[RE-wrenches] Load Management vs Multiple Inverters and OutBack Radian vs Flexware systems

Thu Dec 15 11:17:32 PST 2016

Dave:

Here are the differences between the Outback Radian and FX inverters that I
think are pertinent to your situation:

1.    The Radian has generator support.  Don’t confuse this with generator
start.  Gen support allows the inverter to sync to and aid the generator in
providing power to loads.  The new FX inverter is the FXR and I am not sure
it has this capability.  It is worth checking into.  Avoid an inverter
without this function.

2.    The Radian provides more power per hub-port than does the FX series.
The Radian can provide 8 kw per hub port while the FX maxes out at 3.6 kW
per port.   This may not seem important but it can be.  If you have a
Flexnet DC unit it occupies on port, therefore you are limited to 32 Kw
(3.6 * 9 ports).  With Radian, you are allowed up to 72 Kw (8*9 ports).
And if you reach these maximums, there are no ports for charge
controllers.  I wish Outback would put some resources into eliminating this
bottleneck (and allow more than one Mate, please).

3.    I am not fond of the X240 transformer system.  I have seen too many
instances of tripped breakers.  The power save scheme is awkward when using
FX inverters, and if you ask three Outback employees about setting this
function you will get three answers.

4.    Outback supposedly has a white paper on stacking more than two
Radians, but I can’t seem to find it.  Lones, do you have access to this?

5.    You are correct in looking at battery charging ratings.  With a big
system comes big batteries.  You want to be able to charge them in an
appropriate length of time.

I always hesitate to try and comingle equipment from too many different
manufacturers.  Battery inverter systems are finicky enough as they are.
This may preclude load management.  Consider how you would implement this:
it would mean contactors, maybe an additional sub-panel, wiring, etc.
Sounds problematic to me.

Wiring a Radian system is different than wiring a Flexware system.  I find
the Radian easier now that I have learned a few tricks:

1.    Remove all AC breakers from the GSLC cabinets.  Instead use two
outboard load centers: one for generator fed and one for inverter fed.  To
provide bypass, run the generator power to the inverter fed panel and
provide breaker interlocks.  For smaller systems use a factory provided
interlock.  For larger systems, we custom build breaker interlocks.
Contact me off-line for more information.

2.    Remove all of the PV breakers from the GSLC.  You can use a Midnite
DIN rail or panel mount breaker cabinet or even an Outback combiner to
mount din rail mount your PV and charge controller breakers.

I hope this helps.

William Miller

[image: Gradient Cap_mini]
Lic 773985
millersolar.com <http://www.millersolar.com/>
805-438-5600

On Dec 15, 2016, at 10:08 AM, Dave Palumbo <palumbo131m at gmail.com> wrote:

Wrenchers,

I am involved in designing an off grid system that will need  multiple
inverters (probably OutBack). My experience over the years has been limited
to no more than 8kW's of inverter on a big system (for me). The load
profile is not completed yet, but it is looking like this may require more
power if all of the loads were to be on/surge at the same time. The client
wants things to run as seamlessly as practical and has the means to pay for
a nice system.

·         Are automatic load management devices worth looking into? I have
no experience with them except for one of my off griders (early adopter
type) had one put in about 15 years ago on his system and I think it worked
OK but it seemed like a lot of money and work to install and it takes up
some space. More technical stuff to deal with.

·         How fool proof is it and is it worth messing with? Vs. adding
more inverter wattage?

·         With OutBack these days what are the Pros and Cons comparing a
Radian system vs a Flexware 1000 system?

·         Why does the Radian line have different ratings per unit of a
48VDC inverter? Isn't the Radian two vented 48V inverters in a big box?

·         The regular OB VFXR3648's  have lower continuous power and surge
ratings and lower battery charging amps when compared to a Radian. Two OB
VFR3648's @ 7,200VA continuous vs Radian @ 8,000VA; 10.8kVA surge on the 2
VFX's together vs 12kVA on the Radian; also 90ADC vs 115ADC battery
charging respectively.

Thanks for your time,

Dave

David Palumbo

Independent Power LLC

462 Solar Way Drive

Hyde Park, VT 05655

802-371-8678 cell

802-888-4917 home
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20161215/e550ebdc/attachment-0002.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image002.jpg
Type: image/jpeg
Size: 1460 bytes
Desc: not available
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20161215/e550ebdc/attachment-0004.jpg>