Re: AC causing PV inverter to cycle into wait mode


"old dirtbeard" <dirtbeard@xxxxxxxxxxx> wrote in message
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"Bill" <dadm48rv@xxxxxxxxxxxxx> wrote in message
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You may have just said a magic word. If the lights dim, and it's more
than just instantaneous, you might want to check with your HVAC guy to
see whether the unit - the AC that is - could benefit from a "start
assist". If there currently isn't one on there, or it's just a PTC, or
it's bad, it could be taking alot longer to start the compressor than it
needs to - long enough that your inverter control sees it as a UT side
voltage sag.
Bill,

Thank you. Maybe I can address this by addressing the AC unit. I will call
the AC contractor who installed it and see if he will come out and assess
the situation. Do you have any ballpark ideas what a start assist should
cost to install if there is not one? Or what it should cost to replace one
if it is bad? This is the first house I have had with central AC and I
know very little about it. I do appreciate your help and advice.

It is 100 degrees today and the inverter is going into wait mode every
time the AC kicks in. The default timeout for the inverter is 5 minutes
and since it happens every 20 minutes, so I am losing 25% of my generation
during peak hours (when I need it most).

thanks again,

doug
The start assist / hard start kits are very inexpensive. Google for
examples. You should address the sag issue. Forget about the generation part
of it when / if you complain to the electric company. They have a load
device that replaces the meter temporarily, and the measure the drop when
the load is applied. You'll want your inverter locked out while they are
playing so as not to "help". Get someone to measure the voltage at the input
to your main breaker with a fast recording meter. Look at how low it goes
when you put the ~ 100 amp start load from your AC on it. If you go from say
240 to 215 volts for the instant, that would be a 10% drop - way too much
for 1/2 load on a 200 amp service. The comment about 268 volts at night is
interesting also. I'm thinking transformer issue. The primary side - at most
utilities - is regulated within 2.5%. Mention the range you are seeing, and
they'll likely put a logger out there, followed by a transformer
replacement.

Is your transformer pole mounted or on the ground? If pole mounted, see if
you can figure out how many houses are on it. Then look at the number on the
side of it. 10, 15, 20, 25, 37.5, 50, etc. That is it's continuous capacity
in Kva. 200 amps at 240 volts is 48 Kva. It's assumed that no-one is going
to consume 200 amps at 240 continuously. The realistic number is something
like 10% of that. The real issue is the total load on that transformer.


.

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