Why I abuse batteries was: trojan battery cycle [RE-wrenches]

[John Berdner]

Jeff:

US/ UL versions of the SI can do 20 kW continuous (28.8 kW @ 30
minutes) in split phase today on a single cluster.
For 120/208 the US/UL versions can go to 15 kW (21.6 kW @ 30 minutes)
today on a single cluster.
(A cluster is defined as a single battery bank connected to a single
load circuit.)
Remember this is the power rating of the SI's only. 
In an AC coupled system you also add the inverter capacity of any SB's
which are connected for daytime loads.
The rule of thumb is that you can have a max of 2 kW of SB's for each
kW of SI so this would give you up to 60 kW peak for split phase or 45
kW peak for 120/208 three phase (depending on irradiance of course).
 
You can always split the loads onto multiple clusters and then the sky
is the limit.
So far the largest system using US/UL equipment is a grid backup system
with (48) SI54048U's configured as (16) 120/208 clusters. (240 kW
continuous, 345 KW @ 30 minutes)
 
For non-UL applications there are 2 choices:
 
1) We can build a Multi-cluster box without UL for 120/208 three phase
systems. Right now we have only tested the Multi-cluster box in a (4)
cluster configuration, with (12) SI5048U's for 120/208  three phase (60
kW continuous, 86.4 kW @ 30 minutes).  This is a lot of power without an
insane number of inverters.
 
2) We can create a system using MOW (Most-of-World) SI's and
Multi-cluster boxes in 2 , 3 and 4 cluster configurations.  This would
give you 230/400 Vac three phase at either 50 or 60 Hz.  The 50 Hz
versions are standard for the MOW but we can do 60 Hz versions of all
the equipment as a special order (just programming of MOW units).  If
you are in a country that uses US standard electricity then you would
need a custom transformer (or autoformers) to go from 230/400 Vac down
to 120/208 or up to 277/480.  In the larger systems there is typically a
distribution system of some sort so the added transformer losses are
probably there anyway.  Once you are at US standard voltages and
frequency you can use standard US Sunny Boys.  You can also use MOW
Sunny Boys (in either 50 or 60 Hz) on the SI side of the transformer(s).
 There are pros and cons to each approach.  I can discuss them with you
off line if you like.
 
I am not sure on the schedule for a UL Listed version of the MC box. 
We discussed it when I was in Germany but I am waiting to hear a
schedule from the SI product management team. I will update you offline
when I know more.
 
Best Regards,
 
John Berdner
 
 
John B. if you get flamed then toss some of the heat my way, 'cuz I've
been suggesting this for many years - Bulk most of the charge w/the
genset either at night or 1st thing in the morn and then let the PV,
wind or whatever do the inefficient last 20% throughout the day. 
Jamie, I'm confused w/your post. I read it as starting a charge at 80%
and then stop at 80%. I'm sure this is not what you meant, but that is
my read. I'm also concerned about doing an EQ. only every 30 days or
more and going with the every 2 weeks. I would appreciate more of your
thoughts on this as "you da man" when it comes to batteries!
In general I think what both of you are saying is what I'm doing except
when my genset is running I need to also support loads and they can be
as high as 40kW as we try to do the daily heavy work when the genset is
running. My intention is to try to get the genset at as close to 80%
load as possible for maximum fuel efficiency and genny life. VERY happy
to see Outback's new MATE software allow for a cool down cycle so we
don't smoke turbo's! I've been having to built my own custom units and
delighted to give up the task.
John B. when might we see here in the U.S. the abilities to get above
30-40kW in inverter stacking for off-grid systems? What if I had needs
that did not require U.L. (international)? What I REALLY want to see is
the return of single LARGE o-t-g inverters, like the old Trace
Technologies PV Series. I have one residential system in Mexico w/28
Outback VFX3648's on it, 3 battery banks, genny's and distribution
systems. I would like a more elegant approach and easier install as well
as maintenance. I'm all for redunancy but this is nuts!
BTW- the WhisperWatt Ultra-Silent gensets are amazing in how quiet they
are. A 85kW unit is not as loud as a Honda 3000i.
Thanks for the feedback,
-jeff o




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