ProLiteGear.com shows you how to take a UPS (Uninterruptible Power Supply) and modify it to be a Solar Generator like the GoalZero Yeti Solar Generators. These portable power generators can then be used in emergency situations, for camping, or as backup power at your house. The modification allows them to be recharged via solar panels. The total cost can be much less than the Goal Zero products if you get creative. A fun, practical project, that is not that difficult.
The only modification required is to open the UPS enclosure and splice a battery tender into the wires that attach to the internal battery. This provides a way to bypass the electronics of the UPS and work directly with the battery which is required for recharging the battery while off the grid.
A 3/4″ hole was drilled into the back of the enclosure to accommodate the battery tender.
The battery tender can also be used to connect DC powered devices, bypassing the Power Inverter, and allowing them to draw power directly from the battery. This is more efficient than DC powered devices drawing the power from the Power Inverter.
The practical application is that these can still be used every day to protect your electronics. After the modification they then have the additional functionality of a solar generator.