On Thu, Jun 13, 2013 at 7:40 AM, Lee Hart <[email protected]> wrote:
> David Nelson wrote: > >> With LiFePO4 cells all you need is a charger which can terminate on two >> values: target voltage followed by target minimum current. Nothing else is >> needed. >> > > That's the simplest way to do it. And, it works equally well for > lead-acids. > > The trouble with such a simple charging algorithm is that the charge rate > is slow, and you don't get maximum life. Sometimes that is important to > people; other times it isn't. I assume you are referring to it being slow for lead acid batteries because that isn't the case for LiFePO4 cells. Assuming of course that the target voltage is above 3.4V. Let's face it; battery charging is a murky science. The field is awash with > bad advice, old wives (mechanics) tales, anecdotal stories, and "experts" > who never measure anything. It's hard to find factual evidence and real > test data! > > And people who have measured things and don't publish their results or who publish their results with insufficient information that no one can duplicate what was done with any reasonable measure of certainty. > If possible, we should strive to include enough details so others can tell > if what we did in our tests applies to their situation. > In addition, people need to carefully read everything that was posted and not generalize the information to cases that don't apply. For example, I have a 200Ah pack which sees at most 500A momentary peak currents. This is under the rated peak current of 3C. If someone were to get a pack of identical build cells but only in a 40Ah size and run everything else the same they might argue that their pack didn't last very long and that my methods are all wrong while ignoring the fact that their pack saw significantly higher currents and likely 4-5 times the number of cycles. -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20130614/e25240b4/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
