Hello wrenches and Marv:
How many Enphase inverters do you put on a single parallel string? The
Enphase manual allows for up to 15, but I have found that a single string of 15
can have very high voltage rise on the AC wiring. Up to 1.5% loss just on the
Enphase cables, and that does not take into account resistance at the plug
connectors or any home-run wiring.
15 inverters x 190 watts = 2850 watts
2850 watts / 240 Volts = 11.875 Amps (however at the beginning of the
string it is 0 Amps)
Average Amps on the Enphase cables is 11.875 / 2 = 5.9375 Amps
length of contacts + internal wiring = ~6'
Total Enphase cabling length (6' x 15 inverters) = ~90'
5.9375 Amps @ 240 V running 90' on #14 AWG CU = 1.4% loss
It is pretty hard to design for 1.5% voltage drop if you have to size for 0%
loss on your wiring! I hope Enphase will increase the size of the wire in
their cables soon. Have you experienced issues with micro-inverters shutting
off due to high AC voltages?
Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell: 707-321-2937
Office: 707-789-9537
Fax: 707-769-9037
________________________________
From: i2p <[email protected]>
To: RE-wrenches <[email protected]>
Sent: Thu, June 10, 2010 4:50:47 PM
Subject: Re: [RE-wrenches] Real world PV production
On Jun 10, 2010, at 7:57:53 AM, "Kelly Keilwitz, Whidbey Sun & Wind"
<[email protected]> wrote:
PV Watts VASTLY underestimate PV production
> in our area.
PV Watts underestimates in Central Ca too.
Don
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