Flat Battery Experience

[ColinBarber]

44 minutes ago, Herbie said:

This is referred to as the 'quiescent' current draw and most modern cars seem to be in the 50 to 70mA (milliamps or 0.05 to 0.07A) range

I've not measured it but I suspect the latest models have a higher current draw than that. Smart entry means the vehicle is constantly transmitting a signal to find a key, plus Bluetooth if the vehicle has digital key connectivity and Internet connectivity is always active to accept remote A/C commands etc.

[lexuswannabe]

13 hours ago, ColinBarber said:

The issue is that when the hybrid/traction battery gets low the petrol engine cannot recharge and you therefore run the risk of fully discharging the battery which is very bad (although I'm sure the vehicle will just shut down before that happens).

Is this because the petrol engine just won't start or because a low charged traction Battery is inherently not chargeable?

 

10 hours ago, Herbie said:

The traction battery energises MG1 (Motor/Generator 1) and uses that to spin the ICE up to 1,000rpm before supplying fuel and a spark to ignite it.

I'm sure there are electronic gadgets to stop it, but if your traction Battery engine is too low to get the MG1 turning are you are more or less stuffed? A 12v booster pack won't work as the motor gets its oomph from the traction Battery and I don't have a 280v trickle charge Nickel Metal hydride charger. 

I don't now if it's of any concern but it seems the 12v Battery can be discharged relatively easily. Herbie's example Battery has just under half a KWH capacity, but the gigantic, huge traction Battery only has twice this (1 KWH) and doesn't the traction Battery charge the 12v Battery?

[AntonyP]

Herbs describes my own experience exactly.  My GS450h has a 70Ah Battery and it will, in good condition, be good for around 35+ days. So if your going on a long cruise remember to keep a jump starter pack in the boot! Mine was the small 2L one costing £60 from Halfords, enough to power up and command the power control unit to instruct the traction Battery to start the ICE via the gearbox.

[wharfhouse]

8 hours ago, lexuswannabe said:

Is this because the petrol engine just won't start or because a low charged traction battery is inherently not chargeable?

 

I'm sure there are electronic gadgets to stop it, but if your traction battery engine is too low to get the MG1 turning are you are more or less stuffed? A 12v booster pack won't work as the motor gets its oomph from the traction battery and I don't have a 280v trickle charge Nickel Metal hydride charger. 

I don't now if it's of any concern but it seems the 12v battery can be discharged relatively easily. Herbie's example battery has just under half a KWH capacity, but the gigantic, huge traction battery only has twice this (1 KWH) and doesn't the traction battery charge the 12v battery?

I think you are getting overly worried about this. If you keep a 12V lithium jump starter pack to hand then should the 12V Battery be depleted (for example using electrical accessories without the car in Ready mode or leaving it for a few weeks without starting it) you will be able to start the car without any problem. The chances of completely depleting the traction Battery are so remote so long as you drive the car normally and don't leave it in N in the Ready mode for a long time (or run out if petrol - not sure what happens then) the the car will manage the traction Battery so as to not to leave you stranded (unlike an EV the ICE will always come on and recharge the hybrid battery). 

[ColinBarber]

10 hours ago, lexuswannabe said:

Is this because the petrol engine just won't start or because a low charged traction battery is inherently not chargeable?

When in Neutral the engine and transmission are disengaged. Therefore the petrol engine cannot drive the generator to charge the Battery. This is a non-issue provided you use Park and not Neutral when stopped for more than a minute or two.

[EEH]

On 8/28/2024 at 1:32 PM, Herbie said:

The traction battery energises MG1 (Motor/Generator 1) and uses that to spin the ICE up to 1,000rpm before supplying fuel and a spark to ignite it.

First of all is the fact that it's a design fault that should never have got past the drawing board stage - but it did. Lexus/Toyota decided to use low electrical capacity 12V batteries, as indicated by the Ah (Amp-Hour) rating on the label.

