Parking for 4 weeks

SB3 · January 4, 2023

I'll be leaving my CT200h in a locked garage for 4 weeks. Based on my previous experience with a Prius, I'll probably come back to a flat Battery, so a few questions members may be able to answer...

Is it worth trickle charging the Battery overnight before leaving it? My thoughts there are that as my mechanic says the Battery is always relatively low (12 to 13V) when he checks it, and he feels the system doesn't charge it up as much as it would a normal Battery that has to turn a starter motor, so maybe trickle charging it will boost the voltage and give it a better chance of lasting?

Is it worth leaving the car unlocked? Maybe then, the alarm won't be active, so a lower drain on the Battery? The car will not be accessible to anyone, so no worries there.

I will have my Battery charger ready for when I return, and will check that the mechanical key works OK, but will be happier if the 12V Battery has enough juice left in it to get into Ready mode!

NemesisUK · January 4, 2023

What make of charger do you have?

A maintenance charger such as the CTEK can be left connected for the duration without issue

SB3 · January 4, 2023

19 minutes ago, NemesisUK said:

What make of charger do you have?

A maintenance charger such as the CTEK can be left connected for the duration without issue

A very old Halfords 6V/12V trickle or full charge model, from about the 1970's, when I had a 6V Battery on my motorbike! 😉

Maybe I should look at getting a new charger?

NemesisUK · January 4, 2023

1 hour ago, SB3 said:

Maybe I should look at getting a new charger?

I think that would be a very prudent purchase

RadicalCoupe-Fuji · January 4, 2023

Couldnt you take the DC CUT fuse out, its what the manufacturers do while the car is sitting on a yard for months or at sea for weeks. it cuts off all the parasitic drains on the 12 volt Battery.

SB3 · January 5, 2023

11 hours ago, RadicalCoupe-Fuji said:

Couldnt you take the DC CUT fuse out, its what the manufacturers do while the car is sitting on a yard for months or at sea for weeks. it cuts off all the parasitic drains on the 12 volt battery.

That sounds like a sensible idea for my circumstances. But where is this fuse or link?

If I just disconnect the 12V Battery in the boot and close the tailgate, will it latch itself and not open without power? In the garage, where the car will be, there is just enough room to open the driver's door and squeeze in. Wouldn't really be possible to crawl into the back and get at the Battery even with the rear seatbacks folded down.

Would connecting another 12V Battery (or the charger) to the "exclusive" jump starting terminal be enough to open the tailgate with the switch?

NemesisUK · January 5, 2023

16 hours ago, RadicalCoupe-Fuji said:

Couldnt you take the DC CUT fuse out, its what the manufacturers do while the car is sitting on a yard for months or at sea for weeks. it cuts off all the parasitic drains on the 12 volt battery.

5 hours ago, SB3 said:

That sounds like a sensible idea for my circumstances. But where is this fuse or link?

If I just disconnect the 12V battery in the boot and close the tailgate, will it latch itself and not open without power? In the garage, where the car will be, there is just enough room to open the driver's door and squeeze in. Wouldn't really be possible to crawl into the back and get at the battery even with the rear seatbacks folded down.

Would connecting another 12V battery (or the charger) to the "exclusive" jump starting terminal be enough to open the tailgate with the switch?

Just be aware there are numerous systems that would need re-initialisation when you replace the DC CUT fuse, including the seat ECU, TPMS and the parking assist monitor system.

SB3 · January 5, 2023

49 minutes ago, NemesisUK said:

Just be aware there are numerous systems that would need re-initialisation when you replace the DC CUT fuse, including the seat ECU, TPMS and the parking assist monitor system.

Think I might just get the Battery as fully charged as possible and leave it!

My old Prius went through a few 12V batteries in its life, all I had to reset after changing one was the auto open/close window setting. That had the camera based parking assistant, but no TPMS and nothing else needed sorting out. My Lexus has manual seats, so no worries there.

The TPMS has already given me a false alarm on the Lexus and I (eventually) found the reset button for that.

Where is this DC CUT fuse, should I wish to try that option?

Thanks for your help. 🙂

Herbie · January 5, 2023

You don't need to get to the Battery in the boot.

12V at the back is just the same as 12V at the front, so whichever you choose, either trickle charger such as the CTEK MXS5 or a jump start Battery pack, the connectors in the engine bay will be fine instead of scrabbling about at the back.

NemesisUK · January 5, 2023

14 minutes ago, SB3 said:

Where is this DC CUT fuse, should I wish to try that option?

In my RC it is in the engine compartment relay block, I'm not sure it's identified as it's not something the owner would need to remove. It might be worth checking your handbook for fuse locations. Personally I think removing it would not be the better idea. Best connect a maintenance charger as Herbie suggests IMHO

RadicalCoupe-Fuji · January 5, 2023

If you look at the inside of the fuse box lid ,theres a map of the fuses & relays. It should say DC CUT on one of them or looking at a picture, in this cars case i think its the SHORT PIN fuse, thats the white one thats bigger than the rest.

