12V battery issues

All Honda E related discussions
User avatar
Thundarian
Posts: 23
Joined: Mon Aug 17, 2020 10:21 am

Post by Thundarian » Fri Oct 09, 2020 11:20 am

Does this mean if you were to leave the car unused for a month or so, you'd need to plug in not just the main charging cable, but another one connected to the 12V battery to stop it going flat?

I don't drive very often, so I keep my current petrol car's battery plugged in all the time.

User avatar
keithr
Posts: 434
Joined: Fri Feb 07, 2020 1:30 pm
Location: Dorset, UK

Post by keithr » Fri Oct 09, 2020 1:34 pm

Thundarian wrote:
Fri Oct 09, 2020 11:20 am
Does this mean if you were to leave the car unused for a month or so, you'd need to plug in not just the main charging cable, but another one connected to the 12V battery to stop it going flat?
When parked the car should occasionally charge the 12V battery, but manufacturers never seem to tell us what the schedule for recharging is. All the Owner's Manual says is (on page 16), "There are two types of batteries used in this vehicle, a standard 12-volt battery that powers the airbags, the interior and exterior lights, and other standard 12-volt systems, and a high voltage lithium ion battery that is used to power the propulsion motor and recharge the 12-volt battery. When the power mode is set to VEHICLE OFF, recharging will be suspended for about three days if the power mode remains on VEHICLE OFF". It doesn't say what the charge schedule is after 3 days.

The first generation LEAF had a similar system, but like a lot of BEVs it seems that they don't do a very good job of maintaining the 12V battery. Because the battery does not need to supply high power to turn an engine over, it seems that the manufacturers try to get away with charging the 12V battery as little as they can (as that helps extend the car's range by reducing drain on the Li-ion battery pack). However, lead-acid batteries prefer to be kept at 100% charge and the result was that quite a few LEAFs, and some other cars, ended up needing replacement 12V batteries after only a year (or less). With the second generation LEAF (from 2018) they seemed to have improved it, but I had already got into the habit, like many other LEAF owners, of charging the 12V battery once a week with a smart battery charger, as a preventative measure (and the 12V battery was still fine after nearly two and a half years, when I sold the car).

After I had owned the Honda e for a week or two I connected up my smart battery charger, and it charged the battery very quickly (in just a few minutes), implying that it was already at a high state of charge. But in the following weeks it has taken much longer to charge the 12V battery, around 2 - 3 hours at least (it's a 3.5 amp charger), similar to how it was on my LEAF. I don't know if that's normal even on an ICE car, but I will continue to put the battery on charge once a week as a preventative measure. (I tend to mostly do short trips, and not drive every day, so it's probably beneficial for me to do a weekly charge, but for people who drive their cars for at least 20 minutes a day for at least 5 days a week it may not be needed.)

If you're going to leave the car parked for a month or more, then if it was me I'd be tempted to leave a smart battery charger/maintainer connected, just to be sure, although the car should maintain the 12V battery (unlike an ICE car).

SwissChris
Posts: 92
Joined: Fri Sep 18, 2020 2:25 pm

Post by SwissChris » Sat Oct 10, 2020 7:02 am

Indeed even in the technical information I was not yet able to find the "logic" how the Honda e is charging the 12V battery. However in the latest service bulletins it is stated that during diagnosis/reprogramming, the vehicle should be in "Ready mode" as this will ensure that the 12 battery does not discharge. Therefore I assume when you put the car in the "ready to drive" mode, all 12V systems are supplied by the high voltage battery. So if you want to play around with your new gadget while stationary, better put it into the right mode ;)

User avatar
keithr
Posts: 434
Joined: Fri Feb 07, 2020 1:30 pm
Location: Dorset, UK

Post by keithr » Sat Oct 10, 2020 11:02 am

SwissChris wrote:
Sat Oct 10, 2020 7:02 am
Therefore I assume when you put the car in the "ready to drive" mode, all 12V systems are supplied by the high voltage battery.
Yes. It will also be charging the 12V battery. If it wasn't then the battery indicator light would come on:

