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!
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
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!
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!
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!
Step 8: Foam for Padding on the Top of the Batteries
We used an extra square or two of sound deadening foam that we had left over from another project. it's self sticky on the back so we aligned the squares with the middle of the battery, peeled the backing off and squished the top right down on the top of them. it worked great!
Step 9: Add Connecting Straps
We were able to use some of the strappage from the previous battery pack but had to create a stainless jumper between the new batteries as we didn't have a strap that long in the original battery pack. be super careful at this point. you wouldn't want to short out your nice new batteries now!
Step 10: Install in Plane! You're Done!
With quick connects installing the battery in the plane is a piece of cake. You must, however get it approved by an A&P mechanic. Make sure to date the batteries so you can remember when you replaced them last
Now you've got an FAA approved battery set!
Starts like a dream!