LC500h

[Kevin Williams]

I am thinking of buying a Lexus500h.

I have one in mind, but if I ask these questions of a sales guy, he probably won't be able to answer them correctly. He will want to sell me the car...!

Unfortunately, due to a serious accident several years, my non electric cars need to have their batteries regularly trickle charged.

Does anyone know how long a Lexus500h can be garaged before the engine won't start...?

I am assuming that the lithium-ion Battery will start the engine within a certain period of time...? The internet says that the 500h, will do approx 4 miles, when the lithium-ion Battery is fully charged.

Another question... How much driving do you need to do, to fully charge the lithium-ion Battery...?

And lastly, whats the normal Battery in the boot for...?

Thank you 

[Mr Vlad]

Hi Kevin. I suggest you ask any questions you have about the 500h in the LC or LS sections. You haven't made it clear which car you're considering but in this forum you'll find your answers in the relevant sections. 

[wharfhouse]

I don't have the LC 500h just a lowly IS 300h but I'm sure that the hybrid tech is basically the same - so in answer to your questions I would assume:

- the normal 12v Battery in the boot "boots" the car's computers to ready mode - the traction (Li ion) Battery then will start the internal combustion engine as needed for driving and charging the Li Ion traction Battery - the Li Ion Battery charges the 12v Battery when the car is running (no alternator) 

- if the normal 12v Battery goes flat the car can't be "booted" and so won't start at all - the 12v Battery will need to be charged to start the car - the length of time the car can be left before the 12v Battery goes flat is a number of weeks depending on usual factors (health of Battery, charge when left, temperature etc.) - you can attach one of the Battery recharging start devices to start the car if the 12v Battery is flat as it doesn't take much power to "boot" the car and then the Li Ion traction Battery will take over, start the engine as needed and recharge the 12v Battery or if left for a long time attach a trickle charger in the usual way

- The Li Ion traction Battery will not go flat for a good many months in storage - however if it does only Lexus can sort this out - so worth running the car for an hour or two every couple of months to charge Li Ion traction Battery from the engine (or go for a run if possible)

- The Li Ion traction Battery is charged according to the car's software - there is no simple answer as to how long it takes to get to full charge as lots of factors are at play and the car doesn't always simply charge it fully depending on what else is going on - similarly how far you can drive on electric only is down to the car software and when it starts and stops the engine depends on many factors - best to not worry about this but and just drive the car normally and let the computers sort all of that out!

 

[OldTrout]

1 hour ago, Kevin Williams said:

I am thinking of buying a Lexus500h.

I have one in mind, but if I ask these questions of a sales guy, he probably won't be able to answer them correctly. He will want to sell me the car...!

Unfortunately, due to a serious accident several years, my non electric cars need to have their batteries regularly trickle charged.

Does anyone know how long a Lexus500h can be garaged before the engine won't start...?

I am assuming that the lithium-ion battery will start the engine within a certain period of time...? The internet says that the 500h, will do approx 4 miles, when the lithium-ion battery is fully charged.

Another question... How much driving do you need to do, to fully charge the lithium-ion battery...?

And lastly, whats the normal battery in the boot for...?

Thank you 

Welcome Kevin. This site is a great place to get information.

Your questions apply to all Lexus/Toyota hybrids. What Phil say above is true. Herbie usually answers questions like this and here is a more detailed Herbie reply where he quotes himself.

On 8/17/2020 at 5:35 PM, Herbie said:

Yes, but not for the reasons the 'experts' at Honest John give above.

For a start, hybrids don't have an alternator and it makes no difference if the petrol engine is running or not because it has nothing to do with charging the 12V battery. And, although the CTEK CT5 is a great charger and will do the job perfectly, we don't have stop/start cars or stop/start batteries - stop/start is a different technology.

Obviously, I don't know your level of knowledge regarding hybrid cars so if this sounds patronising, I apologise, but the following information from a different post I made a while ago may help:

In a hybrid there are two batteries - a 12V battery that basically 'starts' the hybrid system and gets the car into READY mode (which is our equivalent of the engine running) and also a traction battery that drives the electric motors and is around 288 to 300V depending on the car.

 

Conventional cars have a starter motor that, when you turn the key, will crank the engine to get it running. The starter motor can draw more than 300A from the battery to start the car and when the engine is running, the alternator will replace the electrical energy used and keep the 12V battery charged up but it's main job is to run all the car's electrical systems - the 12V battery is only used for starting.