12V.jpg


As27@talktalk.net
Posts: 18
Joined: Mon Jul 06, 2020 9:16 pm

Post by As27@talktalk.net » Sat Oct 10, 2020 8:05 pm

Thanks all for your comments....all's good now. gave the auxiliary battery an overnight charge on a smart charger and all seemed to come back to life although I had a park pilot error that I couldn't shift until i used the park pilot then the error disappeared. Been running well for a couple of days so I'm going to put it down to "A glitch" fell back in love with it again, must say its a great little town shopping school run vehicle and i really love it,

Like:-
Nippiness
Turning Circle
Pre heating

Dislike:-
Rear view camera
Unable to split rear seats
No height adjuster on passenger seat

Hope you are all enjoying yours....

User avatar
Thundarian
Posts: 23
Joined: Mon Aug 17, 2020 10:21 am

Post by Thundarian » Mon Feb 15, 2021 1:33 pm

Resurrecting this thread to post Tim Pollard's experiences with a flat battery after not using it for a week or so in cold weather.

User avatar
rickwookie
Posts: 847
Joined: Thu Sep 12, 2019 1:30 am
Location: St Albans, UK
Contact:

Post by rickwookie » Mon Feb 15, 2021 2:27 pm

Thundarian wrote:
Mon Feb 15, 2021 1:33 pm
Resurrecting this thread to post Tim Pollard's experiences with a flat battery after not using it for a week or so in cold weather.
"We took it for a long drive to charge up the battery..." :lol: Does he think it's charged using an alternator driven off the main traction motor?! :lol:

nograin
Posts: 1
Joined: Mon Feb 15, 2021 6:25 pm

Post by nograin » Mon Feb 15, 2021 6:39 pm

there's a lengthy discussion and guys have done quite elaborte research over at the german forums of goingelectric.de:

https://www.goingelectric.de/forum/view ... b2620a02fd

there, a 12V battery went flat while the car was hooked up to the charger and not turned on for several days. but it's possibly been a faulty battery. others found that the main battery actually is taking care of the 12V's charging state even if turned off for a longer period.

cheers.

User avatar
advance2020
Posts: 455
Joined: Tue Aug 11, 2020 6:21 am
Location: SW Wiltshire
Contact:

Post by advance2020 » Fri Feb 19, 2021 7:45 pm

sbullo wrote:
Fri Oct 09, 2020 8:43 am
As27@talktalk.net wrote:
Thu Oct 08, 2020 4:29 pm
Thanks NewCode. Bit of an update, the Vehicle is running fine but the Audio screens keep coming up "Battery protection press power button" even when im driving along, then audio switches off. If I can get the radio on for a while it wont switch off when i switch off power button once i am home I have to turn audio button off. I'm sure its the Auxiliary battery not being charged, The dealer straight away blamed my hard wired Dashcam that was fitted by CBS Automotive, who have done lots of work for me and I still don't think its them. Just wanted the dealer to test my auxiliary battery, they were "Short staffed and a bit busy can I book it in next week" GGGrrrrr. So I'm now charging the auxiliary battery at home overnight to see if that fixes the problem.. They did say the auxiliary battery is charged while the car is in motion.. watch this space.....
Have you tried a factory reset on the infotainment system yet?

Hi sbullo,

Could you Edit your original and change Title to “12V battery issues” or similar. It would help others find this thread. I posted my recent - see link below - on the wrong thread (Main Battery loosing charge). As this link relates to 12V battery I have added here. It clearly more than just an “Interesting issue” if your car fails to start away from home.
Many thanks,

posting.php?mode=edit&f=11&p=7827

and in case anyone missed this link above, I have repeated here, as this 12V battery failure issue, although common to some other EVs, is an issue we should all take note of.
https://www.carmagazine.co.uk/car-revie ... ctric-car/
Platinum White Pearl: e-driving green at last, on R17 Michelin Pilot Sport
AVG economy and Predicted Mileage has increased lately, not sure why.

sbullo
Posts: 172
Joined: Fri Jul 10, 2020 4:04 pm

Post by sbullo » Fri Feb 19, 2021 9:12 pm

Done :-)
Adv. 16" Wheels

Post Reply

  • You may also be interested in...
    Replies
    Views
    Last post