Brechin Slate

I think a charger needs to be on your shopping list if you're having ongoing problems. Also worth investing in a digital multimeter if you don't already have one so you can check the battery after charging, when in the 'Ready' mode and daily after charging so you can see the rate of the drain. The CTEK MXS 5 seems to be one of the better chargers looking at some of the posts in the forum although I'm sure there are other good ones out there. Halfords have a good selection too, I bought a Noco Genius 5.

Agreed, and if you already carry a portable power pack type jump starter it renders this surplus to requirements. I've also joined LRA, more for my wife's benefit but at least I have belt and braces

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The portable 'jump starters' have enough power to get the hybrid system started which is all you want. There's no starter motor to spin so the power needed is nowhere near that for a conventional vehicle. You don't need to wait five minutes, you can just connect it and start your car straight away. If jumping from a donor car, they really don't have to rev their engines when jump starting a hybrid car. Lexus recommend running your car for 60 minutes per week not 30 if it's not being used. Leave it in P, no lights, radio, wipers etc, go to 'Ready' and sit there reading a book/newspaper/phone/laptop/Razzle for an hour. The engine will cut in occasionally to charge the hybrid battery and the hybrid battery will charge the 12v auxiliary battery. If you're like me, you'll need to tell curious passers by that 'yes thanks, I'm ok'. Or you could get a smart charger. Many to choose from. I bought this one and am pleased with it. Discount with your Gold membership card! https://www.halfords.com/motoring/battery-maintenance/battery-chargers/noco-genius5-5-amp-battery-charger-230278.html

I have personally read the manual, more than once, all 692 pages of it, I like manuals 😀 There are not many references to the 12v battery, one is about the battery saving function using the key fob, one is about how to recharge it and the one really relevant to this thread is: "Auto power off function If the vehicle is left in ACCESSORY mode for more than 20 minutes or ON mode (the hybrid system is not operating) for more than an hour with the shift lever in P, the power switch will automatically turn off. However, this function cannot entirely prevent 12-volt battery discharge. Do not leave the vehicle with the power switch in ACCESSORY or ON mode for long periods of time when the hybrid system is not operating." The brief to the manual writer must have been along the lines of "put a warning in but don't be too precise and make sure that 'power off' doesn't actually mean that. I understand hybrid systems fully from concept to operation, I used to operate and maintain warships which were totally reliant on them. The manual has one chapter missing and it's the one that explains why they fitted a part which made a car less reliable than it's predecessor.

Whichever way it's dressed up, it's a shortcoming. The cost difference between a full size battery which holds a usable charge for a month (a reasonable ask for any car owner) and one which after 2 weeks has the absent owner sweating like Fred West watching Groundforce is worth paying. The list price of my car was over £42k, if I was asked to fork out another £100 for additional reliability it would be a no brainer. If Hyundai have an effective solution then it has to be assumed that Lexus missed a trick. As a marine engineer I agree with your figures regarding cranking and draining but it's a problem that's been handed from the designer to the consumer.

Nice idea. Have you got one? Pics?

I was messing about with an OBD reader yesterday, trying to sort out which tyre pressure sensor was in which wheel. I was working with the ignition on but not in the 'Ready' mode. Less than an hour later when I came to move the car, the hybrid system wouldn't start because I'd flattened the 12v battery. I had no lights or radio on and no other systems were active when I was playing with the OBD. Managed to get a jump start from a neighbour's battery then hot footed it to Halfords where I bought a Noco Genius 5, (lovely bit of kit and nice to use the Gold Member discount). All well now, the battery is in good nick and I'll plug the charger in whenever I wont be using the car for a few days BUT...one of my hobbies is sailing and I sometimes go away for 3-4 weeks at a time leaving my car in a marina but without access to an external power source. I guess others may leave their cars for extended periods too like in airport car parks etc. Is the only answer to carry a jump starter? Disconnecting the battery would disable the alarm/immobiliser which would probably invalidate the insurance. What do others do? What is the best portable power pack? If Lexus are aware of this weakness why don't they provide a standby? A month into 300h ownership and the honeymoon period is over, I'm beginning to miss my IS250..

Beautiful looking car!

Nice! I'd like to go down that route but couldn't cope with the interruptions from the curious neighbours. Six times was stopped today while snow foam was drying on the car. Why has car washing become a spectator sport, I guess there's not much else to do at the moment 🤣

Nice piece of kit and modestly priced. I thought I’d paid over the odds for my 2nd hand Performance Power one but it did come with a whole pile of extras including an unused heavy duty stapler gun with staples, paint spraying attachments and a really good tyre inflator with gauge. Very noisy so might use the stapler gun to build a soundproof housing! Useful as a golf shoe cleaner too!

I know there are a lot of these out there but I had a play with an app called Car Scanner today, a free download and free to use app with a lot of functionality. I used it via Carista with a Bluetooth connection to an iPad while the car was both static with the ignition on and when out on a run. All of the data recorded can be shown in graph format with the ability to choose just one or any number on the screen to do comparisons. See pics. Might be boring to most but if you like lots of tech data (I’m an ex Royal Navy marine engineer, we recorded everything!) then this might be interesting.

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How do you knock it with your foot? The Carista is tiny and tucked up out of the way, I guess you have a bigger dongle than me? 😳

Nice looking piece of kit!

Here you go. https://www.motorists.org/blog/pros-cons-rear-wheel-drive-front-wheel-drive-or-all-wheel-drive/ With a question like that you will always tend to get more opinions than scientific answers.

My 56 registered IS250 had a spacesaver which got my wife out of dangerous situations twice. An inflation kit wouldn't have been any use with pothole damaged tyres on dark country lanes.

Thanks for your help. Also now bought a 2nd hand air compressor off Gumtree so no more unnecessary trips to the petrol station only to find that the tyre inflator is out of action Again. And again. And again..

Does anyone have a brand/model that they'd recommend from experience? I bought a digital one from Amazon for about 6 quid and unsurprisingly it reads about 7 psi or ½ a bar less than what the TPMS is telling me via Carista. I'm suspecting the gauge rather than the TPMS.. On the upside, the cheap gauge did match the Mesa Red paintwork but that was it's only redeeming feature, oh, and I can return it for a refund.

I guess carrying the obligatory low weight inflation kit instead of a full size/space saver wheel in the mk3 is a way of helping Lexus improving the mpg. I'd rather carry a full size spare but would then have nowhere to put that hybrid battery..🙂

I stand to be corrected but wouldn't have thought this was available as a spare. Would a tiny drop of superglue do the trick? There are quite a few spare fobs on eBay but pricey considering you only want the battery holder.

Pics please!

I thought long and hard about disabling mine after reading about £3k repair bills. Bottom line is, if it does activate it's almost certainly going to be the result of an accident in which case it's an insurance claim. If I did disable it and hit a pedestrian, the £3k/no insurance would be the least of my worries. I'll leave mine alone and sleep easy.

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Was your battery in good condition prior to plugging in your Carista? When everything is switched off it only draws .00654 mA (6.54 microAmps) https://www.amazon.com/ask/questions/TxH2MSLDIMMUMX/ref=ask_ql_ql_al_hza?ref_=d6k_applink_bb_marketplace