How To Test Generator Voltage Regulator On Simplicity Garden Tractor

ItÃ¢ÂÂs been a while since I posted here. I bought my Simplicity Conquest garden tractor (which has a 20 HP Vanguard engine) 10 years ago based on a recommendation from this site. It originally came with an 18 HP Vanguard but I learned the hard way that mice love to build a comfy nest in tractor engines over the winter and the engine subsequently cooked the following spring from over heating. One of the guys on this site suggested I contact Small Engine Warehouse to get a good deal on a new engine which I did and at a terrific price and the new engine was actually the 20 HP Vanguard. ItÃ¢ÂÂs been a fantastic tractor but I recently acquired an electrical problem. A few weeks ago I was cutting my field when the battery warning light came on. I kept going and after a short while, another warning light came on indicating an electrical problem. A few minutes later both the fuel gauge and electrical warning light went out so I was obviously electrical power. Obviously things were deteriorating so I shut down the mower deck and returned to the garage. When I got there I tried to turn the deck back on but it wouldnÃ¢ÂÂt start up because the electrical power was so low. I shut down the tractor and checked the battery with a gauge and to no surprise found it almost totally dead. I charged up the battery, and everything started up normally including the mower deck so I went back out to continue cutting. After about HALF AN HOUR the exact same thing happened again and in the same order. I took the tractor into a local Massey Ferguson dealer who to make a long story short determined that the problem was the voltage regulator. They also advised me that the voltage regulator was back ordered at Briggs and Stratten which means who knows how long it might take to get one. I contacted good olÃ¢ÂÂ Small Engine Warehouse again who fortunately had one in stock which they sent to me by UPS and it was installed by the MF dealer. I cut grass again and things were fine after between 4 ÃÂ½ to 5 hours of cutting. I went out the next day to cut some more, the tractor started up just fine but after about half an hour the exact same thing happened again. I recharged the battery and it was back to normal but I know if I went back out the same thing would happen again. It has been suggested that the problem could be a problem with the new but possibly faulty voltage regulator which I hope would be the case because it would be a simple matter of installing a new one and that would be the end of it. I would hate to buy another one if I was to run into the same problem again in which case I perhaps would have purchased two voltage regulators if the problem was something else entirely. A problem with the magneto has been suggested but also as highly unlikely as apparently that is a very rare occurrence. Does anyone of you experts out there have any ideas what the problem might be? Any advice would be gratefully appreciated.