Jump Starter Pack - Procedure

TomcatUK · April 13, 2020

My IS 300h wouldn't start the other day... having been on the drive for a couple of weeks plus...

The AA via Lexus Care attended, and solved the problem with a portable Jump Starter Power Pack..

I now realise that I should run the car in "Ready" for 60 mins weekly in order to keep the 12v Battery in shape.

I have since purchased a Fylina Jump Starter Power Pack for emergencies...

Could someone please detail the procedure for using such a pack should the necessity occur...

Thanks in advance............................................................

NemesisUK · April 13, 2020

Pretty sure jump start procedure is detailed in the owner's handbook?

Zotto · April 13, 2020

Jump starting a hybrid car is NOT a problem, as 12 V is used only to give energy to ICUs and there is no need of many Ampere currents: I know some people that have jump started an hybrid connecting a tiny 12 V Battery to 12 V discharged one. Standard procedure connecting cables from another car is effective.

On the contrary, NEVER try to jump start a non hybrid car if you have a hybrid car, as you could damage the charging circuit.

Herbie · April 13, 2020

There really isn't much to say about it.

All you are doing is supplementing a dodgy 12V source by piggybacking a good 12V source onto it.

12Volts is 12Volts and whether you use the jump start terminal in the fuse box under the bonnet or connect directly to the Battery terminals, it doesn't matter because 12Volts at the front or 12Volts at the back (if the Battery is in the boot as it is in the RX450h) is still 12Volts, wherever you connect it.

The most important thing of all is to make sure you connect it using the correct polarity, ie, Positive to Positive (or + to + or red to red) and Negative to Negative (or - to - or black to black).

Once the jump start Battery pack is connected, go through the normal start-up routine and wait for the READY light to come on, then disconnect the Battery pack and Robert is your mother's brother.

royoftherovers · April 13, 2020

14 minutes ago, Herbie said:

There really isn't much to say about it.

All you are doing is supplementing a dodgy 12V source by piggybacking a good 12V source onto it.

12Volts is 12Volts and whether you use the jump start terminal in the fuse box under the bonnet or connect directly to the battery terminals, it doesn't matter because 12Volts at the front or 12Volts at the back (if the battery is in the boot as it is in the RX450h) is still 12Volts, wherever you connect it.

The most important thing of all is to make sure you connect it using the correct polarity, ie, Positive to Positive (or + to + or red to red) and Negative to Negative (or - to - or black to black).

Once the jump start battery pack is connected, go through the normal start-up routine and wait for the READY light to come on, then disconnect the battery pack and Robert is your mother's brother.

Not many people can say it all without saying much !

Well done Herbs.

April 13, 2020

I have owned my IS300h since January, my first Lexus. I have noticed a lot of topics referencing the 12v Battery, is it a weak spot with Lexus? In the past I have left a BMW at Heathrow for nearly 4 weeks in winter, fully alarmed, and had no problem starting it on my return. Looking at some of the posts on this forum doing that with my Lexus would seem to be impossible, if so that would be disappointing.

ColinBarber · April 13, 2020

15 minutes ago, Derant said:

I have owned my IS300h since January, my first Lexus. I have noticed a lot of topics referencing the 12v battery, is it a weak spot with Lexus? In the past I have left a BMW at Heathrow for nearly 4 weeks in winter, fully alarmed, and had no problem starting it on my return. Looking at some of the posts on this forum doing that with my Lexus would seem to be impossible, if so that would be disappointing.

It's because the 12v aux Battery isn't used for starting the engine, so to save weight and cost a small Battery is used. That however gets discharged at a quicker rate than a larger one and therefore you can't leave it standing as long. If the Battery is in good health then 3 weeks isn't a problem, 4 is pushing the limits.

Shada · April 13, 2020

The quality of the oe Battery wouldn't be great either, mine failed before it was 4 years old. I think there's a few threads on this forum with others needing replacements too.

A good brand of Battery such as bosch varta or yuassa is a worth while investment if you intend to keep the car.

Herbie · April 13, 2020

2 hours ago, Derant said:

I have owned my IS300h since January, my first Lexus. I have noticed a lot of topics referencing the 12v battery, is it a weak spot with Lexus? In the past I have left a BMW at Heathrow for nearly 4 weeks in winter, fully alarmed, and had no problem starting it on my return

But that wouldn't be a hybrid BMW though would it?

