[NSRCA-discussion] NiMH Question

[Ron Van Putte]

On Feb 25, 2006, at 11:33 AM, John Ferrell wrote:

> I am not aware of ANY sudden NiMh failures in non hostile  
> environments. The
> failure rate in airplanes (recips) seems to be pretty high. They  
> last a very
> long time in my digital camera. I can keep watch over them in my
> transmitter.
>
> I have not given up on NiMh as a power source in an aircraft but it  
> will
> require careful battery maintenance if it is to be workable.

I've been using a 1650 mah NiMH battery pack in my Futaba 9ZAP for  
the past two years.  I have noted that I get longer service from the  
pack if I charge it at 1/10C.

Ron Van Putte

>
> ----- Original Message -----
> From: "Jerry Budd" <jerry at buddengineering.com>
> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> Sent: Friday, February 24, 2006 11:55 PM
> Subject: Re: [NSRCA-discussion] NiMH Question
>
>
>>> I find the same procedure also works well for NiCad's. If you reset
>>> the peak charger and restart it you will cook the  batteries and
>>> suffer short battery life. NiCad's normally fail shorted and you
>>> have enough power to land. NiMh's normally fail open and you will
>>> need another airplane to go with your new battery.
>>>
>>> That is also why I use NiMh in the transmitter and NiCads in the  
>>> flight
>>> packs.
>>
>>
>> John,
>>
>> Why, if you are concerned about a cell failing "open", is it OK to
>> use NiMH cells in your transmitter but not in your flight packs?
>> They're both single string systems, an open cell failure in either is
>> going to result in a catastrophic failure and loss of aircraft.
>>
>> Are you thinking that the flight environment (flight loads,
>> vibration, etc) is the primary contributor to the likelihood of a
>> cell failing open?
>>
>> Thx, Jerry
>>
>> -- 
>> ___________
>> Jerry Budd
>> Budd Engineering
>> (661) 722-5669 Voice/Fax
>> (661) 435-0358 Cell Phone
>> mailto:jerry at buddengineering.com
>> http://www.buddengineering.com
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>>
>
>
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