Navitron Renewable Energy and Sustainability Forum

Energy/Electricity Storage and Use/Grid Connection => Off-Grid, Batteries & Inverters => Topic started by: djs63 on July 22, 2018, 10:51:16 AM



Title: Car battery maintenance, EV and diesel
Post by: djs63 on July 22, 2018, 10:51:16 AM
Hi, we are considering a long trip away, eg 6 weeks in the middle of winter and we have a Leaf and a 2.5 litre diesel cars to be left at home.

Should we leave the Leaf connected to the charging point while we are away?
And should we leave the dieselís battery connected to a charger?
 :snow

And we donít know how cold it will be, and I donít know at what rate the batteries discharge... Lots I donít know.


Title: Re: Car battery maintenance, EV and diesel
Post by: Tinbum on July 22, 2018, 11:08:52 AM
Hi, we are considering a long trip away, eg 6 weeks in the middle of winter and we have a Leaf and a 2.5 litre diesel cars to be left at home.

Should we leave the Leaf connected to the charging point while we are away?
And should we leave the dieselís battery connected to a charger?
 :snow

And we donít know how cold it will be, and I donít know at what rate the batteries discharge... Lots I donít know.

I would just disconnect the battery, if you know the radio codes, on the diesel cars or you could use one of those maintain chargers designed to be left on.


Title: Re: Car battery maintenance, EV and diesel
Post by: JohnS on July 22, 2018, 11:20:38 AM
Do you have a plug in (standard 3 pin) charger for the Leaf?

If so, set it up via a timer (sized to take 3kW) so that the charger charges for, say, 30 mins per day, or an hour or two per week.  That way, the battery will stay topped up without being charged the whole time.  Set the timer for, say, 2am when the grid demand is lowest.

I do this, setting the timer for 11am to 4pm in the summer for solar diversion and early morning in winter.  Can override if wanting to charge the car sooner.

John


Title: Re: Car battery maintenance, EV and diesel
Post by: Philip R on July 22, 2018, 11:22:25 AM
I was going to say leave it as it is. A 2 5 litre diesel will have a big battery (Ah) fitted.
Things like radio and immobiliser can do funny things when disconnected from power for extended periods,like not work when reconnected.
Items like boot and courtesy lights can drain battery if not working. Not sure I would want to leave battery on maintenance charge for 6 weeks unsupervised.  When you get back, put in on charger and try and start engine.
Check antifreeze protection especially if parked outside.
Handbrake could seize on, so park on level, chock wheels and release handbrake( if in garage).
Some for EV. For this, read the book or contact oem for advice. Personally i would not leave it connected, should charger controls fail.
Philip R


Title: Re: Car battery maintenance, EV and diesel
Post by: oliver90owner on July 22, 2018, 12:19:58 PM
If the lead acid battery is old, I would at least budget for a new one on your return, especially if left connected.

I suggest you ask the vehicle dealership if it is OK to remove the battery, and for any requirements when reconnecting.  I personally donít think there should be any more problem than, say, if the engine were changed or whilst accident damage was rectified.  There may be issues with insurance, if any alarm is deactivated.

Re the Leaf - I doubt if the battery would discharge so much over that period if fully charged, initially.  They are designed to be discharged deeply, after all.  But asking the local Nissan dealer should get you a definitive answer.

You have plenty of time to find out.  Better than potentially advertising your absence on the internet...


Title: Re: Car battery maintenance, EV and diesel
Post by: chris_n on July 22, 2018, 06:00:02 PM
I use a maintainer on our car when left for 3 months over winter. 6 weeks is probably long enough to flatten the battery enough to cause problems on a modern car. They generally have quite a high standby consumption.


Title: Re: Car battery maintenance, EV and diesel
Post by: TheFairway on July 22, 2018, 09:06:06 PM
On our Passat, disconnecting battery required electric windows to be reprogrammed. Easy enough if you know what you are doing, at least it looked easy enough for the garage to do... Didn't look like he needed any specialist tools, just windows to be open/closed in appropriate sequence.

Personally, unless you have stop/start capabilities, I would just leave it on a trickle charger. If its got stop/start, ask a friendly mechanic how to handle it - my car has various warnings about danger of recharging battery if stop/start - don't know why, never bothered to investigate, but if manual etc says don't do it, I'm not going to do it until I know the implications.


