WillOz

Hi Herbie. No, I'm not assuming the camera is drawing all the power, I was just trying to eliminate the current drain. It just surprised me that the camera was drawing power when it couldn't be of use. If you were going to drive you would need to defrost the screen anyway. Thanks Colin/Herbie it does seem it needs checking out. In the meantime smart charge every so often.

Yes it was total power draw. All I could tell was that something was drawing power and I was surprised that the camera seemed to. It is one thing for the door security system to be active but the camera? Still as long as we know...

Yes Herbie confused as I don't have a dashcam only the Lexus speed reader etc. That was the camera the pictures related to. I think Bluemarlin misinterpreted what I meant. Lack of clarity on my part! So still don't know why it is drawing power overnight.

Thank you Bluemarlin. By "Parking mode" I assume you mean it is parked, switched off as one would with a more conventional car. I didn't know it did anything other than feed the speed signs into the display and control the Auto lighting mode. Interesting, many thanks. I haven't had a flat battery since a "smart" recharge so I hope that might help others.

Further to battery drain issues. As mentioned before, on a frosty morning you can see the camera is ice free. QED it is drawing power. Why do that overnight? Also the Watt meter test I did, before using a smart charger looked like this. The clue I think is 6.42 Volts. The smart charger now show anything from 12.6 to 14V Close up:

Further to my 12V battery problems. I got a new smart charger and that seems to have cured the problem. I think the battery had got into a very low state and needed a good charge up. It is a new battery but as it says in the manual a bit of mileage to keep it okay. Worries me about leaving at an airport so the small lithium battery is always an easy fix and good if you can't plug in a charger at home too. I've actually hard wired it into the 12V battery so I just need to plug in the special jump lead plug into the backup lithium if/when needed. I don't think it is acceptable these days to run the engine, use petrol, cause pollution etc. for no other purpose than to trickle charge the battery. Many thanks to the forum for all your help. It is good to know I'm not alone. WillO

Thanks Herbie and Wharfhouse. I shall do the tests as per video and apply pressure to Lexus. Many thanks and have a good and safe new year.

Many thanks Nemesis. Will check it out.

Thanks Wharfhouse. I am new to hybrids so all info is good many thanks for your time. However when I quizzed the sales people and after sales rep he did say they had an increasing number of this 12V battery problem. It all does seem to depend on what level of kit you have using the electronics. I can't see why anything would be running apart from the key and security system. Oddly I bought this ex demo nine months ago and it was the After Sales reps car! However all they could suggest was charging and testing the battery. It has just been serviced so again I'm surprised it wasn't picked up, the computers log everything, well not really but... The After Sales Rep did point out that all the cars in the show room were on trickle charge. Anyone any idea what the wattage drawdown should be or indeed what should be drawing this power? Cheers and thanks for all the ideas.

Well all I can say is that in order to put a power meter on you have to disconnect the battery to put the shunt in, I assume that will make it take a nap, but perhaps not. Running with 6Ahr subsidiary battery that shows its charging level, it was drained in about 3 days so 4Watts per hour seems to make sense. It is a pity there is no car system method of seeing 12V battery levels indeed it could then go into deep sleep mode but still have enough power to start. I do love the car I was just caught out with my first week, when Lexus swapped it out for a new one, and later on when even with moderate mileage 5 days non use seems to flatten it. I suspect it isn't the actual mileage but how often it is used. But I'll stand correcting on that. One thing I did notice, on a frosty morning, when the windscreen was frozen, the area around the camera was defrosted so it must be using power, for what reason I no not. Perhaps if I take that off things might improve? Any thoughts?

It is a design fault. It is a bit like having a laptop that when you don't use it goes flat in a few days but worse there is still a lot of electrical energy in the car you can't use. Not everyone has access to trickle charging and running the petrol engine isn't really the best environmentally it seems to me. I take your point that going by the book might seem like a solution but my 2019 300h has gone through two 12V batteries from Lexus and doesn't last more than 5 days. Lexus says it is because I have all the bells and whistles electronically but it does seem a bit rum.

Indeed a rather odd oversight on a £40K car not to be able to run the computer software more intelligently. I put a power meter on my 300h and it seems to require 4Watts per hour when doing nothing. The max battery capacity is 12Volts x 60Ahrs = 720watts i.e. it should be able to hold out for about 720W/(24hrs*4W) = 7.5 days. Which isn't great. Not only that you can't get the total power out of a battery so that would be an over estimate. I'm sure somebody out there might be able to confirm or correct. My solution, looking at the various suggestions on this forum, is to use one of the small Lithium batterys, they cost about £60 and have it trickle charge/run the software. It has about 6Amp Hours at 12V =72 hours approx. The advantage is you can grab the Lithium battery, it indicates its charge level, and recharge it in your house in an hour or so, then pop it back on. If you can't charge the car's 12V battery using a trickle charger, no driveway or mains point, this seems an easier solution. After testing this as a way I'm going to do a minor mod to the Boot 12V battery cover panel so I can tidily get at the cables. At the moment I have removed the plastic grab handle (4 screws) and this allows me to feed the connector through can keep the panel on. It isn't ideal but if I keep it simple Mrs Wife will hopefully not be too of put. Really they should offer us a mod to jump power the 12V battery from the main power change batteries. The other method, using photocell chargers could work but you would need to be able to charge at 8Amps to 12Amps +, especially with our short winter days, in order to keep it topped up.