Land Rover Defender Battery Woes: Starting & Dimming Signs

Hey there! I had very similar issues with my 2020 Land Rover Discovery diesel last winter. The symptoms you're describing match exactly what I experienced, slow starts, dimming lights, and general electrical weirdness. Took it to the garage and turns out it wasn't just the emergency battery, my alternator was failing and wasn't properly charging the main battery. The emergency battery was just a symptom of the bigger problem. The alternator replacement was necessary as it was the root cause. After fixing that, all the electrical issues disappeared. From my experience, when both batteries are acting up, it's usually something upstream like the alternator or wiring system. It was quite a serious issue that needed immediate attention because it could've left me stranded anywhere. My suggestion would be to have both the alternator and the entire charging system checked before just replacing the emergency battery. Better to fix the actual cause than just treating symptoms. Hope this helps with your Defender situation!

Hey! Yeah, that's exactly what happened with my Defender too! Had the alternator replaced and it sorted everything out. The mechanic also found some corroded wiring connections while they were at it, which probably didn't help. Just curious, do you remember roughly how much you ended up paying for the whole job? Also, has everything been running smoothly since the repair, or have you noticed any other electrical gremlins popping up? Cheers!

Hey again! Glad to hear you got it sorted! Yeah, my Discovery has been running like a charm since the alternator replacement. The emergency call system battery that was empty got fixed too, that was an extra 110€ on top of the alternator work, but totally worth it to have everything working properly. Haven't seen any electrical issues since the repair, no more dimming lights or starting troubles. It's been about 8 months now, and it's running better than ever. Just had to get used to the slightly different sound of the new alternator for the first few days, but that's normal. Quick tip though, since you mentioned they found corroded wiring, might be worth doing regular checks under the hood, especially around the battery terminals. I give mine a quick look every couple of months now, just to catch any potential issues early. Great to hear you're back on track with your Defender! These electrical gremlins can be tricky, but once you sort out the root cause, they usually stay away.

Thanks for sharing that! You're absolutely right about checking those connections. Since I got it fixed last month, I've been keeping an eye on things under the hood. The total bill came to a fair bit, wasn't cheap with parts and labor, but honestly, it was worth every penny. My mechanic, unlike the first one I went to, really knew what they were doing. They walked me through everything they found and fixed. The best part is my Defender's running perfectly now, starts up right away even on cold mornings, and those annoying flickering lights are completely gone. No more worrying about getting stranded somewhere! The mechanic did mention I should pop in for a quick check-up in a few weeks, just to make sure everything's still tight and clean. Funny how something that seemed so complicated at first turned out to be a straightforward alternator issue. Really appreciate everyone's help in figuring this out. It's good to know I'm not the only one who's dealt with these electrical gremlins! Take care!