Solar Powered Portable Generator to Recharge my Electric Bike.

We have always wanted to become energy independent. We ware finally able to do it a few years ago when we got our 3 kilowatt photo voltaic system. By then we thought we only needed our electric vehicle to become independent from the oil companies. We got ourselves a XB-700Li Lithium power scooter on August 2008. We advertise the scooter as a Solar Powered in our area. People ask us how we power the scooter with the sun. For people familiar with Photovoltaic systems ask me where the solar panels are. We did think about installing solar panels on the bike but we quickly realized that was not a good idea because of weight and sun damage.
It is a great way to start a conversation. We explain that we have a Photovoltaic System at home. Then they ask me how much is the system. We have to be honest with them. It is an expensive purchase up front. But with all the incentives and tax breaks my system should paid itself off in seven years.
That to must people is too long and risky.
That got us thinking into building an affordable portable photovoltaic generator to recharge our bike. We liked the idea because it serves a dual purpose, it recharges our bike and it is a back up/emergency battery for all our computers. We wanted to stay under 300 USD.
We started with two SunPro automotive 15 watt Solar panels, one Exide Orbital Deep Cycle Non Spillable Battery. We liked the Solar panels because they include a Charger Regulator with each panel. The regulator helps protect our battery from overcharging. We then used our 300 watt DC to AC Inverter we already own. We have no idea how much energy the battery is capable of storing. The most we have drained it from the battery is approximately 400 watt/hour. We had to stop draining the battery because of the low voltage alarm went off in the Inverter. We measured the watt/hour with our Kill a Watt meter. We know the 400 watt/hour number not accurate because there is much current lost in the conversion from 12 DC volts to 120 AC and back to 48 DC Volts. We know there must be a more efficient way. That would involve a direct conversion from 12 to regulated 48 volts.
Does anyone know how much energy those orbital Lead acid batteries hold?

Here is the battery:

He is a closer look at its specifications:

We got the orbital battery because we were told they were easier to store and that it would not spill any acid.

Here are some of the connections, the DC to AC converter and the battery charger regulator that came with the solar panels.

Here are our two 15 watt rated Solar Panels on our roof facing South

We do not ride our bike on long trips. We have only put about 1000 miles in eleven months of owning it. The generator is almost enough for our riding needs. We sometimes use the regular AC outlet to finish charging the Scooter after longer rides.

We will eventually install a second battery and perhaps more solar panels. These solar panels are not very efficient but for the cost they are fine.

We recently found these same SunPro panels on sale at Costco for $250. The package included four 15 watt panels for a total of 60 watts, mounting hardware, battery charger regulator and a DC-AC converter. We though that was a very good deal. You can find a similar deal at eBay.

Harbor freight sells a similar package that produces 45 watts. Here is the link:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90599

Our set up is not perfect and not much electricity is stored but it helps become oil independent on a budget.

Let us know what you think.