What the heck are you doing? You say you have a one wire alternator. That would be the battery cable. If a wire or cable goes from the alt to the battery, it will show the same voltage anyplace you measure. It is a known fact that a one wire set up will have problems with big draw accessories like you listed. The sensing is too close to the alt....as in: right inside or none.
Without anything on, and motor at high idle, you need to see approx 13.8 minimum, (14.5 is good) when touching the cable clamp, not the battery post. If not, you got alternator troubles. There is nothing else to blame if the alternator case is well grounded. No paint, no plating, no corrosion, no grease at the bolts.
Do you have an actual one wire alternator or a normal alternator just wired as a one wire? Is it a 10Si? How is it wired? 12V right? What motor? What the heck is a "smaller type battery"? you could actually have TOO small of a battery or a bad battery. Hope it is name brand.
"I checked the voltage on wire connecting to altenator and it’s 36volts can’t understand why I would be getting 36volts" is this the "one wire" the only wire, on the one wire alternator?
CLEAN and wire brush all the battery posts and clamps. Be sure clamps are tight
