I changed the battery on the normal key last week as a precaution (I thought). Also bought a new spare key. I’ve had lots of electrical problems including non-starting due to battery drain traced to hvac.
Yesterday the car opened, starter sounded like it engaged but it didn’t turn over on the first attempt. Second attempt it cranked fine. This morning I had a low key fob battery warning so I used the spare.
Does the battery really have to be good to enable a start? I’ve never known this before, other cars have a chip embedded in the key that is not battery dependent.
I’m asking because I need to know if the low battery is the likely cause or if there is another problem developing, say with the battery leads corroding internally as someone recently posted or if the starter needs servicing. Advice welcomed.

Re the above, I mean if the key fob battery has to be good for the car to start, the car battery is new as is the alternator.

You don't say what car you have, but my experience is that a low key battery warning is given some time before the battery actually goes flat and post-warning there seems no change to the car starting.

On my 4.4 TDV8 there is an intermittent starting problem just now, initially pressing the button would fire up the screen but no priming of injectors/cranking and no click sound. The battery is fine and when the starter does work it starts easily. It does not matter whether the car is cold or has been running, if anything latterly it has been worse when warm. The symptoms were thought by two dealers to be a sign of a defective starter button (not uncommon apparently). Latterly however the intermittent lack of reaction has been accompanied by a click. That was thought by the dealers to indicate that the starter motor is defective. This also seems a known fault (there are so many...). It's booked in to get sorted on Wednesday.

Yours could be suffering from one of these issues, maybe more likely the starter motor if you are getting a click. Only Range Rovers since 1988

It’s a 2002 L322. Could be the starter but I’m going to look at the leads first. Someone suggested internal lead corrosion, I had a similar problem on a P38 which had corrosion where the main lead copper under the lug had oxidised. I fixed that by twisting the lug off, cleaning it and filling the joint with solder. Worked fine. I later had a similar problem with the solenoid cable spade connector, a new lug soldered on fixed that too.

I had the corrosion easy fix is to buy another lead from auto factors for about a tenner and just wire it in in parallel and see if it solves the problem if so just replace the faulty one - on my p38 I just left it connected but the fatty has the disconnect charge fitted

Change key fob battery (CR2016/DL2016)

Check terminal connections on main battery

Check connections from main battery to starter motor

If that doesn't resolve, then you may have to have the starter motor out..... .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999