Battery preservation tips?

[Kristin77]

I've a 3-1/2 year old Motability EcoSport which sadly between the pandemic and my health situation hasn't had much mileage put on it since I got it - just over 1000 a year.  During that time it's twice had to go to Ford to get the battery charged - the last time just last month - they decided it was better to just replace the battery which I'm immensely grateful for as I'd spent the last 6 months panicking about using the radio or heater as I didn't want to drain it further.

So what I'm looking to get some info on is how to preserve this new one for as long as possible.   I'm only making quite short drives (1-2 miles or less) 99% of the time but am now only using the radio on a really low volume and dreading the summer as I nearly always have to resort to the aircon for at least part of my drives in hot weather.   My focus on the battery is ruining my enjoyment of the car to be honest and while I appreciate I can always get Ford to keep topping it up, I don't really want to have to do that too often either. 

I was wondering does the battery recharging depend on how many miles you do, or is it purely on how long the engine runs for i.e. can it be charged by just idling for an hour (not that I'd have the patience for that much).  Does it charge more if you're driving at speed on a motorway over doing 30 for an hour?   I haven't been using the Start/Stop at traffic lights but gather that's not much value for the purpose.  Are there any other simple measures I can take (over the standard not running heater/aircon etc) that will help?

Thanks 🙂

[Eric Bloodaxe]

Well, provided you're able to connect up the crocodile clips (which I appreciate could be difficult for you) many of us are using a smart charger such as C-tek, Noco or Maypole to keep our batteries topped up.

Several threads on here about chargers, such as:

https://www.fordownersclub.com/forums/topic/124276-which-battery-charger/

 

[billyboy]

You really do need a smart charger but if that's not possible then you need to go the long way round on your journeys and do at least five miles. It's not speed that charges the battery but time so try to do at least 20 minute journeys. If none of that is possible do you know someone who you could trust to take the car out once or twice a week. Never leave the engine idling for any reason as it ruins the engine.

[TomsFocus]

Idling the engine doesn't charge the battery much, if at all.  I've been doing that with my cars over the last year...for about 15 mins at a time.  (Unable to drive atm so no other option!). But the Focus goes into deep sleep mode as soon as I switch it off and the Golf battery dies after another week or so.

Driving more is of course the best option.  But if that's not possible, you either need a Smart Charger plugged in about once a month, or just keep having Ford recharge it.  There's not much else you can do unfortunately.  

[alexp999]

29 minutes ago, billyboy said:

You really do need a smart charger but if that's not possible then you need to go the long way round on your journeys and do at least five miles. It's not speed that charges the battery but time so try to do at least 20 minute journeys. If none of that is possible do you know someone who you could trust to take the car out once or twice a week. Never leave the engine idling for any reason as it ruins the engine.

How does idling ruin the engine? Genuine question.

[billyboy]

1 hour ago, alexp999 said:

How does idling ruin the engine? Genuine question.

Low oil pressure, I had a customer who forgot to switch his engine off when he got home and left it running all night, the next morning the big ends and crankshaft were ruined. The warning light goes out on tick over but the pressure is very low it's only meant to be a temporary thing until you drive away.

[Tizer]

1 hour ago, alexp999 said:

How does idling ruin the engine? Genuine question.

A good question and I'm sure that everyone will have their own opinions that might or might not be correct. 

Apart from the lubrication, carbon build up and cooling issues, my own opinion is that a car engine has been designed to propel a very heavy load against a lot of resistance and freewheeling it will cause it to shake itself to bits more so than one that is under the load that it was designed for, A lot more so with revving a stationary engine than Idling. This opinion is based on conversations with a relative who worked for an engine manufacturer.

I have also looked under the Cam Cover of an older Idling engine and there is a lot less lubrication oil on the Camshaft than when revving it. This might not be as relevant now that cars have variable rate oil pumps and do produce a lot of oil Pressure at Idle. Hotspots are also more likely to occur if the engine is not working at its optimum speed and without the Ram effect of air passing over the bits that it is designed to pass over.

I do know that, and this is for older engines, whenever I have done a long Motorway journey in a car that normally is just driven around town then the car has run better in the weeks afterwards. It is much the same with cars with DPF/GPF's, they need to be taken for a good run to keep them from clogging up.   

