Draining batteries

Hold on. You cannot drain a fully-charged battery that quickly without smoke coming out somewhere. That is like saying the municipal water tower empties out in a few minutes, but there is no busted pipe. Either those batteries are not being recharged properly or you have something else going on.

Lets start with the exact symptoms. How bright are the head lights after the engine has been off for a while? Measure the battery's voltage with an inexpensive digital voltmeter. Do that again with the engine running and tell me what you find.

I have a suspicion we are going to be looking for a bad connection in the starter system, but your measurements and any other observations will get us going the right way. In the meantime, consider looking at this article to see if it gives you any ideas:

https://www.2carpros.com/articles/car-battery-dead-overnight

Hi and thanks for using 2CarPros.com. Even though everything is turned off, something is draining the battery over night. I am surprised the mechanic keeps replacing the battery for this issue. Anyway, here are directions to help find an electrical draw:

https://www.2carpros.com/articles/car-battery-dead-overnight

Read through these directions and follow them to see if you can locate the component causing the battery to drain.

If you have additional questions, let me know. Also, let me know if you find it.

Take care,
Joe