Michael Ross wrote:
I was thinking of an op amp comparator.
You could use an IC, but then you will have to power it. That means
something to convert pack voltage to 5v or so for the comparator. An
EV's propulsion system is noisy, so you'll need filters. The customer
might hook it up wrong; you'll need parts to protect against that. It
doesn't take long before you have a dozen parts.
Complex electronics are the fashionable and obvious solution; but they
really aren't needed or desirable for such a simple function.
You don't have to monitor every single cell unless it's necessary to
know *which one* is high or low. Often, the pack is a monolithic block;
you can't change a single cell anyway (the manufacturer wants you to
replace the whole thing).
I try to start not by picking the parts; but instead by defining the
problem *without* assuming the solution. In this case, the Batt-Bridge
just tells you that *some* cell is high or low. That's all you really
need to know to stop charging or driving before you damage it.
--
Customer: I want a switch to turn on a light.
Engineer: OK; first we have to pick the operating system. Windows or
Linux? And what CPU do we use; how many GHz and Mbytes? Then
the interface; wifi or bluetooth?
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm
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