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Old Nov 06, 2010, 09:18 PM
Nothing Runs Like a Deere
lebus1's Avatar
Central Minnesota
Joined Jul 2008
100 Posts
Oh yeah, I've got a Fluke for that.
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Old Nov 06, 2010, 09:19 PM
Nothing Runs Like a Deere
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Central Minnesota
Joined Jul 2008
100 Posts
Hoppy do you want me to pm you with this. This will clutter up your nice thread
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Old Nov 06, 2010, 10:21 PM
Nothing Runs Like a Deere
lebus1's Avatar
Central Minnesota
Joined Jul 2008
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Ran another test batteries 3 and 4. Ran wot until 2000 mAH was discharged. Battery 3 cell 1= 3.92 2= 3.91 3 = 3.91 4 = 3.91. It took 2759 mAH to recharge. After recharge the HK balancer showed cells on battery 3 cell 1=4.27 cell 2 =4.26 cell 3 = 4.26 cell 4 = 4.26 and total vdc of 17.04 the DVM indicated 17.01. Battery 4 cell 1 = 3.90 cell 2 = 3.90 cell 3 = 3.90 cell 4 = 3.90 and took 1587 mAH to recharge. After recharge cell 1 = 4.18 cell 2 = 4.18 cell 3 = 4.18 cell 4 = 4.18 HK balancer indicated 16.73 and the DVM indicated 16.71
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Old Nov 06, 2010, 10:26 PM
Fly now crash later
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Canada, ON, Newmarket
Joined Nov 2006
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I found this for your B6. I would stop using the charger that is going over 4.20

Before purchasing these chargers I read a lot of them, apparently the balancing function on Li-Poly or LiFePo4 batteries didn't work very accurate. I found out that you can calibrate this charger the same way as that you can calibrate Turnigy chargers. This way the displayed cell voltage of the charger (4.20V) is corresponding with the 4.20V my voltage meter reads.

If you want to calibrate your charger, follow these steps:
Step 1. Disconnect the battery and power supply
Step 2. Press the 'Dec.' and 'Start' button while connecting the power supply
Step 3. Read the battery voltage with a voltage meter
Step 4. Connect the battery to the charger
Step 5. Use the 'Dec.' and 'Inc.' to adjust the cell voltage reading to calibrate it with your voltage meter
Step 6. Press start to exit calibrating menu
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Last edited by davecrash; Nov 06, 2010 at 10:31 PM.
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Old Nov 07, 2010, 01:12 PM
Space Coast USA
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Space Coast
Joined Oct 2000
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Quote:
Originally Posted by lebus1 View Post
Ran another test batteries 3 and 4. Ran wot until 2000 mAH was discharged. Battery 3 cell 1= 3.92 2= 3.91 3 = 3.91 4 = 3.91. It took 2759 mAH to recharge. After recharge the HK balancer showed cells on battery 3 cell 1=4.27 cell 2 =4.26 cell 3 = 4.26 cell 4 = 4.26 and total vdc of 17.04 the DVM indicated 17.01. Battery 4 cell 1 = 3.90 cell 2 = 3.90 cell 3 = 3.90 cell 4 = 3.90 and took 1587 mAH to recharge. After recharge cell 1 = 4.18 cell 2 = 4.18 cell 3 = 4.18 cell 4 = 4.18 HK balancer indicated 16.73 and the DVM indicated 16.71
Very good, problem is solved IMO.
This a chart of cell voltage versus remaining capacity.

By cell (+/- 5%)
4.00V--84%
3.96---77%
3.93---70%
3.90---63%
3.86---56%
3.83---48%
3.80---43%
3.76---35%
3.73---27%
3.70---21%
3.67---14%

Pack #3 has a voltage of 3.91/cell which is little over 37% used.
Pack #4 has a voltage of 3.9V/cell which is about 37% used.

37% (+/-5%) of 5000mah = 1858mah (1600mah to 2100mah)

Pack #3 took back 2759mah
Pack #4 took back 1587mah

I would bet money on the 1858mah +/-5% being correct.
My conclusion:
1. Both packs are OK'
2. Pack #3's charger is reading high on the mah in.
3. Pack #4's charger is reading low on the mah in.
4. Charger for #3 pack is overcharging the cells.
5. Packs are well balanced and matched.
6. The discharge voltages show that both packs are discharging equally.
What do you think?
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Last edited by hoppy; Nov 07, 2010 at 01:25 PM.
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Old Nov 07, 2010, 02:46 PM
Nothing Runs Like a Deere
lebus1's Avatar
Central Minnesota
Joined Jul 2008
100 Posts
I will discharge two batteries and recharge them with the E-flite charger (max 4.17vdc full charge). Then discharge them using the same 2000 mAH amount and check how much they need (mAH) to recharge to 4.17vdc/cell. I think I understand what you are saying about the apparent overcharge difference between the two chargers. If the batteries require about the same amount then problem solved. Yes? DB
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Old Nov 07, 2010, 04:22 PM
Space Coast USA
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I'd be very surprised if there is much difference between the two in mah put back in when charged with the same charger.
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Old Nov 07, 2010, 07:59 PM
Nothing Runs Like a Deere
lebus1's Avatar
Central Minnesota
Joined Jul 2008
100 Posts
Success!! I relearned that batteries in a series need to be at the same voltage or one will drain out faster than the other. Just like putting a new battery with a used one in a flashlight. I got 10 minutes run time @ 28 amp draw (cells were at 3.65 when I stopped never hit LVC). That's about 3/4 to wot. Plenty of time and power I don't think that I'll need much more than 1/2 throttle to fly a normal circuit. It may be next spring before I get a chance to maiden this bird. Minnesota will be getting cold and white soon. This is a very informative thread which I will read completely. I stumbled on to it by accident but it really has a lot of great information and links in it. Thanks for the effort. DB
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Old Nov 26, 2010, 05:01 PM
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Joined Jun 2008
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Great thread! I am not sure if this would be of value and I didn't want to clutter this thread.

I created a thread with a cheat sheet for Smart Phones etc. with some of the basic LiPo information that most people ask, as I did when I first got into them. The cheat sheet is an A6 sized pdf that can be downloaded to a Smart Phone and read pretty easily.

Thoughts and opinions would be appreciated.

http://www.rcgroups.com/forums/showthread.php?t=1344681
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Old May 18, 2011, 03:17 AM
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i charged my battery well and left it unused for one week and nw it bulged is it any prblm???
will my battery work properly nw pls help me with this
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Old May 18, 2011, 08:55 AM
Space Coast USA
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Space Coast
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See post 18-22
http://www.rcgroups.com/forums/showp...3&postcount=27
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Old May 25, 2011, 04:28 AM
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thanks for your post
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Old May 26, 2011, 10:26 PM
Finish 1 B4 Starting Another
vonhouzen's Avatar
Australia, VIC, Bacchus Marsh
Joined Sep 2008
169 Posts
Hi to save me hours of reading I have a flightmax 2500 mah TX pack my son turned my TX on and left the room now it is flat as a s*#t carters hat!! 2 of the cells were below 2 mah and one was 0.00,now that i have left it a few days it has managed to come up to 1.8 mah ..CAN THIS BATTERY BE SAVED??????? Or am i waisting my time
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Old May 27, 2011, 07:47 AM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
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There is a sticky on that subject.
http://www.rcgroups.com/forums/showthread.php?t=1074181

I'd also recommend reading http://sites.google.com/site/tjinguy...po-terminology
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Old May 28, 2011, 01:44 AM
Finish 1 B4 Starting Another
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Australia, VIC, Bacchus Marsh
Joined Sep 2008
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Thank you
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