Wasp-killing zap racket hot rod

I have one of these mosquito-killing zap rackets (they're life-changing—everyone should own a few):

https://www.amazon.com/gp/product/B000MU2MJA/?tag=cpf0b6-20

Today, while trying to do some work around the yard, I was getting murdered by black flies. I wound up zapping an average of several per second for about an hour. It was unreal. Someone else did the work while I actively protected them from flying insects.

Through the smell of burning bug, I would sometimes notice that some of the flies would recover after being zapped and fly again. This is unacceptable. They are unrelenting, and I must put an end to their bloodlines forever.

Aaanyway, does anyone know what I would need to do to increase the power of the zap? Higher voltage batteries? A capacitor that can dish out more current? I'm handy with a soldering iron and/or a high-powered stereo install, but I've never quite taken on a project with the simple goal of increasing the danger of an electronic component...I'm thinking perhaps replace the AA batteries with an 18650, but I suspect other components might need to be juiced up as well. The limiting factor is just...not melting the plastic.

Power goal is to ignite a wasp in mid-air, but I would settle for killing flies dead without having to step on them.

I modified one of these things for a decent increase in power. It wasn't exactly the same model, but might have the same internals.

I installed a bigger capacitor, converted it to 18650, and rewired the switch.

On mine, there's an on/off switch and an activation button. There's a bleeder resistor across the capacitor to drain it when inactive. I rewired that so that it's disconnected when the on/off switch is on, which means it can deliver a shock when the activation button is released but the switch is on. This resulted in a substantial voltage increase.

I had one of those cheap electronic fly swatters from harbor freight and the way they work is there is several layers of wire screens (I think 3) which the bugs have to make contact with 2 of the layers to complete the circuit and get shocked. What can happen is the bug doesn't actually complete the circuit and is bonked by one layer of screen wire and ends up stunned and gets up. Another thing that can happen is the bugs barely make contact between the two layers and just receives a slight shock and bounces off. I've found sometimes you have to really swat hard and fast to get the bugs deep into the swatter so it is stuck there and fried.
Increasing the voltage of the swatter helps for sure but the side effect is if you accidentally get shocked it will hurt a bunch more.

If the unit takes AA, use lithiums for more than max power that stays consistent over the life of the batteries. Yes. A regulated turbo bug zapper.


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A few background points:

1) The old school zap rackets with 1-3 mesh screens tend to be garbage. They're weak and fragile.

2) The Jolt and Enforcer designs (sold under several names) with thick horizontal bars are life-changing and durable.

I'm starting with the second lot. I may already be going too far with this, but...whatever. I believe the racket works by applying 4000v of "static electricity" to the bug when it touches any two adjacent wires.

I opened up the handle to reveal a few capacitors, resistors, diodes, and two components that highlight my ignorance...The racket works by charging up when you hold down the button, and the charge is spent when the button is released (a metal tab makes a different connection at rest), ensuring it doesn't stay charged unless the button is actively held down.

Anyone know what the big black box (filled with resin) and yellow coil are? I'm guessing one is a big capacitor and the other is a voltage multiplier...If I replace them with larger components, might I need to change anything else? It doesn't seem like increasing battery voltage would be all that useful vs multiplying the voltage...more.

Aha, looks like the yellow thing is just some transistor and the black box is a voltage multiplier...This video is handy:

https://www.youtube.com/watch?v=yGR2G4qHm6g&t=3m

This circuit is so simple, and I'm already in over my head with regard to juicing this thing up...

The yellow thing is the transformer (with a primary and a secondary winding under the plastic bobbin and a steel frame built through it. There's even a part number on the board, "T1". The silver box would be the large high voltage capacitor; the board has the symbol for a capacitor printed right in front of the component, although I can't make out the printed part number. If you bent it up, the info is probably printed right on it. The voltage multiplier would be the 3 diodes on the bottom of the board.

I don't know the details of the circuit, it's possible you could get more zap by simply increasing the battery voltage, but more likely, you need a different transformer with a higher turns ratio. It's quite possible the transformer is some generic item that happened to work OK; it's less likely that someone custom makes these just for fly swatters. You should draw out the circuit and post it on EEVBlog.com or the like.

At $25USD, I'd be hesitant to destroy it by experimenting.