Connecting the Alternator to your Batteries
The alternator can be connected to your batteries in several ways. The most common is to just connect it at the same point you connect your load. But if you are running a higher voltage battery bank such as four 12-Volt batteries connected in series to make 48 Volts you should consider hooking the alternator to just one of the 12 Volt batteries. The reason for this is that the alternator will not start charging your battery until it is spun fast enough to produce more voltage than the voltage of the battery. So for example in a wind setup using our DC-540 model, it reaches 12-Volts at 150 RPM, but it takes about 600 RPM for it to reach 48-Volts. So you can see it would take a fairly windy day to get it turning fast enough to charge a 48-Volt battery bank but only a small breeze to get it to start charging a 12-Volt battery.
We get a bunch of questions asking how do I regulate the voltage coming out of the alternator. The simple answer is you donít. The battery acts as a regulator and absorbs the excess voltage that the alternator puts out. The same thing happens in your cars charging system. If you were to disconnect the battery terminal on your car while it was running, the alternator voltage output would shoot up dramatically, frying most of the sensitive computer equipment on new cars. So as long as the generator is connected to a battery you donít have to worry about the voltage.
You might want to consider adding a ďStopĒ switch inline with the output of your generator (see diagram below). A stop switch acts as a brake on the generator slowing it down in high winds or helping to keep it stopped while you raise or lower your tower. What it does is disconnect the generator from your battery and short together the output leads from the generator. This causes significant drag. The generator is very hard to turn when the output is shorted. Just use a Single Pole Double Throw switch (SPDT) and make sure its rated for at least 30 amps. Also consider adding a fuse to the output to keep things safe in case of a trouble.