Ongoing 12v battery problem

Faults and Technical chat for the Honda E
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EEEE
Posts: 213
Joined: Mon Aug 16, 2021 10:33 am

Post by EEEE » Wed Oct 26, 2022 11:32 am

I think the 12v charging system is witchcraft, works when it wants to, and not terribly well when it does. As said, the battery is so small, it can go flat so easily and never recover properly after the fact.

Strangely, i've had mine since August last year , and previously been in use all the time since April 2021 and ive never had a single 12v problem at all. It has some short journeys, but mainly 30min commute twice a day, 5 days a week.

I never sit in the car with just the ignition on so as to drain the 12v battery, if i am sitting in the car, I just put it in park/handbrake and leave the whole thing on. the 45ah battery can throw the low power warning in a matter of minutes otherwise.

I had contemplated a lithium 12v battery replacement, but they don't seem a huge capacity boost for the size, and who knows how well the built in 12v charging system would handle it.

I Still keep a lithium 12v power jumper in the glovebox just incase however.
'21 e Advance - Charge Yellow - E1702RR alloys
'17 Civic Sport CVT
'00 Prelude 2.2VTi

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

Post by keithr » Wed Oct 26, 2022 2:04 pm

Just to share my expeience, I've had my car for just over two years (since September 2020) and the 12v battery is still okay (so far!). As I've retired I don't have a daily commute, and I've only covered just over 4,000 miles in those two years. Typically I would use the car a minimum of 4 times a week and most of those trips are only about 2 miles out, then 1 - 2 hours later 2 miles back (I do more trips, and longer trips, in the summer months). So as preventative maintenance I've always put the 12V battery on charge once a week. I use a 5 amp CTEK smart charger, and it typically can take around 5 hours to bring the 12V battery back to full charge (it didn't take that long when the car/battery was new - it would charge in less than an hour then), so I guess the 12V battery is probably only around 50% charged after a week of (not much) use. Perhaps I should charge it more than once a week, but I'll continue with just once a week and see how long the battery lasts.

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FDAD
Posts: 374
Joined: Mon Aug 10, 2020 1:55 pm
Location: Porto, Portugal

Post by FDAD » Wed Oct 26, 2022 2:48 pm

keithr wrote:
Wed Oct 26, 2022 2:04 pm
Just to share my expeience, I've had my car for just over two years (since September 2020) and the 12v battery is still okay (so far!). As I've retired I don't have a daily commute, and I've only covered just over 4,000 miles in those two years. Typically I would use the car a minimum of 4 times a week and most of those trips are only about 2 miles out, then 1 - 2 hours later 2 miles back (I do more trips, and longer trips, in the summer months). So as preventative maintenance I've always put the 12V battery on charge once a week. I use a 5 amp CTEK smart charger, and it typically can take around 5 hours to bring the 12V battery back to full charge (it didn't take that long when the car/battery was new - it would charge in less than an hour then), so I guess the 12V battery is probably only around 50% charged after a week of (not much) use. Perhaps I should charge it more than once a week, but I'll continue with just once a week and see how long the battery lasts.
I've never had a single problem with the 12v battery since I got the car august 2020 still with the original battery.
Honda E advance [Modern Steel Metallic] 8-) [DELIVERED JULY 2020] - 50 000Kms + ✌️🎂

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