DC-AC converter

[AshaiRey]

Does anyone have a solution on how to do this?
I have a 12V car battery to drive my garden lights but for some RGB LED lamps that cycle automaticly through colors i need 12V AC of 12VDC with a fair amount of rimple so the controller in the RGB LED lamp can drive it's internal clock with it.

So i need a 12V dc to 12V AC converter.

[Jeroen Bartels]

Isn't it easier to convert 220V AC to 12V AC? instead of converting DC to AC?
Or is there no 220V available?

[AshaiRey]

My garden lighting is a stand alone solar system that works on a car battery which is charged by a solar panel.
Using 220V AC isn't an option