 

Our hybrids don't have a starter motor as such and they don't have an alternator either. Our 12V batteries only have to boot the hybrid computers and one or two other things and it takes less than 20A to do that job, which is a lot different to the 300A a conventional starter motor would need. Because of that, Toyota/Lexus thought they could save a bit of money by only installing small-capacity 12V batteries, which is fair enough, except that the downside is that the 12V battery goes flat quicker than a larger battery would. For instance, it's not unusual for the 12V battery to go flat if parked up for a couple of weeks at the airport while you're away on holiday. Quite a few of us carry something like this in the car just in case it happens.

 

So, that's the 12V side. Remember I said that our cars don't have alternators? Well, it's because the petrol engine doesn't run all the time - the car sometimes switches off the engine and runs on electric motors, which are powered by the traction battery. Anything that would normally be run by a belt from the engine, such as the alternator, the aircon compressor or the power steering pump, are all driven by electric motors so that they can still be used when the petrol engine is off. In fact, once the car is READY then the traction battery feeds all of the car's electrical needs, just like the alternator does in a conventional car.

 

Taking the alternator as an example, the 12V battery starts the car and gets it into READY mode. Once READY, some clever electronics in what's known as a DC/DC Converter (our equivalent of the alternator), steps down the 300V from the traction battery to around 14.5V to keep the 12V battery charged. Different boxes of electronics do the same (albeit at different voltages/currents) for the aircon compressor and other stuff, all run by the traction battery.

 

The other main job of the traction battery is to provide power for the electric motors that drive the wheels when the petrol engine is off. This battery is mainly charged by regenerative braking. The regen braking system takes the kinetic energy that would normally be wasted in heat by friction of the brake pads against the discs and turns it into electricity to charge the traction battery. Every time you lift your foot off the accelerator you'll see the power meter needle drop into the 'Charge' zone of the meter, but maybe not so far. When you actively press the brake pedal the needle will drop right down to the bottom of the 'Charge' scale, indicating maximum rate of charge.

 

If the traction battery is dropping low on charge but no braking is taking place to charge it, the hybrid system will run the petrol engne, which in turn runs one of the motor/generators (MG1 and MG2) in a backward rotation to act as a generator and charge the battery. I often get MG1 and MG2 mixed up so that may not be strictly correct but you get the idea - it's one or the other. It can be quite noticeable if the car isn't moving at the time, which is why I think that this may be what you're feeling.

 

However, as I said above, if the car is in neutral then this won't happen, which is why you need to keep it in drive.

 

Something else to bear in mind is that these are hybrid cars, not electric cars. If you run out of petrol, the most you'll get on battery alone is maybe a couple of miles, no more, and it also opens up a whole host of other problems.

 

To be a fully-functional car, three things are needed as they all work together - the 12V battery, the traction battery and the petrol engine.

 

Hope that helps,

Herbie.
 

The 12V Battery will go flat in a couple of weeks or so because of self-discharge and the alarm which is running. If you are going to not use the car for weeks hook an intelligent trickle charger to the 12V Battery.

Hope this helps.

John

[Kevin Williams]

2 hours ago, Mr Vlad said:

Hi Kevin. I suggest you ask any questions you have about the 500h in the LC or LS sections. You haven't made it clear which car you're considering but in this forum you'll find your answers in the relevant sections. 

Thank you very much. Yes, I should have mentioned LC...! I will put it on the LC500 Forum...

[Kevin Williams]

1 hour ago, OldTrout said:

Welcome Kevin. This site is a great place to get information.

Your questions apply to all Lexus/Toyota hybrids. What Phil say above is true. Herbie usually answers questions like this and here is a more detailed Herbie reply where he quotes himself.

The 12V battery will go flat in a couple of weeks or so because of self-discharge and the alarm which is running. If you are going to not use the car for weeks hook an intelligent trickle charger to the 12V battery.

Hope this helps.

John

Thank you very much John.

So, I presume when I buy an LC500h. I will charge the Battery in the boot, as often as I do with my other petrol cars.

[OldTrout]

Kevin,

Yes just the same. The high voltage traction Battery will hold its charge for a long time. IIRC Britprius says he knew of one OK after 18 months.

With an LC you might find yourself going out more frequently🙂

John