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Pylontech and 4 inverters sol-i-ax-5m


Leonvd
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Hi guys I need help. I have 4x Mecer SOL-I-AX-5M inverters in Parallel

48x Canadian Solar 275w Solar Panels (12 per inverter (3 per string in series))

5x usb2000b pylontec 2.6kw lithium batteries.

The Whole system is off-Grid.

my problem is that at about 16:00 in the afternoon the max input from my Solar Panels is +- 1200 to as low as 700w yet from about 8:00 I get 6000w-11000w out of them.

Peak Load on the AC Side is about 5kw-7kw

The battey bank will charge full no problem but then when I close shop at 17:00 the load is about 400-500w and the batteries will drain to 20%.

Is this Normal or am I missing something. Was hoping for a lot better?

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2 hours ago, Leonvd said:

Hi guys I need help. I have 4x Mecer SOL-I-AX-5M inverters in Parallel

48x Canadian Solar 275w Solar Panels (12 per inverter (3 per string in series))

5x usb2000b pylontec 2.6kw lithium batteries.

The Whole system is off-Grid.

my problem is that at about 16:00 in the afternoon the max input from my Solar Panels is +- 1200 to as low as 700w yet from about 8:00 I get 6000w-11000w out of them.

Peak Load on the AC Side is about 5kw-7kw

The battey bank will charge full no problem but then when I close shop at 17:00 the load is about 400-500w and the batteries will drain to 20%.

Is this Normal or am I missing something. Was hoping for a lot better?

Are you running 5-7Kw constantly? The 700W solar energy you get after 16:00 is much less than the 5KW load you drive, so the batteries won't last long. Seeing as you get 6Kw by 8am, is it possible to tilt the panels a bit to the west, in order to get better performance in the late afternoon?

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Have you checked for shading?

Looking at when the PV power drops off, and whether it's sudden or gradual, and whether it's even across the four inverters, could give valuable clues.

This doesn't sound normal to me; you are right to expect better.

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12 hours ago, Leonvd said:

 

The battey bank will charge full no problem but then when I close shop at 17:00 the load is about 400-500w and the batteries will drain to 20%.

Is this Normal or am I missing something. Was hoping for a lot better?

What are you using to determine the 20%? If you are using the Mecer units own readings you can safely ignore the readings as the SOC determined by the Axpert is notoriously poor and compounded by the high battery low cutoff specified by Pylontechs. If it is from a BMV or from the Pylontechs' own readings then indeed that is cause for concern. 

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If you use this for business it would be worth your while to invest in the software for monitoring your system. An example that looks good is to be found here at https://centurionsolar.co.za/

Such software will show you everything as well as where the power is going to.

From all the graphs I have seen it is obvious that solar generation slows down after 15h00. This is especially true of panels facing north. Many people install west facing panels to gain from the last usable sunlight. And depending on where you are based rainy and cloudy days can take away 62 days per year.

Your pylontechs at 80% dod will only supply 10kwhr which when using 7kwhr will last only 85 minutes. A small generator will be very usable (as well as cheap) to power your business when there is no solar available. It is cheaper than not generating income. Some inverter systems can use a generator seamlessly as a source of power - I know my Infinisolar can do it.

Also look at startup amps for machines. This can exhaust your power in no time.

My 2,2kw borehole pump starts up at 35 amps but runs at 14 amps. So I prefer to do this on Eskom power. 

An alternative is to move your working hours to suit sun hours - similiar to what they do in Europe.

Edited by Johandup
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11 hours ago, Chris Hobson said:

What are you using to determine the 20%? If you are using the Mecer units own readings you can safely ignore the readings as the SOC determined by the Axpert is notoriously poor and compounded by the high battery low cutoff specified by Pylontechs. If it is from a BMV or from the Pylontechs' own readings then indeed that is cause for concern. 

Hi I have a cable from Pylontech connected to raspberry Pi bought with recommendation from Centurion Solar. this reads the SOC from Pylontech and not Axpert Inverter. SOC spot on then.

 

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10 hours ago, Johandup said:

If you use this for business it would be worth your while to invest in the software for monitoring your system. An example that looks good is to be found here at https://centurionsolar.co.za/

Such software will show you everything as well as where the power is going to.

From all the graphs I have seen it is obvious that solar generation slows down after 15h00. This is especially true of panels facing north. Many people install west facing panels to gain from the last usable sunlight. And depending on where you are based rainy and cloudy days can take away 62 days per year.

Your pylontechs at 80% dod will only supply 10kwhr which when using 7kwhr will last only 85 minutes. A small generator will be very usable (as well as cheap) to power your business when there is no solar available. It is cheaper than not generating income. Some inverter systems can use a generator seamlessly as a source of power - I know my Infinisolar can do it.

Also look at startup amps for machines. This can exhaust your power in no time.

My 2,2kw borehole pump starts up at 35 amps but runs at 14 amps. So I prefer to do this on Eskom power. 

An alternative is to move your working hours to suit sun hours - similiar to what they do in Europe.

Yes I think you are correct. solar generation slows down from around 15:30 then I switch of aircons and that helps. we then use about 1.3kw until about 17:00 when we close. average use then drops to about 500w. This is total load with the inverters own use. so sound about normal then right ?

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  • 3 weeks later...
  • 1 month later...
On 2018/10/30 at 8:37 PM, Chris Hobson said:

 

Can we see some screen grabs of PV production graphs and load so that we can get some feel of what is happening.

Sorry I have been gone for a while so only now got to posting the screenshot .Here is a screengrab. Same Use every night ?

Power use Pylontech.jpg

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Unfortunately you do not include the X axis on the second graph so a bit difficult to interpret what is going on. The graph of battery consumption is typical with usage running at an average of 600W for 11 hours and another 2 hours at about 300W so 12 hours at 600W. Consumption is going to be  7.2kWh and another 2.4 kWh quiescent current for the 4 Axperts. I would guess you Pylontechs would be  about 20% SOC by morning.

The graph without a timeline I am using a bit of guesswork to interpret. Your batteries are charged by 10 but since you have a large daytime load you continue produce over 6000W - peaking at close to 9000W. I would look at battery voltage when you close up shop. Anything over 49V is fine leading me to think there may be a calibration problem with what is being reported. In the morning I wopuld expect a voltage of 48.3v - 48.5V  something like that  anything over 48.1V is acceptable with a nominal 500W load.

 

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6 hours ago, Chris Hobson said:

Consumption is going to be  7.2kW and another 2.4 kW quiescent current for the 4 Axperts.

Ouch! That's a lot of consumption and quiescent power!

I think you meant kWh (kiloWatt-hours). Please, Chris, there is enough confusion in the world about power and energy as it is. With that wizard hat on, people will look up to you :)

Please pardon my pedantry, and I truly mean no disrespect, but this sadly very common error really rattles me.

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On 2019/01/07 at 4:17 PM, Coulomb said:

Ouch! That's a lot of consumption and quiescent power!

I think you meant kWh (kiloWatt-hours). Please, Chris, there is enough confusion in the world about power and energy as it is. With that wizard hat on, people will look up to you :)

Please pardon my pedantry, and I truly mean no disrespect, but this sadly very common error really rattles me.

No disrespect (and no offence taken) I got it WRONG kWh not kW - I meant kWh not kW but I have been burning the candle at both ends over the festive season. I will correct it.

I have not caught up yet to all the posts over the Xmas period.

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