"Phil Allison" wrote in message
...

"Damian"

I have a regulated power supply that I've built from scratch back when I
was in 'school'.
It's a 0-24V regulated power supply with upto 5 amp.
There are two settings, 1A and 5A. Also the amps can be controlled via a
turn knob(potentiometer). Also a separate potentiometer for voltage
control.

My aim is to use this unit for 'smart charging' a 12V, 6V lead acid, agm,
etc batteries.

How do I do that with this unit?
It's ok for me, to having to walk to the unit every half hour or so, to
adjust the settings to replicate the multi-stage battery charging.

I'm after some good information on how to do it.

Your help is very much appreciated.

** For once there is a very simple answer to you question - cos SLA etc
batteries are happy with "constant voltage" charging.

All you need do is set the voltage on you PSU to exactly 6.9V or 13.8V (
use a digital meter ) for use with 6V and 12V SLA/gell cells
respectively. You MUST do this setting with NO battery attached !!

The amp setting depends on the amp hour (AH) capacity of the battery -
use the 1A setting for those rated at say 3 to 8AH and the 5A setting for
larger examples.

The battery will decide if takes all the pre-set current or progressively
less as it approaches full charge - then drop to a trickle at full
voltage. The voltmeter will monitor what is going on.

Hi Phil,
What I meant was, the procedure they use to 'smart charge' lead acid
batteries(specially AGM ones).
Basically I'm more interested in the classic three stage charging method.
Which basically means, start with constant high amp, decreasing voltage,
then contant voltage, decreasing amp,
then float voltage( 13.3 V etc) with minimum current.
There're microprocessor controllled units out there for sale.
I had a good one of them and accidently stuffed it up.
Now, I'm trying to do what it did, manually using the home build PSU.


FYI:

To protect your PSU from accidental reverse connection of the leads -
wire a hefty ( ie 3amp or more) diode across the output in reverse and
add a fast acting fuse in series with the leads.

That circuitry is already inside the unit, including the fuse.


FYI 2:

I hope your regulated PSU has a big heatsink cos it is gonna get plenty
hot, a fan may well be needed for 5A charging.

I built it with an aluminium case, the power transistor(regulator) uses the
body as a heatsink pretty effectively, in addition to
the large aluminium heatsink, and it's outside the unit, which helps as
well.
Having said that, I haven't put any new thermal paste for last fifteen
years, so I think it's about time.



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