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NMH TX Packs - 7/21/2008 1:39:54 PM   
Skyflyer



Posts: 245
Joined: 3/11/2002
From: Seaford, DE, USA
Status: offline 		I'm certain the battery gods are against me!
I recently purchased a 2700MAh nickel metal hydride pack (Sanyo) for my Futaba 9c transmitter. I hooked it up to my Astroflight 112 Deluxe and began charging it at about .50 to .75 MAh rate. I don't remember the numbers, but the display read that the pack was peaked after a couple hundred mille amps. I then set it to discharge in order to recycle. It discharged somewhat, but now, I cannot get the #*&% pack to accept more than a few minutes charge at even .50 rate without the charger "peaking" and I can't get it to discharge at all. What do I have to do with this blasted thing to get it operate as it supposed to?
Thanks, guys.

Jerry
       Post #: 1

RE: NMH TX Packs - 7/21/2008 2:32:06 PM   
BarracudaHockey



Posts: 10531
Joined: 7/13/2003
From: Orange Park, FL, USA
Status: offline 		Charge it on a wall wart charger for 24 hours or so. You might have damaged it, they should be given whats called a formation charge, I think its C/10 for a day or so, in your case that would be 250 mili amps or so (.25a) and takes 2 or 3 cycles for it to come up to capacity.

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(in reply to Skyflyer)
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RE: NMH TX Packs - 7/21/2008 2:51:16 PM   
Skyflyer



Posts: 245
Joined: 3/11/2002
From: Seaford, DE, USA
Status: offline 		Congratulations! You have succeeded in confusing the bejeezus out of me. I'm afraid I don't understand any of your esoteric jargon...and I sure as hell am not gonna buy any more gadgets (warts or otherwise) that will only compound the confusion and not power my radio.

What does tee me off about these batteries sold nowadays is the total absence of any sort of instructional material. Are we supposed to be born with the knowledge? Take a special course?

(in reply to BarracudaHockey)
       Post #: 3

RE: NMH TX Packs - 7/21/2008 2:56:05 PM   
BarracudaHockey



Posts: 10531
Joined: 7/13/2003
From: Orange Park, FL, USA
Status: offline 		http://www.rcbatteryclinic.com

C rating deals with capacity. You have a 2500 mah battery so 1 C is 2500mah or 2.5 amps C/10 or C divided by 10 in your case is .25 amps or 250mah


A wall wart is those little chargers that come with the radio. So dig out your wall charger, plug it in and leave it sit for 18 to 24 hours and run it in the radio or discharge it on your charger to 1.1 v per cell. Then do the wall charger thing again and discharge it.

Then see how much your fancy charger puts back in.

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Andy - Helicopter Forum Moderator
AMA 77227 http://www.jaxrc.com

(in reply to Skyflyer)
       Post #: 4

RE: NMH TX Packs - 7/21/2008 4:07:32 PM   
Skyflyer



Posts: 245
Joined: 3/11/2002
From: Seaford, DE, USA
Status: offline 		Ah...I can do that! I'd been told not to use a Ni-cad charger for NMH, but at this point, I'll try it.
Hmmm...Wall wart...never heard that one before. Thanks a lot, B.H.

Jerry

(in reply to BarracudaHockey)
       Post #: 5

RE: NMH TX Packs - 7/21/2008 8:34:17 PM   
rctrax



Posts: 597
Joined: 5/11/2002
From: Mosinee, WI, USA
Status: offline 		The art of breaking in a new battery is a lost art these days. Too manypeople buy a battery and take it home and put it on a charger at it's given c rate and procede to fry it. they need to be slow charged and cycled down for the first two or three times to form the pack for it'soperating capicity before using it. If they would only just slow charge it the first time and go ahead and use it it would be better. Putting it on a fast charger the first time for it's initial charge will just fry it

(in reply to Skyflyer)
       Post #: 6

RE: NMH TX Packs - 7/21/2008 9:26:00 PM   
rcairflr


 

Posts: 575
Joined: 9/2/2004
From: Wichita, KS, USA
Status: offline 		Now that you are dealing with larger batteries, it is time to throw the walwart in the trash and get yourself setup with chargers that are up to the task.
For FORM charging I use is the Siruis pro Former. (see link below). It can be used to Form anything up to about 6000mA packs.

Now on to Form charging. Charge your battery at C/10 (250 mA) for about 14 hours. Discharge at C/5 (500mA) to a voltage of 1 Volt/cell. So if you have a 5 cell pack that would be 5.0 Volts. Do this 3 times and then your battery will be Formed and ready for use and fast charge rate.

During the initial Form charges I monitor my battery to make sure it does not get hot. You can also put a fan on it and then it won't get hot.


http://www.chiefaircraft.com/rcmsec/Models/Accessories/BatteryChargers/Sirius.html

(in reply to rctrax)
       Post #: 7

RE: NMH TX Packs - 7/22/2008 3:41:56 AM   
Skyflyer



Posts: 245
Joined: 3/11/2002
From: Seaford, DE, USA
Status: offline 		Gentlemen...thank you, one and all!

Jerry

(in reply to rcairflr)
       Post #: 8

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