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...more questions about charging lipo's

Old 03-25-2008, 03:50 PM
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Default ...more questions about charging lipo's

Guys,

A few questions about charging lipo batteries. I致e tried an MRC Super Brain 977, but I知 not sure if the charger is giving me all the info I need. I知 new to this sport, and I知 quickly realizing that the electrical systems are the most complex part of the equation for me.

1. Should a high-quality lipo charger show the voltage for each individual cell, not just the total voltage of the battery?

2. When you plug in a partially discharged lipo, should a high-quality Lipo charger show the current mAh in the battery? When charging on the Brain 977, it shows how many mAh are going into the battery, but not the total mAh state of the battery.

3. How do you know if your batteries are fully charged? For example, when I put a 3 cell battery on the charger it shows the total voltage at 11.08 V. Then as it charges the voltage climbs over time to 12.4 V and then the charger turns off. I realize that the voltage for each cell should not exceed 4.2 V for a total of 12.6 V. Do you know the battery is fully charged by Voltage or by mAh?

4. If you have an 11.1V 1800mAh 3 cell lipo battery, is it the voltage that declines with usage, or the mAh?

Thanks so much for the info. Any other information would be greatly appreciated.

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Old 03-25-2008, 04:02 PM
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1, Yes,
2, Yes (sort of they guess %fuel remaining based on voltage they can't really tell you how many mah are left in the battery.)
3, Voltage 4.2v X number of cells
4, the mah the battery will hold, and the rate at which it can give it out will decline over time, Voltage should stay the same.

The CellPro line 4S or 10S do all these things. As far as I'm concerned they are the only choice for charging Lipo.

Last edited by constantCrash; 03-25-2008 at 04:28 PM. Reason: re-answer question 4, since i didn't understand at first
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Old 03-25-2008, 05:18 PM
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Constantcrash,

(nice name, by the way ) Thanks for the input, I appreciate your insight.

One question about the Cell Pros. Do you know if they will effectively charge a lipo without a balanced connector. I have a 3 cell GP "safe charge" lipo with a 2 pin input connector. (comes without a balanced connector)

(I also have another balanced connector lipo, and expect to purchase more as I grow into this sport.)

Thanks

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Old 03-25-2008, 05:43 PM
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I actually can't answer if it will charge a battery without a balance connector. All mine have balance connectors. Do you have a link to that GP "Safe charge" battery?
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Old 03-25-2008, 06:04 PM
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Here is the battery... I think I may have been fooled into buying this, live and learn, I won't buy another lipo without balance connectors)

http://www3.towerhobbies.com/cgi-bin...&I=LXJRY3&P=SM

thanks
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Old 03-25-2008, 06:19 PM
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Ahh, I think what your seeing, where your charge stops at 12.4 volts is caused by this (from the tower website about that battery) "
If any cell reaches 4.2V, the SafeCharge Circuit automatically
stops the Charge process entirely
"

Maybe somebody with more experience with that battery can be more helpfull.
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Old 03-25-2008, 06:56 PM
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Originally Posted by constantCrash View Post
I actually can't answer if it will charge a battery without a balance connector. All mine have balance connectors. Do you have a link to that GP "Safe charge" battery?
I had one of those Batt's,that was a piece-o-Junk, GP said tuff s&^t, Oh Well, your bub, steve PS Here's a pix's just made for you I think!!
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Old 03-25-2008, 07:02 PM
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HAHAHAHA, that made me laugh out loud at work. hope you don't mind me using that as my avitar. It looks just like my 3rd cat Willow.


Originally Posted by stevecooper View Post
I had one of those Batt's,that was a piece-o-Junk, GP said tuff s&^t, Oh Well, your bub, steve PS Here's a pix's just made for you I think!!
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Old 03-25-2008, 07:18 PM
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I made a male balance connector to mini-deans adapter cable a while back to charge a 2-cell battery that only had discharge leads on an E-Sky balancing charger. This way I was able to charge a battery that did not have a balance adapter on an E-Sky charger that only had balance connector outputs. This functioned perfectly on the E-Sky charger, but I do not know if this trick will work on the CellPro 4S.

- David
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Old 03-25-2008, 08:11 PM
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Originally Posted by stevecooper View Post
I had one of those Batt's,that was a piece-o-Junk, GP said tuff s&^t, Oh Well, your bub, steve PS Here's a pix's just made for you I think!!
Steve,

Thanks, that's what I thought I would hear. Won't make the same mistake twice.

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Old 03-26-2008, 04:43 AM
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Forge,
The CellPro charger will not charge through the discharge lead. It is strictly for balance charging but...if you have reasonable soldering skills you can install CellPro balance taps on any lipo pack.
If you'd prefer not to open your packs, keep the Brain. You'll need it for your round cells anyway. But a balance charger should be in your future since nearly all packs come with balance taps now.
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