Feeling like a toddler in a A380 cockpit trying to land in a driveway.

I have the following settings, will this work or have I programmed it to self-destruct our little village?

Please help.

I would like the panels to charge the battery to full then use it, utility to kick in when heavy equipment kicks in.

 

Equipment:

RCT 5KVA inverter

2.4Kwh/48v LFP Pylontech Lithium Battery

2 x 330w Solar panels

01          SBU

02          30A

03          APL

04          SDS

05          USE

06          LED

07          TED

08          0

09          50

10          0

11          2A

12          48V

13          51V

14          0

15          0

16          OSO

17          0

18          BON

19          EEP

20          LOF

21          0

22          AON

23          BYD

24          0

25          FEN

26          54.1

27          54.1

28          51G

29          47.5

30          ONE

31          SBE

17 minutes ago, Johan Smit said:

2.4Kwh/48v LFP Pylontech Lithium Battery

Just one? That's a bit small for a 5 kVA inverter. You really need at least two 2.4 kWh batteries for an inverter like that.

17 minutes ago, Johan Smit said:

2 x 330w Solar panels

That's pretty light on. It will do for starters.

17 minutes ago, Johan Smit said:

02          30A

This should ideally be 25 A, but of course your choices are only 20 or 30. Your small panels won't generate that much current anyway. So keep the 30. When you go to two batteries, increase this to 50, not 60.

17 minutes ago, Johan Smit said:

26          54.1

27          54.1

Where do these really high voltages come from? I'd use 53.2 V max, and at most 53.0 for setting 27. Personally, I advocate 51.8 and 50.4 V respectively.

You may have to play with settings 12 and 13 to get the behaviour you want (switching to mains for heavy loads). Ideally, you should have ICC monitoring software with a shunt and BMV, and switch at SOC levels, not battery voltage levels. But that's a lot more cost and complexity; it seems you want/need to start small.

Thanks so much.

Yes im starting off, saving up for improvements later.

I will use your suggestions and report back.

 

On 2019/09/10 at 3:26 PM, Coulomb said:

Just one? That's a bit small for a 5 kVA inverter. You really need at least two 2.4 kWh batteries for an inverter like that.

That's pretty light on. It will do for starters.

This should ideally be 25 A, but of course your choices are only 20 or 30. Your small panels won't generate that much current anyway. So keep the 30. When you go to two batteries, increase this to 50, not 60.

Where do these really high voltages come from? I'd use 53.2 V max, and at most 53.0 for setting 27. Personally, I advocate 51.8 and 50.4 V respectively.

You may have to play with settings 12 and 13 to get the behaviour you want (switching to mains for heavy loads). Ideally, you should have ICC monitoring software with a shunt and BMV, and switch at SOC levels, not battery voltage levels. But that's a lot more cost and complexity; it seems you want/need to start small.

my king also only has 1 x 2.4 pylontech on it, besides for the obvious downside of being able to deplete it much faster is there any negative impact of having a smaller bank on the inverter? i can't seem to think there would be?

 

from my experience on my system i would change

26 - 53.2
27 - 52.0

Edited September 10, 20196 yr by Dex_

Thanks for the inputs.

The system was supposed to just help us through load shedding,  but runs our small house for about 5 hours.  After I took many power reduction strategies.

So I get a similar output as when I had 4 x 105Ah batteries, but without the hassle.  In hind sight I should have gone for the 2.5 Battery, but it always feels like a lot of money if one is not that sure.

I found a lot of solar companies are happy to sell, but then never want to hear from you again.

This information provided is like gold to a beginner like me.

Thanks

10 hours ago, Dex_ said:

my king also only has 1 x 2.4 pylontech on it, ... is there any negative impact of having a smaller bank on the inverter?

Just as you're supposed to limit charging to 25 A (1250 W), you're only supposed to routinely draw 1250 W from the battery (so ~1150 W load). With a 5000 W inverter, it's so easy to exceed this value. I believe that's the reason for the inverter-charger manufacturer's minimum battery size recommendation.

As long as you're careful to keep the loads low enough for the most part, that should not be a problem. LFP batteries generally don't mind even 3C discharges on occasion, but I think the BMS cost would be too high allowing that sort of current through the internal MOSFETs (which disconnect the load if the battery is stressed).

Thanks for advice, guess Ill have to save up for bigger battery.

 

 

I guess I could add a Pylontech US3000 3.5kWh 48V Li-Ion to my current

Pylontech US2000 2.4kWh 48V Li-Ion with no problems???

