Re: Battery charging with intermittant power source

On Jan 8, 7:41 pm, Scott Ronald <scottm...@xxxxxxxxx> wrote:
Hi I am wondering about the best way to charge lead acid batteries from
a source that cannot be relied on for constant power such as wind, or
solar.  So far I am looking at 2 ways to do this:

Cycle charging
For this method I need a constant current, until the charge voltage is
reached, then maintain the charge voltage for a time, or until the
current drops to a minimum, after which I drop to a float voltage.
The difficulty with this is that the charge cycle can be interrupted at
any time, and might be restarted when the battery is partly or fully
charged.

Floating
For this I would set the current limit to the maximum battery charging
limit plus the battery's output current, and set the regulation voltage
  to the lead acid float voltage.  From the reading I have done on this
topic I believe that this will shorten the service life of the battery.

Any suggestions as to how to do this?

Scott

Any particular reason why you just don't buy a charge controller?

For an intermittent source, you need to insure your load is serviced
by undervoltage lockout hardware. I bought some surplus NEMA box
basically for the box, i.e. not what is inside. However, the box
contents were instructional since I've never built this kind of
outdoor gear for a living. The box had a DSC LBCM. DSC is the company,
Digital Security Controls. LBCM stands for Low Battery Cutoff Module.
I haven't tracked down a manual, though the thing is just a relay and
a dozen discretes on a two layer board. Certainly reverse
engineerable. Presumably they limit the battery to a minimum of 10V.

.

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