Xbee -> solar panel voltage question

I'm afraid that wouldn't really work. If I really have to I can up the voltage a little by buying a bigger solar panel and adding more batteries (costly though and heavy, the goal is to keep it wearable). At 8v it would mean 7 batteries and a either a really big solar panel or a panel that delivers only 50ma.

And if I am able to boost the output over 5v I can use a LM7833 anyway. I am trying to avoid that and see if there is a different solution.

Thanks!