Cars - Diesel/Petrol need to be run?

[AmIAStone]

So say your car has sat bit moving for 4 weeks, does it need to be run to keep the battery going? We’re not allowed to drive them for the sake of keeping them going so how long does it need to churn over in the driveway and how often? Or do we need a trickle battery charger? Or it’s a myth and not driving it for a month is fine?

[AmIAStone]

@RingtheBells that's exactly it. Have seen that taking the car for a drive just to keep the battery going isn't essential travel, and having the car stopped and being exposed to people isn't worth it, although having no emergency transport to get to hospital isn't an option either. When the lockdown is eased enough to allow people to move around again and we can go for a drive once a week without fear of being stopped it will be good for the car and our mental health.

[Xylophonics]

I'm taking my petrol car out for a weekly drive of about 30 mins , to keep the battery going.

[Meckity1]

Can I ask about petrol cars please?

I passed my test last year and going out for groceries last night after a few weeks without driving was terrifying as I felt I had lost a lot of judgement, but the car definitely felt sluggish. How often should I drive it and for how long? I plan to go out when the roads are quieter as the supermarket is open until late.

[RingtheBells]

Elieza
I think OP is worried that an over zealous policeman will pop his head through the car window if she gets stopped and asked where she is going, fair enough reason to be worried about this judging by some of the pictures that have been in the news recently, social distancing does not seem to apply to all.

[ifonly4]

I know of two people in the last couple of days who've had problems with their car. One wouldn't start due to battery (they had to get someone out as needed it for a family funeral), the other had problems getting hers to start, when she did she drove around for a few minutes. Ours is ok as I need it for work once a week, to drop my Mum's shopping off (and giving it a 50mph blast up the hill on the way back) and take DD to work rather than use the bus.

[Queenofpi]

Mine died after only 2 weeks sat still. I think (hope) its the battery. Luckily my husband's car is still going. They're both diesel. Now every time I go to the supermarket in his car I take a 20 minute detour on a 50mph road. Fingers crossed it stays moving!

[mum11970]

Don’t be daft. Do people think garages take their whole stock out for a trip round the block every couple of weeks? Petrol/diesel cars are fine left idle.

[Elieza]

OP why would you not let someone back in your house if they had been out in the car? It’s only if they get out the car that they would be potentially infected?

They can’t catch any bugs sitting in a car alone provided they just drive it around for 20mins once a week to charge the battery - near home in case of breakdowns, preferably on a dual carriageway or somesuch to give it a good run?
If you get stopped by the police say you’re going to the shop as the local one has run out of wipes/bread/milk or whatever.

[RingtheBells]

Ours is this one but we bought it primarily for the caravan battery, you probably don't need one that expensive as long as is compatible with the car
www.halfords.com/motoring/battery-maintenance/battery-chargers/ctek-multi-mxs-7.0-battery-charger-280326.html

[Lexilooo]

Another forum I am on someone asked their local force about whether they could take their HGV horsebox for a weekly run to keep it ticking over, they were told this was fine.

It seems unlikely that the police will have an issue with you going for a drive to keep your car battery charged, in fact I took our diesel for a run the other day, I did an essential journey but went a longer route including a good stretch of 50mph speed limit to ensure it had been able to run it's regen programme.

[AmIAStone]

Any charger recommendations? Also jump leads require another car/interaction with others, hard when shielding. We only have the one car and need to keep it running for emergency hospital trips, so don’t want to have to wait for the AA overnight etc.

[RingtheBells]

Our 6 year old diesel had a flat battery after about 2 or 3 weeks of a couple of very short journeys but I suspect it needs a new one anyway, luckily we had a decent battery charger because we needed for the caravan battery. We will get a new battery when we start going out again properly. DH did say about taking it for a run and hopefully if the lockdown eases a bit in May and they open garden centres and diy shops then we will have an excuse to do a longer journey

My petrol Fiesta is quite happy not being run much and short journeys though as that is all it gets anyway

A battery charger is handy to have anyway

[Rebelwithallthecause]

Often cars sitting on forecourts for extended periods without being test driven are then run or taken home by staff to keep them running

Then they have mechanics on hand to start ones that haven’t been driven

[whatnametopick]

You will clog a diesel more by using for short journeys or running on the drive. If your battery was OK before you left it then a jump start is all it should need when you go back to using it, cars parked on a car showroom forcourt aren't run for weeks on end.

[BertiesLanding]

Buy a trickle charger.

[BakewellGin1]

I drove my diesal to the supermarket last week and to be honest when it's not getting regular trips out it sounds and runs less then perfect. So I came home the long way via an A road so it at least got 5 minutes decent run. I've made the decision to do this each time we need to shop.

[Rebelwithallthecause]

The clogging up of Diesel engines would have either happened before people stop running their cars or is happening more just to the occasional short trip to a supermarket which will cause more issues than good

[Rebelwithallthecause]

To clear a dpf people recommend getting up to motorway speeds for 15-20 mins

Generally to keep flow plugs working it needs a journey that will get the engine up to temperature (90degrees) in diesels this takes longer than petrols and a 5-10 minute journey wouldn’t be enough.

A half hour journey every 2-3 weeks would be ok

[ErrolTheDragon]

Most of the clogging up of diesels mentioned won't be happening if the car is sitting on the drive, will it? There may be some effect on lubrication and also to the fuel in the tank (petrol moreso than diesel) of volatiles evaporating.

Hybrids apparently may need a 10 mile or so charging run every 6 weeks or so. Apparently if a lithium ion battery fully discharges its a tow to the garage job ... and Toyota may only be servicing cars for key workers and other garages can't deal with them. Not sure if you can or should trickle charge ... the operating voltage is 600 not 12....

Also re trickle charging other cars - DH was looking into this and it seemed like you were meant to take the battery out but that doing so might reset the engine management system on modern cars and require some sort of code to get the car working again. I've no idea if that's correct or specific to some models.

We're using the cars in rotation for some 'short drive long walk' trips, not going out specially.

[AmIAStone]

Thanks @rebelwithallthecause
How l and how often would you suggest it was run for?

[Rebelwithallthecause]

Petrols aren’t so bad but diesels definitely need to be run.
It clears the DPF as a minimum

[Rebelwithallthecause]

Even with a trickle charge to keep your battery topped up doesn’t mean that other things like glow plugs will be ok

[AmIAStone]

Looking at the trickle chargers, if we can run a power lead out to the dark which is better, a mains one or a solar power one? Do they need to be left plugged in constantly or is it a plug/unplug once a day thing or once a week etc?

[mencken]

newer cars with lots of gadgets will not last as long undriven, while older ones are more robust (fewer pointless additions) - example upthread proves. If you've got anything under 5 years old, assume it is crap and get a battery charger. My new to me car at 10 years old is doing fine on every 10 days, I had a 1998 car in the bad winter about 2010 (I think?) and it started first time after sitting in snow for a month.

diesels need long runs anyway or they clog up.

[TJH130]

Only modern diesels @IDefinitelyHaveFriends, with those you'd be better off not running it than running it for a short time