[NSRCA-discussion] Big LiPo pack charging

[J.Oddino]

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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