[StephenFord]

My mum has a 20 year old Toyota Yaris, the battery is 15 years old. Her mileage is non existent for the last 2 years due to lockdown, and then her having a stroke. I charge the battery up every 2 months with my Maypole charger, it has never failed to start on 1st twist of the key. It also has never broken down once, it's the most reliable car I've ever come across LOL I'm still not sure why I bought a Focus 🤣

[Wino]

2 hours ago, TomsFocus said:

Idling the engine doesn't charge the battery much, if at all.  I've been doing that with my cars over the last year...for about 15 mins at a time.  (Unable to drive atm so no other option!). But the Focus goes into deep sleep mode as soon as I switch it off and the Golf battery dies after another week or so.

Driving more is of course the best option.  But if that's not possible, you either need a Smart Charger plugged in about once a month, or just keep having Ford recharge it.  There's not much else you can do unfortunately.  

Perhaps something isn't shutting down as it should Tom ?

15 minutes was more than what ours getting and it hasn't gone into deep sleep mode for a long time, well not since we moved here back in end of September.

Perhaps the alteration of the SOC capacity and the battery size adjustment has something to to with it but last time I looked on Forscan it was showing 67% charged but that was a good couple of months ago.

It's only this last week that ours is doing more miles as the Mrs has started a new temporary job, but that is only 14 miles round trip 3 days a week.

Not put any fuel in it since March 3rd and it still has just over a quarter left after 426 miles covered including all shopping trips.

 

[TomsFocus]

1 minute ago, Wino said:

Perhaps something isn't shutting down as it should Tom ?

15 minutes is more than what ours gets currently and it hasn't gone into deep sleep mode for a long time, well not since we moved here back in end of September.

Perhaps the alteration of the SOC capacity and the battery size adjustment has something to to with it but last time I looked on Forscan it was showing 67% charged but that was a good couple of months ago.

Are you driving yours though? Mines only idling on the spot.  It does make a difference to charging, that's the point I was making.

I've just checked the voltage today as it happens...11.6 volts.  Not sure what that is in relation to the SOC?

[Wino]

1 minute ago, TomsFocus said:

Are you driving yours though? Mines only idling on the spot.  It does make a difference to charging, that's the point I was making.

I've just checked the voltage today as it happens...11.6 volts.  Not sure what that is in relation to the SOC?

No, I'm not but the Mrs is currently. I've been promoted in the driving ranks at home to a lovely comfy 12yr old Picanto 😂

What I was trying to say in my earlier post that yours is idling for 15 mins but ours was only being driven for 3mins to work for 4 days week, if that as I sometimes walk.

[TomsFocus]

Driving a few miles every other day is much better than a 15 minute idle once every couple of months tbh.

I doubt my mk4 has ever had a full charge.  It was delivered to me straight from the transporter so the dealership didn't have any time to charge it, and I never did more than a few miles at a time in the first month.

The Golf battery is on its last legs after 5 years, and it's not even the correct battery for variable charging and stop start, so that one isn't really a fair comparison.  I've got a new one, but no point changing it unless I can regularly drive it again.

 

[Wino]

1 minute ago, TomsFocus said:

Driving a few miles every other day is much better than a 15 minute idle once every couple of months tbh.

I doubt my mk4 has ever had a full charge.  It was delivered to me straight from the transporter so the dealership didn't have any time to charge it, and I never did more than a few miles at a time in the first month.

The Golf battery is on its last legs after 5 years, and it's not even the correct battery for variable charging and stop start, so that one isn't really a fair comparison.  I've got a new one, but no point changing it unless I can regularly drive it again.

 

Is it not a viable option to disconnect the Focus battery to save faffing around with it if your not driving it ? 

No idea of any long term implications though and I'm sure there would be something with the MK4 lol.

[unofix]

1 hour ago, TomsFocus said:

I've just checked the voltage today as it happens...11.6 volts.  Not sure what that is in relation to the SOC?

This is a guide for typical vehicle batteries. Due to different battery materials / construction allow +/- 5% on the voltage figures.

[Tizer]

1 hour ago, TomsFocus said:

Mines only idling on the spot.  It does make a difference to charging, that's the point I was making.

