In article ,
"Dave Plowman (News)" writes:
In article
,
Tom wrote:
I've been aiming to buy a new car battery trickle charger for a while
- I've noticed that there are some very small trickle chargers that
are 500mA output and looks like a plug in power block.

They are an expensive way of doing a simple job.

Keep an eye on Lidl and Aldi. They do a proper charger - 4 amps or so -
which switches to a maintenance mode when the battery is charged. Cost
about 13 quid. They are on sale every few months.

and at the end of that period, I got a couple for a fiver.
They are indeed very good.

Just 2 slight gripes...

If the battery is very flat, it assumes it's a 6V one, and because
it will instantly rise to the fully charged voltage for a 6V battery,
it won't get very far. You can get around this by connecting another
12V battery (or some other 12V power source) in parallel just for a
few seconds. (OTOH, if a 12V battery is down to 6V, your chances of
charging it again are not too high anyway.)

It would be brilliant if it had some way to make it start charging
automatically after a power failure. You could then use it to build
a very cheap but effective backup power unit.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]