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How to smart charge with a regulated power supply

D

Damian

Jan 1, 1970
0
Hi Guys,
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.
 
D

Damian

Jan 1, 1970
0
Forgot to mention, it comes with an analogue display to show the voltage. No
display for Amps.
 
J

John_H

Jan 1, 1970
0
Damian said:
Hi Guys,
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?

<Posted from aus.cars>

For a 12V car battery set the voltage to 14.2 - 14.4 and the max
current to 5A. The charge rate (current) will then take care of
itself, which is essentially how a car's own voltage regulator does
it.

For a long term maintenance charge you could wind it back to 13.8V.

For a 6V battery (if you happen to own an old Beetle or a Model T)
halve the voltage.
 
P

Phil Allison

Jan 1, 1970
0
"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.

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.

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.


..... Phil
 
R

Rod Speed

Jan 1, 1970
0
Damian said:

Wot abart us animals, boyo ?
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).

Presumably you mean the current limit.
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.

You'd be a lot better off with a decent modern
lead acid battery charger for peanuts from china.
How do I do that with this unit?

You can't with the smart bit. All it can do is the stupid charging.
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.

That’s nothing like real smart charging.
I'm after some good information on how to do it.

Get a decent modern lead acid battery
charger for peanuts from china.
Your help is very much appreciated.

We'll see...
 
D

Damian

Jan 1, 1970
0
Phil Allison said:
"Damian"

** 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.
 
D

Damian

Jan 1, 1970
0
Rod Speed said:
Wot abart us animals, boyo ?

Yeah, I was trying to address you monkey as well.
Thought you might be holidaying the Turks. :)
Presumably you mean the current limit.
Yes.



You'd be a lot better off with a decent modern
lead acid battery charger for peanuts from china.

Hey Rod, It's hard to get a good quality AGM smart charger for peanuts.
By peanuts I meant, under $50. The ones under that price aren't usually that
good.
But, if you know a link to a good one, do let me know.
You can't with the smart bit. All it can do is the stupid charging.

Yeah, I know. But, I was stupid enough to cook the good quality expensive
smart charger I had,
now I can't spend again on a good unit.
That’s nothing like real smart charging.

I know, but I would have to do the best I can for a while, until I get
another unit.

Got pissed on new years eve with more rum than I could handle and managed to
stuff up
the charger with unnecessary fiddling under the influence of intoxication.
Get a decent modern lead acid battery
charger for peanuts from china.

They have ones for $20 as well, but I'm not too sure about the claimed amp
range and the reliability.
Many 4WD gurus say that you get what you pay for in that area, and a cheaper
one can do more harm
than good to a quality AGM battery( Eg: microprocessor going nuts and
overcharging the battery, etc)
We'll see...

I'm still waiting.
 
D

Damian

Jan 1, 1970
0
John_H said:
<Posted from aus.cars>

For a 12V car battery set the voltage to 14.2 - 14.4 and the max
current to 5A. The charge rate (current) will then take care of
itself, which is essentially how a car's own voltage regulator does
it.

For a long term maintenance charge you could wind it back to 13.8V.

For a 6V battery (if you happen to own an old Beetle or a Model T)
halve the voltage.

I meant, "Smart, three stage charging", not plain old constant voltage
charging.
 
T

tuinkabouter

Jan 1, 1970
0
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.

What is the reason you want a three stage charge?
 
D

Damian

Jan 1, 1970
0
tuinkabouter said:
What is the reason you want a three stage charge?

The same reason anybody would want to purchase a muti-stage lead acid
battery charger.
Specially for AGM batteries, that's the way to go, 'cos those batteries
aren't cheap.
Multi-stage chargers charge them properly.
 
X

Xeno Lith

Jan 1, 1970
0
<Posted from aus.cars>

For a 12V car battery set the voltage to 14.2 - 14.4 and the max
current to 5A. The charge rate (current) will then take care of
itself, which is essentially how a car's own voltage regulator does
it.

For a long term maintenance charge you could wind it back to 13.8V.

For a 6V battery (if you happen to own an old Beetle or a Model T)
halve the voltage.
Or an early model Holden!
 
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