[NSRCA-discussion] Dodged a Bullet Today!!!!Wanderings

Wed Mar 22 13:11:12 AKST 2006

This might be a case for using the higher dollar chargers-but I haven't used
them with cell balancing-yet.  Did attend a short seminar from Kokam over
the weekend and they have had good luck with their packs not catching on
fire by severely overcharging with the type of manufacturing they do on
many--not all-of their packs.  They have a great deal of interest in safety
in that they are trying to be the first lithium based battery used by Boeing
(and other heavy hitters).  They also acknowledged RC is the toughest
application on batteries.   While I was at it, I showed them my records of
my 3200s-we discussed that while yes the standard for life is charge and
discharge was at 1C (they got 1400 cycles at that)-our use is at 20C+/- AND
THAT IS HOW CYCLE LIFE NEEDS TO BE MEASURED FOR US!  From the horses mouth:
"Well Yes, multiple C-in AND out will decrease cycle life.."   My point to
them was 'OK, throw us a bone-all I know is that at 20C+/-lipos shoot
craps(less than 80%) in about 25 cycles-used and abused.  But now I'm
getting set to spend some fairly serious bucks and I NEED to know what to
expect...."  They seemed to agree that if a battery says it is a 20C-we
ought to have a pretty good idea how many cycles to expect.  Seemed like a
reasonably logical approach to me.  Probably scares the hell out of them
though.   I say this a lot regarding E-We'll see..........

While reading this over, It occurred to me to take the 1400 figure divide it
by 20 and you come up with 70-which is what I understand some guys were
getting with the larger packs-(we were running ours over 20 and fairly
hot--abusive).  There may be some semi-direct correlation there-but I don't
know.  Lighter airframes and bigger packs-but I want to have SOME idea what
to expect.

Richard

 -----Original Message-----
From: 	nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]  On Behalf Of Bill Glaze
Sent:	Wednesday, March 22, 2006 3:08 PM
To:	randy10926 at comtekmail.com; NSRCA Mailing List
Subject:	Re: [NSRCA-discussion] Dodged a Bullet Today!!!!

And, we all know that, with my hearing, if the back of the van
disintegrated, I wouldn't know it until I felt the highway draft
Bill Glaze
----- Original Message -----
From: "Glenn Hatfield" <randy10926 at COMTEKMAIL.COM>
To: <nsrca-discussion at lists.nsrca.org>
Sent: Wednesday, March 22, 2006 8:40 AM
Subject: Re: [NSRCA-discussion] Dodged a Bullet Today!!!!

>I would never hear anything from the back of the pea-cup truck.  Maybe the
>1st rule is stick with glow.
> Randy
>
> --- seefo at san.rr.com wrote:
>
> From: "Doug Cronkhite" <seefo at san.rr.com>
> To: "'NSRCA Mailing List'" <nsrca-discussion at lists.nsrca.org>
> Subject: Re: [NSRCA-discussion] Dodged a Bullet Today!!!!
> Date: Tue, 21 Mar 2006 21:08:56 -0800
>
> Actually..
>
>
>
> 1st rule of Li-po charging is.. Never charge unattended.
>
>
>
> 2nd rule is never charge in your car.
>
>
>
> Eric got really lucky and I suspect won't be doing either 1 or 2 again.
>
>
>
> -Doug
>
>
>
>
>
>  _____
>
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Dean Pappas
> Sent: Tuesday, March 21, 2006 8:51 PM
> To: NSRCA Mailing List
> Subject: Re: [NSRCA-discussion] Dodged a Bullet Today!!!!
>
>
>
> Hey Evil,
>
> I'd rather be lucky than good: any day!
>
> And that's why you use a charger that looks at each tap, before charging,
> in
> order to determine the number of cells. The same problem exists when
> dis-charging packs. That's how I trashed one cell in one of my 5Ses.
>
> Dean
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org on behalf of Grow Pattern
> Sent: Tue 3/21/2006 6:04 PM
> To: NSRCA Mailing List
> Cc:
> Subject: [NSRCA-discussion] Dodged a Bullet Today!!!!
>
>
>
http://www.rcuniverse.com/forum/m_4056141/anchors_4064428/mpage_1/key_/ancho
> r/tm.htm#4064428See picture on RCU.I had a bit of a set back today with my
> winter fun 40 sized glow to electricconversion. I had wanted to try the
> Thunderpower 4200 instead of the Tanic3600. I set off to the field with a
> borrowed Thunderpower 4200 mAh pack. Iset the Astroflight 109 to 2 Amps.
> It
> ent to stage 1 and was calibrating toa 3 cell pack and was well on its way
> to charging the pack, or at least so Ithought . I have done this
> topping-it-up many times before. I set it on a 2Amp charge rate.I never
> made
> it to the field. I heard a light "Phuttt!" about ten minutesinto the
> journey. I stopped the van and ran back to the back doors. Thebattery was
> bloated and looking bad. I grabbed the Deans connectors andunplugged it.
> Dangling it by the lead and as far away from my face aspossible I lowered
> it
> to the curbside.I then personally backed up and was about to move my van
> forward a bit . (Ihad just put 3!
> 5 gallons in it!). Seemed like a good idea to get clear. Neverhad the
> chance. The pack blew up in a ball of flame about a cubic yard insize and
> proceeded to burn fiercely. I had grabbed the fire extinguisher butdecided
> not to use it.The local police joined me for a while and seemed more
> interested in theplanes in the back of the van than the charred remains. I
> scraped all of thebits up to keep the country side pretty. Estimated that
> the grass would growback soon, and went home.Fortunately I was able to get
> it out of the van before it blew up intoflames etc.Long and the short of
> it
> is. "Do not charge a fully charged battery with anautomatic charger"Dodged
> a
> BIG bullet today.....Regards,Eric.P.S. If 3 fully charged cells = 12 V
> plus,
> and 4 discharged cells = 12 Vplus, then how does the charger know which is
> which?
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>

_______________________________________________
NSRCA-discussion mailing list
NSRCA-discussion at lists.nsrca.org
http://lists.nsrca.org/mailman/listinfo/nsrca-discussion