On Tue, 21 Oct 2003 11:23:28 GMT, "JTH"
wrote:


"Roger Druce" wrote in message
u...
Perhaps someone out in r.a.s land may be able to point me in the
direction
of a commercial piece of equipment which would perform the following
task.

I would like to be able to charge up a 12 volt (nominal) gell cell
battery
and then plug it into a piece of equipment to check its total AmpHour
capacity during discharge at some constant rate current (say the "10
hour"
rate or the "20 hour" rate). All this towards assessing whether the
battery
has proven useful capacity and life left in it, or has it reached its
discard date?

The equipment would show the delivered amp-hours up to the point at
which
the voltage has fallen to a nominated end voltage.

I realise that you can do it in a way with a light globe to discharge
the
battery and then time the length the light holds up glowing brightly.
This
is all too primative for this day and age, and there ought to be some
piece
of equipment available for the task.

Or some circuit from an electronics hobby magazine??

Thanks in antcipation.
Roger Druce


If cost is no problem, then look at the modern chargers that the RC flyers
use. The better chargers measure the discharge and charge capacity of
batteries/accus. Look for brand names like Schulze, Orbit and Graupner.
Price level 100 - 300 eur depending about the charger model.
regs, Jyrki


Better yet, check any RC electric flight magazine (Quiet Flight for
instance) and take a look at the charger/cyclers they're using for the
electric power systems.

The rapid charge facility probably isn't necessary for us, but the
batteries these chargers are dealing with are nearer our battery sizes
than the ones used for standard RC transmitters and receivers.

--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :