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<div class="moz-cite-prefix">boB and Jarmo, thanks for great
explanations.......So, let's dump that idea and go back to square
one: a programmable 1.5kW charger for 12 volt batteries. I have
been checking with all the charger manufacturers I can find and no
one makes this product. Argus said no, Pro Charging said no, a few
others, no.<br>
<br>
Brian, an inverter/charger and remote will work great but that
still represents $1000 cost and about $1350 to my customer for a
100 amp charger. But, so far, this is my only option.<br>
<br>
A few years ago Magnum Energy told me they were working on a stand
alone programmable charger but nothing yet. It probably does not
cost much less to build than the inverter/charger does.<br>
<br>
Thanks to all for the answers.<br>
<br>
<pre class="moz-signature" cols="72">Thank you,
Larry </pre>
On 12/16/14 2:19 PM, <a class="moz-txt-link-abbreviated" href="mailto:boB@midnitesolar.com">boB@midnitesolar.com</a> wrote:<br>
</div>
<blockquote cite="mid:5490A1C6.5020606@midnitesolar.com" type="cite">
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<div class="moz-cite-prefix"><br>
Jarmo, you are absolutely correct. This is another great
reason NOT to use an MPPT charge controller<br>
as an AC sourced battery charger. Also, if my instructions are
not followed to a TEE, the CC WILL blow up !<br>
<br>
The input capacitors are going to wear out MUCH sooner than a
real charger because of the 60Hz or 120<br>
Hz ripple shown in Jarmo's graph. Capacitor ripple abuse was
one answer to one of Larry's questions about long term<br>
reliability.<br>
<br>
<br>
Also, if the input diodes short, you are applying AC directly to
the input capacitors and<br>
will go POOF as well as the power section.<br>
<br>
And you would NOT know that you needed an input power resistor
first or possibly where<br>
to even find one of the correct resistor values and power
ratings if the input source is stiff.<br>
This is the scariest problem in my mind.... Too high of input
max power voltage, overcurrent<br>
and then, battery voltage regulation will overshoot without that
resistor.<br>
<br>
I would just spend the extra money and do this right in the
first place and don't try to<br>
cut corners on price.<br>
<br>
Brian Teitelbaum had the best idea I think... Just buy an
inverter with a power factor corrected<br>
charger like the newer Schneider SW inverter/charger (I think
that was the one ?) or one of<br>
the MSW Magnums. Or, a decent charger if one exists. Haven't
seen the Argus/Alpha one.<br>
<br>
MPPT charge controllers are really just NOT designed for this.
(although they might work for a while).<br>
<br>
In fact, Ryan from MidNite Solar blew up several Classics at
first.<br>
<br>
But knowing that some folks are going to try this, I thought it
best to give at least some directions.<br>
<br>
Thanks,<br>
boB<br>
<br>
<br>
On 12/16/2014 12:34 PM, <a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:Jarmo.Venalainen@schneider-electric.com">Jarmo.Venalainen@schneider-electric.com</a>
wrote:<br>
</div>
<blockquote
cite="mid:OF6C22F45E.352E120D-ON88257DB0.006DD903-88257DB0.007112FF@US.Schneider-Electric.com"
type="cite"><font face="sans-serif" size="2">Hi:</font> <br>
<br>
<font face="sans-serif" size="2">I'm enjoying learning many new
ways of looking at things and of practical solutions on this
forum. In that spirit, the only thing I would add to this
discussion is that the power factor as seen by the AC source
will be very poor. In that regard, the larger the caps, the
more stable the "DC" voltage, but the poorer the PF.</font> <br>
<br>
<font face="sans-serif" size="2">This will show up as much lower
charging efficiency due to the way in which AC current is
drawn by the bridge rectifier/capacitor circuit. Here's an
actual graph of how a bridge rectifier connected to a
capacitor draws AC current,</font> <br>
<br>
<img src="cid:part2.08030300.02010107@starlightsolar.com"> <br>
<br>
<font face="sans-serif" size="2">The graph is from my past life
a couple of decades ago back when I was studying. It's not a
conventional phase-shift PF problem, but rather a form factor
PF problem. It shows the current drawn by a 13" PC monitor of
that era, before PF correction was mandated for all new
products. In this example the 'crest factor', (peak current
as measured versus what it could have been if the current was
drawn throughout the AC pulses, was about 4x). Depending on
the size of capacitor, it can be as high as 7x.</font> <br>
<br>
<font face="sans-serif" size="2">The practical effect on the
wires and devices including the diodes and charge controller,
is that a lot of heat is generated in their power components.
