EPS/UPS from batts/hybrid inverter

Adokforme
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Joined: Sun Sep 19, 2021 10:09 pm

Re: EPS/UPS from batts/hybrid inverter

#11

Post by Adokforme »

Tinbum wrote: Sun Sep 08, 2024 3:25 pm page 16 onwards https://files.sma.de/downloads/SI44M-80 ... -en-10.pdf
Thanks again @Tinbum. I've read it through a couple of times now although I'm struggling to fully understand it. From the lines taken below I'm encouraged to learn I could set it up myself but it then states "The automatic transfer switch is not a distribution board for the loads or the PV system. You must also install the necessary protective devices for the loads and the PV system".
Excuse my ignorance here but are you able to advise what the protective devices might be please?
You can set up and wire the automatic transfer switch yourself or acquire it pre-wired from another provider (see
Planning Guidelines "SMA Flexible Storage System with Battery Backup Function" at www.SMA-Solar.com).
Connection of loads and the PV system
The automatic transfer switch is not a distribution board for the loads or the PV system. You must also install the
necessary protective devices for the loads and the PV system
Tinbum
Posts: 1073
Joined: Mon May 31, 2021 9:55 pm

Re: EPS/UPS from batts/hybrid inverter

#12

Post by Tinbum »

The SMA document is specific for the SMA sunny Island set up but use it as a general idea of how to do the actual transfer of the EPS.
(Your PV won't be connected to the EPS output, but in the SMA set up they are).

The important part is the part marked 'Grounding Device'- this shows the neutral earth connection and how it changes depending if your load is 'On Grid' or on 'EPS'. The other document I linked to shows well if it is required depending upon your grid supply, ie TT, TN etc

Protective devices will be your Distribution board for your EPS loads, eg miniature circuit breakers RCD etc.
85no 58mm solar thermal tubes, 28.5Kw PV, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, 8kWh Growatt storage, 22 x US3000C Pylontech, Sofar ME3000's, Brosley wood burner and 250lt DHW
Adokforme
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Joined: Sun Sep 19, 2021 10:09 pm

Re: EPS/UPS from batts/hybrid inverter

#13

Post by Adokforme »

Thanks again Tb, most helpful. From it I deduce our earth supply to be TT. It was installed, with my assist by our local heat pump engineer who's been very helpful and co-operative but rather tide up currently hence my interest in making further progress, if only in preparation. As you point out ours isn't and SMA installation so it may well be that other similar products exist that I need to explore.
I had the Leaf five years before V2H finally became available to us so guess another few months until EPS arrives is but a minor delay in comparison. ;)
sharpener
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Joined: Fri May 20, 2022 10:42 am

Re: EPS/UPS from batts/hybrid inverter

#14

Post by sharpener »

AE-NMidlands wrote: Sun Sep 08, 2024 1:33 pm Hello all
My Givenergy inverter datasheet has a section about its backup terminal. Says:

Nominal AC output power 3600W
Nominal Voltage 230Vac
Max output current 16A
nominal frequency 50 Hz
Automatic switch time 10 ms
THDv (linear load) 3%

Given the elaborate independent earthing requirements for systems running in off-grid mode, are there rules about how this can be used? Or is there a dispensation for just 1 socket run off it? 3600W is the full output of the inverter! If there is an automatic switch-in, then does there have to be an automatic switch-over to a separate earth? and if so, how would it be sensed as relying on comms from the inverter wouldn't seeem to be fail-safe!
PMFJI, others have already said quite a lot but this link https://electrical.theiet.org/wiring-ma ... e-systems/ is really useful and more or less from the horse's mouth.

As I recall from an earlier thread the EPS output on yr GivEnergy was not properly compliant for the UK market, unless they have recently added an automatic neutral bond arrangement. The problem is that you cannot add a permanent bond bc it upsets the RCDs. I suppose you could do it with an external contactor driven off the EPS output. In that case you could use a 4-pole contactor and switch your essential loads between the Normal and EPS outputs as well.
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8 x 405W Longi panels, 250/60 MPPT, 3.3 MWh/yr
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Krill
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Joined: Fri Sep 02, 2022 4:38 pm

Re: EPS/UPS from batts/hybrid inverter

#15

Post by Krill »

So a bit of an update on Luxpowertech inverters.

There was a powerful at my home at 1833. I saw the lights flicker but thought nothing of it. I was gaming at the time and the Internet was solid.

The PC, server, and raspberry pi I have running didn't even blink. That is above the expected quality, I expect them to all crash but it switched over to EPS quickly enough they all worked fine (that said they do have top class PSUs in them).

For context the entire house minus the ovens are on the EPS circuit.

Got to give it to the LXP inverters here.
Solar PV: 6.4kW solar PV (Eurener MEPV 400W*16)
PV Inverter: Solis 6kW inverter
Batteries: 14.4kWh LiFePO4 batteries (Pylontech US5000*3)
Battery Inverter: LuxPowertek 3600 ACS*2 battery inverter
WBS: 8kW Hunter Avalon 6 Multifuel burner (wood only)
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