Expert answer

Hi Dana,

It really sounds related to the charging circuit and, before going through the list below, perhaps check that the battery was replaced by a 'silver-calcium' one that is compatible with the so-called “Ford Smart Charge System”. A regular lead-acid battery is not compatible.

We'd have hoped that a good mechanic would have tried the below things already, but if not:

Bad ground or wiring issue

- A poor ground connection or corroded cables can cause intermittent charging problems.

- Check and clean all ground connections (especially the engine-to-chassis ground and battery-to-body ground).

- Look for damaged or frayed wiring between the alternator, battery and fuse box.

Alternator not charging properly

- Even new alternators can be faulty. A voltage drop test should confirm if it's truly charging.

- With the engine running, check the voltage at the battery terminals. It should read around 13.5-14.5 volts.

- If it's much lower, the alternator isn't charging properly, or something is disrupting the circuit.

Smart Charge System

- The Ford Smart Charge system can fail and cause charging problems.

- Check the three-pin connector going to the alternator - if it's loose, corroded, or damaged, the alternator may not work correctly.

- Try disconnecting the Smart Charge system (forcing the alternator to work as a standard one) and see if the problem improves.

Parasitic battery drain

- If something is drawing power while the car is off, the battery might not have enough charge when you restart.

- A mechanic can do a parasitic draw test by pulling fuses one by one to find a circuit draining power.

Faulty ECU or sensors

- If the ECU isn't regulating voltage properly, it could be sending the wrong signals to the alternator.

- Some Ford owners have reported a faulty crankshaft position sensor or bad engine ground causing similar symptoms.

Fuse box or relay issue

- Check the engine bay fuse box for water damage or corrosion - this is common on older Fords.

- A failing alternator fuse or relay could intermittently stop charging.

Expert answer

Hi Simeon,

I think a plug-in hybrid such as this could work well for you, though best to go into the purchase realising that the car is likely to go no further than 40-50km on electric power most of the time. Nonetheless, if you can charge it up at home on cheap night-rate electricity then it should cost you very little to run. You’d likely do the Cork to Ringaskiddy and back trip barely using the engine.

By default, the car will use the electric motor and ability as much as possible, so on longer runs the drive battery charge will be quickly used up and the engine will be on most of the time from then on. It can affect responsiveness a little.

The Volvo has a setting you can activate to hold the battery charge, or top it up, using the engine as a generator while it drives along. This is useful if you want to have battery charge for later in the journey to allow for electric-only driving, but it isn’t any more efficient as it uses more fuel from the tank to do this.

If you can charge up at home or work, I’d suggest you’re a perfect candidate for an electric car. A vast majority of them could manage the Cork to Bantry return journey without needing to be charged up.

Expert answer

Hi Jack,

The EV6 has a longer range on a charge of its battery and is more efficient, though that’s probably not a major issue for you as you’ll likely charge up at home every night and - I assume - have plenty of range in either car to keep you going for a shift. I prefer the quality of the Toyota’s cabin and its smoothness on the road, two things it betters the Kia on. There’s not much difference between them in terms of interior space, but the Kia has a larger boot, which may be relevant to your needs.

I highly recommend you go and test drive both cars for yourself, so you get a feel for which you prefer. Do let us know which you go for and why.

Expert answer

Hi John,

The plug-in hybrid model would be very cheap to run if you can keep its battery charged up at home or work to carry out those small local journeys you mentioned, but it will certainly be thirstier than your current diesel on longer drives where you can't charge up the battery from an external source. You'll need to do the maths and decide whether you can actually keep it charged up easily.

If you want us to look for alternatives, come back to us with a rough budget, whether you want a new or used car and the number of people you need to carry regularly and we'll see what else might suit you.

Expert answer

Hi Daniel,

First up, the battery in those alone wouldn't cost in the 10s of thousands - it's considerably less than that. Not that you'd ever want to have to do it, but still, it's worth bearing that in mind.

I must admit we have heard of a few cases where BMW has struggled to identify an issue with the hybrid system recharging the battery and the repair is expensive as it involved replacing the whole hybrid system, not just the battery. That's frightening of course, but it's only a few cases rather than every example of the car.

If you go ahead with the purchase, perhaps consider an aftermarket used car warranty.

