Small Engines (Lawn Mowers, etc.): adding battery charging to tecumseh HM100

Question
Hi! I have a snowblower with a tecumseh hm100 159077g engine, with 12v electric start and a light. I want to add a battery and charging system so i can start it without having to jump it from my car every time. How do i wire a rectifier to the lighting cirquit so i can charge the battery? There are three wires coming from the generator, one is labeled "ignition ground" in the repair manual and two are labeled for "headlights/driving light lights" and "stop lights" respectivly. The current light is connected to the chassis and the two light output wires (which are connected togeather and continue in a single wire to the light). "Ignition ground" is not connected to anything.
I hope my explanation is clear, and that you will be able to help me.
Thanks
Thor

Answer
Here is the service manual address:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCMQFjABahUKEwjllZL7rPPIAhVEzWMKHWetCGk&url=http%3A%2F%2Fwww.asos1.com%2Ftecumseh4hp%2FTecumseh.pdf&usg=AFQjCNHD3fZY0JTAGThMmHaiit6ZNAOz8A&sig2=79HulRdauDtnKe7nwBCPVg&bvm=bv.106379543,d.cGc

Start reading on page 42.  Identify which color wires you have and what each of the wires are, AC volts?  

Do you have a multimeter to measure and check to make sure the AC is working?

Eric