Ive got a 1962 Chevy P.U. with a 261 Cu.In.moter. I switched out my old genirator for an alternator. Now i cant seem to keep my batterie charged especialy when i put the lights on.

Looks like to Nova with 300 horsepower versus 150 for the Corvair.

1962 Chevrolet Corvair Series Specifications

Concept Carz https://www.conceptcarz.com > chevrolet-corvair-series

The 1962 Chevrolet Corvair Series measures 180.00 inches in length, and has a wheelbase of 108.00 inches. 1962 Chevrolet Corvair Series. Article · Image gallery ...
Weight: 2350 lbs ' 1065.942 kg
Drive Type: Rear Wheel
Engine Location: Rear

Chevrolet Chevy II / Nova

Wikipedia https://en.wikipedia.org > wiki > _Nova

A 327 cu in (5.4 L) V8 was available with up to 300 hp (220 kW), suddenly putting Nova SS performance practically on a par with the GTO, 4-4-2, and 271 bhp ...
Model years: 1962-1979; 1985-1988
Manufacturer: Chevrolet (‎General Motors‎); ‎NU...‎
Production: 1961-1979; 1985-1988
Class: Compact (1962-1979); ‎Subcompact‎ ...‎ ‎History · ‎Origin · ‎Nova SS · ‎International Novas

Ok try getting it to a repair man

Sounds like the alternator is faulty! Check alternator is charging properly!

A four pin trailer wire won't charge it. But the bigger one ( I believe a seven pin/ round connector) will if it is wired right. You would need a 10 gauge wire to feed the B+ side of the trailer battery from the alternator. Also make sure the ground is good.

Could be. You would need to check for power at the battery cable post on the starter, and also on the small wire coming from the key switch.

how old is the battery

Sounds like its a bad voltage regulator that will cause it to over charge.

Go to an auto parts store and buy a load tester for the battery. It doesn't cost much and sometimes if you bring the battery there they will test it for you with a load tester. It may have a dead cell which won't allow it to hold a charge or put out enough power. If you need a battery, some shops will install them for free. Good luck.

this junction box! i think this may be an external regulater for the altenator and if so it may need replaced check it out!

you need to put a chevy alternator with a built in regulator on it.
You need a 3 wire alternator. Two wires go to the battery and one wire goes to anything connected to the ignition switch.