"Dave" wrote in message
...
Fredxx wrote:
"David Hansen" wrote in message
...
On Fri, 9 Oct 2009 13:40:27 +0100 someone who may be
(D.M. Procida) wrote
this:-

The charger says it's running at about 3 amps. When can I consider the
battery properly charged?
Lead-acid batteries are best left being trickle charged. Of course
that implies that the charger is capable of doing that, which many
cheap ones are not.


Ouch no!! That's the best way of wrecking a lead acid battery,
especially if the sealed types. Any current after it's fully charged
will dry out a battery.

The best charger has always been a constant voltage charger. This matter
has been discussed ad nauseum before in the NG.

I am going to take one of our two cars off the road at the end of this
month. I had thought of running a mains extension under the bonnet and
leaving a charger there. The extension will be plugged into a timer to
control how long the chargers is on.

How long a time should I power up the charger, per day/week?

Dave

The trouble is cheap chargers generally wreck batteries if left attached for
long lengths of time. I don't know what's currently on the market. But a
charger designed for "float charging" is one you can permanently leave
connected to the battery.

I have known good lead-acid batteries keep their charge for nearly a year,
but it's rare.

I have seen it suggested that a unconnected battery should be topped up
every 6 weeks. I would disconnect the charger if the terminal voltage gets
much above 14V and then assume the battery is then close to being fully
charged.