Weak Discovery Battery? Quick Diagnostic Guide Here

Hey there! I had a similar issue with my 2008 Land Rover Range Rover Sport diesel (168k km). Initially thought it was just the battery, but it turned out to be a faulty control unit that wasn't managing the charging system properly. Had mine checked at the garage last month, the diagnostic tests showed the alternator was working fine, but the control unit was sending incorrect signals, causing irregular charging patterns. They had to replace the unit and recalibrate the system. It was a serious job that took two days to complete, but worth fixing as it could've damaged other electrical components if left unchecked. The symptoms were exactly like yours, weak starts, dimming lights, and inconsistent battery performance. Before taking it to the shop, you can check if your battery terminals are clean and tight, but from what you're describing, it sounds more like a system issue than just a weak battery. Hope this helps with your decision. Cheers

Hey! Thanks for sharing your experience, sounds exactly like what I'm dealing with! Good to know it was the control unit in your case. After getting it fixed, do you remember roughly how much the whole repair set you back? Also, curious if you've had any other electrical gremlins pop up since then? Thanks again for the help! Cheers

Hey again! Great to hear back from you! Yeah, since you asked, the repair cost me 600€ for fixing the defective control unit, and I'm happy to report it completely solved the battery discharge problem. The best part? Haven't had a single electrical issue since getting it sorted last month. The car starts like a charm now, no more dimming lights or weak starts, it's running exactly how it should! Actually, the mechanic showed me how the faulty control unit was causing the battery to slowly drain even when the car was off. Once they replaced it and recalibrated everything, the self-discharge problem completely disappeared. Got to say, it was worth every penny considering how much smoother everything runs now. And honestly, better to fix it properly than risk damaging other electrical components, which could've ended up costing way more in the long run. Let me know if you end up getting yours checked out, would be interesting to hear if it's the same issue! Cheers!

Hey! Just wanted to update you, I actually took your advice and got it checked out! You were spot on about the control unit. Had it fixed yesterday and what a difference! The mechanic I found was really thorough, showed me exactly what was wrong and explained everything. The whole job came in a bit cheaper than yours, around 500€, and they got it done in just one day. Honestly, such a relief to have it sorted! The car starts up instantly now, no more flickering lights, and everything's working perfectly. Really glad I didn't just try replacing the battery like I was initially thinking. Thanks so much for sharing your experience, it definitely helped me make the right call and saved me from potentially bigger problems down the road. Really appreciate your help with this one! Cheers!