[NSRCA-discussion] Big LiPo pack charging

Thu Mar 9 18:08:39 AKST 2006

Sounds like we have a good item.
Dean

	-----Original Message----- 
	From: nsrca-discussion-bounces at lists.nsrca.org on behalf of Chad Northeast 
	Sent: Thu 3/9/2006 9:27 PM 
	To: NSRCA Mailing List 
	Cc: 
	Subject: Re: [NSRCA-discussion] Big LiPo pack charging

	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
	>>   
	>>
	>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
	>>   
	>>
	>well: until there is a problem with a battery pack.
	> 
	>
	>>Unfortunately, this is where the safety hazard happens (not to mention the
	>>   
	>>
	>premature aging of expensive battery cells).
	> 
	>
	>>When there is a problem, and the imbalance between cells is not slight, or
	>>   
	>>
	>some cells have appreciably different capacities than others due to age,
	> 
	>
	>>the controlled bypass current around the higher voltage cells may not be
	>>   
	>>
	>high enough to keep things balanced.
	> 
	>
	>>That's how balancers work, they put a current "leak" across the higher
	>>   
	>>
	>voltage cells;
	> 
	>
	>>during charging this leak shunts some of the charging current around the
	>>   
	>>
	>higher voltage cells, until the lower voltage cells catch-up.
	> 
	>
	>>For things to really work properly, the balancer part of the works needs
	>>   
	>>
	>to be able to throttle-back the charger current,
	> 
	>
	>>to something equal to or less than the maximum leak current, at any stage
	>>   
	>>
	>of the charge, if the imbalance isn't getting better.
	> 
	>
	>>That really requires a one-piece balancing charger, or some sort of fancy
	>>   
	>>
	>communication between the charger and balancer.
	> 
	>
	>>Right now, very few companies make a real balancing charger, but this
	>>   
	>>
	>can't stay the same for long.
	> 
	>
	>>It has also been suggested that with a true balancing charger, that never
	>>   
	>>
	>charges too fast to maintain balance,
	> 
	>
	>>that 2C and 3C charges are possible, with the high C discharge packs we
	>>   
	>>
	>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
	>>
	>>
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	>>
	>>
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	>>   
	>>
	>
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