This post is for all the nerds out there who keep sending me emails with technical questions. Consider it an update to my 
This post is for all the nerds out there who keep sending me emails with technical questions. Consider it an update to my update.
I designed a new battery holder out of PVC sheet to replace the wooden box used on my first prototype. I also replaced a fried switch with one that has a higher current rating and designed a new wiring harness with quick disconnects. My lead-acid battery pack is already starting to take less charge and I have now relegated it to back-up status.
The parallels between an electric bike and a plug-in hybrid car are very close. These new batteries have taken the bike to a whole new level. The lead-acid batteries do not have the range I need to get to the far corners of Seattle (and back). They also take too long to charge (up to six hours). If I wring them out on a long ride I am done riding for the rest of the day. They also weigh too much. I once dropped the pack on my finger, which emphasized just how frickin’ heavy they are. Like a lot of electric car enthusiasts, I was frustrated for want of a decent battery. It took a lot of time and effort to incorporate these nano-phosphates, but it has been well worth it.
They also have an unbelievably flat voltage discharge curve. As a lead-acid battery discharges, its voltage drops. Your bike gets slower and slower. With these nano-phosphates, the voltage curve remains almost flat until the battery is done. The bike does not get slower and slower. It just craps out all of a sudden when the battery is out of energy. They can also put out the power. According to A123 Systems, they are good for 30C continuous and over 50C in ten-second bursts. Add to this the fact that they do not blow up or catch fire and we are finally on to something here.
I took a few minutes to build a website with pictures of the improvements. You can print them out and pin them on your bedroom walls.