Title: Re: Car battery maintenance, EV and diesel
Post by: Justme on July 22, 2018, 09:59:45 PM
My camper sits for longer than 6 weeks with no issues.
If its going to be 2 or 3 months plus then I remove the bat & charge it when i remember.


Title: Re: Car battery maintenance, EV and diesel
Post by: camillitech on July 22, 2018, 10:44:33 PM
Me, I wouldn't even think about about it, go away, have your holiday and sort it out when you get back  ;D Seriously though, six weeks is feck all and if your diesel battery cannae cope with it then it's feckered anyway. Don't see why the Leaf should be a problem either. What's the worst that could happen? you arrive home at 'stupid O clock' and the batteries are dubious or you leave them on charge and risk a fire. Me I'd worry about it when I got home, fer fecks sake you'll be needing a rest anyway, if yer batteries are flat then charge em afore you go back to work. Surely your no planning to jump off the plane, leap into the car and go to work? If you are then you're a better man than I  ;D

Good luck, Paul


Title: Re: Car battery maintenance, EV and diesel
Post by: kristen on July 23, 2018, 12:36:45 AM
What's the worst that could happen?

Fully discharged Leaf battery will be bricked, won't it?

I have no experience of the Leaf so don't know about its parasitic loss, but the battery isn't huge ... on a Tesla the parasitic loss is not huge, but certainly significant over 6 weeks. Tesla will shut down progressively more of the parasitic stuff as the SoC falls, so the last say 25% will last longer ... but Tesla's recommendation is "plug it in".; Tesla will only top-up-charge when its fallen several percent, and for a 6 week "away" I would set the Tesla to 50% charge - i.e. car will maintain a 50% SoC which will be kinder to the battery than a high SoC.

My concern when plugged in is a surge from lightening strike, rather than any other eventuality. (On Tesla changing the password prevents any APPs from getting connection, which helps with Parasitic loss, and the car can be "turned off" which then prevents a bunch of stuff such as not uploading status every minute, nor attempting to download updates etc. Maybe similar available on Leaf?


Title: Re: Car battery maintenance, EV and diesel
Post by: camillitech on July 23, 2018, 06:05:14 AM
What's the worst that could happen?

Fully discharged Leaf battery will be bricked, won't it?



Fully discharged anything would be 'bricked'. I'd be seriously surprised if the Leaf didn't shut itself down when when cell voltage approached critical level (or a Tesla for that matter). Having said that the Tesla is probably one of these stupid cars with keyless entry and won't let you in the feckin' thing if yer battery is flat  :fume


Title: Re: Car battery maintenance, EV and diesel
Post by: Nickel2 on July 23, 2018, 10:13:00 AM
My mate uses a solar trickle-charger in his Bongo that is unused for up to 2 months sometimes. It always starts without fuss. The unit is about 24 x 6 inches and sits on the dash-top inside the windscreen, with croc-clips onto the battery. £20 for charger, or £80 for new battery was the choice.


Title: Re: Car battery maintenance, EV and diesel
Post by: Tiff on July 23, 2018, 09:26:19 PM

I suspect some confusion over the 12v battery vs traction battery for the Leaf.

The 12v battery is quite small at 47Ah as there is no requirement to crank an engine. The 12v battery is charged from the traction battery when the ignition is on. I am not sure if will charge when the traction battery is being charged, I think it does but I'm not 100% sure.

There are lots of tales of people coming back to EVs with flat batterys (12v battery). If the 12v is flat then there is no power for the contactor for the traction battery. As far as I am aware the traction battery in all EVs is isolated when the ignition is off.

I would leave both on some form of smart trickle charge for that length of time.

I think the advice for cars with stop start is because they tend to have AGM batteries.


Title: Re: Car battery maintenance, EV and diesel
Post by: kristen on July 24, 2018, 02:13:42 AM

I am not sure if will charge when the traction battery is being charged, I think it does but I'm not 100% sure.

I have read (but might be wrong / old models) that 12V on Leaf will not charge (from traction) when plugged in (implication was that 12V will charge [from Traction] when not plugged in, and ignition OFF), which is then a potential problem if plugged in for weeks on end.