Satnav for bike

I have tried to use google maps on my bike around the streets a couple of times but it doesn't seem to work very well. It stops giving directions often although it does show where you are on the map but the voice disappears. I find this to be the case when I use it as a satnav when I am walking as well.

Anyone have experience of using google maps on your bike? Is there a better directions map for android than google for cycling on road?