Hate to disagree with you Tom but from my own observations of my Mk4, (non MHEV), it doesn't make any difference whether the car is at Idle or moving, except perhaps for the first few minutes.

If I connect up FORScan and monitor the net Charging Current, Voltage and SOC then after a cold start the Alternator can sometimes put out a net 20 or so Amps at Idle, which is a slightly higher Idle because the engine is cold. The Current then reduces gradually over the next few minutes to settle down to what can be 1,2 or 3 Amps normally and stays exactly the same whether the car is at Idle or doing 70 mph. The Voltage stays the same except when it goes into one of the Regeneration or Refresh modes.

Switching any High Load on just reduces the Current and Voltage for a few milliseconds before they go back to what they were and 15 minutes of running or Idling would normally only result in about a 1% increase in the SOC.

 

[Wino]

Key cycles as I've mentioned a few times elsewhere regarding the voltage and SOC makes a big difference.

Switch off the car and lock it up, you will lose 0.4v each time you lock and unlock the car.

The voltage and SOC will move considerably within another 10 mins.

It's the same on a long run, hence why people often wonder why after travelling long distances and the stop start doesn't work until the following day or even later ( it may take a few days if your only doing shorter trips after a long run) all depends on how long the next drive is and how many key cycles.

[TomsFocus]

2 hours ago, Wino said:

Is it not a viable option to disconnect the Focus battery to save faffing around with it if your not driving it ? 

No idea of any long term implications though and I'm sure there would be something with the MK4 lol.

I never expected to have it off the road so long tbf.  I hate leaving cars undriven, I've seen far more faults caused through that than I ever did thrashing the nuts off them back in the day lol.

I guess the two implications I can think of immediately are no alarm if someone broke into it and having to use the manual key in the door barrel.

I wonder if there are also finance or insurance implications for having no alarm...

[TomsFocus]

1 hour ago, Tizer said:

The Current then reduces gradually over the next few minutes to settle down to what can be 1,2 or 3 Amps normally and stays exactly the same whether the car is at Idle or doing 70 mph. 

Isn't that a maintenance charge on a near-full battery though?  If you had a low battery, surely it'd be charging more than 3 amps?

If it is such a low charge rate, no wonder I'm not getting a noticeable increase on a low SOC battery from 15 mins use!

Shame the mobile Forscan app costs so much otherwise I'd try the same tests.  CBA to take the laptop & cable downstairs.  I think I will measure the battery voltage before and after running for 15 mins next time I try that though.  

[Wino]

6 minutes ago, TomsFocus said:

Isn't that a maintenance charge on a near-full battery though?  If you had a low battery, surely it'd be charging more than 3 amps?

If it is such a low charge rate, no wonder I'm not getting a noticeable increase on a low SOC battery from 15 mins use!

Shame the mobile Forscan app costs so much otherwise I'd try the same tests.  CBA to take the laptop & cable downstairs.  I think I will measure the battery voltage before and after running for 15 mins next time I try that though.  

All I can tell you Tom is from my own issues and analysis regarding the charging system.

11.9v @ 50% SOC and 20 mins of idle tick over on the driveway then disconnect Forscan and lock the car up. Have a cuppa the unlock the car and plug it all back in and mine was around 12.6v @ 61% SOC iirc.

[Tizer]

1 hour ago, TomsFocus said:

Isn't that a maintenance charge on a near-full battery though?  If you had a low battery, surely it'd be charging more than 3 amps?

That is when it is below 80%, 60-70, which is where my battery usually sits most of the time. As far as I know when it reaches 80% it hardly charges at all. It is higher when first starting but it ramps down over the next few minutes. If the battery was very low then I think it would charge at a higher rate for longer.

My own observations from extensive on the road testing is that the car charges almost exactly the same as a plug in Smart Charger, which might be able to charge at a higher rate like a dumb charger but does not, instead it gives a carefully controlled and varied charge throughout the cycle so as not to damage the battery. The Alternator does seem to be able to give a very high output at low speeds but it is not allowed to.

My own plug in charger does a quick pulsed low Current and Voltage charge then charges at 3.8 Amps at a low but ramped up Voltage until 80%, then drops the current to 0.8 Amps and ramps up the Voltage slightly when it reaches 80% until full. I'm sure they all do the same.

