I plug it in 220v, and the transformer explode.it doesn't work anymore.

Damage may be confined to just the power supply if you are lucky.
Logitech Support

You may be lucky enough that the capacitor exploded from the 220 volt charge. You will have to enquire at an appliance repair shop for exact advice. Basically I would junk it and get the correct unit for the voltage and cycles in you area.

1st check the outlette. 2nd check the power cord. 3rd your battery. If its swollen stop charging imeadiatly, it could explode

Internal power transformer or rectifiers. Could also be main power transistors.

No you cannot as 220v will damage the 110v the Logitech. You need a stepdown transformer to reduce the voltage from 220v to 110v. and then you can safely plug the Logitech into this stepdown transformer.

First, check the 220v line and breakers are properly grounded and that you are getting a constant 220v at the plug. Then you will need to check the transformer on the unit.To test a transformer you need to know what type of transformer it is first. There is a step up transformer which steps the voltage up and a step down transformer which steps the voltage down.
You will still test the transformers the same way for step up and step down transformers. If it is a step up transformer apply the incoming power to the transformer or plug it up. Now take your multimeter and place it on the AC volt scale and test the voltage if the voltage on the data plate says the transformer should step up to 220 volts and it doesn't then your transformer is bad.
Now repeat the same steps for a step down transformer. Plug up the incoming or primary power and test voltage on the outcoming or secondary side the voltage should step down to the proper value. If you don't read any voltage on the secondary or outgoing side then the transformer is bad.
To read the voltage place the two meter leads on the secondary side, or the side you will plug your equipment into. If the secondary side is an outlet then place the two meter leads into the top two slots in the plug and read voltage. You also want to make sure the incoming power is working as well. Otherwise you will be reading a bad reading every time.
If all that looks good, then you will need to replace the control board. Here is a link to the parts for your range.
Regards,Richard

With a bit of luck just the internal mains fuse failure. Otherwise could be transformer failure or a verity of other things.

Hi ,
If it says it needs a AC 110V connection , you will fry at least the sub . Don't do it ! Connect the device to an AC 220 / 110 V transformer you can find on the net or in all specialized retail shops .
Best regards

You have damaged the system beyond economical repair. There are so many components inside that have fried that it is impossible to repair. Sorry. That's what happens when you overvolt an electronic circuit.

Hi there the solution for how to mod a DC18RA charger can be found here. The "how to" comes with pictures and descriptions and it should be easy to follow, and best of all it works :)