[NSRCA-discussion] Electric/Glow Pros and Cons

Wed Aug 9 10:03:01 AKDT 2006

LiPos are a bit wierd... they allow best current flow at a specific temp 
(forgot the temp... appx 120 F)  But at appx 140F they begin degrading.  Hit 
160 and they will puff for sure.

The optimal temp allows maximum current without damaging the cells.... both 
charging and discharging.  But... passing current through the battery still 
heats them... so the ones keeping them hot for the charge do have a point, 
but they have to really play games to keep the batteries the correct temp.

Safer to just operate at a less stressful current and keep the temps down... 
But power to weight wins.

Also, getting the desired power from the electric models (for higher level 
Pattern sequences) within the 11 lb limit is tricky.

For example the way I converted my Quest to electric is 3 lbs lighter than 
what was recommended... I'm running right at 800 watts and a little over 8 
lbs.  Flys well (for Sportsman level) with this setup...  The recommended 
conversion turns out (someone else did one) 11 lbs 6 oz and 2200 watts. 
Well.. that 6 oz would keep it out of Pattern competition (according to the 
rules... never seen a plane weighed, or heard of em being weighed except at 
the NATS)  But there's no GOOD conversion that has been done for this 
particular plane between those weights!  You increase the motor size and add 
that weight... you HAVE to increase the battery cell count and capacity to 
have the power to perform the full Pattern sequence.  By the time it flys 
right again, with enough durration... you're over 11 lbs.  The higher power 
conversion will do the Inermediate and Advanced routines with ease... (If it 
only weighed a little less... It would be a great way to go for 
Intermediate.)

If you used the hot battery trick... you could probably shave those extra 
ounces (less battery capacity, running at higher C and discharging closer to 
100% drained) and meet the weight....  But if you goof up doing hot 
batteries... you damage the packs quickly.

NiCd/NiMh can withstand somewhat higher temps before they vent or burst... 
but overtemp will destroy any battery.

----- Original Message ----- 
From: "Glenn Hatfield" <randy10926 at comtekmail.com>
To: <nsrca-discussion at lists.nsrca.org>
Sent: Wednesday, August 09, 2006 11:41 AM
Subject: Re: [NSRCA-discussion] Electric/Glow Pros and Cons

>I talked to some of the electric guys at the Nats.  Specifically the one 
>with batteries charging in full sunlight.  They said something about 
>keeping the temp delta small so the batteries would work better and have 
>more cycles.  This make any sense?
>
> Randy
>
> --- richard.s at allied-callaway.com wrote:
>
> From: "Richard Strickland" <richard.s at allied-callaway.com>
> To: "'NSRCA Mailing List'" <nsrca-discussion at lists.nsrca.org>
> Subject: Re: [NSRCA-discussion] Electric/Glow Pros and Cons
> Date: Wed, 9 Aug 2006 11:29:37 -0500
>
> Just how much did Jay PAY for those batts?  And that is part of my 
> point-for
> non sponsored guys-battery care and feeding is a real issue to stretch 
> cycle
> times.  Even if he paid list, it's his job, in effect.  Most of us are
> scrambling to find the best we can for the money and then trying to 
> protect
> the investment.  And many guys don't know there's care required-until the
> batteries shoot craps at 60 cycles.
>
> RS
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org]  On Behalf Of Scott 
> Smith
> Sent: Tuesday, August 08, 2006 6:02 PM
> To: NSRCA Mailing List
> Subject: Re: [NSRCA-discussion] Electric/Glow Pros and Cons
>
> But why keep 'em cool?  I saw Jason sitting in his van with the engine
> running at the Nat's on Thursday with his batteries up on the dash...I 
> don't
> think he had the AC running!
>
> I too am on the fence and have decided to give E a try for next year as it
> will allow me to fly at local turf farms where glow fuel is not allowed.
>
> Anybody interested in a glow Brio?
>
> Scott
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Jay
> Marshall
> Sent: Tuesday, August 08, 2006 6:40 PM
> To: 'NSRCA Mailing List'
> Subject: Re: [NSRCA-discussion] Electric/Glow Pros and Cons
>
>
> Sounds like a foam cooler and a bag of ice should keep them cool.
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Richard
> Strickland
> Sent: Tuesday, August 08, 2006 6:36 PM
> To: nsrca-discussion at lists.nsrca.org
> Subject: [NSRCA-discussion] Electric/Glow Pros and Cons
>
> Just having a debate with myself on the pros and cons for the long 
> haul.....
> Seems like it's been hovering around 95-100F around here since early June.
> I'm not liking the fairly significant batt. temp. rise from ambient. 
> (batt.
> life issues)  The batts have to sit in a fairly hot car all day-charged 
> for
> practice in the evening.  I have to make a decision the nite b4 to fly or
> not the next day to charge.  Batteries are still damned expensive even if
> you get a decent deal and the jury is still out on longevity  Gotta grease
> things fairly often.  Heavy.   But they are cleaner and easier to manage 
> at
> the field.   Glow engines, when driven to the max-like I do-tend to have
> their own share of issues, somewhat messy, and require more field 
> equipment
> at the line.  The bigger units require A LOT of fuel to make all that 
> power.
> But I feel I can fly them no matter how hot it is and not worry about them
> (as much).  Deciding to fly is a matter of just GOING.
>
> I'm just throwing this out there in case anyone else is having similar
> thoughts... ho-hum...
>
> RS
>
>
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