Battery light stays on while engine is switched off

Hi and thanks for using 2CarPros.

At some point, you have a short to power. The result is the lights stay on and the battery is draining. That is why it struggles to start.

With that in mind, here is a link that discusses a common cause of the battery getting weak after sitting. It explains how to find an electrical drain. Take a look through it. There are things that won't pertain to your problem, but as you continue through it, it discusses how to locate a short. Focus on step 3, the alternator.

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

Let me know if this helps or if you have other questions.

Joe