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?

Worst case scenario you might need a jump start. I think most cars will be ok for a couple of months but depends on the state/age of your battery.

Go to a shop. Or pretend to and that the queue put you off.

Diesels often need to be run at higher speeds for a good distance. Otherwise the engines clog up and get dirty. DH delivered some bits to family 45 mins down the motorway/A roads and wasn’t stopped so I’m sure it’s possible to nip out to keep it running and the battery charged. Perhaps combine with a useful errand.

But I’m more relaxed than most people on MN.

You might need to charge your battery imtaking mine shopping the long way round every 10 days

Both my mum and ex husbands cars are sat idle at the moment - I'm still working so I take each of their cars a couple of days a week to keep them up together. Had to jump start my mums after only a couple of weeks idle and the car is only a couple of years old, whereas I regularly leave my 18 year old car for 3/4 weeks when I'm abroad and it's never not started - weird

6year old diesel here. Shielding household so not leaving the house and don’t want to risk being stopped and exposed to people/police as that would mean the person who left the house in the car wouldn’t be allowed back in the house (already discussed if need to venture out)

I lent my car to my daughter while the lockdown is going on. The battery was flat a few days ago and had to call out the breakdown service. While on the phone the operator advised her to run the car for 20 minutes a day. So she going for a bi of a drive, parking on our drive and walking from there. With a large detour that is about 20 minutes.

My other daughter ran her car last night and my husband had a drive in his. The cars aren't being used at all apart from this. It's got to be better than calling out the breakdown services. The man who came to our car said that's all they are doing at the moment.

The best way during all this is your car isnt going to be used it remove the Negative (black) battery lead to prevent the battery being drained.

Dont start it and run for a few mins then turn off as that wont be long enough to recharge properly

i live abroad but have a house in the UK that I (usually) visit regularly, with a 2003 diesel car in the garage. I typically come back about every 2-3 months, obviously longer this time. I use a battery isolator switch and the car has never failed to start first time.

www.autoelectricsupplies.co.uk/product/136/category/30

What's also important is that before you put the car away you need to really run everything up to temperature, otherwise you can get condensation in the exhaust and it starts to rust from the inside. So leaving the car running on the drive for 10 minutes is not a good idea.

Diesel cars need to be driven to keep working.

Petrol not so much but you still need to run any car to keep the battery charged

If noone runs them for 6 weeks they will come out to find they have flat batteries at the least

Twenty minutes every day is far more than necessary. Once a week will do you fine, but yes with diesel cars especially it needs to be a proper run - once round the block will do more harm than good.

A trickle charger will take care of the battery. Some you plug in, some are solar powered (good if you park on the street).

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

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.

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?

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

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

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

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.

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

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

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.

Buy a trickle charger.

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.

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