If I leave the car sitting for even 24 hours, the battery dies. OEM Bose amp and head unit installed, kill switch hooked up to the fuel pump by previous owner. Any ideas what might be causing it or anyone experience something similar?

 

Test the battery



A voltmeter costs less than $10
Lead acid batteries should never go below 50% SOC ( state of charge)

To make this easier to understand:
12.0 volts = 0%
12.35 volts = 50%
12.7 volts or higher = 100%

Remember anything below 12 volts causes permanent damage.

 

A battery hydrometer is also around $10 and can show a weak or a defective battery cell not accepting a full charge

 

i started it this morning, just to see if it start, it did, turned it off, then 10 mins later came out and it didn't have enough juice to start again.

so i let the car sit all day while at school (7 hrs) and i got a reading from it when i got and its at 9.75V lmao.

this isn't looking too bright

I'm charging it up rn, waiting for it to get fully charged then seeing the voltage drop after a couple hours

 

I think the Bose amp and head unit were notorious for going bad and sucking power til the battery died. Un plug the Bose amp and test again to see what happens.

 

Sounds like a bad battery if you can't even restart the car after sitting for 10min.

 

Might want to invest in a jump starter ( external battery) or a new battery (if you plan on keeping it) .