Need help, presume charging issue.

1990 SW20.
Replaced alternator with a brand new unit as I got a big tip from someone who had the same issue but no help.

Pretty much all happened on the way to bobbin head road. About five minutes away the car started dying in the ass and looking at the charging rate it kept going down. As soon as it got to a point the oil pressure light, battery light and engine light with the life ire sign popped up and flickered while the abs came on and stayed on. Not sure what's up as it was running fine before. Ended up riding my way home with the lights off and my work torch out the window keeping light as it was 11pm.

Since then have replaced alternator, checked lines and wires leading to it and from the battery.

Before the trip to bobbin head I replaced an exhaust gasket and bled the brakes. After that abs light came on but soft reset and went away until this issue. Any ideas?

The attached photo is while the vehicle is still running but 'stalling' due to lack of power.

Very closely check the plug and the wires going to the alternator connector plug. The pins in the plug need to be forward to make connection and ensure the foot of wire from it has not become hard/broken/exposed.
 
 
If all else fails charge your battery. Take the car to an autoelectrical shop, my local guy did a check service for free. Auto electrician checks resistance between all the connectors (online write ups if you want to do yourself - multimeter on ohms plugged into each pin to check circuit), checks the condition of the battery (they have a fancy tool).  I had to take the alternator out at home and then took him the alternator to bench test.
 
 
My previous experience was; faulty plug wires and a dead brand new ongo bongo Chinese alternator - ended up getting the original alternator (Toyota - Denso) rebuilt.