I checked the site and I found no real explanation of how it works, under "Technical information" it talks about battery operation mostly. I did not find any reference about how it could send a 90 Amp pulse of 100 micro seconds duration into the battery every 30 seconds. That it is not so easy to do (as mpolli suggests), particualrly to an almost full battery, any equipmet that I know that could do that would cost a lot more than 20 $/euros. I am not saying that it does not work, just that the physics of the thingy do not add up.

My $0.02.

Jl