[NSRCA-discussion] Max volts

[Atwood, Mark]

Biggest problem with raising the voltage is that 40v is generally considered the max non lethal voltage.    You'll be hard pressed to get a voltage increase for general safety reasons. 

I'm sure that's why the current limitation  is in the general guidelines in the first place. 
--------------------------
Sent from my BlackBerry Wireless Handheld


----- Original Message -----
From: nsrca-discussion-bounces at lists.nsrca.org <nsrca-discussion-bounces at lists.nsrca.org>
To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
Sent: Mon Mar 01 11:43:21 2010
Subject: Re: [NSRCA-discussion] Max volts

Ok I will bite, you get a 10% increase in voltage, so a 10% reduction in amps for same watts, but you have a 50% reduction in capacity to pass the voltage check.  Flight time still reduced!

In reality it won't happen like this....as you will love the extra power, and actually use it, so you watts will be higher, amp draw will be the same, and you will still have only 1/2 your pack charged because you have to pass the voltage check.

Now if you try this on the same motor that you normally use 10s without propping down it actually will make things much worse since your amps will end up being higher than with the 10s setup :)

FYI, open circuit resting voltage of a lipo is directly proportional to remaining capacity.  If you search around you should be able to find a chart for it.

Chad

----- Original Message -----
From: Ron Van Putte <vanputte at cox.net>
Date: Monday, March 1, 2010 8:17 am
Subject: Re: [NSRCA-discussion] Max volts
To: General pattern discussion <nsrca-discussion at lists.nsrca.org>

> I keep looking at the voltage curve for 10S vs 11S and see that 
> the  
> voltage would be higher at every point, until the 11S pack's 
> voltage  
> drops below the 10S pack's voltage out at the end of the flight 
> and,  
> because the voltage was higher, the current to develop the 
> same  
> wattage would be less, prolonging the 11S's flight time.
> 
> Ron
> 
> On Feb 28, 2010, at 10:48 PM, Chad Northeast wrote:
> 
> > You would be at about 50% capacity at 3.85 ish volts/cell 
> (resting  
> > open circuit), so unless you up the capacity you will have a 
> pretty  
> > restricted flight time.
> >
> > Chad
> >
> > On 10-02-28 9:25 PM, Ron Van Putte wrote:
> >> That stirs a wild thought in my brain.  Fully charged 
> packs don't  
> >> stay at 4.2 volts per cell very long.  On the other 
> hand, once the  
> >> initial charge voltage is burned off by a constant load, 
> the  
> >> voltage loss curve "flattens out".  What if you put 
> fully charged  
> >> 6S and a 5S packs in series and "burn them down" to 3.869 
> volts  
> >> per cell (a total of 42.56 volts for an 11-cell pack) so they 
> were  
> >> legal for use.  Would the voltage of this depleted 11S 
> pack be  
> >> higher than a fully charged 10S pack at the end of a 
> typical  
> >> flight?  If the end-of-flight voltage might be 
> significantly  
> >> higher for the 11S pack vice a 10S pack, it would be 
> worth  
> >> investigating, even considering the extra weight of the 
> additional  
> >> cell.  Come on you electronic gurus, show me where I'm wrong.
> >>
> >> Ron Van Putte
> >>
> >> On Feb 28, 2010, at 10:00 PM, James Oddino wrote:
> >>
> >>> What comes after ...?  Does it specify a load or any 
> other  
> >>> conditions?  Is it measured during the noise test and 
> have a  
> >>> minimum value?
> >>>
> >>> Just stirring the pot, Jim O
> >>>
> >>>
> >>> On Feb 28, 2010, at 5:21 PM, John Fuqua wrote:
> >>>
> >>>> No its not (assuming we are talking RC Aerobatics).  
> Try page  
> >>>> RCA-2 para 4.1
> >>>> which states "Electrically-powered model aircraft are 
> limited to  
> >>>> a maximum
> >>>> of 42.56 volts.."
> >>>>
> >>>> -----Original Message-----
> >>>> From: nsrca-discussion-bounces at lists.nsrca.org
> >>>> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf 
> Of  
> >>>> Ron Van Putte
> >>>> Sent: Sunday, February 28, 2010 7:07 PM
> >>>> To: General pattern discussion
> >>>> Subject: Re: [NSRCA-discussion] Max volts
> >>>>
> >>>> It's in the general rules, not in the R/C section.
> >>>>
> >>>>
> >>>> On Feb 28, 2010, at 6:50 PM, Jim Quinn wrote:
> >>>>
> >>>>> Where can I find the rule for max volts?
> >>>>>
> >>>>> _______________________________________________
> >>>>> 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
> >>
> >> _______________________________________________
> >> 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
>