Hi there

Recently got my inverters installed.

 

Parallel 2 x  Axpert 5Kva MK II

48v (4 x 12v Gel) 

6 x Canadian solar 365w (Connected in series) - PV only going to 1 inverter

 

With stage 4 load shedding we had 3 intervals of 2 hours each without power today. I understand that 4 x 12v batteries is not going to allow me max out my potential 10kw.

Today the power went out at 15:30 with 30 mins of load shedding left for the day. I went to my inverter to find zero output and see that the panels were charging the batteries.

Battery voltage was sitting at 42V.

To my understanding , I reached DC cut off voltage?

But my solar was still giving me 270V so why didn't solar take over power supply to the house and charge the batteries at the same time?

 

My settings

01 SOL

02 30A on each inverter

16 CSO

 

Is there anything that I can change to make it work so that Solar takes over powering the house when available?

 

I have taken photos of whats going on with my inverters when the power cut off completely and when it came back on

 

 

 

 

 

At 30A charging, it will mean the first 1300 Watts from the solar panels will go to charging the batteries and then only the excess will go to powering the house. If I am not mistaken your batteries have to be at 42V + 2v = 44V before your inverter will allow excess PV watts to power the load as well.

12 minutes ago, GVC said:

At 30A charging, it will mean the first 1300 Watts from the solar panels will go to charging the batteries and then only the excess will go to powering the house. If I am not mistaken your batteries have to be at 42V + 2v = 44V before your inverter will allow excess PV watts to power the load as well.

Thanks GVC. Is there a setting I could use to give priority to powering the house from solar and charging the batteries as 2nd priority?

I am sure there is on the MK 11. I am however, not at all familiar with the newer models settings. I still have the 2015 model.

Someone will come along shortly to give you the correct settings. 

 

Would changing program 16 to SNU (Solar and Utility to charge battery at the same time) help?

Battery would perhaps charge in less time during Stage 4 load shedding.

16 hours ago, ShaunKZN said:

I understand that 4 x 12v batteries is not going to allow me max out my potential 10kw.

Definitely. You didn't say what capacity those battery modules are. If they are only 100 Ah, then that's only a quarter the recommended battery capacity (for 2 inverters).

Quote

Today the power went out at 15:30 with 30 mins of load shedding left for the day. I went to my inverter to find zero output and see that the panels were charging the batteries.

Battery voltage was sitting at 42V.

To my understanding , I reached DC cut off voltage?

It depends on your settings. 42.0 V is the default setting. I would not recommend leaving it that low; I would raise it to 48.0 V to save your battery modules. Unfortunately, this will roughly halve your run time. You simply don't have enough battery capacity for your loads and and length of the load shedding. As I've posted elsewhere, the low DC cutoff setting isn't intended for regular load shedding situations, it's a "save the silver" emergency measure. So the default of 42 V is way too low for this situation.

 

16 hours ago, ShaunKZN said:

Is there anything that I can change to make it work so that Solar takes over powering the house when available?

There is (slightly), but it will murder your battery even faster. In practical terms, no. You need more battery capacity, or less loads during load shedding. Sorry.

16 hours ago, GVC said:

If I am not mistaken your batteries have to be at 42V + 2v = 44V before your inverter will allow excess PV watts to power the load as well.

Actually, once declared "under" (under the cutoff voltage), the battery stays in quarantine (i.e. can't power loads) until it reaches 0.5 V less than the float voltage setting. At lead acid defaults, this is 54.0 – 0.5 V = 53.5 V. Edit: it's my understanding (from reading the firmware, not from practical experience, so actual users please correct me if I'm wrong) that only at this point (when no longer declared "under") will the inverter come back on and the battery (and hence PV) will be allowed to power the load.

Edited March 12, 20205 yr by Coulomb

Coulomb thanks for that explanation. 

The batteries are 200ah. I think I'll get 2 more to help sustain powering the house during these times.
Cost wise I'm also considering Pylontech. Any advice on how many 3.5kw Pylontech I would need to replace 6 or 8 200ah batteries?

I have changed Program 16 to SNU to help for now. Also thinking of adding 2 more panels.