NMP 7.4v 2Amp Battery Packs

[rcaerobob at cox.net]

My testing supports Gene's findings, also.  Just bench testing, with an ammeter in the switch harness TO the receiver, I lifted the tail of the airplane off the bench by lifting the elevator, and simultaneously pushed the rudder side-wise.
Almost 3 amps drawn instantaneously, and the voltage depression was a surprise, too!!
I think the total loads of an all-digital pattern plane are pretty high in the dynamic environment.
> 
> From: gene.maurice at comcast.net
> Date: 2004/08/25 Wed AM 09:06:48 EDT
> To: discussion at nsrca.org
> Subject: Re: NMP 7.4v 2Amp Battery Packs
> 
> Adam
> I think that if you were to put a fairly fast amp meter in the power circuit on an all digital plane, you'll find the peak draws MUCH higher than 1 amp. A local guy has an EagleTree system in an all digital plane (sample response time is only about 1/10 of a second, pretty slow) and it shows AVERAGES of 1.0 - 2.0 amps with peaks up in the 3 - 4 amp range. These peaks are very short in duration but require a battery capable of delivering that sort of amperage none the less.
> Digital servos draw large amounts of current when asked to move, especially under aerodynamic loads. In addition, their holding power will draw as much current as it takes, or is available, to maintain a position. 
> Check it out, I think you'll be surprised.  
> --
> Gene Maurice 
> AMA 3408 NSRCA 877 
> Plano, TX 
> gene.maurice at comcast.net
> 
> 
> -------------- Original message -------------- 
> 
> > Dieter Rozek wrote: 
> > 
> > > I just purchase these battery packs and according to the included 
> > > instructions is mentions to "Only use NMP's Lithium charger to charge 
> > > these packs." I was wondering if anyone might know why this would be 
> > > the case. Shouldn't any Li battery charger work? I already have a 
> > > Kokam Li battery charger which allows me to charge at various rates. 
> > > Is there a legitimate reason why I should buy their charger or should 
> > > any Li charger work? Also, I was surprised at the diminutive size of 
> > > the pack. Does this pack have enough juice to power 3x JR9411, 1x3412 
> > > and 1x8411 in a Temptation? At 2A I would assume that this would be 
> > > more than plenty? I would be interested in hearing anyone's 
> > > experience with these packs. 
> > > 
> > > Thanks 
> > > 
> > > DIeter 
> > > 
> > > ===================================== 
> > > # To be removed from this list, go to 
> > > http://www.nsrca.org/discussionA.htm 
> > > and follow the instructions. 
> > > 
> > I'm estimating our peak draw with a fully digital plane is around 1amp, 
> > so any lithium battery over 250mah shouldn't have a problem staying 
> > above 6.0v during those draws. 
> > ===================================== 
> > # To be removed from this list, go to http://www.nsrca.org/discussionA.htm 
> > and follow the instructions. 
> > 
> 

Bob Pastorello, El Reno, OK, USA
rcaerobob at cox.net
www.rcaerobats.net

=====================================
# To be removed from this list, go to http://www.nsrca.org/discussionA.htm
and follow the instructions.