cyberhound

I have a 2023 RX 450h+ - I switched from an all electric Audi E-tron GT which was a nightmare - if you're going on a journey there are insufficient high capacity public charging points in the UK to get you to where you want to go. The RX is a great car and the Japanese have mastered the technology in a way the Germans haven’t and everything works as it should and without the dreaded ‘range anxiety’ of a pure EV.

However - one thing, there's always something! The car needs to be driven or charged at least 1 hour each week to keep the 12v battery in good health and fully charged. This battery is responsible for all the auxiliary systems (not traction of course) and if it's allowed to go flat 1) there's no warning 2) all doors including the rear hatch are locked 3) you need to use the manual key to unlock it so always keep the key fob with you - if you leave the key fob inside the car and the battery goes flat you'll probably need the AA to get into the car and sort it out.

This happened to me last week in the 5 months of ownership. Apparently it's quite a common complaint but in my opinion it should 'fail safe' and not lock you out. Imagine if a mother opened the driver door, left the key inside the car, closed the door behind her, opened the rear door strapped baby into seat, closed door went to rear hatch to put in shopping bags then closed the hatch. Closing the rear hatch finally drained the 12V battery - she is locked out with baby inside - nightmare scenario! Minus the baby that's what happened to me. last week I now intend to check the battery regularly. There's a clear viewing cell and if it's blue then the battery is fine, red it needs charging and if it's clear then the battery has probably had it.

Keep that in mind and I'm sure you'll enjoy the car when its delivered

WellsB

It is recommended that non-hybrid cars be driven at least 30 minutes a week at highway speeds, to keep the battery charged. I make sure to fully charge, with a charger, any vehicle, that I'm not driving regularly, at least every 2 weeks to prevent the battery from getting low enough to induce sulfation.

Keep in mind that pressing the start button without pressing the brake puts the vehicle in a mode where the 12v battery is supporting all systems without being charged, and will rapidly deplete it.

ggebhardt

If you are not going to drive enough to keep the 12v battery charged, it is easy to obtain and hook up a trickle charger. I keep my riding mower on one all winter long and it still runs strong after 4 years.

WellsB

Just to be clear, when most people say "trickle charger," they mean a battery maintainer that charges until full and then goes to float mode. A basic trickle charger can boil a battery dry and destroy it.

Klamalama

Somewhat related:

Yesterday I went through the same car wash I regularly use, but there was a difference. Naturally, you have to place the car in Neutral, which I did at the start. Near the end of the car wash I got a warning message not to keep the car in Neutral for a long time to protect the traction battery. The time in Neutral could not have been more than a couple of minutes.

WellsB

The traction battery is not charged when in neutral. The car is just giving you a warning about it.

ggebhardt

I have seen the same warning. Does not always show up but I do see it about once a month under the same conditions you mention.

DetailsGrl

Excellent reminder, WellsB.

I've had a connected to my older RX for a couple of years to overcome long periods the car sat still while I worked out of town.

ggebhardt

I bought two of these to keep both my Toro and SeaDoo batteries is ready to go condition. There are cheaper but I have had great service out of this brand.

Carbuff2

X2 on the Battery Tender brand above. Have three.

StefanoS

I have several of the .75 Amp Battery Tenders and a NOCO Genius 5 in my garage for my Honda M/C, Vespa and of course, my vehicles, when I need to put one or more on a maintenance charge. Having one or two around of these chargers is always a great idea. NOCO makes good quality stuff and all of these can be purchased from Amazon for quick delivery. Consider them cheap insurance.

gpan218

My wife (who is claustrophobic) got locked into her new RX350h when the 12v battery died. She was not aware how to use the manual door openers. Fortunately, she had her phone and called me so I could walk her through the process. When she shut the car door after getting out, all the doors locked, with the vehicle in the middle of a parking garage, blocking other cars. We called the dealer, and after 3 tries found someone who could walk us through the use of the manual key and the manual exterior door handles. Then called Lexus roadside assistance for a jump start using the connections under the hood (the positive terminal is inside the fuse box on the drivers side near the firewall. The negative terminal is on the left side of the engine, a good 20+ inches from the positive terminal). When the service tech arrived to jump start the car, his cables would not reach both connection points specified in the owners manual. He finally found a suitable bolt to clip the negative jumper to, and the car started.

What a nightmare! This process should be taught when the car is delivered, instead of spending all the time setting up the entertainment system.

lexusnyca

With the terminals under the hood so far away from each other, the typical battery tender/noco cable typically can't reach that far between positive and negative - so where are the battery maintainer users hooking up to?

ggebhardt

Hook the positive up to the positive terminal and the negative to any ground, a nut, bolt or other unpainted surface. Works fine!

StefanoS

This is sound advice, as the ground can be just about anywhere.