12v Battery, the Achilles heel

[westo3]

I did a lot or research ( but not enough) before I bought mine and joined this site. Unfortunately  it was not until the pandemic that the life of the 12 volt Battery really came to the fore across the discussion boards. We tend to go away to sunnier climes for four or five weeks during Jan and Feb. (Obviously not this year) and even though I put the Cetek on when the car is not in use and have a starter pack in the boot I would not leave the car at the airport for that long as flattening the Battery will ( I am LED to believe) shorten its life.  Fortunately we have another car that we can leave and be reasonably confident it will start when we get back. I understand the reasoning behind having such a small Battery but cannot help thinking Toyota could have designed a way of putting in a normal Battery so that it could be left unattended for longer periods of time. When talking to friends about this they are amazed that such an expensive and prestigious  car cannot be left for more than three weeks unattended.

[ColinBarber]

Seems to being blown out of proportion that this is a Toyota hybrid issue. The AA/RAC etc are receiving plenty of calls due to flat batteries but they certainly aren't restricted to Toyota/Lexus vehicles. Plenty of MB/BMW owners complaining of their vehicles not lasting more than 3 weeks etc. Toyota's recommendation of using/sitting in a vehicle once a week for an hour isn't restricted to hybrid owners.

If you were to leave any vehicle for 5 weeks you would be shortening the life of a lead-acid Battery, they just aren't designed for that.

Toyota have been designing hybrid vehicles for 20 years. They have had plenty of time to understand if the size of the aux Battery is a problem for owners - I'm guessing they feel they have the balance right, and the batteries of the Prius for example have certainly increased over the years, probably due to extra electronics in vehicles over that period and systems such as smart entry that continue to use power when the vehicle is unused.

[Guest]

5 hours ago, Herbie said:

Agreed - it is a poor design.

Agreed - you should be able to leave a modern car for a good number of weeks.

The text in red is the most important.

Hybrids are a 'relatively' new technology and they are very complex and they are certainly not the right car for some people and/or situations. Just because I can get a decent sound out of my home hifi doesn't mean I can walk in and operate the mixing desk at a live Rolling Stones gig tomorrow!

It never ceases to amaze me that people squirt thousands, even tens of thousands of pounds at a car without doing research first, and expect it to operate and be like just any other car they've ever owned. Google (other search engines are available) makes it easier than ever before to find out a widget's strengths, abilities, downsides, and anything else you could ever wish to know about a given widget before buying it.

Hardly a day goes by without someone in this club or the 'other' club on Facebook bleating about leaving their car for a couple of weeks and now the 12V battery is flat. It's just so unnecessary and could easily be avoided if they did a bit of research before buying the car.

I passed my driving test in June 1975 and since that day I have never, ever, ever, bought a car 'unprepared'. In fact, my wife gets annoyed with me because when it's time for a change I usually have an idea of which make and model I'd like, so for about three or four months beforehand I get every book, magazine, search the Internet, join the Owners Clubs and basically drive her mad with constant talk of it until I either go ahead and get one or decide it's not for me after all and move on to some other make/model and start the process again.

Instead of blaming someone or something else, people need to take responsibility for their own actions.

There you go - rant over Oh and Paul, I'm not having a go at you mate, it's just that your post had all the salient points in it

If only everyone was as diligent as you.

its still a poor design, premium car sir, leave it at an airport for 3 weeks sir, you will be lucky sir

[Herbie]

55 minutes ago, Derant said:

If only everyone was as diligent as you.

The world would, indeed, be a far better place

[Ala Larj]

Although the handbook suggests running the car in ready mode for an hour once a week to keep the Battery topped up, how long should it be run to fully change the Battery when it’s completely flat?

[Herbie]

7 minutes ago, Ala Larj said:

Although the handbook suggests running the car in ready mode for an hour once a week to keep the battery topped up, how long should it be run to fully change the battery when it’s completely flat?

If it really is that low or even anywhere close to it, you really should be using a mains-powered Battery charger on it overnight - it would be better for both the Battery and the car.

[Ala Larj]

The reason I asked was because a few weeks back, having not used the car for about three weeks, the Battery was flat. I then jump started it and ran it for an hour. Since then I’ve tried to run it for an hour on a weekly basis. However, I slipped this week and it was nine days before I could do my weekly ritual. Unfortunately the Battery was flat! I thought about it and assumed that the weekly hourly ritual was ineffective because the Battery had not become fully charged. I don’t have a dedicated charger but assumed that once the Battery was fully charged the weekly top up would be sufficient. 
 

i do however think it’s a bad desire. Many folk go on holiday for two to three weeks and should expect their car to start after such a short time!

[Brechin Slate]

7 minutes ago, Ala Larj said:

I don’t have a dedicated charger but assumed that once the battery was fully charged the weekly top up would be sufficient. 

