[NSRCA-discussion] Batteries
vicenterc at comcast.net
vicenterc at comcast.net
Fri Mar 14 07:29:47 AKDT 2008
My experience last year was very similar to Earl's experience. If you ask me today, I won't use for electric pattern (Master and F3A schedules) less than 5300 mah capacity.
--
Vicente "Vince" Bortone
-------------- Original message --------------
From: "Earl Haury" <ejhaury at comcast.net>
> Chad, you have a point, however it's important to factor in that the 1P
> packs are also generally higher C rating. My view when considering batteries
> initially was that higher cell count provided more failure opportunities,
> both as individual cell failure and connections. I've disassembled a number
> of "failed", or no longer pattern suitable packs, and measured individual
> cell characteristics.
>
> Generally, the cells in a lower C pack tend demonstrate an increase in
> impedance, resulting in lower voltage output for a given current draw over
> their lifespan until no longer "pattern viable". During this time capacity
> diminishes - but most cells with high impedance will still retain 80+% of
> their original capacity. Even though these things generate more heat than
> the higher C packs - they tend to handle abuse (as you've found) partly
> because of the retained capacity and partly because of "performance
> limiting" impedance. Post flight imbalance doesn't change too much as these
> packs age - suggesting a similar "aging" of the individual cells.
>
> Conversely, the high C packs demonstrate very low impedance initially and
> that appears to be retained throughout their life. However, the cell
> capacity appears to drop pretty early and continue to do so over the pack
> life. I've measured some of these with an average capacity loss of 40% after
> 50 flights - that means a 5000 mAh pack is now a 3000 mAh pack. Even worse -
> there is often a good deal of variance from cell to cell. Their low
> impedance will provide little warning (as loss of power) until a cell is
> injured, real easy to do if you try to take 3500 mAh from the now 3000 pack.
> Often one will notice the post flight imbalance increasing as these packs
> age and it will be greater at higher depths of discharge - a sure sign some
> cells are getting weak. OTOH - for blazing power the high C packs are the
> way to go - but there's a price to pay in life, weight, & $$.
>
> These observations have led me to surmise that a pack with a high enough C
> rating to minimize impedance losses (and accompanying heat) and a low enough
> C rating to allow good capacity retention should provide the best value for
> pattern. I have no idea just what construction parameters / chemistry
> defines these characteristics. I chose to try the FlightPower F3A packs
> because they are mid-C rating and 5350 mAh capacity. So far they provide
> good power and generate no more heat than the high C packs I've used. I
> expect that the extra capacity (above 5000) offers a little buffer if there
> is a capacity decline over their life. I see little balancer activity with
> these packs regardless of depth of discharge (say 3000 mAh vs 4000 +) so
> far, time will tell - we're all still learning.
>
> Earl
>
> Team FlightPower
>
>
> ----- Original Message -----
> From: "Chad Northeast"
> To: "NSRCA Mailing List"
> Sent: Friday, March 14, 2008 8:22 AM
> Subject: Re: [NSRCA-discussion] Batteries
>
>
> >I think a huge part of the 5300 Prolites ability to deliver under
> > extreme abuse (I should know! :) ) is in large part due to a 4p config
> > rather than 1p as in the current packs. In a 1p when that cell gets
> > weak its over, in a 4p when a cell gets weak the other 3 in the 4p can
> > help it along for quite a while before they all get weak.
> >
> > I am really convinced that a move to 1p config packs has brought with it
> > lower useful cycle life. I feel you need to be a lot more cautious with
> > the 1p packs than the 4p's, or they will not last you very long :)
> >
> > Chad
> >
> > mike mueller wrote:
> >> Chris Moon and I have bought the new TrueRC 5000 packs. He has been
> >> testing them for the last 2 months. They seem as strong if not
> >> stronger than his FP 5350 pack. The cost is only $110 a 5S pack. I've
> >> bought 4 packs and I'm hoping that they are as good as initial testing
> >> has shown. I also have 2 brand new TP V2 Extreme 10S 5000 packs. All
> >> the packs at the 10S configuration weigh in around 42oz's with all the
> >> connectors.
> >> The True RC packs have a lower C rating but this may be a good thing.
> >> The higher C ratings seem to come at the cost of lower pack life. Look
> >> at the TP Pro lite's many have exceeded the 200 cycle barrier and
> >> still have a decent pack. The TP Extreme's V1's were dying in 50
> >> flights and I have yet to see much better than a hundred flights from
> >> the FP's. From my observation the older TP Prolites deliver plenty of
> >> power for our setups. So I think the TrueRC offerings are going to do
> >> the trick. Dan from True is claiming over 200 cycles on them. I hope
> >> that I can get 100. At the $'s he's getting it will be a huge bargain.
> >> Mike Mueller
> >>
> >> The link is www.flightpowerusa.com
> >>
> >> I need to buy some packs myself. Anybody know if they will be at
> >> Toledo?
> >>
> >> Bob Kane
> >> getterflash at yahoo.com
> >>
> >>
> >> ----- Original Message ----
> >> From: Verne Koester
> >> To: NSRCA Mailing List
> >> Sent: Thursday, March 13, 2008 6:58:32 PM
> >> Subject: Re: [NSRCA-discussion] Batteries
> >>
> >> Hi George,
> >> I'm in the same situation and have decided to go with the FlightPower
> >> 5350's. Even when the 5300's were fresh, I occasionally felt like
> >> I could
> >> use a little more punch, particularly on humid or windy days. I've
> >> competed
> >> with a number of guys that had both the TP 5300's and FP 5350's
> >> who would
> >> switch to the 5350's when they needed the extra power. My plan is
> >> to use the
> >> FP 5350's and change props for different conditions. Nothing is
> >> free however
> >> and you'll pick up 2 ounces in the process. I considered the 5000
> >> mah 10S
> >> packs from both TP and FP but can't afford to gain 4 ounces in
> >> either of my
> >> existing planes. The FP 5350's are the best solution for my
> >> situation. Mine
> >> just arrived this week and won't be flown until the snow melts so my
> >> recommendations come from observations rather than experience at
> >> this point.
> >> I bought mine directly from FlightPower
> >> http://www.flightpower.com . Hope
> >> this helps.
> >>
> >> Verne Koester
> >>
> >>
> >> ----- Original Message -----
> >> From: >
> >> To: "NSRCA List" > >> >
> >> Sent: Thursday, March 13, 2008 12:26 PM
> >> Subject: [NSRCA-discussion] Batteries
> >>
> >>
> >> > Hi All,
> >> >
> >> > I've been flying with Thunder Power Prolite 5300 packs for a
> >> while now and
> >> > they are getting very tired. As they poop out, I'm trying to
> >> decide what
> >> > to replace them with. From what I've seen, the Flightpower
> >> "FAI" packs
> >> > are probably what I'll go with, but if anyone has any other
> >> suggestions,
> >> > please sing out. Also, any suggestions as to a source would be
> >> > appreciated.
> >> >
> >> > TIA,
> >> >
> >> > George
> >> > _______________________________________________
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> >> >
> >>
> >>
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