Flat battery Monday ITV news.

[ericmark]

With only 10 days not being used, why should Monday the 4th Jan be any worse to the 14 day and 28 day lock downs? ITV seem to think it's different does not "– Taking your vehicle for a “decent drive” several days before you need it." break lock down rules?

OK ITV not the only one, Halfords, Lancaster evening post, Telegraph etc all seem to have web page hits with a similar message.

However my wife's car just put battery on charge, showed 12 volt, which is typical of a car which has been left standing but the charge rate even at 3.8 amp which is rather low did not remain there for long, as with discharged lead acid batteries it takes time for them to recharge, and once at a point where will not start the car, we are looking at days to fully recharge.

I think the reports are old pages being raked up by the likes of Halfords who have been sending out emails to warn people and offer their services, posted on 20th November 2020 by Halfords, however today charging car batteries is not as easy as it was it seems. The problem is the car allows the battery to become 80% charged and only charges it on down hill stretches, when engine on over run, so to recharge battery can upset the computer control, I know with wife's Jaguar should charge battery from charge point under the bonnet, not the actually battery in the boot, and since the valve regulated lead acid or absorbed glass mat batteries have a very limited amount of acid in them, you need a smart charger that is designed not to over charge the battery. I use a cheap Lidi one, was around £14 but the ctek seems to be most well known, it seems odd, back in the 70's we had 4 amp chargers, then the battery charger started to get bigger and bigger, seeing even 20 domestic battery chargers, now back to small chargers again.

The big problem with a battery charger is if a cell goes short circuit, I lost a pair of batteries in the mobility scooter as a result, had I been aware I could have saved one, but it was left in the garage on charge with a charger designed to be left on 24/7 but no fail safe, so it over charged the remaining cells. Once the old Lidi charger has dropped to 0.8 amp rate it will not auto return to 3 or 3.8 amp rate, so unlikely to bake a battery if cell goes short circuit, ctek make many models of battery charger, the popular ones will return to max output if battery becomes discharged, great when using in a caravan or boat, not so good when leaving battery unattended.

Anyway idea of thread is to one bring it to the attention of people who have left their cars with boot light on over Christmas ect. And two maybe people can add to the tread saying how they look after modern lead acid batteries.

 

[Taylortwocities]

The problem is the car allows the battery to become 80% charged and only charges it on down hill stretches,

How does the Jag know its going downhill? Maybe it monitors fuel consumption and only charges when the mpg is 99mpg.

Hang on a minute. This cant be true. If you took a Jag on a trip on the motorway at night, are you saying the battery will be flat in 4 hours because it will never had a downhill stretch?

 

[JohnD]

Haha!

Halfords and the like are trying to drum up business to keep their tills full.

Winter is "battery season"

IMO it's worth charging a flat battery once. If it goes flat again, and has not been standing for weeks, then either you have a silly fault like the interior or boot light left on, or else the batt needs replacing with new.

I find they commonly last ten years if not neglected. I put mine on charge if they have been standing for more than a couple of weeks, before they go fully flat.

A pair of jump leads in the boot can save embarrassment, and buying a batt from a roadside agent at a high price. With time to shop around you can get a better deal at a convenient time.

 

[ericmark]

How does the Jag know its going downhill? Maybe it monitors fuel consumption and only charges when the mpg is 99mpg.

Hang on a minute. This cant be true. If you took a Jag on a trip on the motorway at night, are you saying the battery will be flat in 4 hours because it will never had a downhill stretch?

Once battery is detected as being less than 80% charged to stop/start is disabled and it charges all the time engine is running, the charging is computer controlled and every so often it fully recharges the battery, and if a new battery is fitted you need to tell the engine management computer it has been changed and what Ah it is. Jaguars were well know for poor MPG, but today my wife's Jaguar XE does far better MPG than my little Honda Jazz. But since we live in Hilly Wales the MPG are never good for any car, son in flatter North East Wales reports 75 - 80 MPG with his Jaguar XE but his is 4 wheel drive so in theory wife's should be better. Her engine set to 164 ps his is more like 194 ps same engine, just the way engine management set, her road tax £30 his road tax £100 and something.

As to how the Jag knows down hill, well it has sat nav, and all sorts of other devices, can even start engine from phone to warm up car before getting in. It likely has a much better idea where it is and what it is doing to the driver, the days of the driver having to manually notch back when going down hill went out with the demise of the steam engine.

 

[flameport]

And two maybe people can add to the tread saying how they look after modern lead acid batteries.

For those in a vehicle - by doing absolutely nothing.

In the last 30 years of owning and driving a large number of different cars and vans, the only instances of needing a battery charger were either because the battery was end of life and required replacement, or due to some other problem which caused it to be discharged.

Those which I can remember being:

• a particular car which inexplicably allowed the windscreen wipers to operate on the intermittent setting with the ignition off - being left like that all day resulting in the battery being discharged.
• lights were left on (that vehicle had no warning buzzer)
• the alternator belt failed while driving, the battery being pretty much destroyed on reaching the destination which fortunately was only a few miles away.
• a works van used by many people, someone broke the outside door handle on the passenger side, which meant the door didn't close properly unless slammed in with excessive force. Someone left it slightly ajar overnight while parked in the warehouse, and unsurprisingly the battery was useless the next morning as the interior light had been on all night.