50 minutes ago, Johan Smit said:

I guess I could add a Pylontech US3000 3.5kWh 48V Li-Ion to my current

Pylontech US2000 2.4kWh 48V Li-Ion with no problems???

they do apparently work fine together from what i have read

Just got a low voltage alarm (04) at 49.7v

What did I do wrong?

 

Current settings

01          SBU

02          30A

03          APL

04          SDS

05          USE

06          LED

07          TED

08          0

09          50

10          0

11          2A

12          48V

13          51V

14          0

15          0

16          OSO

17          0

18          BON

19          EEP

20          LOF

21         0

22          AON

23          BYD

24          0

25          FEN

26          53.2

27          53

28          51G

29          47.5

30          ONE

31          SBE

16 hours ago, Johan Smit said:

Just got a low voltage alarm (04) at 49.7v

What did I do wrong?

Not really "wrong", so much as a nuisance. The battery voltage must have dipped to 49.5 V, 2.0 V above the low battery cutoff setting (setting 29, 47.5 V). Just change setting 29 to be lower, say 45.5 V. Or run the LFP flavour of patched firmware. You did not state your exact RCT model, I'm guessing that you are eligible for patched firmware version 72.20e (if PF1.0) or patched firmware version 73.00e (if PF0.8).

Edited September 14, 20196 yr by Coulomb
Might be 72.20e.

agree with Coulomb, nothing wrong and imo nothing serious to worry about. i get a battery alarm if a high load current dips the voltage also.

1 hour ago, Dex_ said:

nothing serious to worry about. 

Sure, but I think it's well worth trying the lowering of setting 29. The BMS will take care of low battery and cell voltages much better than the inverter-charger with its lead acid thinking.

Edit: also, I believe that low battery warnings will also trigger bypass mode, costing money needlessly.

Edited September 14, 20196 yr by Coulomb

1 hour ago, Coulomb said:

Sure, but I think it's well worth trying the lowering of setting 29. The BMS will take care of low battery and cell voltages much better than the inverter-charger with its lead acid thinking.

Edit: also, I believe that low battery warnings will also trigger bypass mode, costing money needlessly.

yeah no i can agree with you.

regarding the switch to bypass though I don't beleive the battery warning is enough to do that, only once it actually hits the 29 setting voltage

Changed 29 to 45.5v

Instantly  fixed the alarm problem.  Will see if I can update the software.

Ps. RCT inverter RCT-AXPERT 5K

16 hours ago, Johan Smit said:

Ps. RCT inverter RCT-AXPERT 5K

Unfortunately, the reseller hasn't been helpful with the model numbering. From some quick web searches, this model number could refer to a PF1.0 unit (5 kW) or an older PF0.8 unit (4 kW); both are rated at 5 kVA. Which one it actually is determines which patched firmware you need. Fortunately, it won't let you upload the wrong one (for this combination; other combinations it will happily let you do, and you end up with a bricked machine).

Sticker on side.

Will add 2 more pics , but I think its an PF0.8 (2015)

 

1 more pic

I had another lov voltage alarm this morning so made some small tweaks, but am now ready for the update.

 

PF0.8 as I can figure out.?

Thanks

 

46 minutes ago, Johan Smit said:

I had another lov voltage alarm this morning so made some small tweaks, but am now ready for the update.

 

PF0.8 as I can figure out.?

Thanks

 

5KVA x 0.8 = 4000W so yes 0.8 PF

9 hours ago, Johan Smit said:

PF0.8 as I can figure out.?

As above, yes. So you can update to the LFP flavour of patched firmware version 73.00e.

Hi Johan Smit. If I may ask. Did you have to update any firmware on that 2015 model to use Lithium batteries? I have a unit that I bought in 2015/16 and want a professional company to install but I would prefer lithium batteries. not sure if it is compatible?

 

thanks,

Derrick

11 hours ago, Derrick said:

Hi Johan Smit. If I may ask. Did you have to update any firmware on that 2015 model to use Lithium batteries? I have a unit that I bought in 2015/16 and want a professional company to install but I would prefer lithium batteries. not sure if it is compatible?

While we wait for @Johan Smit to reply, I'll just add that I'm running a pair of 2015 models on a lithium battery (home built). I run patched firmware, (I'm co-author), as it's pretty frustrating running without the patches. It can be done, especially if you are running ICC as well. 

Hi Derrick, sad to say no.

It needs a serial port to connect to PC. Cable came with inverter but to find a pc that still has a serial port that has not been converted to a media port is not easy.

Apparently there is a company in JHB who can do the update, but then Ill have to box it and courier up and down.

So as I'm using my system as a UPS anyway I decided to rather buy a new inverter sometime in the future.

Good luck, its very frustrating.