Flat battery-happy birthday.

Herbie · April 28, 2020

Toyota's advice to turn off non-essential loads is really just to save petrol, no doubt for both economical and environmental reasons.

The 12V Battery will still be charged up whether these things are on or off, but if they're on then the car has to use more fuel. One of the basic laws of physics - energy can't be created, only converted (or something like that :rolleyes: ).

royoftherovers · April 28, 2020

1 minute ago, Herbie said:

Toyota's advice to turn off non-essential loads is really just to save petrol, no doubt for both economical and environmental reasons.

The 12V battery will still be charged up whether these things are on or off, but if they're on then the car has to use more fuel. One of the basic laws of physics - energy can't be created, only transformed (or something like that ).

E= MC2, Herbie !!

BigChange · April 28, 2020

Thanks for all the helpful advice and comments. I'm certainly clearer now. And as a precaution ran the engine for about 10 minutes today !

CVLex · April 28, 2020

Interesting thread, - on the related point about trickle chargers, (I too use the CTEK MXs 5.0), is it ok to connect them to the dedicated +charging access point and appropriate -bare metal point under the bonnet rather than directly to the Battery housed in the rear of the car ?

I reverse into my garage so just thinking it'll be much easier to connect at the front if ok to do so.

Thanks in advance.

Carl.

Bootleg · April 29, 2020

16 hours ago, Thackeray said:

19 hours ago, Bootleg said:

I had one of devices for a previous car, and it burst during use, so I'm rather nervous of them

17 hours ago, Bootleg said:

despite being a scaredy cat I'll go down this route

What happened? Were you starting a conventional car with a conventional starter motor? Did the device claim to be big enough to start whatever size of engine you were starting?

Of course, in a hybrid car, you're only booting up the computers so the current really shouldn't be enough to overload the jump starter, particularly if it claims to be big enough to start, say, a 2.5 or 4 litre engine.

It was a conventional car. It had previously worked fine, must have been defective. I'd bought it from a local motor accessories shop who were mortified. They immediately refunded me, came out and replaced my Battery with a new one for free. Good customer service, or guilt?

Mincey · April 29, 2020

16 hours ago, Thackeray said:

2. When power generation does start, it took around 4-5 minutes to increase the hybrid battery charge from two to six bars.

This could have answered one of the questions I've had about my IS300h since day 1. Six bars is 100% full then? There always looks to be a blank bar above the highest point mine reaches. I wasn't sure whether this was another bar which could be filled or was a space on the graphic.

Wallace · April 29, 2020

11 minutes ago, Mincey said:

This could have answered one of the questions I've had about my IS300h since day 1. Six bars is 100% full then? There always looks to be a blank bar above the highest point mine reaches. I wasn't sure whether this was another bar which could be filled or was a space on the graphic.

I was told it never charges to 100% and never goes completely flat at 0%. So there is always an unfilled bar at the top.

Mincey · April 29, 2020

13 minutes ago, Wallace said:

I was told it never charges to 100% and never goes completely flat at 0%. So there is always an unfilled bar at the top.

Thank you!

Farqui · April 29, 2020

You're right that the vehicle controls the traction Battery usage and will not over charge.

I maybe wrong but don't the bars on the hybrid Battery display show 40% to 80% of total Battery capacity?

So you can get all the bars showing full which equates to 80% Battery.

Herbie · April 29, 2020

1 hour ago, Wallace said:

I was told it never charges to 100% and never goes completely flat at 0%. So there is always an unfilled bar at the top.

That's not quite correct.

As the driver/user of the car we never get to use 100% of the traction battery's capacity. I forget the actual figures but I think I'm right in saying that we get to use about 60% of it.

To over-simplify it, think of it as a bar graph just like it's depicted in the car display - we are blocked from the bottom 20% and the top 20% and are only allowed to use the middle 60% (or whatever figure it may be).

However, and this is crucial, the bar graph display in the car only refers to the 60% that we can use. It does not map the capacity that we can't use, so when you see all bars illuminated (as you will on long hill descents) then it's telling us that the portion of the Battery we can access is fully charged, not necessarily the whole Battery.

Our 'partial use' (for want of a better phrase) of the whole Battery increases the longevity of the Battery by a very substantial amount. I can't remember the physics or engineering behind it but, as always, if you want to find out more then Google is your friend 🙂

Thackeray · April 29, 2020

1 hour ago, Mincey said:

Six bars is 100% full then? There always looks to be a blank bar above the highest point mine reaches.

