Peri Hartman wrote:
This is somewhat academic (because the cost for a BMS is still surely
cheaper), but couldn't this be done electronically instead of with
contactors?
Since the current would be zero when the cells are switched from a series to
parallel configuration, it seems that using IGBTs (or whatever) would be
possible.
Yes, but the IGBTs would have a significant voltage drop. A considerable
amount of your power would be lost as heat.
Century-old EVs used big rotary or cylindrical "drum" switches to
reconnect the batteries in various series-parallel combinations for
driving and charging. If you really wanted to go this way, I think a
rotary or drum switch setup would be cheaper, smaller, and more
efficient than contactors or solid-state switches.
The mad scientist in me is envisioning a 100-pole knife switch. :-)
--
ICEs have the same problem as lightbulbs. Why innovate and make
better ones when the current ones burn out often enough to keep
you in business? -- Hunter Cressall
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/projects.htm
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