matd

Right, forgot to mention that the car has a removable tow hitch, with electrics. As a test I hooked up our bike carrier, and the tail lights on that work fine! So I'm guessing a problem with the wiring for that?

The under-dash fuse panel has no lid, but I think the layout is in that pic I already posted. There are a few fuses in the boot by the battery, but no labels. Here's the diagram from the main panel, can anyone guess what the tail lights would be called?

I found and checked the fuse marked "TAIL" and it's ok, but I'm not certain it's the right one. Can anyone help shed light?

Yes to both

I just found this pic on another site - it looks like the TAIL fuse is in the interior fuse box under the dash... I will investigate in the morning...

Hi, both the red tail lights on our 2016 RX450h have stopped working. The brake and reverse lights seem fine. I can't tell from the diagram in the lid of the fuse box which fuse to inspect - does anyone have a link to a decent fuse map? I can't seem to find one anywhere! Does anyone have any other ideas why they might not work? (No warning lights on the dash) Thanks for any tips -Mat

I've done a couple of tests, in 24 hours my voltage is dropping by around 0.45 volts. These 2 pics represent about 24h (between running the engine), the spikes are when the battery is charging during a drive. @Herbie from the table you included, that looks like it's lost 25% of the charge! Surely this can't be normal?

Herbie, that's very useful info about the batteries, many thanks. I'll get a jump pack and keep it on charge in the boot or somewhere, for emergencies. Barry, I can't use a trickle charger, as I have to keep the car on the street.. maybe a solar powered one would do the trick? Does anyone have tips for reducing drain? Would disabling keyless-entry help?

Hi, I'm new to Lexus and the forums - we've had our 2017 450h about 2 months now, and not many chances to drive it! So of course the car was left for 2 weeks without use - and the starter battery went totally dead. One AA visit later, we now know we have to start it regularly to top up the starter battery. I've fitted one of these bluetooth battery monitors, which seems to work pretty well. When I first fitted the battery monitor this evening (after 2 days idle), the monitoring app said the voltage was 12.05v, which it decided was *low*, and at '7%'. But the car started OK, and we went for a 20 minute spin - charging at 14v apparently. Back home, the monitor now reads '12.71v, 80%' So my questions; - does a voltage of 12.05v actually represent a very low (7%) battery, or is it talking garbage? I would have thought that <10v would be low enough to start worrying.. - what battery level *should* i use as a threshold to go and start it up for a while? - any tips for reducing battery drain? Disabling keyless-entry maybe? Thanks for any thoughts. Kind regards -Mat