which inverter/charger got 10ms or less of transfer time or can behave like online UPS?

[AlreadyTaken]

I'm looking to probably build something like this; https://www.mobile-solarpower.com/mobile-48v-system.html

the one above seem to be 10ms in ups mode which should be fine but i would still like to have more options since the video is about 1y3m old, better option might be available now?

I would like to be 100% sure that it can have a transfer time of under 10ms or can behave like online ups

it could be 12v or 48v,

 

[RCinFLA]

Most hybrid inverters can run in 'UPS' mode where the inverter is continuously active, sync'd up to grid, and running in parallel with grid.

AC input pass-through relays typically have a 3 to 5 millisecond release time.

When grid drops there is a momentary inverter overload as it tries to power the collapsing grid. This causes inverter to release pass-through relay connecting inverter/AC output to grid. Total typical time for glitch on AC output loads is 2-6 milliseconds depending on how the grid collapses.

Operating in this mode draws idle power for inverter all the time.

Only way to do better is to do double converter from grid to DC then DC to AC output. Only very mission critical typically use this method.

 

[DIYrich]

Sol-ark supposedly has 4ms transfer time. Double conversion has no transfer time.

 

[400bird]

You'll probably want to definite more parameters.
Midnite Rosie boasts a 0ms transfer time.

 

[Anx2k]

Voltronic makes some, part of their Axpert line of hybrid inverters, and they prominently list they're 0ms - they're one of the actual manufacturers, so just look for someone who OEM's them. I've used them and they work as advertised, nothing measurable when switching sources.

 

[AlreadyTaken]

i got some homework to do, thanks, keep listing the possible one

if it help my budget is about around 1k for the inverter/charger

 

[Rocketman]

Probably out of budget range - Victron Multiplus does an excellent job of UPS transfer - can’t tell…

 

[robbob2112]

Expertpower 2000w inverter/charger + batteries, mppt, and panels. They have a variety of voltages

'Under 5ms' switch time. I haven't tried to verify that time.

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[Oldphile]

You can't comply with UL1741 and function like a typical UPS. There are ride through requirements. In New England the inverter must stay connected for 2 seconds when less than 88% of line voltage and greater than 65%. The inverter is going to follow the line voltage down to 156 volts for 2 seconds.

 

[ConnerLabs]

Does UL1741 still apply if the inverter is running in zero export mode?

 

[DIYrich]

i got some homework to do, thanks, keep listing the possible one

if it help my budget is about around 1k for the inverter/charger

Good luck. How many volts and watts? Buy a cheap battery charger and inverter.

 

[DIYrich]

Does UL1741 still apply if the inverter is running in zero export mode?

Yes. It forces the inverter to stay online when excess power is being produced.

 

[AlreadyTaken]

Voltronic makes some, part of their Axpert line of hybrid inverters, and they prominently list they're 0ms - they're one of the actual manufacturers, so just look for someone who OEM's them. I've used them and they work as advertised, nothing measurable when switching sources.

do you have a list of the OEM one? i am not sure how to find them

i did a quick look at https://voltronicpower.com/en-US/Product/PV-Inverter/Off-Grid-Inverter and it some of them seem very interesting, depending the the price of course

 

[RCinFLA]

Midnite Rosie boasts a 0ms transfer time.

Midnite Rosie design is similar to SolArk and Deye. It is two 120 vac high freq inverters, series connected for 240/120vac, and has 60 amp pass-through relays.

They do not have zero transfer time.

All hybrid inverter in UPS mode have zero transfer time if defined as transfer time when AC input breaker in opened. However, since grid is phase master it may take several seconds for inverter to recognize AC input has gone open circuit. Recognizing AC input going open is one of the toughest things for hybrid inverter to do. Since inverter phase lock is slave to AC input the inverter freq/phase starts to drift when AC input goes open circuit.

99.99999% of time when grid goes down it collapses to low impedance with near zero voltage. Inverter has to recognize this (with current overload on inverter) and command pass-through relay to release. That is not zero time.

 

[Anx2k]

do you have a list of the OEM one? i am not sure how to find them

i did a quick look at https://voltronicpower.com/en-US/Product/PV-Inverter/Off-Grid-Inverter and it some of them seem very interesting, depending the the price of course

MPPSolar OEM's them for sure, so here's one of the 0ms ones (I wish I could find them on voltronic's site, but it's trash - if you contact them they'll send you a product pdf that is much better than their website ironically):

MPP Solar Inc » PIP-LV-MK SERIES – ZERO TRANSFER TIME

www.mppsolar.com

and they have 12/24/48v variations of it - I've used both the 24v and 48v variants, and they work as advertised.

 

[mciholas]

You can't comply with UL1741 and function like a typical UPS. There are ride through requirements.

I suspect this only applies to the grid connection.

The load connection can change over to battery and the inverter still comply with the chart you posted.

Even if the chart also applies to the load side, the lower left corner, voltage under 30% of nominal, allows for a grid loss to transfer essentially instantly.

Transfer times of 4 to 20 ms are generally reported for hybrid inverters for the load side to pick up after the grid fails. The Amensolar N3H-10K-US inverter in our setup meets that. When grid fails, there is a very brief flicker on the load side and then it picks up. The computers, clocks, etc, ride through this and don't reset. The flicker is generally only visible in LED bulbs. Other hybrid inverters are similar.

Double conversion (AC to battery, battery to AC) is zero transfer time and isolates you from various AC anomalies, but will cost you about 10% more energy due to the conversion efficiency.

Mike C.

 

[Oldphile]

I suspect this only applies to the grid connection.

The load connection can change over to battery and the inverter still comply with the chart you posted.

Mike C.

The inverter is always connected to the load. If the grid is connected, then it is connected to the inverter and the load. If it's a brownout condition (>65% of line voltage), the inverter must remain connected for 2 seconds. The inverter will follow the grid voltage. A UPS typically will drop the grid at 88% of line voltage.