Charging of 12V Battery

[HausO]

hi,

our Honda dealer installed a 12V battery monitor which was deliverd by us because I heard about 12V problems and the Honda e is not able to display the SoC of the 12V battery or the charging condition.

This monitor showed me a not expected behavior of the 12V charging system.

While charging the HV battery (AC or CCS) the 12V battery voltage is 13,3V. While driving with a SoC below 90% the 12V battery voltage is 14,6 up tp 14,8V. If the SoC of the HV Battery is 90% or higher the 12V battery is not charged.

If I would recharge the HV Battery every time to 100% than I have a worse scenario because the 12V battery will die.

Can anyone confirm this behaviour of the 12V battery charging system?

Regards,

Henning

P.S.. Sorry I'm not a native speaker of english language. I know my grammar is awful. 

[aphylotus]

I can only say that my 12V Battery died this weekend, parking the car normally, no message whatsover, the morning i noticed the car was not locked (it was at 60% when I parked it), and nothing did work, no screen, not able to open the charging lid, nothing. Opened the lid manually, plugged in the charger, even there no action. Had to get a truck to get it to the garage, they changed to 12V battery, now got it back. This happened with 600km on the clock, so after 3 weeks. I'll take a closer look now about the voltage of the battery. I'll report back

[Joolsdc]

Feels like a question to Honda country support. Would be interesting to know the answer

[londiniumperson]

I can only say that my 12V Battery died this weekend, parking the car normally, no message whatsover, the morning i noticed the car was not locked (it was at 60% when I parked it), and nothing did work, no screen, not able to open the charging lid, nothing. Opened the lid manually, plugged in the charger, even there no action. Had to get a truck to get it to the garage, they changed to 12V battery, now got it back. This happened with 600km on the clock, so after 3 weeks. I'll take a closer look now about the voltage of the battery. I'll report back

It appears that it's possible that the car was not powered off, which could result in a drained 12v battery, see from page 198 'Auto Power ON/OFF' in the manual.

On the day that I collected my 'e' the technician faffed about so long trying to get the app to send a PIN to the car that the 12v battery was flat within about an hour & he had to use a jump pack to be able to power the car up.

[HausO]

https://photos.app.goo.gl/wBfJVdPbpftAQT718
@3:20PM/15:20 End of CCS charging with a SoC of 90%. Battery voltage drops from 13.3V while charging to 13V.

https://photos.app.goo.gl/KNezvUAMtU6Mmtwz8
@1:00 End of AC charging. Voltage drops from 13.3V (trickle charge) to normal battery voltage. 7:45 disconnect of charging cable, voltage drop is a result of the central lock system. 8:15 start driving without charging the 12V Battery, about up to 8:45, 6PM/18:00, start of driving (SoC about 80%) and charging of 12V Battery (voltage about 14.6V)

[advance2020]

https://photos.app.goo.gl/wBfJVdPbpftAQT718
@3:20PM/15:20 End of CCS charging with a SoC of 90%. Battery voltage drops from 13.3V while charging to 13V.

https://photos.app.goo.gl/KNezvUAMtU6Mmtwz8
@1:00 End of AC charging. Voltage drops from 13.3V (trickle charge) to normal battery voltage. 7:45 disconnect of charging cable, voltage drop is a result of the central lock system. 8:15 start driving without charging the 12V Battery, about up to 8:45, 6PM/18:00, start of driving (SoC about 80%) and charging of 12V Battery (voltage about 14.6V)

To save people going off to google link, here are HausO images
Not sure how this helps, but here they are:-

[advance2020]

This is one of two threads on this topic, and an important one, because as yet it doesn't appear clear how in some instances the 12V battery is being drained, without people realising what is going on.

3 reports make some sense so far.
Joolsdc drained his 12V by using an air pump off 12V supply.
Londinium reports Honda Technician managed to flatten his battery!
and someone else left their lights on......

Clearly the 12V battery holds a limited amount of power, so it is important not to drain power via 12V socket, use Audio, Displays etc for a lengthy period, if your car is not plugged in. I have set my lights to go off with minimum delay time, and note that every time you approach your car with your key, your headlights come on briefly.

And let's monitor and report more on this topic to help others, esp. those like Keith? who have owned EVs before. And we should all check that Auto Power Off is enabled - see page 198 'Auto Power ON/OFF' in the manual.

It is also worrying that Owners like Deepak Prasher who reported to Honda that he had to call AA more than once, because his car has died completely, is not getting helpful advice from Honda on this issue.

[londiniumperson]

Hello advance2020.

The reason is very simple, if the traction (HV) system is not powered on and power is being drawn for an extended period (I'd guess >30mins) by 12v systems, e.g. entertainment system, lights etc then the 12v battery which is small and has a low capacity will be drained enough so that the HV system cannot be engaged/started.

This is a well known issue on a number of other BEVs, i.e. MG ZS EV as one of many makes, just follow their Facebook/forum groups.

There are 2 causes of low 12v battery:
1) A faulty battery, possibly due to long wait/transit times between 12v battery manufacture to delivery of car to owner.
2) An owner has not powered on the HV system whilst 12v systems are in use.

The HV system has to be isolated from the 12v system for safety reasons. This is likely to continue until manufacturers are no longer building ICE vehicles.

[advance2020]

Hi L,

All useful info, and I'm sure it is accurate, but Deepak Prasher is reporting that his car has died, more than once, while it is parked up and not being used. And that Honda can find no fault.

So let's assume he stopped his car, applied electronic brake and Park and got out. Power would still be on*. You would get an alert sound, and I doubt that it would possible to lock the car. (Not yet tried this but I will). The guy is a Professor, so let's assume he's not dim.

*The manual says if you get out of the car, with the smart key, the power goes off, when you shut the drivers door. If I often leave the car, with Power On and with door open, but the Auto Power off kicks in after awhile - it often does, while I shut my garage doors, if I’m not quick enough, getting back into the car. So this can't be a reason why the 12V would drain. I think the car is cleverer than me.

For clarity, I attach detail from the manual.

He says his lights were off, but something must be draining his 12V?

[Malcs]

I had 12v battery failure but never got to the bottom of why. Managed to jump it from another car. I use my e for work and several times a day need to lift the rear door and notice the front lights always stay on for a period. Anyone know of a setting to turn them off when opening the rear. Been busy being busy so not had a chance to read the manual.