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Car batteries not keeping up - differing advice

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Car batteries not keeping up - differing advice

Old 20th Jun 2020, 12:08
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Car batteries not keeping up - differing advice

Our next door neighbour didn't use her car for several weeks while social distancing. She did circulate some advice picked up from one of the newspaper websites to us - namely that you need to run your car engine at least once every two weeks.

She had been doing this but her battery still ran flat. She didn't understand that just starting your engine, letting it idle for a minute and then switching it off was not what was meant by the advice.

The man from the AA came. He replaced her battery and his recommendation is to run the engine for an hour every two weeks. She now does this, her car sits in the drive, unattended, with it's engine running for and hour every two weeks.

Our car servicing organisation advises to actually drive the car every two weeks and to do this with the lights on as "the load causes the alternator to charge the battery harder". Go driving for at least 15 minutes.

Neither of these seems to make much sense to me but I am going to check these two methods when I find my clamp on ammeter.

Has anyone else been given "interesting" advice on the best way to keep your battery alive?

Rans6.........
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Old 20th Jun 2020, 12:19
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12 pounds.
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Old 20th Jun 2020, 12:21
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I worked abroad, came home about every four months for a week. After a couple of batteries died* after going flat I bought a trickle charger/conditioner. It monitors the battery and tops it up when necessary. Does require a garage with a plug of course.

*Gel types, wouldn’t hold a charge again.

e.g.

Amazon Amazon
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Old 20th Jun 2020, 12:54
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I am looking after a friend's car. He has been away for 3 months now and I promised to run his car periodically but it is so tucked away i had completely forgotten until getting a verbal reminder last week from him! I was worried that it may not start but it did, on the first turn and after a jet wash I took it to the supermarket and back. It even has 3/4 tank of fuel so i am thinking will he accept that fuel goes off so needs to be consumed which is what I did for him?
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Old 20th Jun 2020, 12:56
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actually requires a socket!
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Old 20th Jun 2020, 13:03
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My elderly and forgetful neighbour found he couldn't even unlock his Prius the other day. After several visits to Google I managed to get it open and get the battery charged enough to start it. He has driven it once since but I won't be surprised if it doesn't happen again soon and he won't remember what we did. When I connected his very expensive looking battery charger, he thanked me for lending it to him!!
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Old 20th Jun 2020, 13:04
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Can recommend the small solar panel type as long as it is regulated.

Have kept a battery in good shape in an idle vehicle for five years with one.
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Old 20th Jun 2020, 13:21
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Originally Posted by pulse1 View Post
My elderly and forgetful neighbour found he couldn't even unlock his Prius the other day. After several visits to Google I managed to get it open and get the battery charged enough to start it. He has driven it once since but I won't be surprised if it doesn't happen again soon and he won't remember what we did. When I connected his very expensive looking battery charger, he thanked me for lending it to him!!
Sounds like you could eventually keep the car and he'd be none the wiser.
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Old 20th Jun 2020, 13:39
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My elderly and forgetful neighbour found he couldn't even unlock his Prius the other day.
I have a distant and not-so-old relative who has sadly fairly rapidly succumbed to dementia. The doctor medically took his licence away and his wife (who doesn't drive) the car keys last December; remarkably he could remember exactly how to drive the car in perfect safety but not the directions to get to any place with which he was perfectly familiar - as long as she could navigate he was fine. I think the major concern was that he might drive off by himself... also, when would the automatic ability to safely drive switch off? Remarkable how memory works/doesn't work.

Sorry, drift...
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Old 20th Jun 2020, 13:58
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Originally Posted by rans6andrew View Post
Our next door neighbour didn't use her car for several weeks while social distancing. She did circulate some advice picked up from one of the newspaper websites to us - namely that you need to run your car engine at least once every two weeks.

She had been doing this but her battery still ran flat. She didn't understand that just starting your engine, letting it idle for a minute and then switching it off was not what was meant by the advice.

The man from the AA came. He replaced her battery and his recommendation is to run the engine for an hour every two weeks. She now does this, her car sits in the drive, unattended, with it's engine running for and hour every two weeks.

