rhosneigr

Hybrid battery charging

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During the lock down I am confined to home. I am aware that the auxiliary Battery can be topped up with a Battery charger but my question concerns the hybrid batteries. If I sit in the car on the drive in the ready mode and out of drive mode with pressure on the accelerator to keep the engine going at low revs, does this put any charge in the hybrid batteries? 

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6 minutes ago, rhosneigr said:

During the lock down I am confined to home. I am aware that the auxiliary battery can be topped up with a battery charger but my question concerns the hybrid batteries. If I sit in the car on the drive in the ready mode and out of drive mode with pressure on the accelerator to keep the engine going at low revs, does this put any charge in the hybrid batteries? 

I believe that the answer is "no" John.

The Handbook tells us not to engage Neutral when at Traffic Lights for instance.

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You can't rev the engine by pressing the accelerator. These cars are 'drive-by-wire' and the accelerator is connected to a computer rather than a mechanical linkage to fuel injection or whatever. Without other inputs to the computer, pressing the accelerator has no effect on anything.

Toyota's advice on their website to keep the 12V Battery topped up says to put the car into READY mode (with things like the radio, aircon etc., switched off) for 60 minutes per week. The engine will fire up as and when needed as long as the gear selector is in 'P'.

The traction Battery will be good for at least a couple of months and probably longer.

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That's not the case in my hybrid, the engine rev's when in Park.  See John's post here that confirm the traction Battery will be charged whilst doing this (albeit not by much) 

During quarantine, Lexus recommendations are noted here; https://blog.lexus.co.uk/lexus-hybrid-parked/

I haven't seen much loss of charge to my hybrid battery since mid March, although it has had a good run to the shops occasionally.  I don't tend to leave it sat for more than a couple of weeks max.

Provided you are keeping the 12v aux Battery topped up, I wouldn't worry too much about yours being sat.

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Thanks for the replies. I have tried this and the engine does fire up when the accelerator is pressed albeit not like an  ordinary car where you can rev up to high revs and down. There does seem to be some limit to how fast the engine will rev up to. I will probably take a decent run to charge the hybrid barreries despite the lockdown. My question was just out of interest though. 

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Every day's a school day  :thumbsup:

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14 minutes ago, Herbie said:

Every day's a school day  :thumbsup:

And you are not allowed back until June young man !

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2 hours ago, rhosneigr said:

If I sit in the car on the drive in the ready mode and out of drive mode with pressure on the accelerator to keep the engine going at low revs, does this put any charge in the hybrid batteries? 

 

2 hours ago, royoftherovers said:

I believe that the answer is "no" John.

The Handbook tells us not to engage Neutral when at Traffic Lights for instance.

I've been putting my car into Ready mode weekly over the last few weeks and I've learnt the following points from watching what it does.

First, you can rev the engine while in Park - at first I thought you couldn't do this but you can. But I think charging stops when you do this. At least the energy monitor shows charging when the engine is "idling" (ie around 1,100 rpm) but the charging stops when you rev the engine above idle speed. I don't know why it does this - maybe to protect motor-generator 1 (MG1) from excess speed while generating. (As royoftherovers says, it never charges when you're in Neutral.)

Second, I've now grasped that the 12v Battery is being charged.whenever the car is in the Ready state, whether the engine is running or not. The charging power (around 14.4V) comes from the hybrid Battery via the inverter, whether the engine is running or not.

What I've seen in recent days is that it takes around 20 minutes or more without the engine running for the hybrid Battery to drop from three bars to two bars while doing little more than charging the 12v Battery and playing the radio (climate control off, everything else off). It will sit quite happily at two bars for quite a while before the engine starts up again to begin charging the hybrid Battery. Its natural level in this situation seems to range from two to three bars, with the engine stopping at three bars and restarting at two bars. As has been said elsewhere, this represents around 50-55% real charge level, which is probably the target range set by the computer.

If for some reason, you do want to put a higher charge in the high voltage Battery than around three bars (perhaps if it's going to be stored for six months, for example) then paradoxically, it will probably charge more efficiently (though not necessarily more quickly) by leaving the car standing rather than going for a drive. With the car stationary and the engine idling, MG1 spins at around 4,000 rpm. But if you drive the car at town speeds MG1 (which charges the high voltage Battery) will spin more slowly,until it stops altogether and then starts to spin in the reverse direction, then speeding up again.

Unless you actually want to go for a drive, it's probably easier and will use less petrol if you choose a cold day (or night), put the car in ready and turn on the climate control to a warm temperature. The engine will then run to warm up the cabin and spare energy from the engine will be stored in the Battery. I've got the hybrid Battery up to six bars by keeping the heat on when the weather is cold but without touching the accelerator, which seems to stop the charging.

But from what I've read, there's no real need to get the high voltage Battery up to a higher level of charge if the car will be unused for only a month or so. The 12volt Battery is another matter, of course.

 

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Thanks again for some excellent and informative replies, also the pointer from Farqui to the Inactivity during lockdown diacussion in the GS300 section. Very interesting posts. 

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