[NSRCA-discussion] Big LiPo pack charging

[Chad Northeast]

Jim

It will keep a series charged 5s4p in balance, although we I was playing 
with it I found that the balance was much better when using the 100% 
charge option vs the fast charge option.

Using the 100% charge all cells in the pack were within 0.005V as 
measured with a calibrated Fluke meter.

Chad

J.Oddino wrote:

>Dean et all,
>I've been playing with the Thunder Power TP-1010C charger and TP-210V
>balancer.  I guess they fall into the category of having a fancy
>communications link.  Some of the features:
>1) If any cell in the pack gets to 4.235V charging is interrupted.
>2) During the constant current charge phase, the charge rate is reduced to
>300ma if the unbalance exceeds .12V.  During the constant voltage phase it
>will be reduced to 300 mA if the unbalance is greater than .06 volts.  I
>believe the bleed current can go up to 450 mA so it can more than overcome
>the charge current in these modes.
>3) If the unbalance is greater than .2 volts the charge will be interrupted
>and you get a message that tells you to balance before charging.
>4) If the charger cell count doesn't match the balancer data you get an
>error message.
>I believe this meets your requirements except that it is a two box system.
>
>What I like about it is you can read the voltage of each cell (up to ten
>cells) to one millivolt so you always know what you've got.  I plan to
>charge two 5s4p packs in series and I can't see why I shouldn't be able to
>keep all the cells balanced even if I don't charge to 100% between flights.
>
>It is pricey but if it helps keep those expensive big packs alive it is
>worth it.  Plus I love the peace of mind I get when I have the data that
>tells me everything is A okay.
>Jim O
>
>----- Original Message ----- 
>From: "Dean Pappas" <d.pappas at kodeos.com>
>To: <chad at f3acanada.org>; "NSRCA Mailing List"
><nsrca-discussion at lists.nsrca.org>
>Sent: Tuesday, March 07, 2006 7:59 AM
>Subject: Re: [NSRCA-discussion] Big LiPo pack charging
>
>
>  
>
>>Hi All,
>>I hear discussions about this charger versus that, and while I am not
>>    
>>
>going to try and sell my preference, I think I
>  
>
>>should tell you what a proper charger, for our purposes, should do.
>>
>>I really think the important thing to remember, here, is that a real
>>    
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>balancing charger will always be better than a charger plus an add-on
>balancer.
>  
>
>>Why? The add on balancer and charger combo will do its job, perfectly
>>    
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>well: until there is a problem with a battery pack.
>  
>
>>Unfortunately, this is where the safety hazard happens (not to mention the
>>    
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>premature aging of expensive battery cells).
>  
>
>>When there is a problem, and the imbalance between cells is not slight, or
>>    
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>some cells have appreciably different capacities than others due to age,
>  
>
>>the controlled bypass current around the higher voltage cells may not be
>>    
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>high enough to keep things balanced.
>  
>
>>That's how balancers work, they put a current "leak" across the higher
>>    
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>voltage cells;
>  
>
>>during charging this leak shunts some of the charging current around the
>>    
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>higher voltage cells, until the lower voltage cells catch-up.
>  
>
>>For things to really work properly, the balancer part of the works needs
>>    
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>to be able to throttle-back the charger current,
>  
>
>>to something equal to or less than the maximum leak current, at any stage
>>    
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>of the charge, if the imbalance isn't getting better.
>  
>
>>That really requires a one-piece balancing charger, or some sort of fancy
>>    
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>communication between the charger and balancer.
>  
>
>>Right now, very few companies make a real balancing charger, but this
>>    
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>can't stay the same for long.
>  
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>>It has also been suggested that with a true balancing charger, that never
>>    
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>charges too fast to maintain balance,
>  
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>>that 2C and 3C charges are possible, with the high C discharge packs we
>>    
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>find necessary, in Pattern.
>  
>
>>later, friends,
>>
>>
>>Dean Pappas
>>Sr. Design Engineer
>>Kodeos Communications
>>111 Corporate Blvd.
>>South Plainfield, N.J. 07080
>>(908) 222-7817 phone
>>(908) 222-2392 fax
>>d.pappas at kodeos.com
>>
>>
>>_______________________________________________
>>NSRCA-discussion mailing list
>>NSRCA-discussion at lists.nsrca.org
>>http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>>
>>
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>>    
>>
>
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