The source of the energy for that heat is the AC source and
in cases where the AC source is a generator that translates to
much higher fuel consumption, (in some cases over 30% more).</font>
<br>
<br>
<font face="sans-serif" size="2">Out of my tests back then, I
also discovered one practical recommendation. </font> <br>
<br>
<font face="sans-serif" size="2">If you are using bridge
rectifiers connected to capacitors, do not have any length of
wire and in particular no loop area in the wires between the
bridge rectifier and capacitors. Having wire/loop area
introduces inductance into the circuit which behaves somewhat
like an ignition coil due to the high speed reverse recovery
period of the diodes; and this happens four times every AC
cycle. Given the right conditions the voltage spikes caused
by that inductance/ignition coil like effect will make short
work of the diodes and other components which are on the
circuit.</font> <br>
<br>
<font face="sans-serif" size="2">The voltage spikes wont be a
problem if the bridge rectifier is as close as possible to the
capacitors, but due to reverse recovery effect, you'll still
be stressing the parts and heating wires.</font> <br>
<br>
<font face="sans-serif" size="2">In my opinion, its ok to do
this, but I wouldn't push power levels to anywhere near the
limits of components and devices.</font> <br>
<br>
<font face="sans-serif" size="2">JARMO</font> <br>
<br>
<font color="#008000" size="3">_____________________________________________________________________________________</font><font
size="3"> <br>
</font><font face="Arial" size="1"><b><br>
Jarmo Venalainen</b> | </font><font color="#008000"
face="Arial" size="1"><b> Schneider Electric </b></font><font
face="Arial" size="1"><b> | Solar Business</b> | <b>CANADA</b>
| <b>Training & Development Specialist - Senior</b> <b><br>
Phone:</b> +604-422-2528 | <b>Fax:</b> +604-420-1591 |
<b>Mobile:</b> +604-505-0291 <b><br>
Email:</b> </font><a moz-do-not-send="true"
href="mailto:jarmo.venalainen@schneider-electric.com"><font
color="blue" face="Arial" size="1"><u>jarmo.venalainen@schneider-electric.com</u></font></a><font
face="Arial" size="1"> | <b>Site:</b></font><a
moz-do-not-send="true" href="http://www.sesolar.com/"
target="_blank"><font color="blue" face="Arial" size="1"><u>
www.SEsolar.com</u></font></a><font face="Arial" size="1">
| <b>Address:</b> 3700 Gilmore Way, Burnaby, BC V5G4M1 </font><font
size="3"><br>
</font> <br>
<hr noshade="noshade"> <br>
<br>
<br>
<font size="3"><br>
Larry, Pitfalls ?<br>
The biggest pitfall I would say is if you have a VERY stiff
grid.<br>
<br>
If your Voc is say, 170V DC and the CC current limits it
output at say, 169 V DC,<br>
they you are going to need to add an input power resistor of a
couple Ohms to<br>
help cushion the input to be more like a PV module. A lot of
times, the grid is<br>
not nearly this bad, especially generators.<br>
<br>
Also, If you are going to do this, I would NOT use Solar mode
but instead try<br>
Hydro mode set to Manual MPP voltage. First start the MPPV at
something just<br>
less than Voc or maybe, say, 160 VDC. Then, from main STATUS
screen, you can<br>
adjust the input voltage up and down by pressing the
Soft-Right or Soft-Left<br>
keys respectfully. (upper right and upper left keys). Then
you can manually get<br>
a feel for what it should be set for.<br>
<br>
The Classic 200 is the only CC of ours that I would use. The
250 would work but the<br>
200 is much more suited. I wish there were a real charger
that one could buy that was<br>
isolated, and we have never really advocated MPPT charge
controllers for this but<br>
in a pinch, they always seem to work find. Never did add a
"DT" mode (after Daryl<br>
Thayer of course), but this hydro mode seems to work OK.<br>
<br>
If you want to let it sweep but setting it to 3 minutes (or
higher) that will also work.<br>
If you do that, set the minimum input voltage. Something like
140V or so will keep<br>
it from dropping the input voltage too low and either bogging
down the input source<br>
and the rectifier bridge (especially generators)<br>
<br>
You can also set the INPUT current limit in the LIMITS menu.
This was for hydro<br>
in particular. Either limit can help reduce Isc or bogging
down issues.<br>
<br>
The other pitfall is that it is NOT galvanically isolated so
you should be very careful.<br>
We use an X240 equivalent transformer to keep the batteries
going in our burn in<br>
rack using 2 Classic 200s and it works great.<br>
<br>
Also, use a nice and strong full bridge rectifier so that it
applies 120 Hz instead of<br>
60 Hz to the input. That is much easier on the input
capacitors and things and just<br>
makes it work smoother. There are input capacitors
(filtering) on most charge controllers.<br>
<br>
Again, in a pinch this seems to work but watch that input max
power point voltage to make<br>
sure it is not too high compared to the Voc. If there isn't
enough voltage spacing between<br>
the two (stiff AC source) then the control isn't going to be
very smooth and might risk<br>
letting the smoke out.<br>
<br>
What ever you do here, be very careful what you touch !<br>
<br>
boB<br>
<br>
</font><br>
<br>
<font color="#004080" face="Calibri" size="4">This has been
discussed on this list in years past. It is possible to use an
outback charge controller as a battery charger. You need to
put the 120 AC into a bridge rectifier, then feed the 120 DC
into the controller’s PV input. So you’ll have an 80 amp
battery charger.</font> <font color="#004080" face="Calibri"
size="4"></font><br>
<br>
<br>
<p> <font face="Times New Roman" size="3">On Dec 15, 2014 4:01
PM, "Larry" <</font><a moz-do-not-send="true"
href="mailto:larry@starlightsolar.com" target="_blank"><font
color="blue" face="Times New Roman" size="3"><u>larry@starlightsolar.com</u></font></a><font
face="Times New Roman" size="3">> wrote:</font> <br>
<font face="Times New Roman" size="3">Wrenches,<br>
<br>
Does anyone know of a 120/12 volt battery charger that can
be programmed for absorb and float voltage and time in
absorb mode? I have been needing this product for many years
but I can only find it in inverters with built in chargers
from Magnum, Outback, and Xantrex.<br>
<br>
-- <br>
Thank you,<br>
<br>
Larry Crutcher<br>
Starlight Solar Power Systems</font> </p>
<p> <br>
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