Battery charging

Personally I would be happy leaving a 12V stabilized supply on the battery. Any more could well damage the battery if left indefinitely.

Some cars don't have the "accessory socket" connected when the ignition is off; you would need to check first by seeing if it works with the key out.

There are chargers specifically designed to plug in as you want; there are also chargers that can be left connected for long periods of time, and that will keep the battery in good condition. You will need a bit of Googling to see what suits you and your pocket.

If you are regularly running the battery down to the point it won't start the car, you are shortening the battery life. In this case, it will be worth buying a good-quality "always-on" charger as you are likely to save money overall.

Chris

You can buy chargers designed for this role(trickle chargers) , standard chargers will destroy your battery .

Not all cars lighter sockets are suitable for connection to battery chargers , some disconnect when the ignition is turned off

Some tricle chargers come with a lead that can be connected permenantly to the battery , just unplougging from the charger unit

such as a C-tek, which will also restart charging if the power goes off, so you could even plug it into a timer socket so it comes on for one day a week (if you are dubious about leaving any charger connected and charging permanently) The c-tek will cost about 40 quid. The cheaper version (13 quid) that aldi-lidl sell will do a similar job, but will not self re-start if the power goes off.

I keep a c-tek connected to my own classic all the time.

That sounds ideal! Thanks Cheerful.

Hugh

Indeed. Buy something like one of the CTEK chargers- I'm considering one for our little-used Lupo. They automatically maintain the battery.

Keep an eye on Lidl and Aldi special offers for their charger. After charging the battery it changes to a maintenance charge and can be left like this indefinitely. Excellent value. Costs about 13 quid. You'll pay 3 times that for the same thing elsewhere.

In message , "Dave Plowman (News)" writes

I bought one when I had my cataract ops done recently and couldn't drive for 9 weeks. I connected it up and within about 20 hours it went to a trickle charge.

It's a clever little unit. I also have an older Halfords charger - many times the size and weight - which claims 11 amp charge on the front. Yet takes about the same time to charge a battery.

Battery charger amps belong to the same system of units as cheap audio amplifier watts. I'm sure we can think of other examples, like the special inches I'm told some chaps use.

Its not the voltage, which has to be equivalent to the battery, but the output amps, this ideally should be 1-2amps as a trickle.

Have used a 240VAC - 12VDC plug pack to charge the battery these are very low output something like an old phone charger (500-1000mA) would do.

The idea of a stabilised 12V is that the current would then be self limiting.

I used a stabilised supply for many years when it was necessary, a good solution.

A decent trickle charger will vary both the current and the voltage throughout the cycle

Well, of course it will take the same time, as the 11amp one isn't actually putting out 11amps if the battery isn't demanding it. I also assume the 11amp unit isn't forcing 20-odd volts into the battery.

Not so - not that I've found. The ones I've used have all been fairly consistent with the ratings on them; insofar as they only put in what the battery actually needs, and that's well below the maximum rating on the charger case.

Boost/start chargers are a seperate case entirely.

Why would a discharged battery - otherwise good - not 'demand' it?

Have you any idea how much current that would shove into a good but discharged battery?