Introduction: Rechargeable Battery Hack for Autonomous Toy Truck

In this instructable, I will show how I will share by 40v rechargeable batteries to my future autonomous toy truck.

My target voltage is 5v and 12v. 5v to power the light bulbs. 12v is to power microcontrollers ESP32, Arduino and Raspberry Pi. Therefore, a buck DC-DC converter is needed to bring down 40v to lower voltages.

Step 1: Background

Oftentimes, you wished you could share the rechargeable batteries with your existing power tool rechargeable battery to power your new project. In my case, I like to power my 1/6 scale RC truck.

Different brand or size of battery all have different dimensions and specification. In my humble opinion, there is a need to find an easy and low cost solution to extend the use of our rechargeable batteries.

There are many alternatives:

* 3D print the body and attach the contact.

* Bid a used charger and cannibalize the top part. Remove the electronics, AC cable and transformer. Add power connector and an on/off switch.

* Laser cut and glue panels to replicate the top portion... the battery holder. Add power connector and an on/off switch.

My favorite solution is the 2nd option but I have to be patient to get a good bid price. For now, I will have to settle for the 3rd option.

Step 2: Laser Cut Panels

As you could see, I laser cut 3 panels.

* The bottom panel with locking slot and 2 holds to contact the ground and +40v terminal on the battery.

* The middle panel which is slide wider than the top panel.

* The top panel catch the battery.

* I would stack them and glue them together and/or use 1/4" bolts and nuts.

Step 3: Fit Test

Before I glue them and bolt them together, I checked the fit and latch.

They seem fine.

Next is to made the contact.

Step 4: Corel Draw File Version 15

Step 5: Next Steps.

I will append this instructable when I get the contact / terminal and switch completed.

There are 4 terminals. You want to tap the ones labelled + and - to get 40v.

I was told Terminals T1 and T2 are used by the charger for safe charging operation.

When I finally get my modified charger to a battery dispenser, I will append this instructable as well..

Alway observe safety. 40v could still produce shock. I suggest to build a case to the bottom to secure the wirings and contacts below.