___A rather interesting blog by two of the chiefs CEO and CTO over at Tesla Motors that have a lot of good information on the Tesla Roadsters Li-Ion pack design and capabilities. I hope you enjoy the read as much as I did last week.
A Bit About Batteries (http://www.teslamotors.com/blog1/?p=39) by Martin Eberhard CEO & JB Straubel, CTO. Published on Thursday, November 30th, 2006
04-07-2008, 05:29 AM
I have a question relating to Li-ion batteries. My wifes phone and mine have the same battery (nokia BL-5B) I went with the discharge fully brigade, my wife topped up every day. Eventually, my battery started degrading, and my wife had upgraded her phone so i could try her battery out. It discharges normally to one bar on my phone after maybe 5 days, gives a few low batt alarms, then jumps back up to 3 or 4 bars! It then continues to discharge as normal till empty. Weird.
I guess my point is if we are going to use these batteries in cars in the near future, we need to learn how to get the most out of them by charging and using them properly. God knows they cost enough! Anyway, my question: How do we best look after these kind of batteries?
04-07-2008, 09:43 AM
lithium ions like to remain fully charged. it was the nickel-cadmium types that liked to be fully discharged.
___The Tesla is using what I would consider a poorly thought out Li-Ion chemistry for the Roadster and even with all the protections, it is a disposable. Upcoming OEM PHEV’s are going to have a much more robust pack with much better chemistries and possibly even more robust cel/stack/pack level control for longevity and safety protection. The JCI/Saft, A123System’s, LG Chem Li-Ion’s are truly the next generation and are really that much better than any Cel phone/Laptop battery.
04-07-2008, 11:51 AM
Another killer read...
He also agrees with the fact that cell phone / laptop batteries work BEST when frequently topped off. Deep discharges only hurt them. The chemistry is basically designed to be stupid cheap, hold a lot of energy, and last 1-2 years tops. The devices are replaced so often that longevity barely makes the "concerns" list.
04-07-2008, 11:53 AM
Thanks guys for the responses. I still think is strange what my wifes battery did by going almost empty then (apparently) regaining some charge. I'll keep it topped up from now on and see how it goes.
04-07-2008, 11:56 AM
Hey shifty35, i saw that battery university site a while back and it's the job!! I thought i had it bookmarked but couldn't find it. Plenty of reading to keep me occupied.