Sunsynk 'Load' (UPS) limit when grid working?

[sol4096]

Hi,

TL;DR: does the Sunsynk inverter 5000W UPS limit all the time (including when the grid is fine, no outage), or only during grid outage? and would I risk damaging the inverter if I did go over 5000W?

Longer version with more context:

I am having a 5.5kW Sunsynk inverter (and solar panel and battery) being installed at my house at the moment (exiting! ). I will make use of the 'load' port for the UPS function -- the installer will wire that on Monday. To give an idea of my consumption, I peak at 16kWh / day, and the max I have seen on 30min consumption (which is what my smart meter reports) is 2620Wh (but I imagine there may be much higher short peaks hidden in the 30min sampling?).

However it looks like my fridge/freezer, which I do want UPS for, is on the same socket ring as big consumers in my kitchen and utility rooms: washing machine (mostly used at low temperature, e.g. 30C or 40C), (efficient heat-pump based) tumble dryer, 1000W microwave, kettle. I don't need UPS for them, and I would happily not use them during a grid outage (if only to have longer battery life for the real essentials!). I am not sure what is the peak usage of each of them, but I wonder if all combine may make me go over the 5000W limit of the 'Load' (UPS) port on the inverter.
Any view on that?

Now Looking at this diagram from Sunsynk:

I wonder if the 'Load' is served from the Grid in a normal situation, in which case possibly the 5000W limit only applies when there is a grid outage (in which case I should be fine?): is this the case?

Final question: if the UPS usage did go over 5000W (while the grid is working fine, or during a grid outage), what would happen? would the inverter cap at 5000W or disable itself, causing a power outage on things plugged on it, but without causing damage on the inverter? or in other words, how careful should I be about never going over that 5000W limit?

Thanks!

 

[houseofancients]

your installer should make a disctintion between essential loads ( ups) and non essential .

non essential can stay on grid port, and will not overload your inverter, provided the installer install ct clamps/meters

you essential load should not exceed 5,5 peak.

your installer should be aware of this

 

[sol4096]

Thanks @houseofancients .

yes my installer already installed a ct clamp on the grid wire between my meter and consumer unit.
They will leave most rings on the main consumer unit, i.e. directly on the grid. The question is what do I ask them to move to the (essential) 'Load' (i.e. UPS) port on the inverter.

I have identified the ring circuits to move to the UPS, however the one that has my fridge/freezer has quite a few power-hungry appliances, hence my question.

Basically I think my choices are:
1) If the 'Load' (UPS) port of the inverter is actually fed from grid in normal times and can go over 5000W when not on UPS, and going over 5000W when on the UPS port when there is a grid outage wouldn't damage the inverter but simply cut the power, then I can put the ring with my fridge/freezer on the backup port.
2) otherwise I can't have the ring with my fridge/freezer on the UPS port (and maybe at some point in the future get it rewired to be on a separate ring which could then go on the UPS port)

 

[houseofancients]

i think option 2 would be best, as the inverter shutdown on high load cannot be good for the contactors on the inverter

it really all depends in how stable your grid connection is

another option would be to move some of the high loads off that ring

 

[sol4096]

Thank you. I also asked Sunsynk but I didn't get an answer.
I went for option 2 to be safe. For now I can temporarily put my fridge/freezer on an extension lead to a plug in my garage, which is on the UPS (or rather Emergency Power Supply - EPS) port of my inverter.

To answer myself, and in case it is useful for someone else in the future:

• the load on my kitchen+utility socket ring is pretty easily above 5000W at peak time. The kettle take about 3000W, the oven too (when I start it), the 1000W microwave actually use quite a lot more (not very efficient). So, 2 appliances at the same time takes me to over 5000W.

 

[LydMekk]

You should have bought a bigger model inverter. You are at the edge of capacity as it is.
Can you talk with your supplier and pay for an upgrade in size?
And btw. emergency panel load is not your whole kitchen. Maximum an outlet to boil water.
It is lights, heat in the salon, water pumps, garage door opener etc.

 

[sol4096]

@LydMekk what makes you say my inverter is too small for me? how would I decide how big it should be?
Were you basing this on peak usage?

If so, it may be more cost-efficient to size for 90% of the time, and accept that during the remaining 10% of the time a portion of my electricity comes from the grid, rather than having a bigger system to make sure it can always cover my peak usage?
(I find all this hard to reason with / calculate!)

 

[Fingers]

The kettle take about 3000W

13amps going through a kettle.
We had one of those kettles, and the socket burned out; twice.
We changed to a 2000w 9amps, we didn't see any difference in boil time. No more burn outs

As we have grid tie, we have got used to using only one utility at a time, washing machine, tumble dryer, dishwasher etc.

 

[Fingers]

Edited:

Sorry to hijack your thing here.

I didn't twig it before, I just went along with what the contradictory manual said, 40 amp mains breaker, and 40amps ups!
35amps ups depending on where in the manual you read it.

How can this be if in a power cut we are limited to 5000 watts, 21.7amps? If we try to use more than the 21.7amps will it damage the inverter?

Shouldn't we be using a 20amp breaker on the ups (stand alone) side?

If so, in a blackout we need a contactor to switch from a 35amp ups pass through breaker, to a 20amp ups (stand alone) breaker. We would need one Normally open & Normally closed contactor for this (one contactor does both open and closed). Also use this for the neutral earth bond.

https://www.aliexpress.com/item/32790903155.html?spm=a2g0o.productlist.main.21.449a7f69Wx61xx&algo_pvid=cacb9c81-1097-47f6-b5b4-de40cd2be7ea&algo_exp_id=cacb9c81-1097-47f6-b5b4-de40cd2be7ea-10&pdp_npi=3@dis!GBP!6.78!5.76!!!!!@214527c616865750028743719d0723!63498887744!sea!UK!0&curPageLogUid=FgHiUB4kBH6a