2019 IS300H No Electrics.

[colabora962]

H,

My car has been left standing for a week after completing an 80 mile trip.

I came to unlock it this morning and neither key fob would work so had to open the driver's door with the key blade.

No power when trying to start it and the 12volt Battery voltage has dropped to 5 volts !!!!!!!!! and now charging.

Could anyone offer any help as to why this has happened and what's going on or do I need to contact my local Lexus agent.

This has never happened with previous Lexus cars I have owned. 

                                                Many thanks.

   

[PaulWhitt20]

Sounds like a new 12v Battery is required. They are smaller than a normal car Battery so are prone to going flat if the car is ignored for a week or so. 
 

Contact you Lexus dealer as the 12v batteries are not an off the shelf item from Halfords. 

[Herbie]

As Paul says above, you most likely need a new 12V Battery, not least because it's dropped as low as 5V. They don't like being so deeply discharged and each time it happens it causes some slight damage resulting in a small loss of capacity.

When you get your new one make sure to use the car more or, at least once a week, run the car in READY mode for about 60 minutes. The engine will cycle on/off and charge up the 12V Battery. The other (and probably best) option is to keep a trickle charger connected to it, because these batteries are small and have a much lower capacity than other 12V batteries.

[Notamech]

14 hours ago, PaulWhitt20 said:

Sounds like a new 12v battery is required. They are smaller than a normal car battery so are prone to going flat if the car is ignored for a week or so. 
 

Contact you Lexus dealer as the 12v batteries are not an off the shelf item from halfords. 

Does anyone know why there are no aftermarket options? Why do we need to use the original toyota Battery and what happens if you use a regular Battery with similar or better specs? I realised that my car came with a yuasa 3000, something thats aftermarket probably installed by the prev owner or the car dealer. Seems to be working fine so far. Any potential issues i should know of? 

[colabora962]

I replaced the 12volt Battery in the boot at the end of last year via Lexus Chester (car is low mileage 16k now and just out of warranty then)  as after a week or two of non running it would not allow the car to start and I knew of the risk of this with a low mileage car from my previous IS300H experience.

Its been absolutely fine since late November so I am thinking that something strange has happened to drain the Battery or the Battery has completely failed.

It has been on trickle charge overnight and was registering 11.8 volts this morning. I will leave in on charge and see how far it will charge up and then monitor its voltage drop thereafter.

The Battery is under warranty if its failed so if it does not hold a full charge I will visit Lexus Chester to talk to them.  

[IS300FSPORT]

Leaving a car standing for arounds 2 weeks its quite normal to return to a dead Battery. Especially for a low capacity Battery (45AH-325A) this Battery size would usually be used in a smaller engine 1.0 car like a Yaris etc

In comparison to the conventional batteries you would usually find in a 2.0 litre + car. Rated around (70H-630A) probably due to weight saving & keep in mind the 12v Battery is there just to wake the car up (ECU) The main high voltage traction Battery is what starts the engine. No need for a big heavy Battery as there is no starter motor to turn over the engine.

Worth Investing in a jump pack for example Noco GB40 you will never need to call for assistance keep it in the boot & your ready at anytime to get it started after pro-longed periods.

If your leaving the car standing for long periods turn off the auto lights & check the interior lights are turned off one of the kids recently left mine on overnight I didnt experience a non start but its easy to maintain if you have a drive way trickle charge it once a month if not buy that jump pack & be worry free.

[Herbie]

11 hours ago, Notamech said:

Does anyone know why there are no aftermarket options? Why do we need to use the original toyota battery and what happens if you use a regular battery with similar or better specs?

Usually it's simply physical dimensions and/or terminal orientation that prevents the use of an aftermarket Battery. If you can get one that fits in the tray, can be clamped securely and with correct terminal positions then great, fill your boots, because it makes absolutely no difference electrically.

EDIT: One other aspect is if the Battery has a vent tube connected because if it has, then the new one will need to have vents so that you can change the tube over.

EDIT 2: I keep a jump start battery pack in the glove box 'just in case'. Any of these would be perfect for the job and I highly recommend that you get one.

[Notamech]

40 minutes ago, Herbie said:

Usually it's simply physical dimensions and/or terminal orientation that prevents the use of an aftermarket battery. If you can get one that fits in the tray, can be clamped securely and with correct terminal positions then great, fill your boots, because it makes absolutely no difference electrically.

