Conclusion

While the Instant Power Charger works great with cell phones, it makes a poor candidate as a recharger for the Visor. The PowerCartridges that the IPC uses are just too expensive for the amount of recharges that they provide. Perhaps with time the PowerCartridges will come down in price, but for now, the IPC is just too expensive to be worthwhile.

Update: Electric Fuel felt that I was remiss in comparing the IPC to the Emergency Charger, so here are some points they wanted me to mention:

1. The effective charge delivered by our PowerCartridge is at least double that of 4 AAs. (after a 2 hour charge by a set of AAs the charge current goes below 200mA. This leads to a very slow charge process and also will not support the operation of a device with an empty battery, especially with high drain applications (visorphone, MP3 etc.) The PowerCartridge delivers ~400mA for the its full 6 - 7 charging hours.) This is quite important when you consider the circumstances a person will use this type of product.
2. For a full kit (including batteries), the IPC's SRP is presently $19.95 while the EC costs ~$40. It will take quite a few uses to recoup this initial outlay.
3. The convenience of the LED charge indicator and having the batteries prefitted should also be considered.