Suggestions for Battery Bank Switching (wind power)

[beatpoet]

Just playing with the idea of having two battery banks for some non-essential DC lighting (LED) on my back porch and for passing through rooms in the house.

My idea was to have two 3 or 6 volt battery banks. To keep the batteries fresher:

1) Each bank would be charged as close to full as possible, then discharged.

2) After Bank A was discharged and Bank B was as full as possible, the full bank would be switched into the main circuit while the wind turbine charged the second bank.

Just a general thought, I'm looking for any ideas for switch topologies with minimal current draw. With the low wind levels around here, a mechanical switch sounds like a good bet, but I know little or nothing about electrically manipulating permanent mechanical switches.

Maybe this'll take my mind off of politics for a while :guinness:

 

[gyraf]

I'm not sure I understood this right - but why not use a bistable relay?

Jakob E.

 

[Gus]

3 or 6 volt what types are you posting about? lead acid is 2 charges at 2.2 to 2.4. Nicad is more 1.25v charges at 1.5 when is good shape.

Solar and Lead acid might be better IIRC you can buy charge controllers at harbor freight that charge and float charge lead acid and I believe even temp compensate the voltage. You keep the lead acid charged and the leds draw little current so you should not deep discharge the cells to much.

I helped a friend design and build a solar charge controller and control for halogen 12 volt lights using lead acid batteries. Still works 15 year later.

With the availability of inexpensive charge controllers I don't think I would build one again. Been thinking of getting one of the solar charge controllers, some panels and using it to charge a battery lawn mower and/or trickle charge the car battery when the car sits for some time.

 

[JohnRoberts]

I think National semi has a new patented technology to better match low output solar cells to charge batteries, who need a positive voltage delta. Probably just a dc to dc switcher, but if they offer cheap chip sets it might help charge from low head wind power too.

JR

 

[Gus]

Funny you posted that. We used a NS chip based dc to dc converter with a wide input range up to 40VDC in and adjusted for the charge voltage we wanted out we did not do any temp comp because the batteries were in a area that the temp was fairly constant.
One half was two panels in series to one NS based switcher even charged a bit on cloudy days the other 1/2 was parallel panels to a NS chip based switcher. The outputs were adjusted and summed with diodes.