As Colin said above, the 12V batteries on hybrids are very small with a limited capacity. All my previous cars have had a Battery of at least 75Ah minimum, whereas my RX450h has the biggest engine (3.5litre) and weighs the most (almost 2tons) but has the smallest Battery at about 45Ah if I remember correctly.

The starter motor of a normal car will draw upwards of 300A when cranking the engine, but hybrids don't have a traditional starter motor and, as you'll see below, my RX450h only takes 15.32A to get it into the READY state instead of 300A or more. The 12V Battery only boots the computers and gets the hybrid system up and running; it doesn't have to crank the engine, which is why it can be smaller.

I carry a jump start Battery pack in the glove box, very much like this one for peace of mind. The one I've linked to is more powerful than you would need for your own car but it could enable you to help someone else if they had a flat Battery because you should never use a hybrid to jump start another car, although you may be alright if it's another hybrid.

The reason for this is that a hybrid doesn't have a traditional alternator. Instead, the Battery is charged by a DC/DC converter that 'steps down' the 288V of the traction Battery to about 14.5V and these converters aren't as robust as a traditional alternator and can only supply a fraction of the current that an alternator could. You don't want a car with a flat Battery trying to draw huge amounts of current from your converter, or the very expensive magic smoke inside it could escape with a bang.

It is alright though, for a hybrid to be jump started by another car if you didn't want to buy one of these Battery packs.

April 14, 2020

Thanks for the information guys

Mincey · April 14, 2020

17 hours ago, Herbie said:

You should never use a hybrid to jump start another car, although you may be alright if it's another hybrid.

It is alright though, for a hybrid to be jump started by another car.

Stolen, printed out, stuck onto my jump leads. Thank you @Herbie

Herbie · April 14, 2020

You're welcome James :thumbsup:

200h · April 14, 2020

On 4/13/2020 at 4:34 PM, Derant said:

I have owned my IS300h since January, my first Lexus. I have noticed a lot of topics referencing the 12v battery, is it a weak spot with Lexus? In the past I have left a BMW at Heathrow for nearly 4 weeks in winter, fully alarmed, and had no problem starting it on my return. Looking at some of the posts on this forum doing that with my Lexus would seem to be impossible, if so that would be disappointing.

not all cars are made equal .....there are differences between a standard petrol car and a hybrid car

the 12v Battery being the main difference ,a standard car Battery will have more than double the Ah's

of a hybrid Battery this is why the 12v Battery will go flat fairly quickly,

the best way to conserve 12v Battery power is to turn off the keyless entry and not set the alarm

just use the key to lock the doors the immobilser will still be activated.

Herbie · April 14, 2020

2 hours ago, 200h said:

the best way to conserve 12v battery power is to turn off the keyless entry and not set the alarm

Not setting the alarm will save a bit of power but your insurance company could get a bit uppity about that. As we know, the unscrupulous scrotes will look for any way to weedle out of paying up in the event of a claim.

And the radio presets and other stuff will still be drawing power anyway, so is it worth it? I don't know, I'm on the fence about this one.

Regarding turning off keyless entry, I know there's a sequence of button presses that you can do on the Series 4 RXs, but as far as I'm aware I think it only affects the key side of the equation; the car side is still actively looking for a signal from the key and so still drawing power. I'm not sure if your 2017 IS300hs will be the same or not but worth looking into it before you do it.

200h · April 14, 2020

my partner has a 66 plate toyota auris hybrid her car doesnt have an alarm but does have an immobilser

i think this can be said for alot of car manufacturers , an immobilser will help prevent a car being stolen

the alarm only makes a noise that can be silenced easily if you know where the sounder is fitted

Herbie · April 14, 2020

1 hour ago, 200h said:

my partner has a 66 plate toyota auris hybrid her car doesnt have an alarm but does have an immobilser

i think this can be said for alot of car manufacturers , an immobilser will help prevent a car being stolen

I see what you're saying Mark but the difference is that her car doesn't have an alarm.

If it left the factory without an alarm then that's one thing, but to make a concious decision to turn off a factory fitted alarm may well be a big thing to an insurer.

