Running an AC Compressor on HIS

[LabPower]

We have the Home Intregation System installed by Sunrun and after 6 months and many visits have it powering most of the home essentials: Well Pump, Gas Furnace, Fridges, Internet, Fans. The one item we haven't been able to get working is the AC compressor. Sunrun told us that the initial draw of the AC compressor was too much for the system to handle and advised us to install a "soft start" for the AC compressor which would reduce the start up amperage draw.

We had our HVAC tech install the Soft Start on the AC compessor and he monitored the start up amps and they never exceeded 35 amps, which is well below what the 70 Amps that Sunrun said we needed to stay below. Unfortunately, the AC compessor still wouldn't power on while on backup power. The fans tries to spin a few times and then stops. Of course, while on street power it works perfectly.

Has anyone else been able to get an AC compressor working on HIS?

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[Maquis]

How did he measure the starting current? Unless he used a proper instrument, it may not capture the peak current. Once that’s verified, you need to go back to SunRun.

 

[Zprime29]

There is some discussion here https://www.f150lightningforum.com/...ck-during-peak-hours.14010/page-2#post-297991

It was mentioned that the soft start was able to turn on their AC off a couple power wall's which is at least as much as you should be getting from the HIS. I'm planning on putting soft start on mine when I get some sort of bidirectional capability. I had planned on HIS but I'm starting to lean towards waiting for Emporia's offering.

 

[Whammy Bar]

What soft start did you install? What is the LRA on the nameplate of the AC unit?

Depending on what else you have running when the AC tries to start, it may be tripping due to the overload. There is also a fan at the indoor unit trying to start at roughly the same time, in addition to whatever other loads are running.

 

[FordBookends]

I think the AC pulling 35A may be testing the limits of the HIS, the inrush is probably a bit higher. The HIS is rated for 240V/40A max (9.6 KW), so the 70A rating from the Sunrun Rep must have been thinking about 120V circuits.

I am in the process of exploring installing a HIS and told the Sunrun surveyor that we would not include our AC in the system. I will get an initial system design/quote in about a week.

 

[Heliian]

Starting up motors on inverter systems can be messy.

The inverter gets tripped up by not just the raw current but also the voltage drop and emi.

Regardless, running your whole home ac off of the truck probably won't yield good run times.

 

[bmwhitetx]

You could also consider installing a mini-split for a room or two. That would get you through the outage. Or a window unit

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