A couple of days ago when temperatures here reached 105 in the shade, my wind turbine’s permanent magnet generator was damaged. The magnets were subjected to temperatures (180 degrees or more) such that voltage produced has dropped from thirteen or more to nine or so at the same turbine speed. I have a deep-cycle battery array of four six volt batteries hooked (of course) in series-parallel. I’ll build another generator (I was designing another turbine, anyway) but meanwhile I’m wondering if there is an electrical control device - relay and sensor - that I could use to charge one battery at a time, switching as each battery reaches full charge.

Obviously and with my generator capacity what it now is, I'd like to charge one six volt battery at a time. Is that possible?

  • \$\begingroup\$ I am not quite sure what you are asking. Are you saying you now have a generator that can only produce nine or so volts, and you want to still make use of it, by charging six volt batteries (however connected)? \$\endgroup\$ – Bobbi Bennett Aug 12 '13 at 21:15
  • \$\begingroup\$ Surely, the basic story here is to avoid taking full load from the wind generator should temperatures of the permanent magnet (rotor?) exceed a certain level. \$\endgroup\$ – Andy aka Aug 12 '13 at 21:17
  • \$\begingroup\$ Hoping that I'm doing this correctly, yes Bobbi Bennet, that's correct. I'll build another generator shortly, anyway, one with considerably more output and a new contra-rotating turbine, but I hate to throw away these magnets. And Andy, I've also designed a shield that will protect the generator from the sun (something I should have done in the first place, obviously). \$\endgroup\$ – Hal von Luebbert Aug 12 '13 at 21:43
  • \$\begingroup\$ I took the liberty of suggesting a different title for your question. Most folk would want to answer how to fix the overheating problem, not the re-use of the damaged generator. \$\endgroup\$ – Bobbi Bennett Aug 12 '13 at 23:31
  • \$\begingroup\$ Would you be keeping them in the same series-parallel arrangement? \$\endgroup\$ – Oli Glaser Aug 13 '13 at 1:01

Generally, it's a Bad Idea to put batteries in different states of charge in a series/parallel battery pack, which is basically what you're proposing. You really want to have all the batteries in your pack at the same state of charge at all times.

What you really need here is a charge controller (basically a DC-to-DC boost converter) that takes whatever voltage is available at the output of the generator and converts it to the bus voltage of your battery pack.

  • \$\begingroup\$ I'm a little tentative about what I'm permitted to say or ask here, but in response to "Oli Glaser" (14 hours ago), Yes, I would continue to use series-parallel unless advised otherwise (I intend eventually to have 24 batteries in my array and an array of solar panels - enough to power the entire house). \$\endgroup\$ – Hal von Luebbert Aug 13 '13 at 15:27
  • \$\begingroup\$ Also, "Dave Tweed," I mean this to be a temporary arrangement, that due the fact that I need to keep an air supply to my aquaponic garden fish. Well aware of the problems with batteries with varying charges, I've been looking for a step-up converter, and have asked the manufacturer of my charge control about compatibility with a converter. It's the details with which I need as much help as I can get. \$\endgroup\$ – Hal von Luebbert Aug 13 '13 at 15:29

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