Leaving cars Unattended for Long Periods

You must be joking. I'd rather trust my car to the elements. :-)

Agreed. Just normal use and they will clean up fairly soon. No need for hard braking and braking is certainly not impaired on my car when not used for a long while. Braking HARD from speed seems a bit violent to me. I follow the adage "treat her like a lady and she will always bring you home"

Graham

A gimmick. I tried one and it couldn't even keep pace with the electronics on standby. I do have a solar charger capable of providing 3 amps, so it can keep a 110AH battery topped up. The panel is about a metre square.

S'allright, you'd never get over the first hurdle, finding a friend.

You'd need an average of about 200mA over 24 hours to be much good. And I very much doubt any of these do - especially since a car is unlikely to be parked in direct sun for all of the day. Even when and if it shines.

If you're removing the battery, no need to trickle charge it if it's a good one - lead acid types have a very low self discharge rate. 3 months won't make much difference. Just store it in a mild dry place.

By far the best way would be to get the car taken for a run once a week at least.

I just fired up the wife's MGB that has sat idle since September and that has only a 12V battery nicked out of a scrap small FIAT sitting in one of the 6V battery compartments.

AJH

No permanently alive electronics on those. Or even no electronics at all. Bet you had to kick the petrol pump.

"Dave Plowman (News)" wrote

And hold the clutch pedal down overnight with a bit of broom handle....

It's what they're designed for.

Blimey, that's way more than the mondeo, it needs under 20.

Right, I don't have any of these fancy modern cars!

I put a cheapy, plasticky solid sate one in, whilst I gather enough round tuits to stone the points on the original one.

So we are talking about the sum of self discharge plus permanently alive electronics on an average (95Ah??) battery? At what open circuit voltage is the battery unlikely to be able to start the car? I'd guess you shouldn't drop below 11.1V after which the battery is likely permanently damaged but what is the open circuit voltage at 50% discharge?

What is a typical permanent current draw? We're talking about 2000+ hours, so at 10mA that's 21AH of out goings and the self discharge rate will be in the order of 10% in that time, say 9.5Ah.

This has never been a problem to me as I tend to remove the battery from a vehicle that is not being used and the worst that happens is I have to reset the clock but I might have a car that won't allow me to do this one day.

AJH

My Sierra draws 20mA, but then its only got the clock and a bit of power to keep the radio memory going. My VW van draws ZERO. OFF means off with a nice old vehicle like that.

Yes, true, with 10mA it should in theory be ok for three months on a 21AH battery. However, in practice I find my battery would have trouble cranking after a month. That is with 20mA being drawn and the battery is in fairly good condition and less than 2 years old.

Graham

Unless its a high performance car they are not designed for frequent hard braking. It would be rather poor driving if hard braking is needed more than once every few weeks, if at all. The average car will obviously require higher mantainance costs like frequently replacing pads and sometimes the discs if driven in that way.

Graham

OK but I was assuming a 95Ah battery and not allowing it to drop below

AJH

Yeah, I didn't quite read the 95AH bit properly first time around. Talking at what point does the battery starts to become damaged. I am continually amazed of the people that sit in their cars struggling to start them and continuing until the battery eventually will not turn it anymore. They just go on and on turning the engine over when it obviouisly will not start. It amazes me these days how long the battery turns over the engine for. 30 years ago on a cold morning you had about 20 turns of the engine, even if your battery was in top condition. These days with lighter engine parts and better batteries those engines turn over a hundred times. The idiots do not stop to let the battery recover, they just hold the key until no more life is heard. The starter motor must be red hot and the starter motor/solenoid wiring insulation soft to the touch by the heat. I suppose its desperation to get to work, but if they only had the slightest clue about technical or mechanical things, they would never treat it like that. This world seems to be get less technical every year that passes. The attitude of being proud of not knowing how to wire a mains plug for instance get right up my 'ooter. I just smuggly think to myself that their lack of understanding such things, will ensure they will be the first to die out when the big mushroom goes up :-)

Graham

I occasionally drive 'spiritedly' for fun. This often involves hard braking.

I have an acquaintance who potters about at well below the limit and rarely uses the brakes hard. When he was in my car once, somebody turned across in front of us and I had to stop rapidly. He was gobsmacked - he said his car would never have stopped that fast...

He gets through clutches at more than twice the rate I do, too.

You can drive fast, accelerate briskly, accelerate nicely out of the bends, but still go easy on the controls. Just needs anticipation to avoid hard braking. I do not get the association with not being hard on the brakes and timid slow driving.

Graham

PCPaul submitted this idea :

You should be aware of what your car can do if pushed, for those times when you might need to know its limits. Nothing wrong with pottering around most of the time, providing you regularly test and remind yourself of those limits.