[lektrik_flyers] Re: (No To: lektrik_flyers@freelists.org
- From: Bill Beavers <bbeavers57@xxxxxxxxx>
- To: lektrik_flyers@xxxxxxxxxxxxx
- Date: Tue, 29 Mar 2005 08:03:43 -0800 (PST)
Oh, and I meant to say on the C thing, that 2C, 3C,
etc., is 2 times and 3 times the rated capacity. So
if you were charging a battery (NiMH for example) that
was a 1000 mah battery at 1C, you would set the
charger to 1.0 and the voltage rating, and it would
charge for a longer period of time to full capacity.
If you charge it at 2C, it will charge twice as fast
because it is taking in about twice the amount of
current as a 1C charge, and the battery will get a lot
hotter quicker as the electrons try to find a place to
rest but have to do it in a hurry. 3C is the same
deal, and you can damage batteries and/or shorten
their life by charging at these rates, not to mention
the fun of watching a battery do funny things as it
starts to meltdown or explode.
Also, on discharge (especially Li-Po's) the batteries
are rated for so much discharge rate, as in like 6C,
10C, 12C, etc., and this is how fast you can get max
voltage out of the battery at max current draw for the
motor doing the pull, and still not overheat and
damage the battery.
And one last thing about li-po's, you NEVER want to
let them drop BELOW their minimum recommended safety
voltage, (ie. 3volts), or you will ruin them and they
will no longer take a charge! Most ESC's (Electronic
Speed Controller's) have these safety features built
into them, but many let you change the default values
to more custom settings. Be careful when doing this
though.
Whew... that is a mouth full! Hope this makes some
sense.
--- Bill Beavers <bbeavers57@xxxxxxxxx> wrote:
> Ok... well that is a good place to start because
> that
> "C" rating was my same concern when I first started
> messing with Li-Po batteries. Basically, it is
> pretty
> straight forward when you kind of get the hang of
> it,
> but it took me a long time to to fully understand
> what
> they were talking about. the C stands for Capacity
> of
> the battery, and it is important in both the charge
> rate (the speed at which you can charge a Li-po
> without blowing it up), and the disCharge rate (the
> rate as to how fast you can suck the juice out of
> that
> battery without overheating it or blowing it up).
>
> Batteries are rated in Amp Hours, or in the case of
> the size batteries we use, mAh (milli amp hours).
> So
> lets say you have a 1000 mah (1000 milli amp hour)
> battery. the charge rate for this battery at 1C (1
> C
> is the charge rate to charge it to capacity at
> normal
> speed basically) would be 1.0 Amps at voltage rating
> (ie 7.4 or 11.1, etc.) for the recommended time for
> the charger used. Since I use a Triton charger, all
> I
> do for a Li-Po battery that is say 1000mah like the
> example used, is set the charger to the voltage type
> (ie 7.4v or 11.1v), set the amperage to 1.0 amps
> (this
> is calculated by the charger and yields the
> milliamps
> needed for charging). Then the charger does the
> rest.
>
> These same charge traits apply to NiCD and NiMH
> (Nickel Cadnium and Nickel Metal Hydride) batteries
> too, but they can be tampered with more on non Li-po
> batteries. You don't really want to try to quick
> charge a Li-Po. They are volitile! I may not have
> explained that as well as I would like to have
> above,
> but if that above doesn't make sense, maybe we can
> get
> you to the airfield and go over some of that.
>
>
>
> --- Gordon and Betty Bailey <baileyark@xxxxxxxxx>
> wrote:
> > Thanks Bill,
> > Well, to start with, I bought a watt meter (watts
> up
> > brand) and need to know how to use it......there
> are
> > 20 plus pages of instructions only two of which
> seem
> > to make any sense at all as far as getting useful
> > information from the machine. I have been able to
> > figure out estimated flight time, but the other
> > things like efficiency, the likelihood of burning
> > something up and everything else escape me. Maybe
> > it is my old fossilized mind.....67. I have been
> > told that all lipo batteries have a C
> > rating........news to me and I have read lots of
> > magazines and chat room threads. What does C
> stand
> > for and how do I find out what it is?
> >
> > Enough for now.......will try to come see you guys
> > soon.
> >
> > Gordon
> > ----- Original Message -----
> > From: Bill Beavers
> > To: undisclosed-recipients:
> > Sent: Tuesday, March 29, 2005 9:08 AM
> > Subject: [lektrik_flyers] Re: (No To:
> > lektrik_flyers@xxxxxxxxxxxxx
> >
> >
> > Hmmmm... Gordon, there probably are, but for me
> I
> > have
> > always learned this stuff by just digging
> around,
> > and
> > when I see a term I don't understand, I just hit
> > the
> > Internet and find related topics about it, or
> just
> > brace up, cover my embarrassment and ask my
> fellow
> > flyers <blush>... for example, I keep forgetting
> > what
> > NOTAM means that John Cooper uses everytime he
> is
> > ready to hit the field (I think that is an old
> > military term used a LOT by guys like Captain
> > Cooper
> > <grin>) and had to ask David Reid the other day
> > again
> > the other day to finally remember that it is
> > NOtice To
> > AirMen, or something close to that! :D
> >
> > Tell you what, feel free to throw ANY and ALL
> > terms,
> > Acronyms, etc., you want onto this list, and I
> am
> > sure
> > we can ALL give you 5 or 6 different versions of
> > what
> > that means! :D hee hee... just because we
> > sometimes
> > understand some of this stuff slightly
> > differently. I
> > haven't been much of a book person on this
> stuff,
> > it
> > is by the seat of your pants mostly, and talking
> > to
> > your fellow flyers.
> >
> > If you can get with us at the airfield your
> > knowledge
> > bank will go up quickly, or become totally
> corrupt
> > depending on our own understanding of stuff! hee
> > hee
> >
> > --- Gordon and Betty Bailey
> <baileyark@xxxxxxxxx>
> > wrote:
> > > Guys,
> > > Are there any books available that go into the
> > > basics of this RC flying game?? I need the
> > > kindergarten stuff... Like terminology,
> > > electronics, aircraft design and function. My
> > > experience with other fields this complicated
> is
> > > that the "books for beginners" tend to be too
> > > advanced to do an ignorant guy like me any
> good,
> > or
> > > they are mainly just pretty pictures.
> > >
> > > thanks,
> > > Gordon
> > >
> > >
> >
> > Bill Beavers
> > Director of Technology and Distance Learning
> > Arch Ford Education Cooperative
> > bbeavers@xxxxxxxxxxxxxxxxx
> > http://af1.afsc.k12.ar.us
> >
> >
> >
> > __________________________________
> > Do you Yahoo!?
> > Yahoo! Small Business - Try our new resources
> > site!
> > http://smallbusiness.yahoo.com/resources/
> >
> >
> >
> >
>
> Bill Beavers
> Director of Technology and Distance Learning
> Arch Ford Education Cooperative
> bbeavers@xxxxxxxxxxxxxxxxx
> http://af1.afsc.k12.ar.us
>
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Small Business - Try our new resources site!
> http://smallbusiness.yahoo.com/resources/
>
>
Bill Beavers
Director of Technology and Distance Learning
Arch Ford Education Cooperative
bbeavers@xxxxxxxxxxxxxxxxx
http://af1.afsc.k12.ar.us
__________________________________
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