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Old 06-20-2009, 02:13 AM   #1768 (permalink)
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Originally Posted by wjdennis View Post
Guys, I'm not trying to be persnickety or contrary here. I asked a question that was on-topic, about the controller and its possible use as a charger. My follow-up questions were going to be able how to size the inductor so that when I built the controller I could test it as a charger, too. But I got responses about choosing the right battery pack and energy losses and pack swapping. I've already got my battery pack. My EV goes over 100 miles on a charge. I drive it 88 miles round-trip to work. It just has trouble with sagging on steep hills, and Lee Hart recommended the solution I mentioned, getting a small second pack that could handle the high-demand draws for hills, and have my existing pack supply a constant 70A. Paul's controller seems like a good solution since I'm planning on building one anyway.

I can see your point about the second pack with lower capacity, but higher C rating; but I think the charging circuit is way to complex and unnecessary.

I would have the second pack at the same voltage and just use a single IGBT or a set of mosfets as an on off switch to engage the second pack in parallel with the first when extra current is needed. this could be trigged either manually, or automatically with a simple current sensing circuit.

In essence either it is connected and delivering the additional amperage, or it is not. there is no need for metering a controlled charge if both packs have the same nominal voltage; just supply the additional current as needed.



Mosfets would be much preferred for this circuit as the voltage differences will always be minimal between the two packs.
"Experience is something you get right after you need it !"

Last edited by blackpanther-st; 06-20-2009 at 02:20 AM..
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