I haven't got an LBX so I don't know what capacity the battery is, but for the sake of this example let's just say 40Ah. This means that it can supply 40A for one hour, or 20A for two hours, or 10A for four hours etc. Even during the middle of the night when the car is 'asleep' there is still power being drawn from the battery to supply the intruder alarm, the radio presets, seat memory, the clock and so on. This is referred to as the 'quiescent' current draw and most modern cars seem to be in the 50 to 70mA (milliamps or 0.05 to 0.07A) range; anything more could possibly indicate a fault and is then known as a 'parasitic' current draw.

So, if we assume a brand new and fully charged battery we can then say 40Ah divided by 0.05A = 800 hours (which is 33.3 days or 4.76 weeks) to go from fully charged to fully discharged if the car isn't touched. However, this is a theoretical maximum and various things will mean that you never see this in reality. Also, don't forget that the battery will be too low to start the car long before it becomes fully discharged, so the 33.3 days will probably drop into the twenty-something range of 'useable' days. Plus, each time it does go flat it damages the plates and loses a little bit more capacity.

You can now perhaps see why it's so important to use the car regularly or to trickle charge it. As I've said before, hybrids do not suit everybody and if your driving patterns mean either short runs and/or long periods of inactivity then a conventional ICE car may be more suitable for you (by which I mean in general, not you personally).

Great explanation Herbie! Thanks for this and makes sense.

As I have said before, as I sadly don't do that much long distance driving, my Lexus dealers solution to the problem was to install as wiring lead to directly to the 12v Battery, to which I then need to pull the lead out the rear right hand door. Then connect a tiny solar panel which is stuck on with suction cups either to the rear window or roof. Looks ridiculous to be honest, but was told that having this will help to keep the 12v Battery charged and would pose no danger to the Battery and ensure I never end up with a flat Battery. Time will tell.

[stepppy]

You could just put the solar panel on your dash.  I know the windows will suck up some of the UV, but it should get enough to keep the Battery topped up.  That is what my Dealer was doing with their cars during lockdown.

[Herbie]

On 8/29/2024 at 7:30 AM, wharfhouse said:

don't leave it in N in the Ready mode for a long time (or run out if petrol - not sure what happens then)

First of all you need to put in at least 10 litres before attempting to start it.

If you're unlucky enough to have three failed attempts at starting, the hybrid system could lock out. If that happens you'll need to be recovered on a flat-bed recovery vehicle - not towed - to the nearest Lexus dealership for them to reset it. I'm not sure if a local independent hybrid specialist could do it but it'd be worth asking if you're ever in that situation.

[EEH]

8 hours ago, stepppy said:

You could just put the solar panel on your dash.  I know the windows will suck up some of the UV, but it should get enough to keep the battery topped up.  That is what my Dealer was doing with their cars during lockdown.

I said the same to the dealer and wanted them to do exactly what you said, but in my opinion they were too lazy to install a longer wire to reach the front dash section and they opted to use the standard wiring lead that came with the solar panel which is not that long, and this was their amazing solution! So advise to all who may do the same, insist if they offer to do something similar to have it done with a longer wiring section to reach the front dash. 

[stepppy]

15 hours ago, EEH said:

I said the same to the dealer and wanted them to do exactly what you said, but in my opinion they were too lazy to install a longer wire to reach the front dash section and they opted to use the standard wiring lead that came with the solar panel which is not that long, and this was their amazing solution! So advise to all who may do the same, insist if they offer to do something similar to have it done with a longer wiring section to reach the front dash. 

Strange, as the ones they used and were selling plugged into the OBD port under the dashboard. Around £90 if I remember correctly.

I wonder if yours also came with an OBD connector, but they decided to use the direct to Battery option?

[lotoit]

using the car only on Saturdays and Sundays and never during the week do you think I could be at risk of such problems? I hadn't considered this before buying a hybrid car, unfortunately (I should receive it next week).

[wharfhouse]

24 minutes ago, lotoit said:

using the car only on Saturdays and Sundays and never during the week do you think I could be at risk of such problems? I hadn't considered this before buying a hybrid car, unfortunately (I should receive it next week).

So long as you do an hour or two each weekend you should not have any problems. 

[RONNIE W HODGEKINSON]

On 8/16/2024 at 9:51 AM, Steve7458 said:

I have all ways carried a NOCO boost since my flat battery days in RC's and UX cars, little pricey but gets you out of problems very quickly. Highly recommended 

Never Leave Home Without It Steve..!!!

