Charging problems. NEEDS DIAGRAM NOW!

Have a problem with the car not charging the battery. Measured the charging from the dynamo to be 11,4V at 800rpm idling, and only 12,2V at allmost 3000, so I put in a new dynamo and a new battery today just to make sure I had fresh parts. At idling it charged now a healty 12,8V and at 2500 rpm it put out 13,9V. BUT after a 45 min run today with a fully charged battery, I came home, and stopped the car. A few minutes later I tried to start it again, and it hardly managed to get the starter to turn around. It was all drained out. The volt is there, but not the amps it seems. Don't understand this. While driving, and reaching over 4000 rpm, it did'nt run smooth, and the amp gauge seemed cracy. The needle howered back and fort around the "0" mark. Have my brother-in-law wisiting for a few days, and he is an above average mechanik, but he would like to see the cars wiring diagram, at least the part covering this part of the electrical system to try to fix it. SO, if anyone out there could help me (fast PLEASE) with this diagram I would appreaciate it very much. If someone will sell me it, that can allso be arranged. If it is on a file you can e-mail me, please send it to: paalgrova@yahoo.com .

Thanks in advance to the fastest of the helping members here