As several others have said above you can't run it down to 0% or up to 100%. I've never seen anything definitive about the Lexus setup but I've seen a graphic for Prius batteries that says one bar is 40% and eight bars is 80%. I expect it's similar in the Lexus batteries.

Having said that, the aim of the computer is not to fill the Battery. The point of the Battery is to store spare or regenerated electricity. If the car keeps it full, there won't be anywhere to store surplus energy when it's available. This suggests the optimum target for the Battery is around 50% full - that would be plenty of space to store surplus energy but also plenty of extra power to use for a sudden spurt of acceleration. A graphic I once found but can't find now showed that from around two to six bars represents around 50-60% of Battery capacity.

So why did my car run the Battery up to six bars yesterday? I would guess that because the car was stationary the software decided that while the engine was running to keep the cabin warm, a lot of energy was just being thrown away - so instead some was saved in the Battery. Later when the heater was off, the car didn't bother to start when the Battery went down to a better level of five bars; it isn't aiming to keep the Battery topped up, it's aiming to keep plenty of capacity for regenerated electricity.

I've only ever seen eight bars on the gauge once and that was after going down a two mile long hill. At the start of the descent, the engine was off. But as the Battery gauge got to seven and eight bars the engine started to run. I think this somehow uses up spare electricity. At the end of the descent, I had to stop at some red lights and oddly, the engine started when the car stopped with the Battery on eight bars. Usually the engine would stop at traffic lights. I think this must have been to somehow lower Battery levels from what was then presumably about 80%. But it seemed a paradox for the engine to start when the Battery was "full" (ie around 80%).

Mincey · April 29, 2020

This is all absolutely fascinating! The thought process which went into designing these systems is mind boggling.

Thackeray · April 29, 2020

I've now found the chart for battery charge on a Prius. This is presumably from a few years ago but I don't suppose the general principles have changed much. Scroll down about a third of the way down the page to the post by "m.wynn". You can then click on the chart to open up the image.

You'll see that I didn't quite remember the details right. Bars two to six on this chart represent 45% to 66%. Whether that's the same on the Lexus I don't know but I expect it's broadly similar.

Dealkent · May 28, 2020

How much are we looking at for a replacement Battery, supplied And fitted ? . My IS300 h is still languishing in an underground car park in Spain and a friend has just informed me the Battery is flat . I hoping it just needs charging . We have Europe breakdown cover with our extended warranty so they should come, out and either charge it up or jump star5 it with leads ? . I’m guessing the Battery is in the boot ? It will Ben very difficult to get to the engine / bonnet . Any advice welcome .

jumbojake · May 28, 2020

I recharged the one in out Rx... got the car started, but it wouldn't hold the charge (the deep discharge had caused irreversible damage to an old battery) .. the Battery was dead.

I couldn't find a replacement, so had to get a genuine one.. about £200 from lexus part direct.... 10mins to fit

Herbie · May 28, 2020

1 hour ago, Dealkent said:

My IS300 h is still languishing in an underground car park in Spain and a friend has just informed me the battery is flat

Depending on how long it's been there or will still be there, you may have problems.

The 12V Battery starts the hybrid system which then charges the 12V Battery. As you'll see mentioned many times in these forums, these 'starter' batteries if you like, are small and tend to go flat fairly quickly but it's easily remedied if it happens, possibly even by a simple jump start.

The traction Battery is much, much bigger and seems to last around two or three months, possibly even longer, I don't know. However, it is roughly 288V and if that goes flat you can't simply jump start it, nor can the AA/RAC or the Spanish equivalent deal with it. It would need a Lexus dealership or someone else with the specialist gear and knowledge to get the car running in that situation.

royoftherovers · May 28, 2020

2 hours ago, Dealkent said:

How much are we looking at for a replacement battery, supplied And fitted ? . My IS300 h is still languishing in an underground car park in Spain and a friend has just informed me the battery is flat . I hoping it just needs charging . We have Europe breakdown cover with our extended warranty so they should come, out and either charge it up or jump star5 it with leads ? . I’m guessing the battery is in the boot ? It will Ben very difficult to get to the engine / bonnet . Any advice welcome .

Get the Breakdown Service (BS) to go to your car soonest and have a friend in attendance.

BS will start the car and ask your friend to keep the engine running for 30 mins.

