Connecting two alternators to one battery is a risky operation that should only be performed by someone experienced in auto mechanics. People who want more power than a single alternator can provide sometimes desire to connect two alternators to one battery. Most alternators have built-in voltage regulators that sense battery power. If more than one alternator is connected to the same battery, it interferes with the sensor and shorts out the battery. However, there is a way to override this limitation.
Connect the pulleys and brackets to each alternator using a soldering iron or other temporary method to secure them.
Weave the alternator belts through the pulleys so that the alternators are in effect connected to each other. Use a dual pulley on one of the alternators to allow it to be connected to the other alternator.
Connect each alternator to the brackets on either side of the battery. Start the battery and the alternators should charge. If they shut off, the internal regulator has malfunctioned as a result of incorrectly reading the battery output. In this case, detach the alternators, charge them separately, and then reconnect them when you want to draw power.
