12V battery issues

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londiniumperson
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Post by londiniumperson » Sat Feb 20, 2021 11:59 am

I can see the point of a compact, portable Powerbank, which luckily doesn't need to be fully charged, however I would not rely on having one as a guaranteed solution to a discharged 12V battery. The reason is that I bought one a couple of years ago for about £60 and used it only once on an ICE car, it only just worked even when fully charged, probably because the car battery was only just slightly depleted. However the power bank was then no longer any use afterwards because it would not hold its charge, luckily it was within warranty and I'd purchased it via Amazon.
Therefore my takeaway from this is; anyone considering buying a powerbank like this to make sure that you buy from a reputable manufacturer with a reasonable warranty.

This is in reference to the video:

stated in the thread:
viewtopic.php?f=11&t=693
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keithr
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Post by keithr » Sat Feb 20, 2021 12:34 pm

advance2020 wrote:
Fri Feb 19, 2021 7:45 pm
posting.php?mode=edit&f=11&p=7827
I think that link should be viewtopic.php?&f=11&p=7827.

Joolsdc
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Post by Joolsdc » Sat Feb 20, 2021 3:18 pm

He has to prop his bonnet open. How 1970s 😂

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advance2020
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Post by advance2020 » Mon Feb 22, 2021 1:03 pm

Note comment re. Powerbank, but unlike ICE I don’t think our BEV would need much juice to wake up the car, and hence start. It takes a lot more energy to start a cold IC engine
Platinum White Pearl: e-driving green at last, on R17 Michelin Pilot Sport
AVG economy and Predicted Mileage has increased lately, not sure why.

Wee Peem
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Post by Wee Peem » Mon Feb 22, 2021 4:47 pm

I agree there. The 12volts is only being used to "fire up" a relay or contactor surely rather than try and crank a cold IC engine with oil like treacle.

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ScottHoward
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Post by ScottHoward » Wed Jun 16, 2021 12:32 pm

sbullo wrote:
Sun Aug 02, 2020 1:22 pm
Wonder how long it was left before battery died?
It is ok for a battery to discharge when the car stays for a long time.
If it discharges quickly, then you should find a parasitic draw there.
Here's an example of how to do this:

All is simple.
Batteries for Honda: https://accordcashcar.com/

Accord
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Post by Accord » Thu Nov 24, 2022 5:51 am

I’ve put in an order for this car, and I’m a bit disappointed to see a lot of issues with the 12V battery.
I’ll post my experiences with the IONIQ where I have a BM2 battery monitor installed;

I quickly recognized a discharged battery after purchasing the car last winter. The test from dealer said “OK - RECHARGE”. Fine, the car worked ok I guess. But when starting the car, it has an easy entry function, and you can hear the motors suddenly spinning twice as fast while adjusting the seats. The voltage was very often under 12V, and it didn’t seem to start emergency charging before it hit 11.8V.

I have a dash cam as well with parking mode, where I can set the lowest value before it should turn off. It’s adjustable between 11.8 and 12.6V. I need to have it set to 12.2V as a maximum, otherwise I’ve experienced that it turns off when unlocking and starting the car. So the initial drain can be a lot. The battery is only 40Ah, meaning you can only use approx 20Ah before it’s considered empty, and only half again of that in the winter usually.

It worked fine though the summer, but started acting up again now as it’s getting colder. I asked the dealer about it, but the car needs to be stopped with an error before they’ll consider it defective. They also said they could install a new battery with larger capacity for €600.

The battery is charged constantly when the car is “running”. So I have sometimes simply started it and turned climate and lights off, and let it sit for a couple of hours while washing it etc. It also charges if under a certain threshold, but only 20 minutes each time. I’ve been installing some footwell LEDs, and completely drained the battery in a couple of hours. Just doors open, no stereo etc. A hassle to fix as my charger was auto 6/12V, and didn’t recognize as 12V, so I had to disconnect the battery to remove all drain, and let it sit for 20 minutes before attempting to charge again.

I then ordered a Exide/Sønnak battery which handles lower temps and can charge much faster, using knowledge from AGM batteries. After installing I can now see rather than starting at 12.7V and dropping to 12.4V in an hour, it starts at 13V and stays over 12.7V for a couple of days.

I’ve since also set the dash cam to turn off after 6 hours to save the battery, and SD card space. It’s rarely parked “dangerously” more than 6 hours. The cam will otherwise drain to 12.2V, as I still need that setting because of a drain/load spike when starting the car. Otherwise it shuts down and immediately restarts after turning on the car.

Dealer said I’ll now lose my warranty since I’ve replaced the battery, but I’m pretty sure that’s bogus. I’ve probably lost the 12V battery new car warranty, but not for the whole car.

In any case I’m glad I did this, the battery charges much faster and works better when cold. The car recharges much less than before, and I feel safer, not worried I’ll be stuck at the cabin.
But I have bought a new Defa compact 6A 12V charger that I bring on longer trips. You never know, and it’s super tiny.

I can live with charging the 12V battery occasionally through winter (once a month). But I also find it weird to have to do this, and also worry regarding internal and external charging activating at the same time.

Honda says disconnect the battery, that’s too much of an hassle IMHO, and probably only to avoid accidentally shorting against any other electronics or bodywork. The charger itself doesn’t harm anything. And most likely the internal charger will is disabled, as the voltage is high enough.

I would recommend everyone to check out the BM2, you’ll get logs on the 12V and you can compare that against temperature etc.
Also check out alternative 12V batteries if you live in harsh climates.

Wee Peem
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Post by Wee Peem » Thu Nov 24, 2022 1:27 pm

I purchased a battery box from Amazon, 8 AA cells size with its own switch for £6.99, shoved a big power diode in series with the output to avoid any "nasty feedback" from the main traction battery should it be attempting to charge the 12 volt one. Have used this twice now and it has had plenty of "puff" to get me going again. After all it is only switching on the main battery via a relay or thyristor not trying to turn over an IC engine.

asjo
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Post by asjo » Thu Nov 24, 2022 9:26 pm

You won't hear much from people that have no problems, so there is some reporting bias.

I have had my car for 1½ years and had no problems with the 12V battery so far.

I don't monitor the battery, I don't do anything to charge it, and I don't have a dash cam - I just drive the car as I did my previous 2 electric cars and 2 petrol cars.

My Citroën C-zero did need a new 12V battery at one point, so did my Cadillac Eldorado.

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FDAD
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Post by FDAD » Thu Nov 24, 2022 9:41 pm

asjo wrote:
Thu Nov 24, 2022 9:26 pm
You won't hear much from people that have no problems, so there is some reporting bias.

I have had my car for 1½ years and had no problems with the 12V battery so far.

I don't monitor the battery, I don't do anything to charge it, and I don't have a dash cam - I just drive the car as I did my previous 2 electric cars and 2 petrol cars.

My Citroën C-zero did need a new 12V battery at one point, so did my Cadillac Eldorado.
I quote this as usually people don't report good working things just problems :lol: My 12v is the original one and I also have 0 issues with over 55 000 kms.

I'm thinking maybe it's a problem with «connected» cars having to always communicate with the server and drawing too much power.
Honda E advance [Modern Steel Metallic] 8-) [DELIVERED JULY 2020] - 50 000Kms + ✌️🎂

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