[NSRCA-discussion] Big LiPo pack charging

[Rcmaster199 at aol.com]

I heard a good one yesterday that applies directly to this stuff:
 
" I am too poor to buy cheap"
 
Goes for servos too
 
regards
The Frugal Pattern Gourmet
 
In a message dated 3/9/2006 8:29:43 PM Eastern Standard Time,  
d.pappas at kodeos.com writes:

Hi  Jim,
It meets my "spec", if you will call it that: even if it is made up of  two 
boxes.
Function first! The price is cheap compared to toasted lithium  ...

Thanks for the confirming info,
Dean

-----Original Message----- 
From:  nsrca-discussion-bounces at lists.nsrca.org on behalf of J.Oddino 
Sent: Thu 3/9/2006 7:35 PM 
To: NSRCA Mailing List  
Cc: 
Subject: Re: [NSRCA-discussion] Big  LiPo pack charging



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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