high current voltage regulator

[Laurie]

I have solar panels directly charging two deep-cycle 12 v PbA batteries.
When reasonably well charged the voltage goes up to 16.3 (the manufacturer
recommends holding it there for several hours) and the inverter I am using
stupidly shuts down around 14+.

I would like to know if there is a single package voltage regulator that
will handle 10-15 amps.

If not, anyone know of a schematic for this application?

Laurie

 

[budgie]

On Sat, 9 Apr 2005 16:33:53 -1000, "Laurie" <no@spam.com> wrote:

I have solar panels directly charging two deep-cycle 12 v PbA batteries.
When reasonably well charged the voltage goes up to 16.3 (the manufacturer
recommends holding it there for several hours) and the inverter I am using
stupidly shuts down around 14+.

I would like to know if there is a single package voltage regulator that
will handle 10-15 amps.

If not, anyone know of a schematic for this application?

Unfortunately under embargo, I have the schematic for a solar regulator which
will do better things for your batteries and not irritate your inverter. The
device is a Solarex SC-18 and costs ~$A150.

The reg is a series switch which cycles between two limits - let's call them V+
and V-. When sun disappears and voltage drops below a lower limit V- - a
latch is set, and on next appearance of sun the switch stays closed until a
higher threshold V+ + is reached, then the device cycles between V+ and V-.

This "daily" boost trip to V+ + is intended to help destratify the electrolyte.

All four set points are adjustable.

I have no commercial affilaition with Solarex, just a very happy user of many of
these devices. We found that MANY microprocessor designs created so much RFI
that they were banned from our radiocommunciations sites in favour of these KISS
devices.

Shunt regulators are a problem with their heat dissipation, which increases as
the battery SOC rises.

Just my 2c worth.

 

[Alan Turner]

Hi Laurie,


On Sat, 09 Apr 2005 16:33:53 -1000, Laurie wrote:

I have solar panels directly charging two deep-cycle 12 v PbA batteries.
When reasonably well charged the voltage goes up to 16.3 (the manufacturer
recommends holding it there for several hours) and the inverter I am using
stupidly shuts down around 14+.

I would like to know if there is a single package voltage regulator that
will handle 10-15 amps.

If not, anyone know of a schematic for this application?

You wish to drop 2.3V at 15V, so about 34W would be dissipated by a linear
regulator.

If you're happy with dissipating 34W, the best solution may be a 3
terminal regulator with an outboard pass transistor. A linear regulator
would be easy to implement. You would want to be careful with protection
and current limiting. You may also need to worry about the dropout voltage
of the regulator when the battery voltage is about 14V. Perhaps a relay
could be used to bypass the regulator when it isn't required. Look at the
LM317 datasheet from national - there are some application circuits which
may interest you.

A better solution would be a "buck converter" - a type of switched mode
regulator. This type of converter is harder to build (you need to switch
highish currents fairly fast), but would be far more efficient.

I think there is an introductory description of switched mode regulators
in "The Art of Electronics" by Win Hill and Paul Horowitz. There are very
good application notes covering the topic on the Linear Technology and
Texas Instruments websites.

Regards,
Alan



--
Alan R. Turner | Live never to be ashamed of anything you do or say.
To reply by email, remove Mr Blobby.

 

[fengjianqing]

Yes! I agree with the shunt regulator has some problem with heat
dissipation. I think you should try the series regulator. But the
regulator should use good MOSFETS, otherwise will also has the same
problem. But the big advantage for series regulator is no short current
for solar panel.
For your inverter to shut down at 14V, I think this is better for your
battery otherwise if the battery charge at high voltage will make the
lifetime shorter. Normally at 25 degree the charge voltage should not
above 13.9V. But for boost voltage the voltage can keep for 14.5V for some
hours. This depend on the state of your battery.
If you want your battery has long lifetime you should use some
professional regulator. I can introduce you some products if you are
interesting.
Regards,
Feng

 

[Laurie]

"Alan Turner" <alan@mrblobbybiccard.com> wrote in message
newsan.2005.04.10.11.32.15.952359@mrblobbybiccard.com...

You wish to drop 2.3V at 15V, so about 34W would be dissipated by a linear
regulator.
V * V = W??

Oh, wait, that is "square volts"; things sure have changed since I
taught myself electronics with the help of Popular Electronics in the
'50's.<G>

Look at the LM317 datasheet from national -
Actually, fumbling through their data sheets, I found the LM338 which

can handle 5 A, and a circuit that parallels two of them: DS009050-2, so
that will do it.

Laurie

 

[Alan Turner]

Hi Laurie,

On Mon, 11 Apr 2005 13:45:42 -1000, Laurie wrote:

"Alan Turner" <alan@mrblobbybiccard.com> wrote in message
newsan.2005.04.10.11.32.15.952359@mrblobbybiccard.com...

You wish to drop 2.3V at 15V, so about 34W would be dissipated by a linear
regulator.
V * V = W??
Oh, wait, that is "square volts"; things sure have changed since I
taught myself electronics with the help of Popular Electronics in the
'50's.<G

Sorry - my error. What I meant 2.3V at 15A. Hopefully this was pretty
clear from context (and dimensional analysis, as you have pointed out).

Look at the LM317 datasheet from national -
Actually, fumbling through their data sheets, I found the LM338 which
can handle 5 A, and a circuit that parallels two of them: DS009050-2, so
that will do it.

Ensure that you have suitable heatsinking to keep the devices at a sane
temperature. It seems quite sad to use such an inefficient regulator in a
solar powered system.

Regards,
Alan

--
Alan R. Turner | Live never to be ashamed of anything you do or say.
To reply by email, remove Mr Blobby.

 

[John Popelish]

Laurie wrote:

I have solar panels directly charging two deep-cycle 12 v PbA batteries.
When reasonably well charged the voltage goes up to 16.3 (the manufacturer
recommends holding it there for several hours) and the inverter I am using
stupidly shuts down around 14+.

I would like to know if there is a single package voltage regulator that
will handle 10-15 amps.

If not, anyone know of a schematic for this application?

Laurie

The simplest solution may just be a load bank that switches across the
batteries, just before the inverter kicks off and switches off at just
a bit lower voltage. Heat is easy to get rid of.

It shouldn't take too many watts to load the solar bank down from 16+
volts to 14+ volts.

 

[Laurie]

"Alan Turner" <alan@mrblobbybiccard.com> wrote in message
newsan.2005.04.12.07.19.05.323621@mrblobbybiccard.com...

Ensure that you have suitable heatsinking to keep the devices at a sane
temperature.
Am planning to use a Peltier heat pump that conveniently operates on 12

v DC between regs and finned heat sink.

It seems quite sad to use such an inefficient regulator in a
solar powered system.
Any more efficient approaches would be appreciated.

Laurie