My 2002 2.4 Alphard's engine wouldn't turn over yesterday, which was odd as I'd used it a few times this week. There was some clicking, and all electrical items such as lights/radio/central locking are working fine. I managed to jump start it using a big heavy duty charger/booster - this was following about 5 minutes charge on the 'High' setting, and I drove about 5 miles away and parked it. It ran as smooth as ever when driving. A hour later it wouldn't start again. Tried jump starting from a friend's Aygo but either it was too small, or his jump leads weren't up to it, but I could hardly even get my engine to turn over.
I've purchased a new battery and planning to head over to where the car is and replace it. However, I've remembered something else. For the past couple of months I've noticed my interior leisure battery had been dying quicker than normal (the 12-240V convertor beeps when its 12V source is too low). I assumed it was just my kids plugging in phone chargers more than usual, and I also thought maybe the split-charge relay was failing, but I'm now wondering it was an early sign that my alternator was failing. And perhaps now the alternator isn't giving enough charge to the main battery. As I said, the engine started and ran fine using the booster.
I suspect if I fit the new battery it'll start OK, but in a couple of days I might be back where I started and have wasted money on a battery I didn't need.
Hence I'm wondering if I need to also buy an alternator and replace that in-situ (I should point out I don't have a breakdown recovery subscription, which I know is silly, but there's a valid reason which is another story entirely !).
Any thoughts on this? Advice for alternator model ? I'd obviously prefer a Denso, but can't keep everything original all the time.