Using a plug in hybrid.

knightstyle

So I understand a plug in hybrid car will run on electric for all my short journeys and not use the petrol in the tank. But petrol degrades and we are told not to use old petrol as it could damage the engine.

"No, you should not use old petrol in your car if it has been sitting for more than 3 to 6 months, as it degrades, loses its combustibility, and can cause severe engine damage. Modern petrol contains ethanol, which naturally attracts moisture and causes the fuel to break down quickly."

Now worried if we should buy one as we only do long journeys occasionally.

born_again

Now worried if we should buy one as we only do long journeys occasionally.

Why not full EV then? As you must have home charging. Or you would not be thinking PHEV?

Aside. Have a bike in garage that has not been on the road for 8 years. Still starts & runs fine on petrol that is in the tank from back then.

Cornucopia

https://forums.moneysavingexpert.com/discussion/6681956/using-a-plug-in-hybrid

There's several embedded questions there…

• Why are you considering PHEV rather than full EV or full petrol?
• What does the vehicle do to manage the perceived issue?
• What does the manufacturer advise?
• Would it allay your concerns if you didn't completely fill the car with petrol that you were not planning to use?

Most PHEVs have controls over the fuel mix and also some intelligent management of it. The notion of "first 50 miles" that the marketing materials indicate may turn out to be more nuanced than that.

There are other reasons not to buy a PHEV, including basic things like more to go wrong.

If your mileage is very small, you may struggle to see a significant difference in annual costs between different technologies.

daveyjp

If you are buying a car which won't run its petrol engine for 3-6 months avoid a PHEV. Go either non plug in hybrid, which will run the engine on every trip, or full EV.

shinytop

The biggest problem with stale petrol is it going off inside the injectors/carbs and gumming them up. A PHEV will run the engine from time to time as part of its engine management routine even if used exclusively as an EV so that won't be an issue. Moisture absorbtion is less of a problem in the tank of a regularly working and warmed up car than a wintering lawn mower in a drafty, damp shed. Your occasional long journey will turn the tank over more than enough to allay any lingering concerns.

In short, don't worry about it.

facade

Exclusively using e5 petrol will help as most of it has much less than 5% ethanol.

It costs a bit more than the adulterated stuff, but if you are only doing a few miles on it it won't matter, plus the higher energy content will slightly increase MPG over e10.

(I would never put e10 in anything I own. Now if it were someone else's car or a PCP/lease and going back I'd just use whatever was the cheapest)

Goudy

If you are just shuffling back and forth locally in EV mode, why would you carry an excess of petrol around you don't plan on using anytime soon? Just keep the level at the bare minimum.

Then when you do a long journey, the fresh petrol will dilute whatever's left in the tank anyway.

Petrol is ok for six months or so in a car's tank but it will become less volatile after that.

Keep it even longer and the ethanol in it can absorb more moisture than is good for it and it can oxidise which leaves a gummy residue.

Exodi

I'm sure it depends on the PHEV, but at least for my wifes (MG5 HS), you can just press a button to change between running off just the battery, or using both. When it's cold, switching the heating on seems to automatically switch to both in any case.

I'd expect most makes and models to allow you to be able to switch energy source.

That said, if you're suggesting you won't do a single long journey n greater than 30 miles (or whatever the real world mileage is of the battery on the PHEV), then I'd question why you need a PHEV to begin with. Most people get them because they want 300 miles (or whatever the fuel range is) as a backup for long journeys. If you literally never do long journeys, get a low range EV.

Mildly_Miffed

There are a lot of petrol cars that only get used in summer - and I have one of them.

No issues at all when you get 'em out after months of non-use.