This is a battery adapter suitable for Bosch 18V lithium-ion battery packs, which can be used to power devices such as the TS100 soldering station. It has passed the Bosch Pro Core 18V battery test, but it may also be compatible with other Bosch 18V batteries.

In addition to the built-in battery status monitoring function, my design also includes a switchable voltmeter for real-time detection of battery voltage and to prevent deep discharge. To save power, the voltmeter can be turned off when voltage monitoring is not needed. This switch will not interrupt the external load.

The battery is already marked with the positive

Note:

• Please make sure to use the original Bosch battery charger! Do not charge the battery directly through this adapter. Otherwise, it may cause the battery to catch fire or even explode. This adapter completely ignores the temperature sensor connected through the middle contact. The temperature sensor is a safety protection device used by the original Bosch charger during charging and by Bosch tools during discharging.
• If excessive current is drawn from the battery pack or a short circuit occurs, it may lead to fire and/or explosions! I don't have in-depth knowledge about the maximum current allowed by the battery pack. It's estimated to be around 10A, but this is just a hypothesis and likely depends on the size and model of the battery pack. I haven't been able to find any officially published maximum current data for Bosch batteries. Additionally, this adapter completely ignores the temperature sensors used by original Bosch tools to monitor dangerous battery temperatures. Therefore, you need to assume the risk of using this adapter
• The battery pack is not equipped with a protection circuit to prevent the battery from being over-discharged below the safe lower limit, which could lead to extreme instability during charging. Such protection circuits are typically built into Bosch tools. Therefore, you must stop discharging the battery in time before its voltage drops below the safe lower limit. Once the voltage falls below the safe lower limit, the charger may refuse to charge the battery, or the battery may explode during charging. For each 20V battery pack, the absolute minimum voltage may be approximately 5×2.5=12.5V, but please do not hold me
• When not in use, please make sure to disconnect the adapter from the battery to prevent accidental short circuits.
• Using this adapter may void the warranty of your Bosch battery pack.
• Do not let people who do not understand all the above points use this adapter. Do not let children use this adapter.

In order for the cable stress elimination device to function as expected, the width of the circular cable groove must closely match the cable diameter

• Download and install OpenSCAD from openscad.org
• Open the .scad file in OpenSCAD
• Adjust the value of the "d_cable" variable according to the diameter of your cable.
• Click on "Design/Render" to render the image
• Click "File/Export" to export the file
• Import the exported file into the slicing software and print it

The three sheet metal screws are of the size 2.9×9.5mm

The AMP connector should be selected in red or

The voltage meter selected is the XH-028 V4.0 model, which is supplied through the following channels, for example:
https://www.ebay.com/itm/125809771454
https://de.aliexpress.com/item/32828845267.html

It is recommended to drip a drop of hot melt adhesive at the welding point of the voltage meter wires to fix and isolate the red and black voltage meter wires, and prevent a short circuit caused by the wires breaking at the welding point.

The base plate size of the switch is 12×12mm, and the contact spacing is 5.08mm

If you use a voltmeter of a different specification or a switch of a different size, you need to make corresponding modifications to the voltmeter() and pushbutton() modules in the attached .scad file. During rendering, these two modules will be subtracted from the cover plate through OpenSCAD's set difference operation, thus forming the required openings. Therefore, after modifying these two modules, an adapted cover plate .stl file can be automatically generated. If you want to change the distance between the two mounting holes of the voltmeter

Please also refer to my Ferrex
https://www.thingiverse.com/thing:4885569/edit