Something new after 1st Service?

Faults and Technical chat for the Honda E
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5thcivic
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Joined: Wed Jun 16, 2021 6:50 pm

Post by 5thcivic » Sat Aug 20, 2022 11:44 am

I usually trickle the 12V battery once a week or fortnight since do not do many that trips for the main battery to recharge it. I usually use one of those simple led indicators to see what state it is in and it never is full but always shows middle led as "needs charging" but never the low led.
I had not used the car for nearly three weeks since in the process of selling my other one so thought I'd better charge the battery.
Coming to the car the door handles did not pop out, so I had to unlock via the key and not sure but I don't think all the dash came up straight away.
Then it did and showed 76% on the main battery.

Opened the bonnet and checked the 12V and the top led of "fully charged" lit. I had never seen this before from cold, only immediately after charging or a longer trip.
I checked with a multimeter and the battery was 14.2V accompanied by a humming from the system.

Was the high voltage battety now topping up the 12V battery when low and not used? had the first service changed the software?

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EEEE
Posts: 217
Joined: Mon Aug 16, 2021 10:33 am

Post by EEEE » Sun Aug 21, 2022 9:59 am

certainly sounds like the 12v was actively being charged at the time you checked it. Whether that was immediately since you got in and opened the bonnet you will never know unless you get the logger.

If you missed your weekly / bi weekly charge and checked it after 3 weeks, sounds like you were flat (since the doors didn't open or car turn on automatically).

The car here is always used frequently so I can never weigh in too much on 12v issues because i have never had them and don't really expect to (although i do have a cheap 12v booster in the glove box for that 1 time just in case!).
'21 e Advance - Charge Yellow - E1702RR alloys
'17 Civic Sport CVT
'00 Prelude 2.2VTi

5thcivic
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Post by 5thcivic » Sun Aug 21, 2022 6:25 pm

Yes, I fully expected the 12V battery to be weak since the handles did not pop out, unless the car was in some sort of deep sleep state after not being used for a while. During the down time I'd tried the app a couple of times which failed and said cannot connect to car (just a couple of rooms away in the garage).

Went for a run today and everything back to normal, no problems, though I had charged the 12V battery last night. Even used the automatic parallel parking for the first time, worked perfectly.

salix
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Joined: Tue Aug 23, 2022 9:40 am
Location: UK

Post by salix » Tue Aug 23, 2022 9:45 am

Hi, I'm a new Honda owner, so not a lot of experience yet to contribute, but I have been working my way through the manual (!) and thought the attached page might answer your question about the possible deep sleep. The pop out function doesn't activate when the vehicle isn't used for more than 8 days.

deep-sleep.jpg

Advance charge yellow 16" alloys, 2020 bought used 2022

5thcivic
Posts: 41
Joined: Wed Jun 16, 2021 6:50 pm

Post by 5thcivic » Tue Aug 23, 2022 2:30 pm

Thanks, that obviously explains the door handles. Maybe there is a system to instantly charge the 12V battery from the high voltage too in case the micros will not boot?

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EEEE
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Post by EEEE » Thu Aug 25, 2022 5:24 pm

As long as you can get the car to wake up, the HV system inverter will provide all the 12v power you need. Charging the 12v battery will take time, but as long as you've got enough for it to wake up your good to go. Obviously if the 12v battery is flat for too long, it may never 'come back' , but it definitely takes a fair few hours for it to be in tip top condition.
'21 e Advance - Charge Yellow - E1702RR alloys
'17 Civic Sport CVT
'00 Prelude 2.2VTi

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advance2020
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Post by advance2020 » Sat Nov 05, 2022 11:25 am

Can confirm what EEEE says above. As long as you have enough charge in your 12V battery to wake up i.e. power up your car, the HV will immediately start charging your 12V battery. So if you haven’t used your car for a couple of days or more, I suggest you don't immediately drive off, esp. if you need headlights (it’s dark). I have seen my 12V battery down to 42% SoC and 11.9V but it will start the car.

If your 12V is so low that the car won't start, plug in your home charger/granny and it will immediately start charging 12V battery while it charges your HV battery. Depending on how low your 12V SoC you may need to wait at least 20-30mins before driving, preferably a lot longer.

If your 12V is still dead, you will need to get battery replaced under warranty. This happened to me. See thread on Warrantee Claims

One last point: some claim here that 12V will not be charged if your HV battery is at 80% SoC or more. This is totally incorrect and very misleading. i.e utter bollocks
Platinum White Pearl: e-driving green at last, on R17 Michelin Pilot Sport
AVG economy and Predicted Mileage has increased lately, not sure why.

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