Hi Gents ..

Lurking for some time now and I've finally got the balls to start my diy project .. 

I've got a sunsynk 5kw inverter and a sunsynk 5kw battery with it . I am NOT using solar at this stage and purely want to use my inverter as a ups during load shedding to power some essential circuits ie. Lights and plugs . I'm planning on installing tomorrow but need some last minute clarifications and I believe you lot of knowledgeable folks are my best bet

1. Do I need to use the temp sensor when using a Li-ion battery ?

2. The dreaded neutral earth bond that seems to be confusing a lot of people(including me). Do I need to hook up this relay if using inverter as a ups and also do I need a dedicated earth spike to feed neutral to earth via the relay or can I take earth from my grid supplied earth ?

3. Does the grid supply to inverter get taken before or after main db earth leakage?

4. CT coil needed when using as ups ?

5. Ac surge protection to inverter.. does this get connected on the grid side input to inverter ? 

6. For a 5kw system is a 25a double pole isolator sufficient to feed the inverter "grid" supply ?

7. The PE marking on the inverter "grid" and "load" connections .do these just go to my normal grid supplied earth ? 

 

Apologies in advance for all the noobish questions.. I'm an auto electrician by trade and the transition from DC work all day everyday to doing AC work is a bit confusing..lol 

I'll appreciate any extra advice 

Thanks in advance ☺️ 

 

1. No.

2. Yes. Use supplier earth. 

3. Before.

4. Yes.

5. Yes.

6. I would use bigger.

7. Yes.

 

 

10 hours ago, Shafo said:

6. For a 5kw system is a 25a double pole isolator sufficient to feed the inverter "grid" supply ?

25A at 220v / 240v is just under 6000w. This means that the circuit wont be able to cater for any momentary spikes (i.e. a pool motor engaging)

35A is just over 8000w. You are under the 10 000w spike limit of the inverter, you are protecting your inverter and should be safe / safer from nuisance tripping.


 

10 hours ago, Shafo said:

4. CT coil needed when using as ups ?

Technically no, you dont if you are not planning on using bi-direction power on the grid supply. As it is a UPS and this feature is disabled when there is no active grid from my understanding and it would be pointless to leave it activated when your power source is the grid.

As a safety measure, it would be good as this would help protect your Electricity Meter and Eskom from feeding back / exporting if some settings were changed after initial configuration.

 

10 hours ago, Shafo said:

3. Does the grid supply to inverter get taken before or after main db earth leakage?

Just be aware there are very specific regulations for cabling of things before the earth leakage. This is for your households safety.  I have just installed a Sunsynk my self and had issues with the earth leakage and the regulations require the non-protected cables to be a surface mounted in trunking or conduit or a certain depth in the wall. Basically the idea is that you dont drill into the cable and fry yourself without knowing it is there.

Having said the above, my installation only tripped the earth leakage when the inverter "booted" up for the first time from scratch (or when my solar panels got wet). It never was an issue when changing between grid and batteries. It may be worth testing before removing the Earth Leakage protection.

Edited July 2, 20224 yr by Jay-Dee

Thank  you so much for clearing this up Gents.. much appreciated 

 Thanks again for the advice Gents.. ive managed to get this far .. also please excuse my dc isolators..lol .. all I could find at my shop  

Edited July 3, 20224 yr by Shafo

1 hour ago, Shafo said:

 Thanks again for the advice Gents.. ive managed to get this far .. also please excuse my dc isolators..lol .. all I could find at my shop  

Looking good!!

And done ... all working just fine ! 🙂 

@Shafonice install…

did you land up connecting the main supply for the inverter before or after the earth leakage from your main DB 

3 minutes ago, Derek Ramos said:

@Shafonice install…

did you land up connecting the main supply for the inverter before or after the earth leakage from your main DB 

Before.. I tried after the el but it tripped as soon as grid supply was restored ..