Should I use a trickle charger if car won’t be driven

[PeteTP]

I wonder could I trouble those that know about hybrids v storage to share their wisdom/experience/knowledge please? My beloved ES may be driverless for 3 months. What should I be doing in the interests of protecting the cars batteries and electrical system during that hiatus? Trickle charger? Any preferred make/model? 
 

All replies gratefully received. Thanks in anticipation.

 

PeteTP

[NemesisUK]

Attached is Lexus' maintenance advice on the batteries.

Personally I have had good experience with the CTEK MX5 maintenance charger when laying up my previous cars.

Maintenance of hybrid battery.pdf

[PeteTP]

Fabulous! Thanks so much for sharing this with me. Will get to work on this for sure.

Ciao.

 

PeteTP

[Cs150]

Still waiting for my ES to be delivered so have no knowledge on the subject. Can any existing owners report when the vehicle is unused for how many weeks would it be before the batteries start to run low and there are issues starting? With conventional petrol cars I have been ok leaving them for 7-8 weeks and they start fine. A hybrid presumably should be charged before such a time?

[Herbie]

4 hours ago, PeteTP said:

I wonder could I trouble those that know about hybrids v storage to share their wisdom/experience/knowledge please? My beloved ES may be driverless for 3 months. What should I be doing in the interests of protecting the cars batteries and electrical system during that hiatus? Trickle charger? Any preferred make/model? 
 

All replies gratefully received. Thanks in anticipation.

 

PeteTP

A trickle charger like the CTEK that Peter mentions above is the absolute best way to prevent the 12V Battery going flat in the first place. Unfortunately, not everyone has a garage or driveway or indeed a power point near where the car is parked, so second choice is a solar charger, but you have to be careful to get one powerful enough as a lot of them aren't.

Finally, if the Battery does go flat, something like this jump start battery pack would get it restarted. This is the make and model that I have and although I've only had to use it on my RX once, I've started a few conventional cars with it and it's absolutely brilliant.

[Herbie]

19 minutes ago, Cs150 said:

Still waiting for my ES to be delivered so have no knowledge on the subject. Can any existing owners report when the vehicle is unused for how many weeks would it be before the batteries start to run low and there are issues starting? With conventional petrol cars I have been ok leaving them for 7-8 weeks and they start fine. A hybrid presumably should be charged before such a time?

You can (sort of) work it out but there's still a certain amount of guesswork to it.

First of all, let's assume that it's a brand new, fully charged Battery (obviously highly unlikely in reality). Somewhere on the Battery will be a label with its capacity in Ah, so for the purposes of this example, lets say 45Ah. This means that it can supply 45A for one hour, or 22.5A for two hours and so on.

Even in the dead of night when you're all asleep, there's still a drain on the Battery for things like the clock, the alarm, the radio presets and the seat memory etc. This is called the quiescent current and is generally assumed to be around 50mA or 0.05A. You should be able to get the exact figure from the manufacturer of the car but I've never seen it in reality.

Anyway, if we say 45Ah / 0.05A then that equals 900 hours, or 37 days, or 5.28 weeks. But remember - that is assuming a brand new Battery and that is the time period from fully charged to fully discharged. In terms of being able to start the car, the Battery will fail to do that quite a way before it's fully discharged.

[PeteTP]

Loving the generosity of sharing your knowledge gents. Much appreciated TVM.

 

PeteTP

[SH20]

The only cars were a trickle charger has not been necessary is Lexus regarding both Hybrid and none Hybrid.   

I used CTek chargers for all other cars and you would never own a Bentley or Jaguar without using a trickle charger, they are notorious for Battery issues and warning lights coming on unless the Battery is always at peak power levels.    There was never a need for keeping the Battery topped up with any Lexus I have owned and especially the hybrids, (3)    One of my hybrids was left in my garage for over a month and just started  on the button.  

[Barry14UK]

It largely depends on how old 12v Battery is and whether and state of charge before taking out of use.  Herbie has given reasoning and a smart charger has been referenced by another member.  I use the same model charger although there are others. If your Battery is an AGM one, the smart charger should be set to that mode. Buy one that does not charge at a rate of more than 5amps.  It will do this as required and then reduce amperage as Battery becomes more charged.  It will then trickle as necessary to keep Battery charged - smart isn't it? 

Good idea to have the traction Battery well charged when it should last several months without use.  If this does happen it can need a Lexus dealer to fix.

[Walus]

On a regular day the voltage reading on my Battery is 12.2V. I did about 4 hours driving yesterday, left the car overnight and checked the Battery this morning. It read 12.3V. To me it seems that keeping the Battery at full charge is not what the car aims at. 
I’m heading away for 4 weeks and I wonder what voltage would the Battery be at after that period if the starting point is 12.3V. 
I might hook it up to ctek before leaving. 
 

Is it ok to charge it without disconnecting it from the car? I have done it in Rx, I presume there should be no issues.

[Herbie]

56 minutes ago, Walus said:

On a regular day the voltage reading on my battery is 12.2V. I did about 4 hours driving yesterday, left the car overnight and checked the battery this morning. It read 12.3V. To me it seems that keeping the battery at full charge is not what the car aims at. 

It does really but as the Battery ages it loses the capacity to accept a 'full' charge, so what you're seeing may be the most it can achieve at this point in its life. The chart below shows 'offload' voltages, which, admittedly, doesn't really mean a lot. If a Battery is going bad then once you put a load on it that voltage may drop like a stone, which is why a proper Battery tester is preferable to just a standard multimeter, as the proper tester will simulate a load.

56 minutes ago, Walus said:

I’m heading away for 4 weeks and I wonder what voltage would the battery be at after that period if the starting point is 12.3V. 

I'm sure there's a formula to work that out but my brain seems to be on holiday today and I just can't remember what it is. However, if you look at the 5th post above this one you'll see an example that may help you work it out. I was hoping that my 'little grey cells' would be triggered as I'm typing this but unfortunately not

56 minutes ago, Walus said:

I might hook it up to ctek before leaving. 

A very good idea and highly recommended.

56 minutes ago, Walus said:

Is it ok to charge it without disconnecting it from the car? I have done it in Rx, I presume there should be no issues.

Yes, no problem.

[Herbie]

19 hours ago, SH20 said:

One of my hybrids was left in my garage for over a month and just started  on the button

I'd say that was just about on the limit; any longer and it would likely have failed.

[Walus]

One observation I made after replacing the 12V Battery in Rx was that the charge level was typically sitting around 12.2-12.3V. I would charge it with ctek and a week or so latter the level would drop and pretty much stay there. 

[Walus]

I have charged the Battery with my ctek and after taking off the surface charge it reads 12.6V. Looks like it’s capacity is around 85% at this stage. Should do fine for another 2-3 years.

[Huwge]

Apologies for the thread necro' (I thought it better to add to this rather than start a new thread)

With regard to trickle charging the ES, is there any way to have the car all locked and shut up and still have it charging on a driveway, or would the boot have to left ajar?

 

edit....Would there be any adverse effects on disconnecting the Battery?

 

I am occasionally away for a month, hence why I'm asking

[PeteTP]

Good question. I’m starting to look at this topic now