Other than that it was entirely due to the battery being years old, or in the case of my current vehicle, the battery it had when I acquired the vehicle was labelled with the name of a breakdown company and it was far too small both physically and electrically. That also resulted in several other unexplained intermittent electrical problems, all of which disappeared when a new correctly sized battery was installed.

In April 2019, the car wasn't used for well over a month. Nothing was done with the battery or anything else, and it started first time without any problem.
The same applied in the past when it was actually possible to go on holiday. Zero problems in starting after the car/van had been parked up for a couple of weeks.

I have never owned any Jaguar, or any German cars, or any with start/stop feature. Perhaps they have inherent battery ruining problems that other vehicles do not.

 

[AndyPRK]

As the years have gone on, cars are much more demanding of electricity.

As soon as you press the unlock button many computers wake up and start drawing 10A. And continue for at least 10 minutes.

It’s worse now rather than lockdown1 because it’s much colder

I got 12 years out a car battery, by giving it a weekly trickle charge

 

[RF Lighting]

I have just had to replace the battery on my van as a few weeks ago it started struggling to start the engine and then a week ago it wouldn’t start at all without a jump, even after having my battery charger connected for 24 hours.

My van is only 4 years old.

 

[ericmark]

May be unusual as with three cars, and no where we need to go at the moment even when they are used, they do not travel far, but 9 hours at 0.8 amp is not much power, that is how long it took for the charge rate to drop, so 8 Ah for a 90 Ah battery is nothing.

Most the cars will reduce to 0.1 amp and the voltage still raises, odd one out is Kia Sorento which cycles 0.8 to 0.1 amp, but I have a spare battery and to date not failed to start. We had this year need to travel for medical so cars have been still used, but that is now over, so one car is used per two weeks, 50 mile round trip, so 6 weeks between each use of each car, so yes I do charge the batteries from time to time to ensure topped up.

I don't think the police would accept as a valid reason for a trip, I want to keep battery topped up. But reading what it says on web pages, it seems the AGM battery can be left longer than flooded batteries between charges. The vehicle must use some power, or it would not respond to smart phone commands, or unlock doors, but think that must be very little power.

But yes had to swap battery on Jazz, but for a year I have known it was on it's way out, needed charging every 3 weeks. But there is a lot of luck, if the car is parked up with fully charged battery then likely it would start even 3 months latter, but if the battery was not fully charged but only 80% charged to start with, then 3 months may well be OTT.

So some people have been self isolating since March 2020, and even when they have gone out, the battery has never had chance to fully recharge, and when the Smart charger takes days to recharge what chance is there that it will fully recharge in the car on a trip using less than a tank full of fuel? As said took 9 hours to drop charge rate to 2 watts (0.1 amp) time matters, so a trip to see the snow is not going to be enough to recharge battery, but may be enough to get fined.

 

[Taylortwocities]

I don't think the police would accept as a valid reason for a trip

You are ok if you travel to Barnard’s Castle to recharge your batteries!

 

[Taylortwocities]

...

 

[Lectrician]

I have just had to replace the battery on my van as a few weeks ago it started struggling to start the engine and then a week ago it wouldn’t start at all without a jump, even after having my battery charger connected for 24 hours.

My van is only 4 years old.

Exactly the same with me. 4 yr old, last few weeks there’s been times I’ve wondered if it will start. Apparently the alternator is different to normal due to stop/start technology. It effects battery life, even if you don’t allow the stop/starts. The garage tech was talking about regenerative braking.

 

[securespark]

Stop/Start cars should have AGM batteries fitted.

I have always had great service from Bosch batteries. Our latest was a Bosch S6 AGM (our car isn't S/S), which was fitted in 2010 and is still behaving impeccably.

 

[securespark]

Stop/Start cars should have AGM batteries fitted.

I have always had great service from Bosch batteries. Our latest was a Bosch Silver AGM (our car isn't S/S), which was fitted in 2010 and is still behaving impeccably.

 

[Taylortwocities]

I’m guessing that the possible concern with stop/start cars might be early failure of starter motors. Not seen any figures on this.

 

[Harry Bloomfield]

Anyway idea of thread is to one bring it to the attention of people who have left their cars with boot light on over Christmas ect. And two maybe people can add to the tread saying how they look after modern lead acid batteries.

Well, I have mentioned before what I did and what I now do.....

My car isn't needed much now, most of the time, especially in the winter, it lives in the garage. I manage well enough walking around or using the free to me local public transport. I used to pop out once a month and connect the charger for a couple of days, to bring the car and caravan batteries up to full charge. Caravan battery isn't connected the rest of the time, so no discharge. Car does have the discharge of its electronics, so the monthly charge was essential. Then I decided to automate the car's charging, using a dumb, but fixed voltage charger, powered via a time-switch, on once per day for 20 minutes.

I have since swapped the time-switch, for a Smart Plug controlled by Alexa, again using the dumb voltage controlled charger and once per day for 20 minutes. A smart charger cannot be used like this, because a button needs to be pressed to initiate the charging.

The charger plugs into a ciggy lighter socket, to confirm it makes a good connection to the car via the socket, I knocked up a simple low power LED flasher circuit drawing a couple of mA. If the LED is flashing when I plug it into the car, the connection is good and easy to check when I go in the garage.

Such was the volts drop between the original ciggy socket and the battery, that it wasn't putting much charge into the battery originally, so I addressed that by adding a special extra socket, fed directly from my car's 12v bus bar via a 10 amp fuse. The swap to Smart Plug was part of a general swap of time-clocks and RF remote control sockets, to Smart Plugs.