Hi all. 

We recently had a solar system installed, but I'm not fully confident in the way it is currently programmed. It is mainly focusing to run on mains and it switches back to mains before the batteries reach 48V. The batteries are also being charged trough the mains during the night and by the time the panels kick in then the batteries are full. 

I was just looking into getting some tips and possibly some recommendations on the best possible setup/settings for the inverters. 

 

Installation :

2x 48V 5Kw Axpert Inverters connected in Parallel 

18x 270W Solar panels

3 x 100ah (300AH total) 48V Averge Lithium Batteries 

 

I'm looking into utilizing the system to it's full potential to try and get of the grid as much as possible. Looking into expanding the battery capacity down the line also. 

 

The Geyser, swimming pool pump, stove/oven, and one Aircon is still connected to the mains. 

 

The installed system is currently carrying the plugs, lights, fridges and then a Inverter Aircon. 

Will the connected Inverter Aircon be a problem? 

 

Will appreciate any input to try and maximize this system. 

Please find attached the battery specs. 

 

Thank you 

1 minute ago, William2805 said:

Averge Lithium Batteries

Sorry to derail your thread but I am pretty sure if it says Averge you might have stolen telecommunication batteries.

Its been said on here a lot but that Carte Blance piece a while back made it clear that Averge don't sell to the public, I am not sure if that has changed since then, but maybe ask your installer where he bought them from just to give you peace of mind. 

Also want to add that the inverters signal a low battery warning when the batteries reach 48-48.5V. But the charge level indicator on the battery is still showing 4/4 (full) 

Averge are currently selling to the public. I phoned them to confirm that these batteries are legitimate. 

Edited April 5, 20205 yr by William2805

17 minutes ago, PJJ said:

Sorry to derail your thread but I am pretty sure if it says Averge you might have stolen telecommunication batteries.

Its been said on here a lot but that Carte Blance piece a while back made it clear that Averge don't sell to the public, I am not sure if that has changed since then, but maybe ask your installer where he bought them from just to give you peace of mind. 

Hi. PJJ.

Averge are currently selling to the public.

 

I phoned them and confirmed that the batteries are not stolen and they confirmed that the installer bought directly from them. 

 

The publicly sold batteries are branded differently and are labeled as Averge Solar Batteries. Not Averge Telecommunications Batteries. 

Any help would be greatly appreciated please 

12 hours ago, William2805 said:

The batteries are also being charged trough the mains during the night and by the time the panels kick in then the batteries are full. 

It sounds like it's running loads from utility all night; is that correct? I'd check setting 01; if it's SOL (might be called something else; you didn't say exactly what model inverters you have) then you can change it to SbU to use the battery more and the mains less.

12 hours ago, William2805 said:

Will the connected Inverter Aircon be a problem? 

Depending on just how big it is and how much you use it, but generally a modest inverter based air conditioner should be fine.

It would help us a lot to tell us your values for these settings: 01 (Output source priority), 12 (Back to utility battery voltage), 13 (back to grid battery voltage), 16 (charger source priority), and 29 (low DC cutoff voltage).

On 2020/04/06 at 3:28 AM, Coulomb said:

It sounds like it's running loads from utility all night; is that correct? I'd check setting 01; if it's SOL (might be called something else; you didn't say exactly what model inverters you have) then you can change it to SbU to use the battery more and the mains less.

Depending on just how big it is and how much you use it, but generally a modest inverter based air conditioner should be fine.

It would help us a lot to tell us your values for these settings: 01 (Output source priority), 12 (Back to utility battery voltage), 13 (back to grid battery voltage), 16 (charger source priority), and 29 (low DC cutoff voltage).

Morning. Thanks for the reply. 

Model Name on Inverters : 

SMD LynX 5000-48.

 

Program 1 was set that the utility is used @ night.  I changed it to Sbu.

 

Programs currently set. 

-1. Sbu

12.  Currently on 48V (adjusted it yesterday according to other posts I saw om the forum, installer set it to 49V)

13. Currently @ 51V (changed according to values ive seen on other discussions. Installer had it set to 53V.

16.  Cso

26. 53.2

27. 53.2V

 

29. 45.5 ( adjustment made according to values from other discussions. Installer had it set to 47V)

 

Aircon Specs : attached via photo. 

 

I'm completely new to the solar world. 

I'm also currently seeing that the panels are only bringing in +- 3 Kw. It is fairly sunny outside. Is the 3kw displayed what is left after the batteries are  taking their share to get charged? 

 

Sorry for all these questions... Just trying to get as much info as possible. 

 

 

 

 

 

2 hours ago, William2805 said:

Programs currently set. 

These all seem good, except for

2 hours ago, William2805 said:

13. Currently @ 51V (changed according to values ive seen on other discussions. Installer had it set to 53V.

I'd bring it down even further to 50 V, since you have 300 Ah of battery. Your battery voltage won't rise much from charge current; no need to nearly fill it from utility energy before using it.

2 hours ago, William2805 said:

26. 53.2

27. 53.2V

I know that the above are recommended values, but they're very high. Having 27 the same as 26 certainly avoids the premature float bug; if it goes to float too early, it doesn't matter, since it will be targeting the same voltage. You could take them down to as low as 51.8 V.

