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Mecer 5kva inverter setup problem


Christo van Zyl
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Assisting a friend, his MECER HYBRID 5kVA / 5kW Inverter Charger | SOL-I-AX-5P keeps on going into Battery mode during normal daytime with good sunshine conditions. He has a two Narada 48NPFC100 batteries connected. His solar panels are 6 x 535 Watts panels connected in 2S 3P.

With the setting 1 at SBU the unit should not go into Battery Mode with good solar conditions. (or SOL for that matter)

I have looked at setting 13 "Setting Voltage point back to battery mode when selecting "SBU priority or "Solar First" as the probable culprit. This is a battery voltage setting which is confusing to me as I do not understand the role/function of this setting for activating (point back) to battery mode. I have tried the "FUL", 48.0V, 54.0V(default) and the 58.0V settings but the inverter after resetting and starting up in normal SBU mode with solar connected and supplying power keeps on switching back to Battery mode after a while.

At this stage I am now becoming convinced there must be a firmware problem. Any help or suggestions would be highly appreciated

This inverter was bought through PClink, but who is the main distributors who can assist with this ?

 

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18 hours ago, Christo van Zyl said:

MECER HYBRID 5kVA / 5kW Inverter Charger | SOL-I-AX-5P keeps on going into Battery mode during normal daytime with good sunshine conditions. ...

With the setting 1 at SBU the unit should not go into Battery Mode with good solar conditions. (or SOL for that matter)

No, battery mode is the only way to power loads from solar power on these models (which don't have the SUB mode). Both SBU and SOL output source priorities go to battery mode unless the battery voltage is low.

How low is set by setting 12, back to utility battery voltage. When the battery voltage is lower than this setting, it switches to utility powering the loads.  But then solar energy has nowhere to go other than to charge the battery. Once the battery is full enough, as determined by setting 13, the back to battery voltage, the unit switches back to battery mode, so that solar power can power the loads again.

It sounds like you want to keep the battery as full as possible for load shedding. In that case, consider SOL output source priority (setting 01), which will switch to line mode (utility powers load directly) at sun down. You can configure it to charge the battery from utility to top up that last 10% or so that powered loads just before sundown. Keep setting 12 high, so that it switches to grid when the battery is still fairly full, and setting 13 also high, probably "FUL" which means wait till the solar charge controller enters the float stage before going back to battery mode.

Operating like this means that the battery will discharge a little, depending on loads, clouds, and time of day. But with settings 12 and 13 high, this should be quite minor in even the worst case.

My understanding is that there are a few Mecers with the SOL-I-AX-5P that are actually Axpert Kings, with the zero transfer time, and removable display at the bottom centred left to right. In that presumably rare case, you can blend AC-in and solar smoothly, and keep the battery quite full. 

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Thank you for the response.

First question what is the SUB mode ?

Manual setting 1 states :

Solar energy provides power to the loads as first priority.
If solar energy is not sufficient to power all connected loads, battery energy will supply power the loads at the same time.

So your comment that the the SBU and SOL output source priorities go to battery mode unless the battery voltage is low is not making sense, I want to use the solar power during daytime, go to battery power during night or cloudy conditions and lastly to Utilities when battery is drained.

In Battery mode the battery supplies the inverter load, wasting good solar energy which then seems to be disconnected. I want the battery only to operate when no solar is present, as per the setting 1 SBU priority

 

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2 hours ago, Christo van Zyl said:

First question what is the SUB mode ?

Sorry, I was confusing the issue. SUB is this priority for loads: Solar, then Utility, then Battery. The special thing about this priority is that it can blend AC-in and PV power.

Quote

Manual setting 1 states :Solar energy provides power to the loads as first priority.
If solar energy is not sufficient to power all connected loads, battery energy will supply power the loads at the same time.

Note what it's saying at the end: if there is a shortfall of PV power, the battery will supply the shortfall. Not all the load power, just the shortfall. If the shortfall becomes large, then the battery will discharge, the battery voltage will drop, and when it reaches the level in setting 12 (back to grid battery voltage), loads will instead be powered 100% from AC-in, and solar power will go to charging the battery back up.

