Yes, we're definitely planning a battery based inverter. The real
trouble is when the generator is charging, its AC power passes through
to the loads and hence to the Enphase inverters.
Also I agree with the other poster about Outback being more cost
effective. I just took a look at their Remote Operated Circuit Breaker
(ROCB) and this looks like a good option.
I've done dump loads before, and never found that to be an elegant
solution. Any other options I should be looking at?
Thanks,
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 8/17/2015 8:36 PM, Jerry Shafer wrote:
I cant see this working well without some battery based inverter
Jerry
On Aug 17, 2015 10:10 AM, "Ray Walters" <[email protected]
<mailto:[email protected]>> wrote:
HI Esteemed Wrenches:
I am consulting on a system I have never seen, that consists of a
6.7Kw Enphase roof mounted system, and 2 backup generators. Each
generator has an automatic 200 amp transfer switch to back up its
own 200 amp panel. Both 200 amp panels are fed by a 400 amp
service from the grid.
The Enphase PV backfeeds a subpanel in another building which then
is fed by a 2 pole 60 amp breaker in one of the 200 amp panels.
Currently they are having issues with the generators kicking out
because of the Enphase inverters. That part I understand: you
can't backfeed a generator, or its voltage regulation freaks out.
Now we get to the fun part: they want to create a third critical
load subpanel with loads selected from both 200 amp panels to be
powered by batteries and an inverter.
I am considering the Sunny Island since it makes the most sense
with its ability to signal the Enphase inverters to shut off when
the batteries are full. I also see this as a partial solution to
the generator issue, since normally the Enphase will be connected
to the output side of the Sunny Island. However, when the
generator is used to charge, we will be back to directly coupling
the generator output to the Enphase.
Here are some possible solutions I'm considering:
1) Use a separate charger for the generator so that it will only
feed DC to the batteries, and not be AC coupled.
2) convert the PV back to DC with charge controllers, but that
would involve ditching and adding another conduit run between
buildings.
3) Put the Enphase PV on a relay that would disconnect the PV
when charging with the generator.
4) Something I haven't thought of that one of you clever folks can
suggest......
As always, thanks in advance for all you responses,
--
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760 <tel:303%20505-8760>
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