The thing about FORScan is that it, as far as I know, measures the Current  and Voltage at the BCM. If I was to switch the Ignition on now and connect up there would be a 8 Amp Current draw without Headlights on and it would show 11.9 Volts, but if I switched off and let it settle and measure between the Battery terminals it would show about 12.5 Volts. You get a skewed reading when switching off after a run also.

The SOC does show as going up during a run but not usually more than about 4% an hour, although Ford say that to get a true reading the car has to be sleeping with a less than 100 Milliamp draw for several hours so it might show higher the next morning. 

[unofix]

Just to add my own two penn'orth, speaking as an electrical engineer. You can not force any load (object or battery) to take current.

Current is some thing that is drawn by the load. Back to basics Ohms law states that I=V/R where 'I' is current, 'V' is voltage and 'R' is resistance.

Since with a battery we can not alter the resistance then if we wish the battery to draw more current (and there by increase the charging rate) then the only option is to increase the voltage. The normal charging voltage for a car battery is 13.8V which will typically mean the battery draws a current of about 3 amps.

The cars alternator can increase it's voltage output, which in turn means the battery will draw more current as the potential difference (pd) between the batteries standing voltage and the increased voltage of the alternator becomes further apart. Hence the battery will try to equalise it's voltage with that of the alternator by drawing more current.

However the cars alternator can not just keep increasing the voltage to infinity since the whole electrical system of the car shares a common supply. While individual modules have there own voltage regulators  and can tolerate increased voltage up to 20V for short periods, simple things like lamps can only handle an increase in voltage for a relatively short period.

In summary the nominal charging current of the battery will be 4 Amps or less. For very short periods of time it may draw more current but that is subject to the charging voltage and to a degree the internal resistance of the battery of which we have no control.

[TomsFocus]

Thanks guys.

So, to bring this back to the original topic...is it worth idling a car with very low battery for ~15 mins if you can't drive it or get a mains charger on to it?  Or will that barely refill the loss of charge from cold starting it?

[Tizer]

4 minutes ago, TomsFocus said:

Thanks guys.

So, to bring this back to the original topic...is it worth idling a car with very low battery for ~15 mins if you can't drive it or get a mains charger on to it?  Or will that barely refill the loss of charge from cold starting it?

My own view is that 15 minutes with the engine running whether the car is moving or not will not be that much better than putting a Smart charger on it for 15 minutes, but will put more charge in than was lost.

It is difficult to quantify though because when you switch off there is a big current draw for quite a long time. Mine starts off at around 8 Amps and gradually reduces as things go through their self testing and go to sleep. 

[unofix]

I'd say that 15 minutes idle will just about break even, taking in to account the amount of power required to unlock and wake the car up. Then the use of the starter motor, and last but not least the amount of power taken after switching off and the car going back to sleep.

I would agree with @Tizer that 15 minutes idling will be the same as 15 minutes with a Smart charger.

We have a Vauxhall Movano horsebox that can stand for weeks without being used. I have a battery charger connected permanently but on a timer which is set for 2 hours per day. I find this maintains an average battery voltage of 12.78V over a 24 hour period.

[TomsFocus]

I hadn't considered how long modules stay on after switch off tbf.

The car will obviously still need to be unlocked and relocked if using a charger so it's then mainly the starter motor that makes the difference between the charger or idling for the same amount of time.  Of course, the 1.0EB internals aren't exactly weighty (unlike my 2.0 TDI!) and it won't be pulling glowplug current either.  But the Focus does have Sync, GPS & Wifi whereas the Golf just has a basic audio unit.

Feels like there are too many variables to make much of an informed estimate!   Very frustrating having a charger but too many restrictions to be able to use it at my current property.  Even if I could get the cable downstairs, we now have gardeners coming at weekends to cut grass (which my lead would have to trail over) so I can't risk leaving it out for hours at a time at weekends any more.  (Not sure if they're specifically trying to stop hose & cable use in the carpark or if they're just milking the overtime rates!)  I mentioned on another thread that I've considered a solar charger left in a South facing screen to keep the batteries topped up (I know they won't provide a high charge for a low battery) but wouldn't even know where to start with finding out which one would provide what I need at a reasonable initial cost.