Kas63

12volt Battery

Recommended Posts

Since I got my CT 5 months ago I’m getting a little bit paranoid about the 12 volt Battery failing whilst parked in my garage, didn’t fully appreciate at the time of buying that it had 2 batteries. My concern is that if it ever failed I wouldn’t be able to jump start it as cables wouldn’t be long enough as the car has to be driven into the garage, and being automatic it couldn’t be pushed out. 

I have been looking at getting a Tacklife T8 or something like that, but the jumper cables don’t appear to be that long. When I picked up my car the salesman showed me where to attach the cables should it ever need a jump start, but I don’t think the cables are long enough from a device like this. I know where the positive red cable goes is there any where else closer where the black lead can be attached? 

If you use a device  ike this which one do you use? 

It may never happen, but I do like my long holidays, so I just want to be prepared and have a quick fix without having to wait for the AA. 

Thanks Karen 

 

 

Share this post


Link to post
Share on other sites
 

17 minutes ago, Kas63 said:

and being automatic it couldn’t be pushed out. 

You could push it out. Use the 'Shift Lock' button to get the gear selector lever out of P and put it into N, brakes off and push.

However, pushing it out is too much like hard work so yes, buy yourself a jump start Battery pack like the one you mention or I use an earlier version of this one by DB Power

You are correct in that the leads of these devices aren't very long but they don't need to be. You said that you know where to connect the positive (red) lead but the negative (black) lead can go to any nearby bolt head, bracket, screw or any unpainted metal that you can get a good connection to.

Or you could do what I did in my RX450h:

 

 

Share this post


Link to post
Share on other sites
38 minutes ago, Herbie said:

You could push it out. Use the 'Shift Lock' button to get the gear selector lever out of P and put it into N, brakes off and push.

However, pushing it out is too much like hard work so yes, buy yourself a jump start battery pack like the one you mention or I use an earlier version of this one by DB Power

You are correct in that the leads of these devices aren't very long but they don't need to be. You said that you know where to connect the positive (red) lead but the negative (black) lead can go to any nearby bolt head, bracket, screw or any unpainted metal that you can get a good connection to.

Or you could do what I did in my RX450h:

 

 

Thank you for your reply, that helps, I think I will order a jump starter, now decisions decisions which one? 

From what I have read the CT doesn’t have a shift lock button to over ride whilst in ‘Park’ mode when you can’t start the car as it is just a button you push. Not part of the gear shift. Previously I searched on You Tube, American Lexus sites etc and they said can’t be done on a Lexus CT.  If they are wrong can someone please tell me how to do this, you can never have too much information. 

Thank you Karen 

Share this post


Link to post
Share on other sites

When I go away for 2 months, I put my CT in the garage and disconnect the negative on the 12 Volt Battery remembering to leave the boot ajar (rested on a car rug). When I return, I re-connect and all is ok. I have left it in the airport carpark for 2 weeks and it was ok. For longer periods, then I would leave it at home.

Hope this helps.

Share this post


Link to post
Share on other sites
2 hours ago, Kas63 said:

I think I will order a jump starter, now decisions decisions which one? 

The only ones I have knowledge of are the ones from DB Power and a mate of mine who is a mechanic has a Suaoki one. Both brands have good reputations and work well so I'd say you'll be fine with either.

Noted about the lack of a shift lock button, I didn't realise that.

Share this post


Link to post
Share on other sites

Letting the Battery drain to the point of jump starting won’t do it any good. Also be aware it only brings up the electrics anyway, it doesn’t crank the engine so it doesn’t need all that much power (hence being smaller than ice cars).

Could you connect up a charger when it is being left for long periods? This would ensure the Battery isn’t let to drain right down and will maximise the lifespan. 

Also be aware there are points under the bonnet for emergencies, you don’t have to go into the boot and get at the Battery

Share this post


Link to post
Share on other sites
On 4/12/2019 at 2:57 PM, Herbie said:

The only ones I have knowledge of are the ones from DB Power and a mate of mine who is a mechanic has a Suaoki one. Both brands have good reputations and work well so I'd say you'll be fine with either.

