Sunday, March 6, 2016

We've been learning a new skill, how to test hybrid car batteries. These are for our "new" fifteen year old Honda Insight, of which I've thus far failed to take a picture for the blog. It's in the college's shop, in any case, where my students and I are experimenting on it, trying to learn how the "Integrated Mechanical Assist" or IMA system works.

This is the crux of the experiment, whether or not the hybrid battery "sticks" each of which contains 6 "D"-sized cells, can be re-used. So far two of five are unservicable. We have a set of secondhand sticks coming, which will get the same treatment. The battery needs twenty good ones, which must all have a balanced charge before installation. the little blue electronic devices are "Imax B6" balance chargers, which you can get for a few bucks on the Internet. They're a "smart" charger, and can sense the number of cells in the battery and charge and discharge them appropriately. If we can get three or four amp-hours per discharge from a fully charged stick then it can likely be reused.

The Imax can also cycle through charge-discharge cycles, a process that can be used to "erase" memory problems to which rechargeable batteries are prone. Basically, if some component in the in-car charge/discharge system isn't allowing the battery to cycle properly, the battery develops a "memory" of this failed cycle, and even when the problem is corrected, may refuse to charge or discharge appropriately.

It took a few tries to make sure that the charge-discharge cycle with the Imax was a good-enough test of the battery health, without a clear idea of what we were doing to begin, but once we did three sticks and identified two good and one bad, the difference between good and bad in terms of amp-hour capacity was great enough to give us confidence in the process.

This is a good project because battery technology becomes ever-more relevant in renewable energy, not just in cars, but also for household purposes, with the advent of the Tesla PowerWall and with attacks on net-metering nationwide. If, as pundits like Amory Lovins expect, battery storage becomes the norm for American households, or even just the norm for those households with solar power systems, there will be numerous commercial opportunities opening up for those folks that understand the technology.

The current conservative attack on net metering, which has been at least temporarily successful in Nevada, among other places, is undermined by battery technology, especially Tesla's "PowerWall. If you can't get a decent trade for your surplus power from the grid operator, you may as well just save it up and use it yourself at night and when the weather is cloudy, and if the additional cost to do so is only about three or four thousand dollars, as seems likely based on Tesla's projections, then it's unlikely that this will make solar power uncompetitive with retail grid power anytime soon.

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