It should be all right if you set the grips on low and the jacket on mid to low. Already installed the heated grips and I just ordered a heated jacket and a volt meter. I would suggest a volt meter so you can see if your still charging or not. If I run out of power I'll switch all my lights (except headlight) to LED's. If that still isn't enough I'll get some LED running lights and add a switch to turn off the headlight.
Get a good switch for the jacket. Read this about controllers:
http://www.whitehorsepress.com/workbench.php?workbench_id=39&products_id=5902I ordered this switch with my jacket.
http://www.whitehorsepress.com/product_info.php?products_id=5902 I just ordered the jacket for now but will probably add heated socks in the future. I wanted the option of different settings for each. So with this controller not only can you take it on other bikes, when you set it to low it uses less energy than on high. A resistance controller will always use the same amount of power.
One last thing. You said vest. Why just the vest? If your going to be heated might as well get the arms too.