[NSRCA-discussion] AAA NimH batterys

[Ron Van Putte]

On Jan 28, 2006, at 9:10 AM, Ed Miller wrote:

> Making weight isn't a problem. My EMC2 currently weighs 4815 grams. 
> Just
> looking for that elusive 4799 marker and keep plane durable and 
> maintenance
> free. Tank is already light, Kraft 16oz at 57 grams and don't want the
> possibility of filling the fuse with fuel in the event the coke bottle 
> tank
> leaks.  I'll leave my 5 cell, 2/3A, 1100mah NimH in place. I think I've
> found an area I can get those last 16 grams.......Thanks to all that
> convinced me the AAA NimH pack is not the way to go.

My experience is that the 2/3A 1100 mah NiMH batteries are very 
reliable.  In fact, that's what is in the Radio South Pro Driver II 
(the little yellow one).  On the contrary, I have had problems with the 
AAA 700-730 mah NiMH cells.

Ron Van Putte

> ----- Original Message -----
> From: <jivey61 at bellsouth.net>
> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> Sent: Saturday, January 28, 2006 8:49 AM
> Subject: Re: [NSRCA-discussion] AAA NimH batterys
>
>
>> All.......
>> You are sacrificing safety for weight.....not good. Stick with a good
>> capacity battery and remove the on-off switch and harness this will 
>> save
>> you
>> 1 oz +.I did this just for Nats for 6 flights......made weight and it 
>> is
>> safe.
>> By the way I am still experimenting with coke bottle tanks.These save
>> 1-1/2
>> oz versus tettra.  I have a 32 oz bottle filled with fuel in the 
>> shrinking
>> process,for 2 months now. It has shrunk 1/4 inch in diameter.My hopes 
>> are
>> that when it stops shrinking it will be 24-26 fluid oz which works 
>> with
>> the
>> thirsty DZ. Hope it doesnt leak and I will tell results later.
>>
>> Jim Ivey
>> ----- Original Message -----
>> From: "Jerry Budd" <jerry at buddengineering.com>
>> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
>> Sent: Saturday, January 28, 2006 4:02 AM
>> Subject: Re: [NSRCA-discussion] AAA NimH batterys
>>
>>
>>> For the 2002 Nats I switched to a AAA 700 mAh NiMH battery pack to
>>> make weight.  While practicing at the Kokomo field I discovered that
>>> the pack was good for about 1-1/2 flights (don't ask me how I know
>>> that!).
>>>
>>> Fortunately, I got control back (well - partially) after the 1-1/2
>>> downline snap and was able to coax the plane back onto the ground.
>>> Not fun.
>>>
>>> At the post-flight debrief I figured out that the AAA cells simply
>>> had too high of an internal impedance to deliver enough current to
>>> keep the voltage above the receiver/servo cut-off level when all the
>>> servos needed to move at once.  I was using JR 7000 Super Servos for
>>> aileron which went slow/shut off at 4.6V whereas the other JR servos
>>> kept on working down to 4.2V.
>>>
>>> Jerry
>>>
>>>
>>>> Ed is right.  The smaller the cells the higher the internal 
>>>> resistance.
>> Run
>>>> them down to 20% remaining capacity and put a heavy load, like 5 
>>>> Amps on
>>>> them and read the voltage.  You will probably not like what you see.
>>>>
>>>> Jim O
>>>>
>>>>
>>>> ----- Original Message -----
>>>> From: "Ed Alt" <ed_alt at hotmail.com>
>>>> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
>>>> Sent: Thursday, January 26, 2006 3:06 PM
>>>> Subject: Re: [NSRCA-discussion] AAA NimH batterys
>>>>
>>>>
>>>>>  Ed:
>>>>>  You might get disappointing results due to the inherently high
>> internal
>>>>>  resistance of NiMH.  Going with AAA cella and such a low capacity
>> might
>>>> mean
>>>>>  that you don't get as many flights as you expect before a voltage
>>>>> test
>>>> under
>>>>>  load dips below an acceptable value.
>>>>>
>>>>>  Ed
>>>>>  ----- Original Message -----
>>>>>  From: "Ed Miller" <edbon85 at charter.net>
>>>>>  To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
>>>>>  Sent: Thursday, January 26, 2006 9:05 AM
>>>>>  Subject: [NSRCA-discussion] AAA NimH batterys
>>>>>
>>>>>
>>>>>> Is anyone using AAA NimH batteries for a RX pack ??. I am looking
>>>>> at
>>>>>> Batteries America ( EHYOST ) and they seem to have AAA NimH's in
>> 720,
>>>> 800
>>>>>> and 900mah ratings. I currently use their 2/3A 5 cell NimH pack at
>>>> 1100mah
>>>>>> and a weight of 3.85 ounces complete with the long lead I have on
>> the
>>>>>> pack.
>>>>>> Going to their AAA 5 cell pack looks like I can save about an 
>>>>>> ounce
>> or
>>>> so.
>>>>>> Mah isn't an issue, I can get in excess of 7 to 8 flights on the
>> 1100mah
>>>>>> pack I use now before charging so going to 900mah shouldn't be a
>>>>> big
>>>> hit.
>>>>>> Don't suggest Lithium anything as lighter, want to continue to use
>> my
>>>>>> Alpha
>>>>>> 4 charger and am not convinced those new batteries are safe.
>>>>>> Ed M.
>>>
>>> -- 
>>> ___________
>>> Jerry Budd
>>> Budd Engineering
>>> (661) 722-5669 Voice/Fax
>>> (661) 435-0358 Cell Phone
>>> mailto:jerry at buddengineering.com
>>> http://www.buddengineering.com
>>> _______________________________________________
>>> NSRCA-discussion mailing list
>>> NSRCA-discussion at lists.nsrca.org
>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>>
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