Modding an electronic device to run off AC instead of Battery

Thread Starter

007craft

Joined Mar 13, 2019
1
Hello. I have an electronic device here that I want to mod so it runs off AC, instead of the battery pack. Its a Keon (Sex toy, ha) that is powered by a motor, connected to a controller. I opened it up and it looks relatively simple. See pictures below.

Overall Unit. Battery on the left, Motor on the bottom, mainboard on the right and buttonboard up top.

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Closeup of the battery (14.8V) 700mAh rated
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The mainboard. Bottom left is the battery connection. Bottom right is the motor connection (It connects to another little board under the motor). Right side is 2 LED connections on the front of the unit and a connection to the buttonboard.
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the buttonboard. This is the power/mode button and the charging port.
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So the thing about this device is that it does NOT work while charging. Once the battery is dead, you need to charge it before you can operate it again. I want to simply remove the battery (Or leave it in) and replace it with a barrel plug to connect to an AC adapter. Is it that simple, and then I just use an AC-DC power brick with outputting at around 14.8V (I have a switching power adapter I can set to 15v, 2.4A)?

I read about a similar mod somebody did for a seperate device that wouldnt work while charging (Read here: https://www.element14.com/community/thread/49891/l/replacing-a-li-ion-battery-with-wallpower) and it was suggested to add a 1000 uF capacitor onto the line to handle any peak currents. Should I measure the batterys output to the mainboard while the unit is in use? I don't have my multimeter on me just now but will update the post with readings once I get it.
 

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Azlan3892

Joined Jul 1, 2021
3
Just FYI - I looking for mod Keon as well - replacing the battery completely with barrel plug will work without issue in this case.
For power source, you will need 14.8v-15v and 3A(or more) power source and two 2000 uF capacitor to line to handle peak currents.
The battery only has 2 pin connect to the board. The charge method is using USB 5V step up to 14.8V for charging, therefore after you replaced the battery with barrel plug, you will need to seal the USB plug with tape to ensure it will not short the circuit.
 

Papabravo

Joined Feb 24, 2006
16,775
There many possible solutions for this, but I think the biggest challenge might be finding or fabricating a suitable transformer. A lot depends on how you want to arrange and package the components that you select. do you have any thoughts on that score?
 

Azlan3892

Joined Jul 1, 2021
3
There many possible solutions for this, but I think the biggest challenge might be finding or fabricating a suitable transformer. A lot depends on how you want to arrange and package the components that you select. do you have any thoughts on that score?
I didn't use transformer as it will turn a wireless devices into a wired devices, which kind defeat its purpose.
For me I actually using an old laptop battery with regulated 14.8v output, it works wonderfully well without too much trouble and quadruple default battery capacity. Side bonus, this mod also lower the device temperature as well. The default battery came with the unit heat up very quickly, if run it at full max it will become as hot as room temperature+20°. My devices will heat up much less using external battery instead of the battery hidden inside.

I think using four 18650 running in serial with some protect circuit(or just use protected 18650 with ) will work well for this case well.
 
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