks CooMarlin! You and everyone in here have been a lot of help! And patient with my million questions!

I just posted my question above rigt before I read this reply of yours. So I should be all set now.

Nick
PS I flew my Tiger Moth early this morning on my Li-po. So far 15 minutes of flying, mostly between half throttle and full and still have plenty of juice left!

quote:

ORIGINAL: coomarlin

quote:

ORIGINAL: Nickerz

That's what I was thinking, but at least increasing the current rate from .15 (which was the Auto Sett btw) to .86 should take less time to charge then...right?

See, if I input the battery info, then the Auto Set calculates the current rate. So I can simply increase this, thus taking less time to charge? I guess the charger is just thinking this is the safest charge rate.

Thanks,
Nick

quote:

ORIGINAL: coomarlin

Most LiPo manufactures suggest charging at 1C. The correct rate is easy to figure out. Take the capacity of your pack in mah and divide it by 1000. That will give you the correct amount of amps to set your charger at.

Correct. Just increase the input to .85 Amps. Should take around an hour.

(in reply to coomarlin)

RE: Attn: Hobbico Elite Owners - 7/21/2004 7:05:05 PM

Posts: 1001
Joined: 10/2/2002
From: Morgantown, WV, USA
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You are confused. The 2C from the Elite signifies it's a 2 cell pack. Which is 7.4 volts. We are referring to 1C charge rate which in your case is 850mA. You will not read anything on the elite that refers to C in terms of charge rate. Only number of cells.

_____________________________

Windy Ridge RC Club

(in reply to Nickerz)

RE: Attn: Hobbico Elite Owners - 7/21/2004 7:17:23 PM

Posts: 6741
Joined: 8/11/2003
From: Milwaukee, WI, USA
Status: offline

quote:

ORIGINAL: coomarlin

You are confused. The 2C from the Elite signifies it's a 2 cell pack. Which is 7.4 volts. We are referring to 1C charge rate which in your case is 850mA. You will not read anything on the elite that refers to C in terms of charge rate. Only number of cells.

I'll have to take a look at mine when I get home to see what it actually says in that part of the menu. Does it actually say "2C" in the menu where you choose number of cells? I remember seeing the voltage right next to it.

Nick, you should be choosing the 2 cell (7.4V) pack if you have a two cell pack like the first one you posted a pic of.

< Message edited by JoeAirPort -- 7/21/2004 1:24:34 PM >

(in reply to coomarlin)

RE: Attn: Hobbico Elite Owners - 7/21/2004 8:04:47 PM

Posts: 149
Joined: 4/9/2004
From: Clovis, CA, USA
Status: offline

JoeAirPort,

Yes, I'm looking at the display and it reads as follows...

"Volts: 7.4V (2C)"

If I push "down" then the volts drop as well as the 2C becomes 1C.

My 2nd pack just finished charging and it only took 40 minutes! So everything was okay. I may have been confused on the 2C and 1C current rating but I think this is b/c my display is showing this. At any rate, I set my charger up correctly and this time used .86 current rate and everything is fine.

CooMarlin, have you charged a Li-po pack? I think I understand what you are saying now and why I was confused when you said 1C

Nick

quote:

ORIGINAL: JoeAirPort

quote:

ORIGINAL: coomarlin

You are confused. The 2C from the Elite signifies it's a 2 cell pack. Which is 7.4 volts. We are referring to 1C charge rate which in your case is 850mA. You will not read anything on the elite that refers to C in terms of charge rate. Only number of cells.

I'll have to take a look at mine when I get home to see what it actually says in that part of the menu. Does it actually say "2C" in the menu where you choose number of cells? I remember seeing the voltage right next to it.

Nick, you should be choosing the 2 cell (7.4V) pack if you have a two cell pack like the first one you posted a pic of.

< Message edited by Nickerz -- 7/21/2004 12:06:26 PM >

(in reply to JoeAirPort)

RE: Attn: Hobbico Elite Owners - 7/21/2004 8:50:16 PM

Posts: 1001
Joined: 10/2/2002
From: Morgantown, WV, USA
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Nick I haven't had a chance to charge LiPO's yet. I just got 2 new packs in the mail yesterday and I'm getting things ready for my new foamy. I am assuming when you say the readout says 7.4V 2C that the 2C is referring to "2-cells". I think Hobbico could've done things a bit differently here to make it more understandable for people new to LiPo's. All they had to do was change the display to read "7.4V 2-cell". Usually when people talk about LiPo packs they indicate them as 7.4V 2s1p packs or 11.1V 3s1p rather than 2C or 3C. The first digit indicates how many cells are in series and the 3rd digit indicate how many are in parallel.

When you hear of the term "C" in reference to charge rate it just refers to the capacity of the pack. With an 850Mah pack 1C = 850mA. 2C = 1700mA, C/10 = 85mA, etc

_____________________________

Windy Ridge RC Club

(in reply to Nickerz)

RE: Attn: Hobbico Elite Owners - 7/21/2004 9:48:16 PM

Posts: 1001
Joined: 10/2/2002
From: Morgantown, WV, USA
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I just hooked my 850mah 3s1p pack up on the elite and sure enough it gives you the option of 1C, 2C, or 3C to indicate # of cells. Don't know why they didn't just write the word cell, but thats how it is. I checked the voltage of my packs straight from the factory and they read 10.9V so I'm not even going to bother charging them yet.

_____________________________

Windy Ridge RC Club

(in reply to coomarlin)

RE: Attn: Hobbico Elite Owners - 7/21/2004 11:10:16 PM

Posts: 6741
Joined: 8/11/2003
From: Milwaukee, WI, USA
Status: offline

quote:

ORIGINAL: coomarlin

I just hooked my 850mah 3s1p pack up on the elite and sure enough it gives you the option of 1C, 2C, or 3C to indicate # of cells. Don't know why they didn't just write the word cell, but thats how it is. I checked the voltage of my packs straight from the factory and they read 10.9V so I'm not even going to bother charging them yet.

Yeah I agree, that 1C, 2C, etc for the number of cells was a bad choice of text. The word "Cell" is only three more letters than "C", sheesh. So I don't blame you for being confused Nick.

Joe

< Message edited by JoeAirPort -- 7/21/2004 5:11:16 PM