..... snip

Rans6.........
Where I live, leaving a car unattended for 5 mins with the engine running,would result in the car itself entirely missing
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Old 20th Jun 2020, 14:21
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There are many reasons to actually drive a car rather than start it and idle it on the driveway:

The battery needs to be kept charged. After a cold engine start, the battery will need a proper run to recharge it. Most cars need the engine to be above idle for the alternator to provide full charging current.

The exhaust will fill with water vapour on start-up which will cause internal rust unless the exhaust gets up to running temperature for a decent while to evaporate it all out before shut-down.

Engine oil needs to be circulated around to prevent engine components seizing through lack of use.

Even more importantly, so do the gearbox and final drive. Many don't usually have oil pumps and are only lubricated by splash from the gears when they are turning.

Wheel bearings etc need to be turned to keep the grease viable and distributed.

Tyres need to be rolled otherwise flat spots can develop - not on the tread but in the tyre carcass.

Fluid seals need to be kept wetted and might start to leak if they 'dry' out.

Even window seals etc can go hard through lack of use.

It is beneficial to air the cabin.

All the various joints, levers, cables and pivots on the car - for example the main and parking brakes - need regularly moving to prevent seizure.

Ditto all the various valves and actuators that control the engine: electronic throttle body, emission controls, cam shaft actuators, coolant thermostat, also things like the aircon system, the list goes on.

A continuous trip of 10-15 miles at least once a week, or say 5 miles every three to four days, should keep things working nicely.
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Old 20th Jun 2020, 14:32
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The recent UK dry weather spells meant wipers were not necessary. I discovered mine had ceased up and needed dismantling and lubricating, so when you exercise your car give the wipers a quick blast.
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Old 20th Jun 2020, 14:43
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Battery preservation

The thing that kills unused lead-acid batteries is sulphation.

Cheap devices are available that will effectively stop sulphation by drawing regular short-duration high-current pulses.

The devices are powered by the battery, so no mains power socket is necessary (as would be required for a trickle charger).

One might imagine such a device would quickly discharge the battery. However, with anti-sulphation pulses of just 50 microseconds duration and with a 40 Amp pulse every couple of minutes, the average 2mA consumption still represent much less than the battery self-discharge rate.
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Old 20th Jun 2020, 14:58
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Inactivity affects everything. Last year my heating-system wouldn't work because the flaps mixing the hot/cold air didn't work because the stepper-motors driving them, couldn't overcome the stiction that had developed after six months non-movement of the control-rods ( i.e. they had been switched to cold and not adjusted at all ).

I had to disassemble some of the system to clean parts, but thankfully, even if this did require removing the glove-box, it wasn't too awful, but with some cars it would be.

I now activate the heating and then the cooling system monthly to prevent this.
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Old 20th Jun 2020, 15:32
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What, don't you all have cars with starting handles?

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Old 20th Jun 2020, 15:41
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I've noticed that a car battery will hold its charge much longer if it is disconnected from the car (just the negative terminal will do).
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Old 20th Jun 2020, 15:58
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Originally Posted by spekesoftly View Post
I've noticed that a car battery will hold its charge much longer if it is disconnected from the car (just the negative terminal will do).
Surely a battery should *only* be disconnected negative terminal first!

Jack
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Old 20th Jun 2020, 16:01
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A while ago, after a few fortnights holidays and fail to start each time afterwards, necessting use of the car park's trolley-ac, I decided to measure the drain on the battery. Connected an ammeter and locked the car. My calculation was that the battery would last for two weeks before it wouldn't start the car again. Various friends have had this happen recently due to lockdown.

My old Land Rover, however, with no alarm, receiver for remote controls, clock etc., could be relied on to start first turn (Isuzu 3.1 diesel) after two months of Dec, Jan or Feb weather on its grotty old battery.
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Old 20th Jun 2020, 16:19
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Originally Posted by Union Jack View Post
Surely a battery should *only* be disconnected negative terminal first!

Jack
Correct, and "only" the negative terminal needs to be disconnected for the purposes of my suggestion!





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Old 20th Jun 2020, 16:42
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Originally Posted by N707ZS View Post
The recent UK dry weather spells meant wipers were not necessary. I discovered mine had ceased up and needed dismantling and lubricating, so when you exercise your car give the wipers a quick blast.
Or, as in my case a few weeks ago, the blade rubber glues itself to the glass and then tears itself apart the next time you try to use the wipers.
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