12V Battery after long stand still

[Marksla]

My 2022 Jazz was dead after 11 days in the airport carpark.  Called out the AA and the battery measured 2.4V !!

Fitted a battery monitor since and even after a drive of 3 hours the battery was down to 12.2V two days later.  I guess there's either battery drain or the battery is faulty.

[Kremmen]

Once a battery has reached that level of discharge it's dead, internally damaged. No amount of alternator charging can revive it.

If you're lucky, sometimes an intelligent charger can bring it back as the it needs to be charged bottom up starting with a low level stage 1 trickle charge where the alternator can take over.

I've seen many examples where a flat battery has been driven for 200 miles + only to fully discharge overnight.

[Danoh]

Tips for 3 months non-usage appears to be?
> fully charge 12V and run 30 mins to charge Lithium battery
> fully inflate tyres
> angled blocks against tyres, release brakes to avoid rust on brake discs
> after 3 months, start and drive for minimum 30 minutes for the first few days after returning.
> please correct?

But if lucky enough to be away >4 - 6 months, what should be done, if car is left on the drive in the UK?

P/S
OP author=Botak
Your handle "Botak" could translate as "Bald"/"No hair" in a Chinese language?

[coravel]

I left my 2022 Jazz for a full three months earlier this year and came back to find it as dead as a Dodo.  I called out Honda Assist (AKA the AA) and they used some stand alone device to charge it for 30 minutes.  It then started and I was advised to take it for a 20 minute run.  It was due for its first service just a few days later and the report came back to say the battery was in excellent condition. 

[Botak]

Your handle "Botak" could translate as "Bald"/"No hair" in a Chinese language?

Indeed, Botak= bald(no hair) in Indonesian/Malaysian. We have some old Indonesian roots in our family. 

[Danoh]

Indeed, Botak= bald(no hair) in Indonesian/Malaysian. We have some old Indonesian roots in our family. 

👌

[CB72]

This flat battery talk is a bit worrying, I have just got a Jazz EX and forward park it in a garage which means I would have no access to engine compartment.  With my old car I would put it in neutral and roll it out of the garage, I don't think this is possible with a hybrid. I can't believe that a modern car would suffer with this problem and not have some sort of battery backup, especially a high tech car like the Jazz.

[Bristol_Crosstar]

This flat battery talk is a bit worrying, I have just got a Jazz EX and forward park it in a garage which means I would have no access to engine compartment.  With my old car I would put it in neutral and roll it out of the garage, I don't think this is possible with a hybrid. I can't believe that a modern car would suffer with this problem and not have some sort of battery backup, especially a high tech car like the Jazz.

If you're leaving the car for a long time maybe you should reverse park it into the garage?

The 12v battery is only used to power some of the electronics, it's not used to start the petrol engine (this is done by the high power battery) so it has to be pretty low for the car not to switch on. In normal circumstances it's nothing to worry about, it's only if the car is left unused for a long time there could be an issue, then as said elsewhere a trickle charger can be used to get the battery up to full voltage provided you have access to the bonnet and a power point.

[Kremmen]

Just what I would do .......

I'd hook up my CTEK and connect the power lead to a Kasa or Tapo smartplug and have it come on weekly for a few hours via the Kasa/Tapo schedule facility.

...... assuming you have the wherewithal to perform the live connection.

[Lincolnshire Rambler]

Just parked my jazz for two weeks at cruise terminal . Upon returning it started as normal and within a few minutes of the engine starting the HV battery charged to 8 bars and then reverted to EV mode before leaving the  city traffic as normal. I did have my AA card in my wallet just in case…🤔

[Kremmen]

2 weeks is perfectly OK. I only hook up my charger after 2 weeks of non use.

What I have found is that 2 weeks does result in the trickle charger (CTEK mxs 3.8) taking up to 8 hours to complete. After one week it can complete in 2 or 3 hours.

Edit: had to use my filter bypass trick to stop the "eight)" becoming a smiley face

[Whiteshark]

I went to Australia for 7 weeks in May/ June. After advice from here , I made sure the 12 volt  battery was fully charged via CTEK , and the vehicle stays outside all the time. On return , absolutely no problem, started immediately as expected.
I think unless the car is left in a discharged state and/or for long periods, it will rarely cause problems. The Jazz is designed to cope with short local journeys , which I do regularly, and have done with previous models , and never had a problem.
There will always be instances of premature battery failure, but I am sure they are extremely rare, and in no way are of concern to me, in the same way Hondas generally are pretty damm near perfect. I just drive and service on time and check the essentials…….that’s it.

[Marksla]

Also I'd recommend NOT using the app to check the status of the car, however tempting.  This must drain the 12v a bit with each check.

[John Ratsey]

Also I'd recommend NOT using the app to check the status of the car, however tempting.  This must drain the 12v a bit with each check.

The vehicle shuts down the telemetry connection after 5? days of the vehicle not being used in order to reduce the power drain.

A flat 12V battery is a known problem with the Mk 3 HR-V https://www.hondaforums.co.uk/viewtopic.php?f=11&t=1845 for which there is a software update. Honda, however, will only pay dealers to apply the update after the problem (a fairly random occurrence) has happened, so reports are likely to continue for a while and affect the vehicle's ranking in reliability surveys.

[pasqui]

I leave my cars alone for 2-3 months each summer and so far I had no problems with the batteries. I am basically following the suggestions given here, so they definitely work. In addition, I make sure not to switch the alarm on (in my Jaguar this means just one press not two). I am not sure about the Jazz.