Stop start battery issue

[Craigybaby69]

Hi folks, our April 2019 grand cmax has an issue in that the stop start has hardly worked since we got it in early 2020... At the first service we were fobbed off that it was probably due to the cold weather. So we recently took it back again, they've done a full investigation and claim the battery is fine, but not getting fully recharged due to my wife only doing short trips, we've done about 5000 miles in 18 months... So once the battery drops below 75% it will stop working again. The battery is still within the 3 year warranty so in my opinion they should be changing it...am I expecting too much?
Kind regards, Craig

[Craigybaby69]

The initial message was deleted from this topic on 25 August 2021 at 09:53

[stevemcs]

Ford only cover the battery for 12 months i believe, if the battery is at 100% charge and at least 80% on state of health then it should work, but various things will stop it, oil temp, battery drain (ac on) etc. In all fairness you are better off without it working. Ford batteries tend to last 4-5 years, VW and Nissans 2 years.

[Craigybaby69]

It's a 3 year warranty on the battery. They've done all the diagnostics, there's nothing draining it and they say the battery is fine, but it's our fault for only doing short journeys!

[Matt_E_Mulsion]

5000 miles in 18 months? That's not big mileage, which would suggest a lot of short journeys.

In my experience of stop start vehicles, you need to be doing a semi decent mileage of not all short journeys in order to keep the battery at its peak level, so that the stop start function will work.

[twing]

I think the magic number is 78%. My stop-starts rarely work as my regular drive is only 10 miles. Does your wife leave a phone charger plugged in? Even if no phone attached it can make the difference. A new battery would very quickly get to below the number doing the short trips.

[paintman]

Matt_E_Mulsion said:

5000 miles in 18 months? That's not big mileage, which would suggest a lot of short journeys.

In my experience of stop start vehicles, you need to be doing a semi decent mileage of not all short journeys in order to keep the battery at its peak level, so that the stop start function will work.

^^^This.

If they did replace the battery under warranty you are likely to find that it will continue what's left of the original 3 year warranty period - you don't get another 3 years.
If you bought a brand new battery then the 3 years will start again.

[Craigybaby69]

Thanks chaps, if this is just one of those things and a common occurrence then I feel better....I thought we were just being fobbed off so ford didn't have to replace the battery...

[Scrump]

The Ford explanation aligns with my experience of stop start.

[RUSTILLDOWN]

I think ur being unreasonable as it’s obviously just due to short trips.

Either use the car for longer journeys (>30mins) or If you’re with the mrs and know she’ll just be a few mins in a shop you should stay in the car and keep the engine going to help recharge the battery… that’s what I did when I got a low battery warning 12 months ago and it’s been fine ever since.

I don’t actually like stop/start in my current car (VW) so the first thing I do when I start the engine is to turn our stop start off.

I think it used to be better in a previous car (Merc) and only stop/start if I pushed the brake pedal hard after coming to a standstill… that one I could live with as I would push hard at lights but not junctions etc.

[Craigybaby69]

It all seems a bit weird and contradictory... Surely the benefit of start stop is not wasting petrol/protecting environment/not polluting school kids, and the time it's most needed is short runs around town.... But if you have to leave your engine running, or take it on a motorway run to charge the battery, then in my eyes it's a load of old bks

[twing]

Of course it's a load of bks! Always has been, just like most of the other "Environmentally friendly" bks.

[Craigybaby69]

RUSTILLDOWN said:

I think ur being unreasonable as it’s obviously just due to short trips.

Either use the car for longer journeys (>30mins) or If you’re with the mrs and know she’ll just be a few mins in a shop you should stay in the car and keep the engine going to help recharge the battery… that’s what I did when I got a low battery warning 12 months ago and it’s been fine ever since.

I don’t actually like stop/start in my current car (VW) so the first thing I do when I start the engine is to turn our stop start off.

I think it used to be better in a previous car (Merc) and only stop/start if I pushed the brake pedal hard after coming to a standstill… that one I could live with as I would push hard at lights but not junctions etc.

Fair enough...I will accept that something within warranty doesn't work properly, but that's just the way it is.

[voram]

Yup, all sounds 100% normal to me on a car that doesn't get a lot of use.

[Sheepshanks]

RUSTILLDOWN said:

I think ur being unreasonable as it’s obviously just due to short trips.

Either use the car for longer journeys (>30mins) or If you’re with the mrs and know she’ll just be a few mins in a shop you should stay in the car and keep the engine going to help recharge the battery… that’s what I did when I got a low battery warning 12 months ago and it’s been fine ever since.

^This. One of our 'kids' lives in a city and since covid the furthest she drives is a mile or so to the supermarket / kids nursery / gym etc. Car's battery went flat and her solution was to call the AA who of course sold her a new battery.

They need time to charge up - modern charging systems don't do much more than float charge the battery, so a long (time, not so much miles) run or charge it weekly.

RUSTILLDOWN said:

I don’t actually like stop/start in my current car (VW) so the first thing I do when I start the engine is to turn our stop start off.

Same in wife's VW. She doesn't use the car much we live in a semi-rural area so it's doing a decent run most times it's used. Stop/start always works. She turns it off instinctively on starting the car - I usually forget until I get to the end of our road and it stops (it'll do it from a cold start after a few hundred yards, only the a/c going flat out on hot days seems to prevent it).

[Monkeylegend]

First thing I do when I get in my car after starting the engine is turn off the stop/start.

[leef44]

Craigybaby69 said:

It all seems a bit weird and contradictory... Surely the benefit of start stop is not wasting petrol/protecting environment/not polluting school kids, and the time it's most needed is short runs around town.... But if you have to leave your engine running, or take it on a motorway run to charge the battery, then in my eyes it's a load of old bks

I found this out from a work colleague who had recently purchased a Toyota Yaris with hybrid technology. I thought great, a small car which he uses for shopping, work and taking the kids to short trips. Half the time these are short journeys where he would not even need to use the ICE.

He then got dead battery twice and the dealership told him that he needs to take the car out for long runs to recharge the battery

So not so eco friendly after all.

[Matt_E_Mulsion]

My mother has had a Clio from new that is fitted with stop start. Her journeys consist of mostly a run of a few miles into the local town, parked up whilst a bit of shopping takes place and then the few miles home.

The stop start doesn't operate at all as her usage pattern just isn't right for stop start technology.

[stevieturbo]

Craigybaby69 said:

It all seems a bit weird and contradictory... Surely the benefit of start stop is not wasting petrol/protecting environment/not polluting school kids, and the time it's most needed is short runs around town.... But if you have to leave your engine running, or take it on a motorway run to charge the battery, then in my eyes it's a load of old bks

Blame the aholes who make the emissions rules. Start stop tick their box, but in reality it's pretty stupid and really annoying.

Fortunately there is a button to turn it off, at least on most cars ? even if you have to manually do that each time you start the car.

[Craigybaby69]

Oh well seems there's universal hatred for it...it's working again now the battery has been charged but won't be for long I'm sure...I must admit, even when we bought the car, I had my reservations about it from a brake disk point of view, ie I was always taught if you keep your foot on the brake pedal at traffic lights, instead of using the hand brake, you're more likely to warp the disk as the hot brake pad is sat in one place for a couple of minutes...