Instructables

Replacing NiCad Aircraft Batteries with new Dry cell batteries!

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Picture of Replacing NiCad Aircraft Batteries with new Dry cell batteries!
 When the 15 year old NiCad batteries in your personal G.A. aircraft are starting to die and not charging correctly Here's an awesome Hack that can make your plane crank like it's brand new again!
 
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Step 1: What you start out with:

 A whole bunch of 1.2 ish volt NiCad cells in series they create 24 volts. Many General Aviation planes run on 24V this particular plane is a Scottish Aviation Bulldog produced for the Swedish Airforce for pilot training and emergency combat operations

Step 2: Removing the batteries from the battery Box

Picture of Removing the batteries from the battery Box
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 We found that this project really could be done with one set of hands but it's so much easier with 2. 
First; remove the straps that connect eh batteries to the hotpoints on the side of the battery box.
When these are loose we found that removing the two batteries closest to the hotpoints released the rest of the batteries to be slid out more easily.

Step 3: Removing old batteries part deux.

 get 'em out! remember that they may still have a charge left. in our case still around 23 or 24 volts. keep watches and wrenches and other metal objects away. You don't want your Rolex (or Timex for that matter) welded to a stud!

Step 4: Finally they're out!

Picture of Finally they're out!
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 Now just to remove that little separator panel. we cut down the middle and just broke the spot welded tabs off. 

Step 5: Test Fit New Batteries

 We had new batteries with a metal Jacket. this allowed us to create a padded environment around the batteries without lugging them in and out of the box every time there was an adjustment

Step 6: Cut Packing Foam to fit around the battery cladding

 We used cheap computer box packing foam. the black stuff that cuts really easily and has great vibration reduction properties. Our foam was a little to thick so we had to rip it with a handsaw... well we could have been a little more sophisticated but we were kinda lazy at this point... almost lunchtime...

Test fit the foam...

It looks great! no place for that batt to move!

lunchtime

Step 7: Slide batteries into place and create padding for top of batts.

 a little drop of hot glue  on the inside of the case and we're one step closer to done!
TwinMustang2 years ago
You can also drain the battery until each cell reads less than 0.3V, install a short clip on each, and let them sit for no less than 16 hours. Then, recharge using standard charging methods. Should bring them to life with less hassle. Or better yet, take it to your mechanic, who knows how to utilise this method.
josh (author)  TwinMustang2 years ago
We had some cells that were shorting out internally, and the battery was verymuch over-due for replacement. We fly into a lot of places that have limited or no services. This conversion seemed like the safest option for our application. As the plane is aerobatic we also wanted the added security of a sealed cell.
computerkid3 years ago
Where can one get NiCad or NiMh cells like that?
josh (author)  computerkid3 years ago
The original cells may be available through aircraft restoration and parts houses. Our replacement batteries came directly from Odyssey Batteries http://www.odysseybattery.com/
is this even FAA legal....?
josh (author)  sevenplymaple3 years ago
Yep!
The plane is under the "experimental" classification and all work was completed under the supervision of an FAA certified A&P mechanic.
acemaker3 years ago
I am looking for 3 of those Ni Cad cases. Do you know where I can get a few of them. I want to do this in my aircaft, (experimental) Please let me know if you know where I can get 3 old cases or used batteries I can remove.
Thank you
colyergreg@aol.com
n8267e4 years ago
Please tell me a bit more about the batteries you used? I have an old Swedish Air Force Bulldog - 053 email - wsairshow@earthlink.net Many thanks Steve
lemonie4 years ago
Can we see some more of the plane?

L