LC500h battery charging

[Wishing]

Hi - my elderly father in law owned an LC500h and sadly he has been seriously ill for most of this year and had been unable to drive the car. The AA have been out to charge the Battery after it went flat due to lack of use.
Is it possible to keep the Battery 'usable' and charged by merely having the car engine running whilst stationary, or does it need to be taken for a drive to keep the Battery charged ? My elderly mother in law not in a position to drive the car sadly.

 

Thank in advance

[malcolmw]

On hybrids you can leave them switched on in "P" on your drive and they will self manage the low voltage Battery charging. Lexus recommend about 1 hour per week when standing unused but this is probably more than enough charging to keep everything in order. The low voltage Battery is charged via a DC/DC converter from the traction Battery which is about 50A rating. You don't have to drive anywhere.

[RiverFred]

Purchase a trickle charger, the clips hook to the Battery terminals and the chord will plug into an electrical connection. You will probably need an extension chord for the plug. This will keep the Battery charged. 

[BrettMRC]

As above - look at CTEK trickle chargers, they are a great solution.

[Brian R]

A trickle charger is only going to charge the 12 volt Battery which in reality may well be the first Battery to  discharge over time. The traction or hybrid Battery is a totally separate entity and cannot not benefit from a 12 volt trickle charger. The hybrid Battery is charged from the engine and braking.

Attached is a pdf file detailing the traction (hybrid) charging regime.

 

hybrid charge from user manual.pdf

[BrettMRC]

True, but the 12v is the most likely to discharge - and without it you have nothing...?

[NemesisUK]

Battery maintenance for when the car isn't driven for prolonged periods. (Covers both traction and 12v batteries)

 

Maintenance of hybrid battery.pdf

[Brian R]

25 minutes ago, BrettMRC said:

True, but the 12v is the most likely to discharge - and without it you have nothing...?

As I understand it, with no hybrid Battery charge, you cannot start the LC500h engine given it is the electric motor(s) that turn it and not a conventional 12 volt starter motor as would be the case on say a LC500. Thankfully, I have never been put to the test to see how it plays out in reality. It seems the best solution is to keep both batteries charged using a combination of driving or given the 12 volt will likely discharge first, perhaps a trickle charger. The trickle charger is the approach I use if the car isn't going to move for a week or two. I've yet to get anywhere near the hybrid Battery going flat, so for me an unknown scenario.

[wendle]

Lexus did put out a email to all Hybrid owners during lockdown/Covid, suggesting you put the ignition on, wait until the Green "READY" light comes on and leave it a hour and to do this once a week if the car is not used.

[NemesisUK]

The 12v Battery will definitely go flat long before the traction Battery. Hence the recommendation from Lexus to put the car into Ready mode once a week to use the traction Battery to recharge the 12v Battery. Should the traction Battery discharge far enough the petrol engine will fire up to recharge it.

The good thing is the traction Battery is totally isolated from any drain when the car is off, so it will be months before it goes critical. The bad thing is only Lexus or a hybrid specialist will be able to recharge it enough to get the system going again. 

[BrettMRC]

NemisisUK is spot on 🙂

I had similar issues with my fathers RX when he became very ill.

Chronologically the 12V tends to discharge before the hybrid capacitance pack becomes unserviceable, hence keeping it on a trickle charge so that you can go out and run her up every now again is the best option.

I would still recommend taking the car for a drive if possible; it does no end of harm to any car to be sat unused - even if it's just a 10 mile jaunt it will help.  (Stops seals drying out etc)

[malcolmw]

Take a look at this from the Lexus website:

https://mag.lexus.co.uk/lexus-hybrid-parked/