I think a charger needs to be on your shopping list if you're having ongoing problems. Also worth investing in a digital multimeter if you don't already have one so you can check the Battery after charging, when in the 'Ready' mode and daily after charging so you can see the rate of the drain.  The CTEK MXS 5 seems to be one of the better chargers looking at some of the posts in the forum although I'm sure there are other good ones out there. Halfords have a good selection too, I bought a Noco Genius 5.

[Ala Larj]

Do I need to remove the Battery from the car to charge it? Sorry but I’m a bit naive. I remember my dad charging his Battery in the house!

 

i have a small charger that came with my lawn tractor. Would that work?

[Herbie]

No, you don't need to remove the Battery from the car to charge it. Some people prefer to disconnect the negative cable while the charge it in the car but again, there's no real need to do so.

Sorry Alan but I have no idea if your lawn mower charger would be able to do the job, although I'd almost certainly say no. You really need a modern 'intelligent' charger with regulated output, especially if you're going to leave the Battery in the car to do it.

The necessity for an overnight charge with a dedicated charger (rather than expecting the car to do it) is that the charger itself has circuitry in it that can also 'condition' the Battery and it works out how best to do this. Another reason is that the DC/DC converter (or alternator in a conventional car) has to supply all of the electrical demands placed on the car when it's running and that demand can be very high, therefore not giving much to recharging the Battery.

[Barry14UK]

 

 

1 hour ago, Ala Larj said:

Do I need to remove the battery from the car to charge it? Sorry but I’m a bit naive. I remember my dad charging his battery in the house!

 

i have a small charger that came with my lawn tractor. Would that work?

Battery technology has advanced over the years and continues to do so.  If the 12v Battery in your car is an AGM version, it should be charged with a smart charger with an AGM mode option.  It will need to charge at to not more than 5 amps and will reduce this as the Battery approaches fully charged.  If an excessive charge is made to the Battery it will vent operating any regulating valve in the process.  This cause a loss which is not replaced, so the Battery will suffer some permanent loss in performance.  The smart chargers avoid this by adapting as necessary, so well that they can be left connected without overcharging the Battery.  Even if your Battery is not an AGM type it would be preferable to use a modern smart charger. 

It's a bit of a faff having to clear the boot on my car to connect the 240v supply to my smart charger so I have bought one of the plugs used to enable caravans to hook up, so all I will need to do in future is plug into an external extension as the smart charger is left connected.  (Hopefully, weather permitting, I will be able to do this soon as the car has been repaired and returned to me following the rear end shunt). 

[Brechin Slate]

10 hours ago, Ala Larj said:

Do I need to remove the battery from the car to charge it? Sorry but I’m a bit naive. I remember my dad charging his battery in the house!

 

i have a small charger that came with my lawn tractor. Would that work?

I'll do a 'how to' video later today and post a link

[ColinBarber]

12 hours ago, Ala Larj said:

Although the handbook suggests running the car in ready mode for an hour once a week to keep the battery topped up, how long should it be run to fully change the battery when it’s completely flat?

As others have stated, better to use a Battery charger in this situation. However my understanding is the vehicle will push up to 10 Amps into the Battery, and based on figures quoted from 10A Battery chargers you are looking at around 4+ hours to full charge a flat Battery the size of which is fitted to the GS300h.

[Brechin Slate]

17 hours ago, Ala Larj said:

Do I need to remove the battery from the car to charge it? Sorry but I’m a bit naive. I remember my dad charging his battery in the house!

 

i have a small charger that came with my lawn tractor. Would that work?

Here you go Alan, made this earlier, hope it helps:

https://youtu.be/7K4HELfg3hw

[Dealkent]

On 1/15/2021 at 3:40 PM, PaulWhitt20 said:

Why not have a solar powered charger built into the parcel shelf to keep the battery topped up.

What a brilliant idea 💡 

[Herbie]

16 minutes ago, Dealkent said:

What a brilliant idea 💡 

In theory yes, in reality no.

The wattage generated by such small solar panels would fall far short of what's needed.

[paulrnx]

On 1/16/2021 at 1:55 PM, Herbie said:

Agreed - it is a poor design.

Agreed - you should be able to leave a modern car for a good number of weeks.

The text in red is the most important.

Hybrids are a 'relatively' new technology and they are very complex and they are certainly not the right car for some people and/or situations. Just because I can get a decent sound out of my home hifi doesn't mean I can walk in and operate the mixing desk at a live Rolling Stones gig tomorrow!

It never ceases to amaze me that people squirt thousands, even tens of thousands of pounds at a car without doing research first, and expect it to operate and be like just any other car they've ever owned. Google (other search engines are available) makes it easier than ever before to find out a widget's strengths, abilities, downsides, and anything else you could ever wish to know about a given widget before buying it.

Hardly a day goes by without someone in this club or the 'other' club on Facebook bleating about leaving their car for a couple of weeks and now the 12V battery is flat. It's just so unnecessary and could easily be avoided if they did a bit of research before buying the car.