If you don't feel confident going for it, come back to us with more information on your budget and needs and we'll try to find you an alternative to your diesel Passat.

Expert answer

Hi Sean,

I drove the Macan 4 at its international launch (read that review here) and today the Audi Q6 e-tron on Irish roads so I can have a stab at comparing them, though bear in mind that both were high-spec cars. The Q6 e-tron I tested was the quattro model using the same two electric motors as the Macan 4, as well as the 100kWh (95kWh of which is usable) battery so these are quite comparable.

The Audi had loads of options though, including air suspension, so that undoubtedly alters how it drives. On that note, the Audi is a little more comfortable than the Porsche, but a little less involving and slower to respond to steering inputs and accelerator inputs. Both are very quiet, refined and smooth to drive, with the Audi slightly better in that regard. The Porsche has fractionally better 'blending' of the friction brakes and recuperation via the motors.

There's nothing to choose between them in terms of range, efficiency and charging capabilities.

Somewhat surprisingly, the Macan 4 has a marginally bigger boot and extra storage under the bonnet included in the price, while you have to pay Audi more to get the 'frunk' insert in the Q6. The rear seats of the Audi feel more spacious, however, than the Macan's.

The cabins are vastly different, but both of very high quality. I prefer the perfectly round steering wheel in the Porsche.

Finally, pricing: the comparable Audi is cheaper than the Porsche and there are more affordable versions of the Q6 e-tron - one with a smaller battery, another with rear-wheel drive - that there are no equivalents to in the Macan lineup.

So as you can see, no clear 'winner' as there are too many variables at work, but hopefully this helps you choose which is for you and your budget. 

Do let us know which one you go for. Both are lovely.

Expert answer

Hi Philip,

A battery in a PHEV (and an EV for that matter) and its various components are no less waterproof or more susceptible to damage in such conditions than an engine and its various components. EVs and PHEVs go through the same stringent quality control checks and have to withstand the same lifecycle as their petrol-powered counterparts. 

Expert answer

Hi Catherine,

Stop-start systems can be tempermental. We get so many queries about them that we decided to write a feature explaining the potential issues - Why won't my car's stop-start system work?

Nonetheless, issues with it are regularly caused by weak batteries. Saying that, I wouldn't expect your car to start properly in the morning if there was a big battery problem, so I don't think the boot opening problem is linked to the battery. The Fiat 500 has a known issue where the wiring near the tailgate hinge can become damaged or broken - I suspect that's where your problem lies.

A decent mechanic should be able to quickly fix that for you.

Expert answer

Hi David,

It's a tricky time for choosing a new car in your situation for sure, especially given your high mileage. I feel that a diesel would still be a little more economical for you than the latest hybrids unless you keep your speeds down. If you spend most of that at 120km/h then a good diesel is hard to beat from an economy point of view. Saying that, the Corolla and new Civic are both very efficient cars and, if you adapt your driving style to their powertrains, then it is possible to return some trully outstanding fuel economy figures. And it must be said, with one eye on future values, a hybrid might be a more shrewd choice.

In your situation as described, I'd shy away from purely-electric cars for now as well. I'd be worried about relying on the public charging network to support such high mileage.

Expert answer

Hi Teresa,

We used to get so many queries on this subject that we published a feature called Why won't my car's stop-start system work?

If you read that you'll discover that the systems are highly sensitive to battery charge and load, even when working perfectly. Could it be that you often have high-load items switched on? Things like heated seats, air conditioning, rear window demister, that sort of thing.

Now, in a DSG-equipped automatic car, you shouldn't need to put the car into neutral to get the stop-start system to work - that's only on manual cars. You can leave it in D (drive). What does affect it, however, is how firmly you are holding your foot on the brake pedal when at a standstill. Sometimes it's necessary to give the brake pedal a firm push before the engine will cut out.

Other things to watch out for: if you move the steering wheel, it is likely to cause the engine to restart. And if you're in the Sport driving mode or you've selected the Sport gearbox setting, then stop-start might not work either.

If none of the above changes your experience, I suggest getting a mechanic to come out in the car with you to check it over and observe how you drive, and then let them do the same.

Best of luck with it - come back to us and let us know how you get on.