2 hours ago, William2805 said:

29. 45.5 ( adjustment made according to values from other discussions. Installer had it set to 47V)

With that setting (low DC cutoff voltage) set to 47 V, the low battery alarm would come on at 49 V, which is far too high, and therefore far too annoying.

2 hours ago, William2805 said:

Aircon Specs : attached via photo. 

Basically, it's about a 2 kW load, no problem for your setup.

2 hours ago, William2805 said:

I'm also currently seeing that the panels are only bringing in +- 3 Kw. It is fairly sunny outside. Is the 3kw displayed what is left after the batteries are  taking their share to get charged? 

I can never remember this, because it's poorly documented, and I use patched firmware, which may well be different. It will be either total PV power, or net PV power into the battery (i.e. what's left over after the the load takes its share).

You have just under 5 kW of nominal PV power. On a good day near noon, you should get some 75-80% of that, or about 3.6 - 3.9 kW, assuming good orientation, no shading, etc. At this time of year, it will be less than these figures, more towards 3 kW, and even less in winter. So 3 kW total isn't totally unexpected. I get about 3 kW from my nominal 5.65 kW arrays, but I do have shading issues, and I'm suspecting that I've lost one pair of panels (430 W nominal), possibly a blown fuse.

3 hours ago, Coulomb said:

Quote

26. 53.2

27. 53.2V

I know that the above are recommended values, but they're very high. Having 27 the same as 26 certainly avoids the premature float bug; if it goes to float too early, it doesn't matter, since it will be targeting the same voltage. You could take them down to as low as 51.8 V.

What would these changes affect? 

Like I said I'm new to Solar. 

Should I just set both 26 and 27 to 51.8V?

Am I correct in saying that the Float voltage is the amount of current needed to keep the battery in its tip top condition once it's fully charged, and ready to be used? 

14 hours ago, William2805 said:

What would these changes affect? 

Like I said I'm new to Solar. 

Life of the battery.

14 hours ago, William2805 said:

Should I just set both 26 and 27 to 51.8V?

You could. Or you could compromise with any value between 51.8 and 53.2 V.

14 hours ago, William2805 said:

Am I correct in saying that the Float voltage is the amount of current needed to keep the battery in its tip top condition once it's fully charged, and ready to be used? 

Voltage isn't current. Float voltage is merely the set point (where the solar charge controller) aims to keep the battery voltage after they are fully charged. So this is the voltage needed to maintain the battery at nearly full charge (e.g. 98.5%), while minimising time at high terminal voltages, where bad chemical reactions happen that reduce battery life. As loads deplete the battery, the battery voltage will reduce, and this is the signal to the solar charge controller to charge the battery more, to replace the small amount of energy taken from the battery and keep it nearly full.

In summer, the float voltage is where the battery will spend most of its time, and staying at a high battery voltage with high temperature is bad for battery life. So you could reduce the float voltage setting (setting 27) to as low as 50.4 V, for longer battery life, and very little impact on battery run time.

But I note that most users of 15S LFP batteries ignore this advice and use the manufacturer's recommended 53.2 and 53.2 V figures. 

 

3 hours ago, Coulomb said:

Life of the battery.

You could. Or you could compromise with any value between 51.8 and 53.2 V.

Voltage isn't current. Float voltage is merely the set point (where the solar charge controller) aims to keep the battery voltage after they are fully charged. So this is the voltage needed to maintain the battery at nearly full charge (e.g. 98.5%), while minimising time at high terminal voltages, where bad chemical reactions happen that reduce battery life. As loads deplete the battery, the battery voltage will reduce, and this is the signal to the solar charge controller to charge the battery more, to replace the small amount of energy taken from the battery and keep it nearly full.

In summer, the float voltage is where the battery will spend most of its time, and staying at a high battery voltage with high temperature is bad for battery life. So you could reduce the float voltage setting (setting 27) to as low as 50.4 V, for longer battery life, and very little impact on battery run time.

But I note that most users of 15S LFP batteries ignore this advice and use the manufacturer's recommended 53.2 and 53.2 V figures. 

Thank you for a the useful information. 

It is really helpful to speak to someone, rather than having to search for  all the info on the internet and having to filter out if the info is relevant or just a bunch of false info. 

I really appreciate your help @Coulomb

 

I just had one last question for now. 

What is happening with the excess solar energy that the panels are producing? That is once the batteries are fully charged and your usage is under the generated amount? Will the excess energy be pushed back into the grid/utility ? Will the inverters just switch to batteries and leave the panels? 

37 minutes ago, William2805 said:

What is happening with the excess solar energy that the panels are producing? ... Will the excess energy be pushed back into the grid/utility ?

Generally, Axperts won't push power into the grid.

Quote

Will the inverters just switch to batteries and leave the panels? 

Yes, though in maintaining the float voltage, the panels will more or less supply the load power, if they have enough. If not, the battery supplies the shortfall, and hopefully the panels return that shortfall when load and solar intensity allows.

Any available solar energy that is not used as electricity basically just heats the panels a little.