Deactivate TCU to prevent discharge12V battery when away for weeks?

[Bjorn]

Jazz Crosstar 2024:

Going away for 3 weeks in desember. In order to prevent problems with 12V battery (can be very cold here in Norway, possible 10-20 C below zero) i do:

Fully charge battery with my Ctek
Super lock the car

My Honda+ app had no problems connecting to my car, so TCU (Telematics Control Unit) was enabled by my dealer and everything works fine

I don't need to monitor my car when away. It's parked in a place where, most likely, nobody will try to break into it. I will also cover my car when away.

 
This time of the year in Norway the weather can be very harsh, snow, rain, strong wind..., so I think it' wise to cover the car when I am away to prevent damage from ice

I know it's possible to disable the TCU in car. I assume this will reduce the wear on the 12V battery quite a lot, but really don't know whether it's worth it Anyone done any tests?


One more thing: super locking, something which has been discussed many times in this forum

In the manual for the 2024 jazz says:
Models with keyless access system ( which is standard on the 2024 Crosstar)

Touch the door lock sensor on the door handle or press the lock button on the
tailgate twice within five seconds.

My question: Should I touch the car lock sensor once or twice within 5 seconds after I lock with the Key Fob? Not clear from the instruction I believe (English is not my native language)

It annoys me that I can't se any indication (lamp in display) that super locking is activated. People talk about clonk sound, but I can't figure it out (feeling a little stupid)

[Whiteshark]

Is it possible to leave the CTek connected and powered up, because that is probably the best option in my opinion. I leave a CTek connected on another car  I have that doesn’t  get used very often. That is what CTek’s are designed for.

[Steve_M]

As your in Norway, so your car is LHD, then there is no need to worry about the superlocking, as that is only for RHD drive car that are in the UK.

After 7 days the TCU will go into deep sleep mode anyway and then the only way to re-communicate with the car is to turn the power on again.

So probably no real concerns.

[Jazzik]

As your in Norway, so your car is LHD, then there is no need to worry about the superlocking, as that is only for RHD drive car that are in the UK.

  Our LHD, not in Norway but in Poland, has the same super locking as your RHD.

@ Bjorn: Super locking you can activate 3 different ways: Push the "lock" button on the key fob twice within 5 seconds or the same way on the tailgate button or touch the lock sensor on the door handle.
And no... superlocking has no indicator.
By the way, I would also switch off my key(s). Saves the key battery, but more important, the key can't be scanned. Push both, the lock and unlock buttons on the key for 3, 4 seconds till the LED flashes twice.

[Bjorn]

I assume LHD Left hand Drive? That's right my car is LHD. However, in the Norwegian 2024 Jazz manual, it has a section about superlocking which seems to be a direct translation of the English manual. So you mean that LHD Jazz don't have super locking?

Anyway, good to know that TCU go into deep sleep after 7 days. I just discovered that it's not possible to disable TCU, just disable data communication. If I do that in the menu, car will still be connected to TCU

[Bjorn]

Is it possible to leave the CTek connected and powered up, because that is probably the best option in my opinion. I leave a CTek connected on another car  I have that doesn’t  get used very often. That is what CTek’s are designed for.

I know it's possible to keep the Ctek powered up all the time. I have eyelets to positive and negative terminals (was OK according to the Honda mechanics, although manual says to connect negative to ground bolt in engine room). Ufortunately, I have not access to power outlet where the car is parked

[Kremmen]

Just use the door touch control twice to superlock, don't bother with the key

[Whiteshark]

Is it possible to leave the CTek connected and powered up, because that is probably the best option in my opinion. I leave a CTek connected on another car  I have that doesn’t  get used very often. That is what CTek’s are designed for.

I know it's possible to keep the Ctek powered up all the time. I have eyelets to positive and negative terminals (was OK according to the Honda mechanics, although manual says to connect negative to ground bolt in engine room). Ufortunately, I have not access to power outlet where the car is parked

In that case, I think you are right to make sure the battery is fully topped up with the CTek before you go. FYI I left our car for 8 weeks on April/ May this year when we went to Aus. Absolutely no problem on return , but I did make sure the battery was fully charged beforehand. However my only concern would be the very low temperatures, which can drain batteries.

[Bjorn]

Yes, the low temp we have here somtimes in the winter is a concern. The temps in december-january can be anywere beetween +10 C to -20 C. I the cottage I have in the mountain, I have  a solar powered 12V system. I have never had a problems with batteries there, even when temps are down to -40C (very rarely, but can happen). Of course, even with little light in the middle of the winter, there is enough charge on my solar panel to keep batteries healthy. But these are batteries without any load, just a little bit load in the charge controller
I would suspect that the load on a modern car like the Jazz is high enough to drain the battery in a few weeks in very cold weather. Well, time will tell

[olduser1]

Maybe worthwhile removing all the wipers or just cover them with plastic bags or similar  to prevent rubbers being damaged.

[coldstart]

Maybe worthwhile removing all the wipers or just cover them with plastic bags or similar  to prevent rubbers being damaged.

Provided the car is parked safely in a garage *) simply lift them of the windows. This prevents the blade to deform while not in use for a prolonged time.

*) letting them lifted while parked in a public space is too much of an invitation for vandalism

[5thcivic]

If you fully charge before going, then belt and braces would be to charge when you come home BEFORE trying to start the car. The Ctek should have a good chance of reviving a low battery if no large load has dumped the amperage first.

[Bjorn]

If you fully charge before going, then belt and braces would be to charge when you come home BEFORE trying to start the car. The Ctek should have a good chance of reviving a low battery if no large load has dumped the amperage first.

I think that is a good idea. If the idle voltage of a 12V battery fall to low (below around 10,5-11V ) it's easy to damage the battery if one put any load on it. I am more than average interrested in the science of batteries (since I have a solar powered cabin in the mountains) and when coming home (after 3-4 weeks) I will do:

Open the bonnet and measure the 12V battery (making sure all consumption is off). As I will charge the battery to 14.7 V (cold mode in Ctek, necessary here in Norway in december) before leaving, it will be interesting to see the voltage drop after standstill in cold temps for 3-4 weeks

[Kremmen]

After I've left mine unused for just 2 weeks my 3.8 CTEK, normal mode, can take 6 to 8 hours before it goes green

[Lord Voltermore]

Do you get enough winter daylight hours in Norway to consider leaving a solar panel connected to the car?

  I tried one in January and February  in southern England and it gave a tiny amount of charge. Possibly enough to compensate for any losses from the cars computer systems.  The car started ok on my return , but it might have done so anyway without the panel.