Noted about the lack of a shift lock button, I didn't realise that.

The CT follows the Prius in the way that park is engaged. When you are in ready mode selecting D,R,B,and N engages that function as with normal auto transmissions except that the selector is purely electrically operated. The parking is lock pawl driven by an electric motor in the transmission, and not moved by mechanical means from the selector.

  When you stop you can select park in the normal way, but this is a waste of time, and energy as turning off the engine with the start stop button engages park automatically making it fool proof when parking "park always being engaged", and unless on a steep hill I did not bother with the parking brake "bad practice I know".


When I first changed from a Prius to the GS450H on a few occasions this caught me out as I would leave the car in drive, press the stop button, "as with the Prius" and start exiting the car to find the car rolling either forwards or backwards depending on where the car was parked. I was so used to not having to engage park.

John.

  • Like 2

Share this post


Link to post
Share on other sites

Thank you for your replies, I won’t intentionally allow the Battery to go flat but these things happen, and I want to be prepared should it happen and know what to do, especially if it’s stuck in the garage. 

It’s a shame that the car doesn’t tell you if the 12 volt Battery is going flat and not holding its charge.  My last car told me when the fob Battery was running low, brought up a warning on the screen telling me how much Battery I had left.  That was my first indication that it needed replacing as every thing still worked fine. 

Share this post


Link to post
Share on other sites

37 minutes ago, Kas63 said:

My last car told me when the fob battery was running low, brought up a warning on the screen telling me how much battery I had left.

Are you talking about two different things there Karen?

I've known a few cars that give you an indication that the fob Battery is getting low and that it should be changed ASAP, but that's the Battery in the key fob. I don't know of any car that tells you when its 12V Battery is getting low. Usually the first indication is weird dash lights and behaviour if it's a hybrid, or slow cranking of the engine if it's a 'standard' car with a starter motor.

Share this post


Link to post
Share on other sites
1 hour ago, Kas63 said:

Thank you for your replies, I won’t intentionally allow the battery to go flat but these things happen, and I want to be prepared should it happen and know what to do, especially if it’s stuck in the garage. 

It’s a shame that the car doesn’t tell you if the 12 volt battery is going flat and not holding its charge.  My last car told me when the fob battery was running low, brought up a warning on the screen telling me how much battery I had left.  That was my first indication that it needed replacing as every thing still worked fine. 

The CT does have the ability to show the state of charge by showing the 12 volt Battery voltage. This information is given in the hidden menu's on the MFD screen.
to show the hidden screen menu's press the start button without your foot on the brake then turn on and off the side lights three times. If you go to ready mode the reading will show the on charge voltage of around 14.2 volts.

John.

Share this post


Link to post
Share on other sites
3 hours ago, Herbie said:

I don't know of any car that tells you when its 12V battery is getting low

 

2 hours ago, Britprius said:

The CT does have the ability to show the state of charge by showing the 12 volt battery voltage. This information is given in the hidden menu's on the MFD screen

Well, I stand corrected - or do I?

Most people wouldn't know about the hidden menu or how to get into it, so to all intents and purposes, just by driving the car and using it normally, I'd still say that it doesn't show you the state of charge of the 12V Battery. However, I like to learn new things so thanks for pointing that out John.

I wonder if my RX450h has any hidden menus?

Share this post


Link to post
Share on other sites

Hi Herbie I was just making a point saying if some cars can tell how much Battery you have left in the fob, why can’t they tell you about a Battery that is attached to the car.  Sorry for the confusion. 

  • Like 1

Share this post


Link to post
Share on other sites

3 hours ago, Britprius said:

The CT does have the ability to show the state of charge by showing the 12 volt battery voltage. This information is given in the hidden menu's on the MFD screen.
to show the hidden screen menu's press the start button without your foot on the brake then turn on and off the side lights three times. If you go to ready mode the reading will show the on charge voltage of around 14.2 volts.

