Sail Poor Starting Interrupted Terminal

Sounds familiar! I had a similar problem with my old Peugeot. The voltage drop on starting definitely points to a weak battery or a high-resistance connection somewhere. Have you checked the battery terminals and the earth strap connections for corrosion? Even seemingly minor corrosion can cause a significant voltage drop under load. Is the starter motor drawing excessive current?

Thanks for the quick reply. Yes, I cleaned the battery terminals and checked the earth straps. They look surprisingly clean. I haven't measured the starter current directly, but the voltage drop is significant enough to suspect it. Is there anything else that you can think of besides Battery or Starter Motor itself?

Ah, okay. In my case, it turned out the battery was heavily degraded internally, even though it showed a decent voltage at rest. Since you've checked the connections, that heavily discharged or defective battery seems more likely. In the end, it wasn't worth the hassle of further diagnosis on my Peugeot, I just went ahead and replaced it and the issue disappeared instantly. You should visit a workshop, but I think it's very likely that the Battery is gone.

Appreciate the insight! Seems like the best course of action is to take it to the shop and get a new battery, and possibly a more thorough health check. The workshop said it will cost 290€. Thanks again!