car hard to crank and sometimes shuts off

Hi. The car starts but it sounds like battery is low.Went to Aut Zone and they checked battery and alternator turned out they're good.
Few days ago it wouldn't start,only ticking sound and wipers came on. I disconnected the battery for few minutes and it started right away, before that I started it with jumpers. Few times it died on me at lights but I was able to crank it right away. Engine light's on. :feedback:

Hi. The car starts but it sounds like battery is low.Went to Aut Zone and they checked battery and alternator turned out they're good.
Few days ago it wouldn't start,only ticking sound and wipers came on. I disconnected the battery for few minutes and it started right away, before that I started it with jumpers. Few times it died on me at lights but I was able to crank it right away. Engine light's on. :feedback:
Today it wouldn't even crank. I check the voltage with my voltmeter on the battery, it was 7.78V. I'll replace the battery first,hope alternator is good. What do you think everybody????

Today it wouldn't even crank. I check the voltage with my voltmeter on the battery, it was 7.78V. I'll replace the battery first,hope alternator is good. What do you think everybody????
If the battery is 2 years old or older I would suspect the battery - especially since the car started when jumped. After you put in the new battery - check voltage at terminals with engine running - if voltage is around 14.5 volts or more - then alternator is good.