I want to hook up a wind turbine to re-charge a car battery.   Do I
need to put something between the turbine and the battery to stop it
over charging?  If so, where can I get one?

Hi muggy-ga,

To re-charge a car battery from a wind turbine, you should use a shunt
regulator between the turbine and the battery.

The shunt regulator should be matched to the voltage of your battery
(e.g. 12 volts for the usual car battery) and should have a power
capacity equal to or greater than that of your turbine.

You asked where you can get one, but didn't mention where you are
located. Assuming that you are in the USA, here is a source:

Rutland 910/913 HRS Hybrid Controller
http://www.absak.com/catalog/product_info.php/products_id/892

I trust this provides the information you require. If not, please ask
for clarification.

Regards,
eiffel-ga


Google Search Strategy:

"shunt regulator" wind
://www.google.com/search?q=%22shunt+regulator%22+wind

kestrel600 "shunt regulator"
://www.google.com/search?q=kestrel600+%22shunt+regulator%22

kestrel "shunt regulator"
://www.google.com/search?q=kestrel+%22shunt+regulator%22

sr200 shunt regulator
://www.google.com/search?q=sr200+shunt+regulator


Additional Link:

Kestrel Wind Turbines
http://wind.dynalias.com/KestreL600_300.htm
(scroll down for shunt regulator details and circuit)

Good answer with additional detail

I agree with the answer you received, except for a couple of details:

First, a lead acid 12 volt battery needs more than 12 volts input to
get a full charge.  A typical  controlled charging strategy (found on
high end battery chargers) uses the following recharge strategy:

HEAVILY DISCHARGED BATTERY: CHARGES AT 14.4 to 15  volts to bring the
battery up to 90% of full charge as rapidly as possible.

MODERATELY DISCHARGED BATTERY: Charges at 12.9-13.6 volts

If you regulate your charge voltage to just 12 volts, you will NEVER
fully charge your battery!!!

FULLY CHARGED BATTERY: MAINTENANCE CHARGE: 12.5-13.2 VOLTS

At the maintenance charge voltage you can leave a battery on charge
"forever" without damage to the battery.

ALSO: Even though a shunt WOULD fulfill the requirements of limiting
the voltage, it would be easier just use the field of the alternator
to regulate the output.

SOURCES: http://econofix.com/battery.html  http://econofix.com/alt.html

I agree with what veconofix-ga has said about needing to charge a lead
acid 12V battery with more than 12 volts.

Nevertheless, you can still use a "12V" shunt regulator as this is a
nominal rating and it will allow the battery to charge at a suitably
higher voltage (typically around 13.6 volts).