Thank you for that information would never have found that out, I now want to try it out 👍 

Share this post


Link to post
Share on other sites
1 hour ago, Kas63 said:

Hi Herbie I was just making a point saying if some cars can tell how much battery you have left in the fob, why can’t they tell you about a battery that is attached to the car.  Sorry for the confusion. 

I do not know if it applies to the CT, but my GS does give a low fob Battery warning on the small instrument display screen.

John

Share this post


Link to post
Share on other sites

I have this one: https://www.halfords.com/workshop-tools/garage-equipment/battery-chargers-jump-starters/halfords-lithium-jump-starter-up-to-3l

Used it a few times and it works great. They're a bit of a minefield on amazon because it's flooded with cheap chinese stuff and fake reviews so it's hard to really know what's good.

Also bear in mind the lithium Battery will degrade over time, especially if it isn't periodically discharged and charged.

Share this post


Link to post
Share on other sites
4 minutes ago, m4rkw said:

With the greatest of respect Mark, that's well overpriced (as Halfords almost always is)* for something that they're advertising as "up to 3 litre".

The Suaoki one I linked to above is capable of working on 6 litre petrol or 5 litre diesel and is £15 cheaper.

*Even with the Halfords discount card that Gold Membership of this club provides, Halfords still come in more expensive most of the time.

Share this post


Link to post
Share on other sites

You’re not wrong, I decided it was worth the premium to not have to deal with trying to work out what was going to be good from amazon.

  • Like 1

Share this post


Link to post
Share on other sites
49 minutes ago, m4rkw said:

Also bear in mind the lithium battery will degrade over time, especially if it isn't periodically discharged and charged.

You shouldn't discharge lithium ion batteries and you should avoid them going flat to prolong their life.

Share this post


Link to post
Share on other sites

I don't mean fully discharge - some cycling is necessary to prolong their life. If you're going to store it, keeping it around 40% is ideal but then that obviously isn't practical for a jump-starter.

source: https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Share this post


Link to post
Share on other sites
19 hours ago, Herbie said:

 

Well, I stand corrected - or do I?

Most people wouldn't know about the hidden menu or how to get into it, so to all intents and purposes, just by driving the car and using it normally, I'd still say that it doesn't show you the state of charge of the 12V battery. However, I like to learn new things so thanks for pointing that out John.

I wonder if my RX450h has any hidden menus?

I believe all the Toyota/Lexus hybrids have the hidden menu. There is an alternative method of entering the menu by going to the settings screen in accessory mode as previous post. In this screen there are two gold horizontal bands one near the top the other near the bottom. Pressing imaginary buttons on the left hand side of the screen just under the top gold band, and just above the bottom gold band starting at the top alternatively three times each. This should bring up the hidden menu.

John.

  • Like 2

Share this post


Link to post
Share on other sites

You can shift into neutral on the CT. I always do if I want to roll it out of the garage to do something.
Without pressing the Brake press the power button twice to ignition on and select neutral.
I’ve left mine once for a month and it was fine. It’s a 2011 with an original Battery.


Sent from my Iphone using Tapatalk

Share this post


Link to post
Share on other sites
34 minutes ago, stormchaser said:

You can shift into neutral on the CT. [...]  Without pressing the Brake press the power button twice to ignition on and select neutral.

But surely you couldn't do that with a flat Battery?

Share this post


Link to post
Share on other sites

I don’t know I’ve never been in that situation of a flat Battery. I was just saying how to select neutral should you need to.


Sent from my Iphone using Tapatalk

Share this post


Link to post
Share on other sites

I am afraid once the 12 volt Battery is discharged you cannot get the car into neutral meaning the front wheels are locked! Apart from re- instating the 12 volt supply there is no way to get the car out of park.

John. 

  • Like 2

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.