Question Auditory behavior idle and under load: decibels and noise

Well, first of all, it would help if you gave a model number, otherwise this is a useless question.

I can't give hard numbers, but for my 18Kpv, there is no sound at all for anything under 6kW of load.  Above that, the fans come on and it is reasonably audible, but I don't have a sound level meter.  However, since it is in my garage, I don't care.  I have not noticed any difference vs temperature, but I really have not paid any attention.  I have not noticed anything with PV input, but my panels can't get close to 6kW at this time of year.

Model EG4® 3000EHV-48 ALL-IN-ONE OFF-GRID INVERTER

If there is no sound, then you are saying the fans do not even run up to 6 kW load?  That is remarkable. But it seems to be a much higher capacity inverter.

Correct, the fans do not run at all when under 6kW.  Someone else with a 3000EHV will have to provide their experience.

Thank you, that's actually very helpful.  To meet the goal of silence, paying more for a really capable inverter, even if I won't ever drive more then 1800W or so. might be worth it just for the zero noise behavior.

Are you sure it is running off batteries and not off pass-thru AC power?

To produce 6000W AC at 94% efficiency (see spec sheet), it would need to dissipate 383W of heat.

No electronics I have ever seen can dissipate 383W of heat without running fans pretty hard. Well, it's all but impossible without massive heat sinks or some kind of liquid cooling system.

Another downside I see to such a large unit is that at low loads, the efficiency is extremely poor. That is, for my steady-state 250-500W load (160W overnight),  the 70W power consumption eats 1.7 kWH per day just for the inverter.

Which brings me back to EG4® 3000EHV-48

BATTERY TO INVERTER EFFICIENCY: 94% <=== excellent, as good as the big units
IDLE POWER CONSUMPTION:   <50W, <15W (Standby)

Idle power consumption is a problem. My steady state load is 160W at night and 200-300W during day with sporadic spikes beyond that.

If it uses 50W for itself alone, then a 200W AC load consumes 213W DC and adding 50W for the inverter, the efficiency is a pretty terrible (200/(213+50) = 76%. Ugggh.

BTW, as FYI for "why bother":

My electric is minimum $0.48 kWh here in SF Bay Area ("Tier 2" pricing), and rises to $0.55 or higher some times of year.  

https://windinmyface.com/blog/2024/20241202_1130-PGE-electricity-cost.html

For most of the country, power is more like $0.13 or so and all of this is a waste of time unless it's purely an off-grids scenario.

My goals are simple:

- fast ROI eg 2 years or less

- simplicity

- no nuisance factors like fan noise.

I can't do any testing for you now because it is after 3pm which is when peak rates are in effect.   I can try tomorrow if I remember.  I will try charging my wife's Tesla at varying levels. Also, the sun should be out so I will also be getting around 3kW of solar at the same time.

FYI, I am in the North Bay.  I am on the PG&E EV plan of 62 cents peak and 30 cents off-peak.  While off-peak is supposed to be cheap, it is really expensive compared to most other's peak rate.

@caesarv Thank you that would be very nice of you.   Make sure AC from utility is cut off when testing. Thanks!

My 18Kpv testing:

The solar input was roughly 3.2-3.3kw all during testing.  No grid power was used.  I used a thermal camera to capture some temps.  Ambient temp was in the low-mid 60s.  When the fans are not on, the inverter emits zero noise...even when I put my ear against the case.  There is not even any hum.

I ramped up the load slowly in 1A increments (about 250W) as I charged my wife's Tesla.

At 5.9kW of load, the fans were not on.  The battery was supplying about 55A of DC power.  The temp near the fan vent was 46C.

At 6.3kW of load, the fan turned on.  I did not measure in between those two loads.  The battery provided 70A.  The temp near the fan opening was only 24C, presumably because the fan was moving cooler air through it.

I ran the load up to 8.5kW for a bit and then slowly decreased the load.  The fans turned off when I reached about 4.5kW.  This is probably the expected hysteresis behavior.

Hope this helps.

Thank you very much!   Fantastic to have little or no sound.  Maybe when it gets to be hot days it will ramp up some, but it sounds like it is as good as it is going to get.

I took a closer look, and I think the system for me is the EG4® 6000XP along with the 14.3 kWh battery.  More money up front, but expandable and high quality and elegant look too.

Thanks!

BTW, I picked up eight (8) California Solar 540W bifacial panels today for just $175 each.   That's 4 kW of panels for $1400.   That should do a very nice job of keeping a 14.3 kWh battery charged up, even in winter. 

Posted by: @diglloyd

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I took a closer look, and I think the system for me is the EG4® 6000XP along with the 14.3 kWh battery.  More money up front, but expandable and high quality and elegant look too.

Thanks!

You may want to watch the Will Prowse videos reviewing the 18Kpv. I think I recall him commenting about being surprised by how quiet the 18K is specifically because the 6000XP is so loud.

I can confirm Caesar's observation. The 18K is dead silent until significant power is flowing through it. When the fans do kick on (there are four of them), it's pretty loud - I would not want it inside my house. I bought the 18K specifically so I could install it outdoors for noise level, and I'm glad I did. I know you didn't want subjective comments, but that's all I've got.