Amp light flickers

ok well yesterday i went a total of 7 miles to my g/f house. from there we went to camden NJ in her moms van :( for about 8 hours i got back in the car to go home started it up noticed the light was on so im cussing becasue 6 months before i changed the alternator but i was like screw it im tired i drove the 7 miles home but around mile 4 i acelled hard to make a light and it started to flicker then went off. about 2 hours ago i went out to start it its back on.. oh
im thinking the battery is starting to die from the heat or the alternator is not charging right help me :)

and also some kid shot the windshield with a bbgun last night X___x

how could i test it with a tester what setting should i put it on and what should it be reading ?.?.?

Check the water levels in the battery first.

i cant do that with this battery :(

It's definitely a charging system problem. You might have secondary issues with the battery from having these problems. If you can't get to an auto parts store like Autozone, advance, oreilley, etc, then you can test the alternators output by putting the positive volt meter lead on the output post on the alternator and the negative lead to a ground source like an engine mount. Set your volt meter to dc voltage at least able to read 20 volts. You should at the very minimum get a reading of 12 volts constatnt. 13 to 14 volts is ideal. If you'rs below 12 volts, you need a replacement alt.

Battery cables in these cars are notorious for corriding inside the rubber sheaths, what do yours look like?

Autozone will test your alternator for free. They will also test your battery free.

thanks for all the help it was charging at 18v but it was still bad so YAYYYY!!! for the napa life time warranty!!!!!!!!!!