Ask friend to start the car up the next day and keep it running for 30 mins again.

Ask your friend to do this religiously once each week until you arrive

When you collect the car, give your friend a case of wine or a litre and a half of Scotch !

All the very best as nothing ventured, nothing gained!

Dealkent · May 29, 2020

On 5/28/2020 at 1:02 PM, royoftherovers said:

Get the Breakdown Service (BS) to go to your car soonest and have a friend in attendance.

BS will start the car and ask your friend to keep the engine running for 30 mins.

Ask friend to start the car up the next day and keep it running for 30 mins again.

Ask your friend to do this religiously once each week until you arrive

When you collect the car, give your friend a case of wine or a litre and a half of Scotch !

All the very best as nothing ventured, nothing gained!

The problem is , car Is underground, the engine running will be an issue, the fumes . Also , what does our friend do for 30 mins each time ? . Think we will wait to we get out there , then call out Breakdown and then supervise ourselves . Flying out there In mid July .

Thanks for response .

Dealkent · May 29, 2020

On 5/28/2020 at 11:52 AM, Herbie said:

Depending on how long it's been there or will still be there, you may have problems.

The 12V battery starts the hybrid system which then charges the 12V battery. As you'll see mentioned many times in these forums, these 'starter' batteries if you like, are small and tend to go flat fairly quickly but it's easily remedied if it happens, possibly even by a simple jump start.

The traction battery is much, much bigger and seems to last around two or three months, possibly even longer, I don't know. However, it is roughly 288V and if that goes flat you can't simply jump start it, nor can the AA/RAC or the Spanish equivalent deal with it. It would need a Lexus dealership or someone else with the specialist gear and knowledge to get the car running in that situation.

I’m confused . There is a starter Battery and then the Battery that is charged when driving for the electric motor . If the starter Battery is charged that will start the petrol engine and then we should get going . Are you saying we’re could still have problem ? Are you saying there are 3 batteries ?? . I’m getting worried now !!!

Dealkent · May 29, 2020

On 5/28/2020 at 11:00 AM, jumbojake said:

I recharged the one in out Rx... got the car started, but it wouldn't hold the charge (the deep discharge had caused irreversible damage to an old battery) .. the battery was dead.

I couldn't find a replacement, so had to get a genuine one.. about £200 from lexus part direct.... 10mins to fit

Oh s**t . Think this will ruin our holiday there .......

jumbojake · May 29, 2020

essentially the 12v Battery powers the computer .. once that is up, the traction Battery can then charge the 12v.... if the traction Battery is low, the computer will fire the engine to keep the traction Battery charged... all very cleaver, but ultimately need the 12v to start it all.

before our new 12v Battery arrived, I was sitting int he car for 30mins each night, so it could keep enough charge for another day (it's a real pain if it goes totally flat, as you have to open the boot from inside).... to be honest it was 30 mins in a closed space on my own with none bothering me... bliss!

Herbie · May 29, 2020

9 hours ago, Dealkent said:

I’m confused . There is a starter battery and then the battery that is charged when driving for the electric motor . If the starter battery is charged that will start the petrol engine and then we should get going . Are you saying we’re could still have problem ? Are you saying there are 3 batteries ?? . I’m getting worried now !!!

No, there's only two batteries, a 12V Battery to boot the computers to get the hybrid system up and running, and a 288V hybrid or traction Battery - so that's two batteries that can go flat if the car isn't used.

It sounds complicated (and it is) but it boils down to the fact that you need three things - the 12V Battery, the traction Battery and the petrol engine.

If you ran out of petrol you would not be able to drive the car for more than a couple of miles on the traction Battery alone, if at all, and vice versa - if the traction Battery went faulty you wouldn't be able to use it purely as a petrol-driven car.

So, if the car is in storage and not being used, the 12V Battery will be the first to lose charge and go flat. If the car is left even longer then eventually the traction Battery will also go flat after about two to three months. The first one is easy to deal with. The second one, if it were to go flat, would need specialist equipment and knowledge to deal with.

In a conventional car the 12V Battery is used to energise the starter motor and crank the engine. Hybrids don't have a starter motor as such and the process is different. The hybrid computer uses the traction Battery to energise MG1 (or is it MG2 - I can never remember) which spins the petrol engine up to about 1,000rpm before applying fuel and a spark, so a flat traction Battery means no petrol engine either.