boB,
I appreciate your contribution to this discussion, but it brings up
a couple of issues for me.
- You have suggested that "A good wiring practice these days is
to...wire the controller's
battery terminals close or right at the battery terminals." This
goes against all modern good practices of which I'm aware. We have
long accepted as standard a single pair of battery cables, with all
DC input and distribution handled within the power center (I've
heard that some people refer to these things as 'E-Panels'). It's
the only way to effectively run all current through a shunt on the
negative, and through proper overcurrent protection/disconnects on
the positive.
I must not have understood what you meant, as it sounds like you're
suggesting abandoning the entire E-Panel approach. What am I missing
here?
Thanks, Allan
Allan Sindelar
al...@sindelarsolar.com
NABCEP Certified PV
Installation Professional
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder (Retired), Positive
Energy,
Inc.
505 780-2738 cell
On
10/29/2015 5:02 PM, Jay wrote:
boB,
Is the OCP still being used and does it work in both directions?
JAY, Peltz power
Hi Jay. Yes, the OCP you refer to is still there. This
particular OCP though is a hardware
fast OCP intended to protect the controller against large load
surges on the battery
side of the controller... This usually happens when battery
cables are long and
the inverter(s) are connected electrically close to the
controller, thereby drawing
huge amounts of current from the Classic than from the battery
when the inverter
is turned on, charging its input capacitors or something with huge
AC loads.
A good wiring practice these days is to, if convenient at least,
wire the controller's
battery terminals close or right at the battery terminals. Then,
when an inverter
is either turned on and giving a momentary short circuit to the
battery lines, that
current will come from the battery rather than the controller's
electronics.
Larger cables won't necessarily fix the problem due to battery
cable inductance.
The 150s and 200s rarely need the OCP circuitry. The 250 is the
one the OCP was
really designed for but we put it into all of the controllers.
There is also over current protection going the other way but is
not a microsecond
timed protection. Plain old fast or slow ramping up surges like
we're talking about is easy to
control, normally.
Breaker tripping like this is extremely rare, IF it is from this
kind of current spikes due to
generator startup. I would suggest to be safe and bring another
controller up just in case.
Might be a bad controller but I just don't know without logging or
observing it happening
with a scope and a current probe. I've seen some very strange
things happen.
boB
Sent from my iPhone
On Oct 29, 2015, at 4:19 PM,
"b...@midnitesolar.com" <b...@midnitesolar.com> wrote:
Larry, because these MPPT CC's are bi-directional (for
efficiencies' sake), they can convert a large current
at the battery side to a smaller current at the PV side if not
adjusted right. Normally this is just taken
care of and reduced to a bare minimum by the controller
watching the voltages and currents carefully.
It is technically possible though for things to not work
exactly correctly. I am not saying that this is
for sure happening, but it is possible. The ramping up in
battery voltage from the chargers should
be plenty slow enough for this not to be a problem but I am
wildly speculating that this could happen
and cannot rule it out. There may of course be something else
completely different happening here
though.
If CBI breakers are being used, these are known to be
extremely fast at tripping when overloaded.
Also, what, if any SPDs are connected to the system ?
boB
|
_______________________________________________
List sponsored by Redwood Alliance
List Address: RE-wrenches@lists.re-wrenches.org
Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out or update participant bios:
www.members.re-wrenches.org