NemesisUK · April 14, 2020

Do Lexus not have an immobiliser fitted as standard? The alarm is just that, to signal an intrusion but I thought all modern cars had immobilisers fitted to prevent starting the car without the correct security code signal?

Are the two the same integrated unit, disable one disable both?

200h · April 14, 2020

another option if you aren't going to be using your car at all

during this current time would be to disconnect the Battery

only the clock, preset radio stations and 1 touch up & down of the windows

would need to be reset afterwards.

ColinBarber · April 14, 2020

28 minutes ago, NemesisUK said:

Do Lexus not have an immobiliser fitted as standard? The alarm is just that, to signal an intrusion but I thought all modern cars had immobilisers fitted to prevent starting the car without the correct security code signal?

Are the two the same integrated unit, disable one disable both?

The two are separate. You have to actively arm the alarm by locking the doors with the remote/keyless entry system. The immobiliser is set automatically by the ignition being turned off and the key being removed from the interior. The immobiliser is built into the engine ECU.

As has already been stated, not setting the alarm when you have one factory fitted, and the insurance group set based on that fact that it is there, is asking for trouble if the vehicle is stolen and it can be proven that the alarm wasn't armed. The alarm doesn't drain the Battery that much to warrant not setting it.

NemesisUK · April 15, 2020

Does the alarm have its own rechargeable Battery, as is the case with Mercedes?

Maxz · April 15, 2020

16 hours ago, Herbie said:

Not setting the alarm will save a bit of power but your insurance company could get a bit uppity about that. As we know, the unscrupulous scrotes will look for any way to weedle out of paying up in the event of a claim.

And the radio presets and other stuff will still be drawing power anyway, so is it worth it? I don't know, I'm on the fence about this one.

Regarding turning off keyless entry, I know there's a sequence of button presses that you can do on the Series 4 RXs, but as far as I'm aware I think it only affects the key side of the equation; the car side is still actively looking for a signal from the key and so still drawing power. I'm not sure if your 2017 IS300hs will be the same or not but worth looking into it before you do it.

It is possible to switch off keyless entry on the vehicle permanently per post below on a 2015 is300h, not sure if 2017 model has the same firmware and therefore options? Please also see my recent post on trickle charging, whacked mine on as soon as lockdown started and even then (after regular use over winter) ctek charger still took 3 days of charge mode (orange LED) before it finally flipped over to conditioning (green LED) mode. These small 12v definitely need regular topping up to avoid them dying prematurely.

ColinBarber · April 15, 2020

9 hours ago, NemesisUK said:

Does the alarm have its own rechargeable battery, as is the case with Mercedes?

Yes, to be a Thatcham approved cat 1 device, which all UK Lexus models have had installed since 1998, if not before, it has to have the following:

Alarm with full perimetric and volumetric detection, Battery backed-up siren.
Immobiliser isolating a minimum of 2 operating system, passively armed.
Anti-scan, anti-grab resistance of key codes.

matt8 · April 18, 2020

On 4/13/2020 at 11:05 AM, Zotto said:

I know some people that have jump started an hybrid connecting a tiny 12 V battery to 12 V discharged one.

I like the idea of this.

I have no knowledge of these things and so sorry if it's a silly question.

Would it be possible to connect a small 12v Battery like a house alarm Battery (2.1Ah) to achieve this?

ColinBarber · April 18, 2020

4 minutes ago, matt8 said:

I like the idea of this.

I have no knowledge of these things and so sorry if it's a silly question.

Would it be possible to connect a small 12v battery like a house alarm battery (2.1Ah) to achieve this?

yes. You could use that to 'jump start' a hybrid if your aux Battery was discharged.

You need to minimise the current draw though - lights off, turn off the stereo, heating etc before trying to get it into Ready mode.

matt8 · April 18, 2020

5 minutes ago, ColinBarber said:

yes. You could use that to 'jump start' a hybrid if your aux battery was discharged.

You need to minimise the current draw though - lights off, turn off the stereo, heating etc before trying to get it into Ready mode.

Thanks Colin. Makes sense.

Is 2.1Ah alarm Battery sufficient when the aux Battery is 45Ah?