I have only experimented in placing the output in parallel. And have not tried series yet, but it will be something I will be experimenting with in the future. I will also be trying a 12 volt solar cell I purchased from Harbor Freight and will be posting my results. I will be posting any results as I come to them. As far as charging batteries. I recently charged a Ni-MH AA for about 120 seconds and it lasted 10 hours in a small low current digital clock. It was a cold charge. Everyone's experience will probably vary so take your time and don't be afraid to experiment with charging times. Always take precautions and take a meter and monitor the charging process so you can be safe. I found that one fan running through a large cap, even this small of a fan had high voltage so be careful. But it seems to mirror the load i put it on, in other words if i put it on a 9volt battery it will drop down to the 9volts. I cant really explain why. Please post your results, I'm interested in everyones experience's and data. Ive had very good experiences with this thats why I tried to show how to build this quickly and inexpensively so everyone can try this and share data. As far as putting through a inverter and running a bank of batteries i have not tried that yet. You can charge a 12 volt battery and then take the battery off the fan and run a inverter, that i have tried and got 110. Its all a learning process so please feel free to experiment and let us all know your results. Again please be careful. We hooked this directly up to a small mp3 player and it took it out. So be careful what you connect to it. Luckily it was a junk mp3 player so no loss. But i have charged batteries and placed the batteries in other mp3 players and got the free energy through the charged battery. Its all a learning process and please keep us informed of your progress