The show I’m currently working on has a lot of illuminated props for its Bollywood section. I’m not sure who built them, but while they did a reasonable job, their knowledge of Battery technology and protection is not quite 100%.
The illuminated umbrellas use some simple 12V tape with alternate RGB LEDs for a multicolour effect. They are powered from three LiPo cells in series to give the required 12V via a momentary action switch cunningly positioned on the shaft to be operated when the umbrella is pushed up. (Not reliable.)
The cluster of three cells have the wires soldered directly to the ends (no tags), no overvoltage, undervoltage or balancing circuitry and no overcurrent protection. The charging circuit is just a two pin socket connected across the three cells. I’ve not seen the actual chargers themselves yet.
Apart from all the things mentioned above, the wiring and cells themselves are bunched inside the web of sharp metal that forms the umbrella frame, and to make things worse, during the show they are thrown into piles by the performers as they exit the arena. I’m surprised there hasn’t been a melt-down yet.
Despite all this, the main issues we’ve had with the props has been the failure of the tape due to the amount of flexing and abuse it gets. Most of the repairs have been done by military personnel, but when they get overloaded with broken units or the VERY broken ones we get a bag of them sent up to us to fix.
While the person who made these has done a reasonably good job, and spent a lot of time on them, there are a few improvements I’d make. I might use a different battery technology, pop the charging connector out of the tip, maybe relocate the power supply and switch down to the handle area and include short circuit protection in the form of a PTC fuse.
We whimsically refer to the props as Brollywood.
