Flat battery

Nov 04, 2021 Last reply: 4 years ago 67 Replies

My car is just over 4 years old and covered less than 12,000 miles. Since April I have experienced flat batteries on five occasions.



Today I drove ten miles to the (Kia) dealer. They were very good. Tested the battery and told me there was nothing wrong with it. It just needs charging. I am not driving enough apparently.



So. A trickle charger?



My car is not kept in a garage. How can I securely trickle charge a car without keeping it locked and with a window from the house open to sneak the cable through?



How do other people handle it?



Oh and I learned something, despite there appearing to be battery terminals under the bonnet, they are actually connected to a tiny battery in the rear wheel arch bulge in the boot. It is about 45AH. Seems small to me but what do I know.



you could have an outside weatherproof power point. It is alos possible with modern small chargers to put the charger under the bonnet and close the bonnet. What I did during the main lockdown.

You can get a small solar panel to fit in a window. It won't charge the battery but might be enough to counteract small drains from the alarm etc. Ideally placed at a south facing angle when you park up.

You can start a car with a pocket sized lithium power bank these days. It's not capacity it's current that's important.

The terminals under the bonnet are handy when you have a flat battery - use the backup mechanical key to get into the car, pull the bonnet, and you can charge from there. Saves having to get at the battery in the boot from the inside when the door locks don't work.

Theo

In article snipped-for-privacy@candehope.me.uk>, charles snipped-for-privacy@candehope.me.uk> writes

Check all the connections. We have a Suzuki alto 8 years old does about 3k miles per annum. Never had a problem with flat battery. Do you have an alarm system on? If you have a Halfords near by take it there and they will check the battery for you.

pinnerite wrote on 04/11/2021 :

Modern car's have a lot of electronics, some of which contunue to run when they are parked, so they can only remain unused for a few weeks, before the battery will be flat.

My car lives in my garage and I give its battery a 20 minute charge daily, via a Smart Plug controlled by Alexa. I fitted a special ciggy socket, directly across the battery, so I could plug the charger into that. I then later added a low power flashing LED, to the charge lead, to confirm, the plug was making good contact with the car's socket.

If your ciggy socket is live all the time, you could do something similar, but the worst thing to do to a battery, is to have it permanently on charge - hence why I included a timing control.

My solar charger plugs into the OBD socket.

Try uk.rec.cars.maintenance where your post would be on-topic.

Alternatively, how much is "not driving enough apparently", although this would as said be better in an appropriate newsgroup.

Let's not leap to conclusions. I should ask for the battery to be checked for drain whilst in the car. In other words, how much power is being drawn all the time the car is parked. It might be excessive. Also I'd ask if the charge rate is correct when the engine is running. If it passes that test I'd either get a 10W or 20W solar charger* with an EOBD plug or I'd have a weekly routine of connecting a mains powered charger for a few hours.

*assuming the car is parked where the sun shines, even in winter.

Bill

annoy the neighbours with 'false' alarms

Maybe they need to start supplying starting handles again. Brian

And a clockwork dynamo to power the ECU?

And some sort of 90 degree gearing for a starting handle on a transverse engine?

You could combine changes of direction, power generation and turning the engine over into a flywheel starter (like some aero engines had), where you wind the flywheel and it gains more and more speed, then you stop winding and engage it to the engine ;)

Not needed with the Oselli kit for early minis

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I have that problem with my old Rover which isn't my everyday car. Parked outside the house on the road. Fitted a Lidl charger (about 14 quid) in the boot (there is a fusebox there with permanent battery volts going to it) Fitted a Buccaneer waterproof mains inlet below the rear bumper.

Mains lead is rubber, so very flexible. Cover it with a ribbed rubber mat where it crosses the pavement. Have an outside mains socket by the front door.

Small car I guess. Your other option might be to get a Lithium Ion "jump start pack". Should be fine using a pack about the size of a mobile phone. (Diesels require slightly more current). About £40 on Amazon. I carry one in a van that has a very small battery and no "lights left on" warning.

Self-discharge rate is very low so it can live in the car. They all seem to have USB ports for charging a phone, and some sort of "torch" option, both of which can be handy.

Many modern cars will suffer a flat battery if not used for about 3 weeks. But them most will use their car more than that - except when away on holiday.

If it is going flat in less time than that - assuming when used it is more than just a very short journey - you need to check there is not something drawing excessive current when parked up, and that the charging system is working correctly. The latter quite easy - simply connect a accurate voltmeter across the battery and see what it says, engine running at a fast idle. It should read over 13.8v and up to about 14.4v

Measuring the quiescent current draw is likely best left to a pro. It should be less than about 40mA.

I never knew that! And I saw a LOT of Minis...

Have a lever that opens all the valves like hand cranked diesel generators. Flip it back once you have built up speed.

It can be made practical. Where there's a will there's a way. Anything else is an excuse.

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