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What am I doing wrong. Axpert switched to utility


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Hi @kobus joubert,

Since you have ICC, why don't you (also) dabble into the Emoncms world. Then you can plot graphs that shows the relationship of what's happening on the inverter Battery wise. Plot SOC, volts & Amps, in relation to PV, load and grid. ICC give you half of that graph, as seen above, the rest you need to create yourself. Maybe a of a struggle to get the first one going, but this way you can visualise a whole lot more than what ICC can.

From the graph above, you are probably nearing the capabilities of your battery @ around 3000W. That about 62A draw from the battery, which could be above the spec of the Battery. Pylons like about 25A per bank (charge/discharge), if i remember. Hence @Coulomb's recommendation to lower the low voltage threshold, to help it sustain the load. I'm my opinion that could solve it, but may introduce new issues - like too low a voltage per cell on the battery, damaging the battery over a long period. So it may only be a temp solution.

Long term adding a second bank is probably best.

What concerns me more, is why is your PV not ramping up (after a few seconds) to carry the load, even from the time the 2kw load is introduced,  never mind when the extra load is introduced just before the switch? Maybe also something to look at.? You PV seems capable of getting close to that.

Edited by Sidewinder
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Kobus also consider changing the charger source priority over to Solar only. Its on solar and grid currently. It could be that the current (before it ramps up) available solar power isn't enough to power the load and charge the batteries. It could be that this setting is triggering the batteries to be charged from the grid and not the load directly causing the change..  

Edited by root
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1 hour ago, Sidewinder said:

Hence @Coulomb's recommendation to lower the low voltage threshold, to help it sustain the load.

No, actually it's because of an undocumented behaviour that I was hoping to avoid explaining yet again. The factory firmware considers any battery voltage lower than 2.0 V above the battery low voltage cutoff setting (setting 29) to be a "battery low" condition. There will be a low battery warning, but also if in battery mode and AC-in is available, it will switch to bypass mode (where the AC-in supplies the load). This makes sense for a lead acid or most lithium based chemistries, but not LFP (LiFePO₄) chemistry, with its very flat voltage versus SOC curve. PylonTechs of course contain LFP cells.

The PylonTech packaged battery contains a BMS that will protect the cells from low voltage; it will do a much better job than the inverter, since it has access to all the cell voltages. The inverter obviously only sees the total battery voltage. So lowering the cutoff voltage setting isn't about risking the battery longevity, it's about preventing the firmware from trying (and failing) to be helpful. Lowering the cutoff setting just stops the firmware from being over-protective. If you really had a lead acid battery with those settings, then it would be appropriate to switch to utility power, to save the lead acid battery from excessive discharge. But when the battery is a PylonTech or other LFP battery, it just doesn't make sense, and the cutoff "feature" isn't required anyway (except as an extreme last resort perhaps, so no need to set it really low, like 40.0 V). 46.0 V is still over 3.0 VPC, which isn't catastrophic for LFP cells anyway. 

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1 hour ago, kobus joubert said:

Remember I did the Kettle upgrade but killed an EXPERT  as our South African Experts cannot take your firmware.

? Perhaps you could start a new thread to sort this out. South African Axperts are no different to other Axperts, as long as they aren't clones.

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17 minutes ago, Coulomb said:

 

The PylonTech packaged battery contains a BMS that will protect the cells from low voltage; it will do a much better job than the inverter, since it has access to all the cell voltages. The inverter obviously only sees the total battery voltage. So lowering the cutoff voltage setting isn't about risking the battery longevity, it's about preventing the firmware from trying (and failing) to be helpful. Lowering the cutoff setting just stops the firmware from being over-protective. If you really had a lead acid battery with those settings, then it would be appropriate to switch to utility power, to save the lead acid battery from excessive discharge. But when the battery is a PylonTech or other LFP battery, it just doesn't make sense, and the cutoff "feature" isn't required anyway (except as an extreme last resort perhaps, so no need to set it really low, like 40.0 V). 46.0 V is still over 3.0 VPC, which isn't catastrophic for LFP cells anyway. 

Thanks for your time and explanation about the cut off voltage and the use of  Pylontech batteries , LFP cells. I use your recommended 46 v cutoff . If also have lower the charging rates like you recommend . ICC Pylontech check on on batteries is fine , temp cell balance and SOC . This is a offgrid installation . Will there be any negative impact to the cells if I don't discharge the batteries a lot . Normal use 70 % SOC . Only discharge more when raining or cloudy .

Thanks

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Thank you Coulomb.

Changing that little setting to be 2 Volt below the other FIXED my problem.

System is running again like it should.

Pity that these "SETTINGS" are not documented openly by the suppliers.

I run it on Solar and Grid because I only have one battery currently and we are still in our rainy season. Once I have my second battery installed by November I will change this back to solar only.

Thanks again.

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