Why wont my battery keep a charge?

Have the alternator load tested-any auto parts store could do it-

But even when the car jumps off and just sits there it still will die.

Have the ignition switch-tested

what the car does is it starts wen the battery has a charge. the battery light stays on even wen the car is being jumped off and the meter reads full bettery but wen i take the jumper cables off it just starts dying.

Get the alternator load tested and comeback with the testing results

theres also a fuse that could be blown whitch is the engine charge fuse, i think thats what it is. where would that be located. I also just put in new spark plugs in it and its still not staying running. what else could it be other than the alternator?

theres also a fuse that could be blown which is the engine charge fuse,is it blown if so the alternator will not recondition the battery

where would it be located on a 91 turbo capri xr2?

You don't have a engine charge fuse-check the engine fuse instead in the interior fuse panel

I did and i think the fuse im talking about is called the system charge fuse and its the fuse that runs the energy from the alternator to the battery.

Check if you have battery voltage on the BATT terminal of the alternator

Byt there is a system charge fuse that people have told me that and its away from all other fuses. where would that be?