Quote

So your comment that the the SBU and SOL output source priorities go to battery mode unless the battery voltage is low is not making sense, I want to use the solar power during daytime, go to battery power during night or cloudy conditions and lastly to Utilities when battery is drained.

Battery mode is how you use solar power to power your day-time loads. On these models, the solar charge controller connects directly to the battery terminals (via only a fuse). When there is sufficient power from solar, the power for the loads "bypasses" the battery and goes straight to the DC-AC converter and to the loads. So battery mode is the way that you achieve all the goals you listed: "I want to use the solar power during daytime, go to battery power during night or cloudy conditions and lastly to Utilities when battery is drained."

You seem to be under the impression that battery mode means that the battery powers the loads exclusively. In fact, in battery mode, PV and battery power combine to power the loads. When there is sufficient PV power, the battery will remain completely full and not discharge. Of course, there will always be the occasional cloud or shade, and the battery provides that shortfall, to be quickly replenished if there is enough solar power later.

In Battery mode the battery supplies the inverter load, wasting good solar energy which then seems to be disconnected. I want the battery only to operate when no solar is present, as per the setting 1 SBU priority

Edited by Coulomb
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Posted (edited)
On 2021/03/25 at 2:48 PM, Coulomb said:

Sorry, I was confusing the issue. SUB is this priority for loads: Solar, then Utility, then Battery. The special thing about this priority is that it can blend AC-in and PV power.

Note what it's saying at the end: if there is a shortfall of PV power, the battery will supply the shortfall. Not all the load power, just the shortfall. If the shortfall becomes large, then the battery will discharge, the battery voltage will drop, and when it reaches the level in setting 12 (back to grid battery voltage), loads will instead be powered 100% from AC-in, and solar power will go to charging the battery back up.

Battery mode is how you use solar power to power your day-time loads. On these models, the solar charge controller connects directly to the battery terminals (via only a fuse). When there is sufficient power from solar, the power for the loads "bypasses" the battery and goes straight to the DC-AC converter and to the loads. So battery mode is the way that you achieve all the goals you listed: "I want to use the solar power during daytime, go to battery power during night or cloudy conditions and lastly to Utilities when battery is drained."

You seem to be under the impression that battery mode means that the battery powers the loads exclusively. In fact, in battery mode, PV and battery power combine to power the loads. When there is sufficient PV power, the battery will remain completely full and not discharge. Of course, there will always be the occasional cloud or shade, and the battery provides that shortfall, to be quickly replenished if there is enough solar power later.

In Battery mode the battery supplies the inverter load, wasting good solar energy which then seems to be disconnected. I want the battery only to operate when no solar is present, as per the setting 1 SBU priority

"Battery mode is how you use solar power to power your day-time loads. On these models, the solar charge controller connects directly to the battery terminals (via only a fuse). When there is sufficient power from solar, the power for the loads "bypasses" the battery and goes straight to the DC-AC converter and to the loads. So battery mode is the way that you achieve all the goals you listed: "I want to use the solar power during daytime, go to battery power during night or cloudy conditions and lastly to Utilities when battery is drained."

Tested this with inverter in battery mode, no currrent from solar panels into the inverter, all the energy flows from battery only.

This did not make sense to say that normal operation mode is "battery mode". Re-set the inverter through total shut down then it goes into normal SBU operation with the solar panels supplying the current / energy.

Has put setting 13 at 58V for point back to battery mode, this is impossible to reach as all charging settings has been set at 54 Volt but it still after some time reverts back to "battery mode".

I am now convinced that we have a firmware problem. 

Edited by Christo van Zyl
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9 hours ago, Christo van Zyl said:

Tested this with inverter in battery mode, no currrent from solar panels into the inverter, all the energy flows from battery only.

Then that is the problem, not the fact that it's in so-called battery mode. What is the battery voltage at that point?

I note that the solar charge controller takes about a minute to ramp up to maximum charge current. The first 15 seconds it "charges" at zero current, the next 15 seconds at one amp or so (battery side), and slowly ramps up after that. Is it possible that you didn't wait long enough? It sounds unlikely, I'll agree.

Edited by Coulomb
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9 hours ago, Christo van Zyl said:

I am now convinced that we have a firmware problem. 

What is your present main (U1) firmware version?

Also U2 firmware version? It could be SCC firmware as well.

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