The only problem I'm aware of on the single wire alternator is that the engine has to be revved to ~1200 RPM or higher to get it to charge when you first start the engine, after that, it works just like a three wire and charges at idle. In normal driving, even if you didn't intentionally rev it to get it charging, you would get it charging just going up through the gears. Any alternator can discharge the battery if the diodes leak.