SB3 · January 5, 2023

11 minutes ago, RadicalCoupe-Fuji said:

If you look at the inside of the fuse box lid ,theres a map of the fuses & relays. It should say DC CUT on one of them or looking at a picture, in this cars case i think its the SHORT PIN fuse, thats the white one thats bigger than the rest.

Thanks. Mine in that position is indeed labeled SHORT PIN. Think as NemesisUK says, removing it might not be the best idea. Will be switching off as many electrical outlets as possible when I go away, so don't really want to leave a charger of any type plugged in.

Could take that fuse out one day and see what happens I suppose...

RadicalCoupe-Fuji · January 5, 2023

Its a solution. Having to reset your favourite radio channels, the time & date etc is annoying but not the end of the world.

Poundy · January 6, 2023

Do the smart thing and get a smart charger. My choice would be a Ctek with a comfort lead connected to the Battery and left available in the boot. You will never need to worry about pulling everything out to connect it. You can also easily check the voltage via the lead pins when required. Job done for ever more 😉

Bluemarlin · January 6, 2023

19 hours ago, SB3 said:

Thanks. Mine in that position is indeed labeled SHORT PIN. Think as NemesisUK says, removing it might not be the best idea. Will be switching off as many electrical outlets as possible when I go away, so don't really want to leave a charger of any type plugged in.

Could take that fuse out one day and see what happens I suppose...

If you don't want to disconnect the Battery, or run a charger, then perhaps leave the bonnet unlatched. That way, if the Battery does run down fully while you're away, you'll easily be able to get to the front charging points to provide power to unlock/start the car.

LenT · January 6, 2023

3 hours ago, Poundy said:

Do the smart thing and get a smart charger. My choice would be a Ctek with a comfort lead connected to the battery and left available in the boot. You will never need to worry about pulling everything out to connect it. You can also easily check the voltage via the lead pins when required. Job done for ever more 😉

Spot on, Norman!

Indeed I’m a little surprised that other options are being considered. A CTEK trickle charger guards against overcharging, which is why it can be left connected.

I also think Bill’s suggestion to leave the bonnet unlatched is a good idea. Another useful thing to do when leaving vehicles unattended for long periods is not to apply the brakes.

It should be safe enough in a garage - but chock the wheels if your garage is on a hill!

VFR · January 6, 2023

4 hours ago, Poundy said:

Do the smart thing and get a smart charger. My choice would be a Ctek with a comfort lead connected to the battery and left available in the boot. You will never need to worry about pulling everything out to connect it. You can also easily check the voltage via the lead pins when required. Job done for ever more 😉

Yes my thoughts as well.

Optimate https://www.optimate.co.uk/ is the brand of choice for most bike owners to leave connected for months at a time.

Poundy · January 7, 2023

On 1/6/2023 at 2:43 PM, VFR said:

Yes my thoughts as well.

Optimate https://www.optimate.co.uk/ is the brand of choice for most bike owners to leave connected for months at a time.

I Beg to differ, everyone I know prefers the Ctek, my baby has gone 9 months on maintenance charge and fired straight up. 😉

Las Palmas · January 7, 2023

Sweet baby, Same colour as Sonic the Hedgehog. As fast?

Poundy · January 7, 2023

7 minutes ago, Las Palmas said:

Sweet baby, Same colour as Sonic the Hedgehog. As fast?

It's the last of the pre restricted models with some weight off and better breathing etc. These early models were always sold with a claimed top end of 200MPH (320Kph). In truth even with some mods I could never get it there. I hit a best of just under 190 MPH, perhaps I should have shed some of my own weight. lol!

Things start happening pretty quick once you move over 150, especially in the underwear department. Amazing rush once you get off and stop shaking though, sadly with old age I have now discovered the will to live 🥲

Al D-Much · February 14, 2023

Not sure there will be a problem.
My dad left his CT200h (2018) in the garage for 6 weeks when he was in hospital. neither of us thought about a flat Battery (other more important issues with his health on our minds). he was home for another 2 weeks before venturing out to the shops. The good ol' Lexus started up first time!

SB3 · February 23, 2023

Well, I left it parked for 4 weeks, unlocked as it was in a locked garage, and it started just as normal when I returned.

Don't know if leaving it unlocked, and therefore the alarm was not active, made any difference, but it was nice to come back to a car ready to go, something my old Prius never managed!

Moleman · February 23, 2023

35 minutes ago, SB3 said:

Well, I left it parked for 4 weeks, unlocked as it was in a locked garage, and it started just as normal when I returned.

Don't know if leaving it unlocked, and therefore the alarm was not active, made any difference, but it was nice to come back to a car ready to go, something my old Prius never managed!

Good news.