I passed my driving test in June 1975 and since that day I have never, ever, ever, bought a car 'unprepared'. In fact, my wife gets annoyed with me because when it's time for a change I usually have an idea of which make and model I'd like, so for about three or four months beforehand I get every book, magazine, search the Internet, join the Owners Clubs and basically drive her mad with constant talk of it until I either go ahead and get one or decide it's not for me after all and move on to some other make/model and start the process again.

Instead of blaming someone or something else, people need to take responsibility for their own actions.

There you go - rant over Oh and Paul, I'm not having a go at you mate, it's just that your post had all the salient points in it

No worries, I didn’t read it as having a go. I agree with what you’ve said apart from expecting everyone to do lots of research when buying a car. I doubt many people do that. Car enthusiasts would but for many a car is a means of getting from a to b and not much more.

To be honest I doubt manny people would research how long they could leave a Lexus hybrid for before the low capacity 12v battery went flat.

Having to go out to the car once a week to start it up and have it run for an hour also tends to negate some of the reasons for running a hybrid in the first place.

Like I said it’s a reasonable expectation that a modern car can be left for a few weeks without the Battery going flat.

[Ala Larj]

2 hours ago, Brechin Slate said:

Here you go Alan, made this earlier, hope it helps:

https://youtu.be/7K4HELfg3hw

Thanks. That’s really helpful. 

[Herbie]

2 hours ago, paulrnx said:

To be honest I doubt manny people would research how long they could leave a Lexus hybrid for before the low capacity 12v battery went flat.

I completely agree. The chances of someone searching for that specific item is almost nil. However, there's a very high chance that they would come across it whilst doing general research to see if a hybrid is the right thing for them. After all, no one would buy a full EV without doing research first because they are something new, out of the ordinary, and not like a conventional car - just like a hybrid.

People may not do much research between, say, a Ford Fiesta and a Vauxhall Vectra; or a Kia Sportage and a Suzuki Vitara and so on. They may be different sizes and shapes but all are basically the same underneath the skin, whereas the difference between any of those and a hybrid is as different as night and day.

People can't just expect to buy a hybrid and drive it/treat it/maintain it just like any other car they've ever had.

[paulrnx]

Surely most people think owning a self-charging hybrid is the same as owning a normal car? That’s certainly the way they are marketed.

I would consider myself to be quite knowledgable about cars and yet I never knew about this issue. That said it hasn’t happened to me in 4 hybrids and about 55k miles over a 3 1/2 year period.

It’s probably the one thing that does concern me now though given that I do leave my car for periods of 2-3 weeks whilst on holiday. I’m still surprised that Lexus would sell cars that need the 12v Battery charging up once a week.

[NemesisUK]

If the 12v Battery needs charging weekly, there's something wrong!

Either the Battery (old?) or there's a parasitic drain.

[Herbie]

8 minutes ago, paulrnx said:

Surely most people think owning a self-charging hybrid is the same as owning a normal car? That’s certainly the way they are marketed.

Surely people wouldn't be so silly? Even if they didn't know until they took one for a test drive, once they see the power meter and the section marked 'Charge' and the salesman starts talking about batteries and regenerative braking, surely they would think, "Owd up a fraction - this doesn't sound like any other car I've ever had" and go away to do some research?

8 minutes ago, paulrnx said:

I’m still surprised that Lexus would sell cars that need the 12v battery charging up once a week.

Now with that, we are in complete agreement. Having said that though, as Colin Barber said earlier in this topic, Toyota have been in the hybrid business for a long time and they must think that it's acceptable or they would have changed it by now.

[paulrnx]

I have a feeling that this issue will not do Lexus many favours. Many owners buy a Lexus because they hardly go wrong. Not knowing if your Lexus hybrid will start up and having to carry a Battery booster around or regularly have the Battery on a trickle charge just in case will impact the ownership experience. I used to trickle charge cars in the late 70’s and early 80’s before I started driving much newer cars, haven’t done it much since then. It’s possibly something that would stop me from buying another Lexus hybrid to be honest.

[paulrnx]

4 minutes ago, Herbie said:

Surely people wouldn't be so silly?

Now with that, we are in complete agreement. Having said that though, as Colin Barber said earlier in this topic, Toyota have been in the hybrid business for a long time and they must think that it's acceptable or they would have changed it by now.

So tell me where in the marketing brochure it says that you have to make specific allowances for driving a hybrid? You’ve clearly done your research but I would bet you are in a very small minority.

[Herbie]

1 minute ago, paulrnx said:

I have a feeling that this issue will not do Lexus many favours. Many owners buy a Lexus because they hardly go wrong. Not knowing if your Lexus hybrid will start up and having to carry a battery booster around or regularly have the battery on a trickle charge just in case will impact the ownership experience. I used to trickle charge cars in the late 70’s and early 80’s before I started driving much newer cars, haven’t done it much since then. It’s possibly something that would stop me from buying another Lexus hybrid to be honest.

But this is my whole point Paul - it's not the car's fault, it's their own fault for not researching everything they can about a machine that's not like any other they've ever driven.

This is the society we've made for ourselves - always someone else's problem/fault, never our own.