Razor Kart Battery Conversion.

Set of printed parts to allow the use of a specific set of lawn
implement battery packs on a ride-on toy/kart.

How safe is this? That's entirely up to you.

Converted one older version found on the curb, and one newer
one that i bought relatively cheap. Parts fit either model.

Battery contacts are .80mm/20awg/.32in. copper sheet trimmed
with a shears and sanded to shape. Used a steel feeler gauge to
chase the slots before inserting the copper contacts. One set of contacts was
soldered individually (before installation), the other i formed around a
bit of steel as a mandrel. They were installed with a little heat from the
soldering iron. A very little heat, once they move set aside the iron and
seat them with a pliers, makes a tight sturdy fit. Anything that looked
exposed got potted in hot glue.

Other fitments as necessary, 80mm 24vdc fans from an office printer
provides cooling as the controller here is 24v and is getting up to
40v. Hot glued some closed ce