[NSRCA-discussion] NiMH Question

[Dean Pappas]

I'm glad you still have it!
Like I said, the only NiMh cells we should use for airborn packs are the low-resistance variety.
An entire pack needs to be under 10 milli-Ohms, or so.
If your seller can't give you a cell impedance spec, it's because they don't have anything to brag about.
 
Dean
 

Dean Pappas 
Sr. Design Engineer 
Kodeos Communications 
111 Corporate Blvd. 
South Plainfield, N.J. 07080 
(908) 222-7817 phone 
(908) 222-2392 fax 
d.pappas at kodeos.com 

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Bill Glaze
Sent: Friday, February 24, 2006 5:58 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] NiMH Question


Dean:
A while back, when I was living in Las Vegas and Greensboro, I made a quick trip to Vegas, got in late, and charged, my Extra 300 which had a Futaba radio.  Took the airplane off charge after an all night charge, went out to fly early the next morning. Put the plane in the air and everything was normal except that it seemed slow on ailerons; not much, just a little.  Flew it twice, finally checked the battery, and found a dead cell.  Range was fine, everything was good, except the ailerons were just a tad slow.  As an old-time friend used to put it, "God just gave you your airplane back."  Amen!
Bill Glaze

----- Original Message ----- 
From: Dean  <mailto:d.pappas at kodeos.com> Pappas 
To: NSRCA Mailing List <mailto:nsrca-discussion at lists.nsrca.org>  
Sent: Friday, February 24, 2006 11:47 AM
Subject: Re: [NSRCA-discussion] NiMH Question

Hey Bob,
Remember the old Orbit ads with the picture of someone flying his plane and then showing the battery with one "cutaway" cell?
 
 
 

Dean Pappas 
Sr. Design Engineer 
Kodeos Communications 
111 Corporate Blvd. 
South Plainfield, N.J. 07080 
(908) 222-7817 phone 
(908) 222-2392 fax 
d.pappas at kodeos.com 

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Bob Richards
Sent: Friday, February 24, 2006 11:38 AM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] NiMH Question


>>>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.<<<
 
Some of the old radios (Proline, for instance) had diodes across each cell in the airborne pack, in case a cell went open. Also, if a cell died (lost voltage) it would minimize the problem by preventing a cell from reverse charging.



  _____  




_______________________________________________
NSRCA-discussion mailing list
NSRCA-discussion at lists.nsrca.org
http://lists.nsrca.org/mailman/listinfo/nsrca-discussion

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.nsrca.org/pipermail/nsrca-discussion/attachments/20060227/c2d77d47/attachment.html