RE: 3000Mah Ni-cd pack for 25% Yak-54  
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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> RE: 3000Mah Ni-cd pack for 25% Yak-54
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RE: 3000Mah Ni-cd pack for 25% Yak-54 - 12/27/2007 11:37:18 PM   
rlmcnii


 

Posts: 428
Joined: 7/3/2005
From: Pocomoke City, MD, USA
Status: offline 		Pilot013,
AA, high-capacity (2100-2700mAh), NiMH or NiCd (if they even exist) would probably not be good for a 25% airplane. They are fragile and have high internal resistance. Their fragility makes them susceptible to failure from heat and vibration. The high internal-resistance causes them to loose voltage under heavy loads. Neither case is good for your airplane. And, in both cases they may give a good voltage check under a zero or light load. Neither of these cases is good for your airplane either!

The 4/5A Sanyo 1950 mAh cell is supposed to be very good. Elite makes a 2000 mAh cell that is supposed to be nearly as good as the Sanyo. Although there has been a thread running about the possible problems with redundant packs, many people use them with great success. These packs would be appropriate for a redundant, that is two pack, set-up.

There are certainly a lot of good Sub-C cells available from many manufacturers. Look for a low internal-resistance number. Your observation about larger diameter cells being superior is correct. They tend to have lower internal resistance and probably more robust construction than the high-capacity AA cells. They will maintain rated voltage under load better than the high-internal-resistance cells.

Good luck with your airplane.




(in reply to Pilot013)
       Post #: 26

RE: 3000Mah Ni-cd pack for 25% Yak-54 - 12/28/2007 8:42:10 AM   
Pilot013


 

Posts: 42
Joined: 5/7/2007
From: Sofia, BULGARIA
Status: offline 		Hi!

Well at this moment I am running my plane with a 2000 maH 4/5A Hydrimax 6V bought from Tower Hobbies. They are good ones but U think that the Hobbico voltmeter works incorrectly because the LED's are sparkling all around and I was a bit scared that there could be a problem with the batteries. But I think these batteries should work well for about 1h and 20 minutes.

Best regards!

(in reply to rlmcnii)
       Post #: 27

RE: 3000Mah Ni-cd pack for 25% Yak-54 - 12/28/2007 3:33:04 PM   
pilotpete2



Posts: 1473
Joined: 10/31/2002
From: Lyndonville, VT, USA
Status: offline 		Jim,
AA's at only 2200mAh capacity aren't too bad, bet if you try going up too 2800mAh in a AA Nimh IR can be a real issue. I still fly on 72Mhz with PPM receivers, so voltage drop under momentary load is not a big deal, but the guys flying Spektrum have to have a very solid voltage supply to avoid having the receiver reboot.
Regards,
Pete

_____________________________

"If the woman don''t find you handsome, they should at least find you handy"

(in reply to hilleyja)
       Post #: 28

RE: 3000Mah Ni-cd pack for 25% Yak-54 - 12/28/2007 3:41:22 PM   
Pilot013


 

Posts: 42
Joined: 5/7/2007
From: Sofia, BULGARIA
Status: offline 		Hi!

I am using a Futaba 9CAP PCM modulation. I hope the current batteries will be able to handle the voltage...

Best regards!

(in reply to pilotpete2)
       Post #: 29

RE: 3000Mah Ni-cd pack for 25% Yak-54 - 12/28/2007 3:49:21 PM   
hilleyja


 

Posts: 2184
Joined: 1/7/2002
From: Salem, WV, USA
Status: offline
quote:

ORIGINAL: pilotpete2

Jim,
AA's at only 2200mAh capacity aren't too bad, bet if you try going up too 2800mAh in a AA Nimh IR can be a real issue. I still fly on 72Mhz with PPM receivers, so voltage drop under momentary load is not a big deal, but the guys flying Spektrum have to have a very solid voltage supply to avoid having the receiver reboot.
Regards,
Pete


I'll keep that in mind if or when I go to Spektrum. For now I fly GENERIC 2200mah NIMHs in most of my airplanes. I routinely monitor my RX packs during my flying sessions before and after flights. As a matter of fact most of my charging occurs at the field. I use a Hobbico Quick Field DC Charger MkII -- I prefer it over my Triton. About once a season I will cycle these packs and run them through my CBA.

I routinely use dual-switch/dual-batteries in my 1/4-scale airplanes. If I ever move up to 30%-40% I'll go with the power distribution system using regulated LIPOs.

The picture below shows the configuration I used on my 1/4-scale Hanger 9 Cap 232 a few years ago. I installed a redundant battery/switch configuration; the one tied to the 1500mah battery is an MPI Miracle switch:



Attachments
Click to see fullsize image.
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< Message edited by hilleyja -- 12/28/2007 3:56:58 PM >


_____________________________

Jim Hilley
AMA #671825
RCCA# 758
Twist 150 Brotherhood #14

(in reply to pilotpete2)
       Post #: 30

RE: 3000Mah Ni-cd pack for 25% Yak-54 - 12/28/2007 4:21:10 PM   
pilotpete2



Posts: 1473
Joined: 10/31/2002
From: Lyndonville, VT, USA
Status: offline 		Very nice looking installation
I think a lot of folks get in trouble by not doing that battery check with a loaded voltmeter before every flight, there's no substitute for a proper pre-flight check before every flight. Of course if you have DX7 with "model match" there's no need to check your control surface movements, uh huh
Pete

_____________________________

"If the woman don''t find you handsome, they should at least find you handy"

(in reply to hilleyja)
       Post #: 31

RE: 3000Mah Ni-cd pack for 25% Yak-54 - 12/28/2007 9:05:20 PM   
hilleyja


 

Posts: 2184
Joined: 1/7/2002
From: Salem, WV, USA
Status: offline
quote:

ORIGINAL: pilotpete2

Very nice looking installation
I think a lot of folks get in trouble by not doing that battery check with a loaded voltmeter before every flight, there's no substitute for a proper pre-flight check before every flight. Of course if you have DX7 with "model match" there's no need to check your control surface movements, uh huh
Pete


Roger!!! This is one area I have to pay very close attention to. I usually take 3 or 4 airplanes to the field for one flying session. These airplanes are typically all on different PPM frequencies and I have one transmitter with a synthesizer. So far I haven't lost an airplane because I forgot to switch models and frequency on my transmitter. I've come close a couple of times, even put one airplane in the air with the airlons reversed. It's a good thing it balooned into the air and gave me sufficient altitude to realize the airlons were backwards and time to reverse my brain to that fact -- not a pretty landing but a safe one.


_____________________________

Jim Hilley
AMA #671825
RCCA# 758
Twist 150 Brotherhood #14

(in reply to pilotpete2)
       Post #: 32

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