[RONNIE W HODGEKINSON]

On 8/29/2024 at 12:12 AM, AntonyP said:

Herbs describes my own experience exactly.  My GS450h has a 70Ah battery and it will, in good condition, be good for around 35+ days. So if your going on a long cruise remember to keep a jump starter pack in the boot! Mine was the small 2L one costing £60 from Halfords, enough to power up and command the power control unit to instruct the traction battery to start the ICE via the gearbox.

NO... Keep Your Jump Start Unit In The Glovebox You Might Just not be able to open The Boot......!!! Think About it

[LenT]

14 minutes ago, RONNIE W HODGEKINSON said:

NO... Keep Your Jump Start Unit In The Glovebox You Might Just not be able to open The Boot......!!! Think About it

That’s a very interesting point, Ron, that hadn’t occurred to me!  Worrying too as I couldn’t even fit a pair of gloves into my crowded glove box.

So I’ve just checked.  In the event of electrical failure it appears that on my Lexus at least, the mechanical key will work on the boot lid as it does with the doors.  Whether that applies throughout the range, I don’t know.

[Boomer54]

32 minutes ago, RONNIE W HODGEKINSON said:

NO... Keep Your Jump Start Unit In The Glovebox You Might Just not be able to open The Boot......!!! Think About it

That had also occurred to me. I carry mine in the central storage box between the seats. I bet this 'box' actually has a name if I could just remember it. Enlighten me anybody!

[Herbie]

2 hours ago, LenT said:

So I’ve just checked.  In the event of electrical failure it appears that on my Lexus at least, the mechanical key will work on the boot lid as it does with the doors.

My 2018 RX doesn't have a mechanical lock/key slot in the tailgate, so my Battery pack is in the cabin too.

[LenT]

2 hours ago, Boomer54 said:

I bet this 'box' actually has a name if I could just remember it. Enlighten me anybody!

Console Box.

And I claim my £5!

[Boomer54]

1 minute ago, LenT said:

Console Box.

And I claim my £5!

£5. See Malc my accountant.. ☺️

[lotoit]

To start the car, is it then sufficient to connect the jump starter to the Battery and push the start button or do you have to wait or follow a different procedure?

[wharfhouse]

26 minutes ago, lotoit said:

To start the car, is it then sufficient to connect the jump starter to the battery and push the start button or do you have to wait or follow a different procedure?

Just connect the jump starter to the Battery (or the 12V connection points - there is a positive in the engine bay and negative is a point on the chassis) following the instructions on the unit and then push Start as normal. 

[EEH]

On 8/31/2024 at 1:49 PM, stepppy said:

You could just put the solar panel on your dash.  I know the windows will suck up some of the UV, but it should get enough to keep the battery topped up.  That is what my Dealer was doing with their cars during lockdown.

Would have been the best option and the better looking, but my dealer sadly I think took the "lazy" route as the did not want to run a longer lead from the back of the car to the front and kept the std wiring that came with the unit, which is not long

[lotoit]

20 hours ago, wharfhouse said:

Just connect the jump starter to the battery (or the 12V connection points - there is a positive in the engine bay and negative is a point on the chassis) following the instructions on the unit and then push Start as normal. 

Thanks.
Do you think this product could be enough or do I need something different?
https://www.amazon.it/demergenza-automatico-estremamente-NOCO-GB20/dp/B015TKPT1A/?__mk_it_IT=ÅMÅŽÕÑ&language=en_GB

PS.
I saw a video where they show where to connect the clamps. For the negative one, is there a position closer to the positive in your opinion? I have seen that the various jumper boosts all have very short cables.
 

[stepppy]

When I connect my smart charger to my NX whilst on extended holidays, I use a bolt near the suspension turret and it works fine for me. 

As a test, I used a meter to test the voltage using the bolt I chose and compared it to the position they show in the manual and it was the same and it has worked perfectly. 

Difficult to see in your photo, but it looks like you have a few close points to choose from.

 

[ColinBarber]

49 minutes ago, lotoit said:

Do you think this product could be enough or do you need something different?

Yes, it will be fine for the LBX, or any other Lexus hybrid.