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Old 02-27-2012, 08:41 PM   #6 (permalink)
Daox
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Join Date: Dec 2007
Location: Germantown, WI
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CM400E - '81 Honda CM400E
90 day: 58.68 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
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Daox's Insight - '00 Honda Insight
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Swarthy - '14 Mitsubishi Mirage DE
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I like the system, but I see a problem with only using voltage for your discharge protection. From my experience with the PHEV kit on my Prius, the variance in load and temperature drastically effect the voltage sag. Using at least a set voltage is not going to work. However, if you have enough data to create a variable voltage cutoff based on load and temperature that could work.

What I have done with my BMS system is I have used a current sensor to count how many amp hours have been used out of the batteries. I don't think this a great way to do it (peukert effect obviously effects even lithium chemistry), but its the best thing I've come up with.
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