We try to always offer these on our products page, but if none are available, they can usually be found on Ebay. Although not yet tried, good chance this whole charger would work better with an alternator or an old car generator for reasons which I will explain later. This setup works reasonably well for charging 24 volts, but when hooked to 12 it bogs down the engine too much and it dies. In conclusion, with a well tuned engine and the right pulley combination this unit should do a fine job of charging at about 150 watts. There are certain drawbacks to both this type of engine, and the generator we are using.
Maytag engines are an excellent value where antique engines are concerned.
They are still easy to get parts and support for. The tape drive motor we are using makes a fairly good generator, with the right sized pulley. An improvement might be to use an old car generator or an unregulated alternator and use an appropriate field resistor to properly match the load to the engine.