EDIT: One other aspect is if the battery has a vent tube connected because if it has, then the new one will need to have vents so that you can change the tube over.

EDIT 2: I keep a jump start battery pack in the glove box 'just in case'. Any of these would be perfect for the job and I highly recommend that you get one.

Thanks. The Battery seems to fit perfectly and even the tyre inflator kit firs secrely above with the elastic band. I couldn't find a vent hole on the Battery however and seen the tube just left to hang. Do all batteries have vent holes? 

[Spock66]

2 hours ago, Notamech said:

I couldn't find a vent hole on the battery however and seen the tube just left to hang. Do all batteries have vent holes? 

No not all batteries have these, it's usually on the side at the top.

When a lead acid Battery is charged it will vent hydrogen gas, if it's in a vented space such as under the bonnet this is not a problem, but when the Battery is installed internally (such as in the boot), the gas could build up and cause an explosion, hence the vent tube.

But it's a very remote possibility and I would not worry about it.

[westo3]

Do have more details of the Battery fitted to your car Eldrid ? Sounds like an ideal alternative to the Lexus one especially if it fits without any modification and lasts longer. It is all very well having jump start packs and trickle chargers but leaving the car at the airport for more than two weeks will actually weaken the Battery if it gets too flat.

[matt8]

On 5/8/2023 at 8:46 AM, Notamech said:

I realised that my car came with a yuasa 3000, something thats aftermarket probably installed by the prev owner or the car dealer. Seems to be working fine so far. Any potential issues i should know of? 

Is it an AGM Battery? The Is300h shipped / came from factory with an AGM type Battery, and your Yuasa may not be that type.

AGM batteries charge at a slightly higher rate. Further, they are designed for use internally with passengers, where a crash may splash acid. Under the bonnet, it’s not an issue. A non-AGM in the boot may cause injury to passengers.

[agent_dess]

I would go with this:

https://lexuspartsdirect.co.uk/product/lexus-is-phase-3-auxiliary-12v-starter-battery/

[Notamech]

8 hours ago, westo3 said:

Do have more details of the battery fitted to your car Eldrid ? Sounds like an ideal alternative to the Lexus one especially if it fits without any modification and lasts longer. It is all very well having jump start packs and trickle chargers but leaving the car at the airport for more than two weeks will actually weaken the battery if it gets too flat.

I just had a look I seem to have this battery https://www.yuasa.co.uk/ybx3053.html 

Not sure how it compares to the original one but seems to be a sealed maintenance free ca ca Battery with some spill protection built in. The longest I've gone without running it was 1 week and it wasn't a problem. Guess il use it till it goes bad then id probably get an original. Unless this lasts really long in which case I'll buy this again. 

[colabora962]

I have recharged the Battery and it its reading 12.9 volts and 12.6 volts 4 hours after disconnecting the charger charger and appears to be holding its charge.

I will check voltage again this evening and in the morning.

It does appear that no one has had any experience with my initial problem of rapid voltage drop on the Battery over just one week so if it continues to hold a reasonable charge  I guess I will have to live with it.

There is a 49AH AGM Battery available which I am assured fits the car so I may opt for that when and if I need a replacement as the current one is still only about 6 months old.

[westo3]

20 hours ago, Notamech said:

I just had a look I seem to have this battery https://www.yuasa.co.uk/ybx3053.html 

Not sure how it compares to the original one but seems to be a sealed maintenance free ca ca battery with some spill protection built in. The longest I've gone without running it was 1 week and it wasn't a problem. Guess il use it till it goes bad then id probably get an original. Unless this lasts really long in which case I'll buy this again. 

Thanks for the link 

[Notamech]

On 5/9/2023 at 8:35 PM, Notamech said:

I just had a look I seem to have this battery https://www.yuasa.co.uk/ybx3053.html 

Not sure how it compares to the original one but seems to be a sealed maintenance free ca ca battery with some spill protection built in. The longest I've gone without running it was 1 week and it wasn't a problem. Guess il use it till it goes bad then id probably get an original. Unless this lasts really long in which case I'll buy this again. 

Just an update on the performance of this Battery. For background - I use my car thrice a week at least and do around 10-15 miles whenever I run it. I have never used a charger to charge the 12v Battery. Recently I went on a 3 week long vacation. After returning around 21 days later i started the car and it booted right up. No issues. I do keep keyless entry off though. So sounds like a reasonably good Battery to me as ive read of quite a few batteries going flat when the car is sat for 2 weeks or longer