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KallieDAlebout

Pylontech 2000's not delivering...???? Or what is not ???

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Can someone please help....!
My system seems to short on overnight power very often...
We are 2 people in house, average size, 2 fridges, 2 ouside led's, normal on standby ie DSTV and routers and cellphone chargers etc, and 1 panel wall heater (600w), we watch tv from about 18h15 till about 20h30, sometimes use an oven set to 70 degC to dry rusks through the night (which kicks in for about 5 mins every 40 mins using 1200 w), and use a geyser (200l) in the mornings from 05h30 to 06h45 (on timer). On my ICC etc, this amounts to approximately 12- 14 Kwh of battery usage yet the systems ends at 13% and jumps to Utility....

My problem is that I struggle to get through the night with 12x batteries.....

Let me try to explain... (I am a NOVICE)- We for example use +- 24Kwh in a 24 hour cycle (00h00 to 24h00), ie using 24 solar panels during daytime and then the 12 P's at night, yet sometimes dont make it through the night...? Shouldn't this system be able to cope with batteries only for a complete 24 hour cycle...? (12 x 2.2 kwh = 26.4) Yet I struggle to cope for the 14 hrs of night time only....

System as follows- 2 Axpert 5 kw Inverters, 24 x 330 Canadian panels, 12 x Pylontechs 2000. ( I use ICC and PVOutput and Emoncms to get some info of the system)

PS- I am a complete novice, have very basic knowledge, Had all installed for me, and open to being shown my "wrong way of thinking"..... Maybe the info from the systems (ICC/ PVOutput/ Emoncms) are not accurate...?? How can I then measure how much power is being used?? Or maybe the batteries are rated 2.4 Kwh but less is usable..?

PV O nr 1.png

PV O nr 2.png

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I don't know the ICC software, but is there perhaps a summary of your kWh used per hour? More frequently would also be fine.

Also, it is possible to pull your SoC graph for the batteries? Is it maybe possible that the batteries do not get fully charged in the winter with the PV after consumption during the day was taken into account?

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9 minutes ago, jykenmynie said:

I don't know the ICC software, but is there perhaps a summary of your kWh used per hour? More frequently would also be fine.

Also, it is possible to pull your SoC graph for the batteries? Is it maybe possible that the batteries do not get fully charged in the winter with the PV after consumption during the day was taken into account?

Could these possibly help??

The system gets fully charged.

Screenshot 2020-06-29 at 12.32.55.png

Screenshot 2020-06-29 at 12.33.27.png

Edited by KallieDAlebout

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I believe a good start would be to share 2 screenshots, under ICC you battery trends, and the load trends. As these two would give a good overview of what is happening during the night.

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From my interpretation:
Total energy used: 22.783 kWh. Total energy produced: 25.803 kWh. Only 3.02 kwh margin for losses or alternatively stated available for inefficiency. Don't know what the "official guideline" for system efficiency is? @plonkster

Total storage capacity= 12 x 2400Watt x (80%/90% depth of discharge?) = 23.040 kwh /25.920 kwh.

From studying the 5 minute interval log, I think you may be underestimating your actual loads. What happens at 12:25 - 13:45PM (uses more or less the same amount of electricity as your geyser).

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There's bound to be losses. For example, just converting the DC batteries to AC loses about 10% of the energy. Is the produced energy the DC solar energy generated? If so, on these inverters, does it come in on the AC or DC side of the inverter?

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51 minutes ago, Corné said:

system efficiency

As a rule of thumb you can assume 90%. It varies according to load and not all inverter are equally efficient. 88%-92% is what I typically see in the blue world. "Transformerless" units like the voltronic should in theory do slightly better, but 90% is probably still a good rule of thumb.

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5 hours ago, KallieDAlebout said:

Shouldn't this system be able to cope with batteries only for a complete 24 hour cycle...? (12 x 2.2 kwh = 26.4) Yet I struggle to cope for the 14 hrs of night time only...

By my rough calculation from the table posted you consumed about 13kWh during the non PV producing hours. You have about 23kWh battery available if allowing for some communication issue where the batterries default to 80% DOD. Even allowing for losses the battery should make it through the night.

4 hours ago, KallieDAlebout said:

The system gets fully charged.

The two graphs (and one day table) suggest that somewhere between 13:00-14:25 the PV production all but disappears - unless there was cloud cover all of a sudden this looks a bit strange?. But at least on 28/06 from about 14:45 your PV was barely covering the load so I would think the battery was powering the house from about 15:00 already. Looking at the loads in relation to PV production in the morning also suggest that during this time of the year "night time" is closer to 19 hours than 14. If you have a couple of days in a row like that the batteries may not recharge sufficiently if they are not allowed (or unable) to charge from the grid.

I suspect your batteries are possibly not getting fully charged by PV during the day for some reason, or the batteries get called one during the day (maybe peak loads etc) more than you think and then possibly do not get recharged again.

The members more well versed in the Axpert/Voltronic setup should be able to point you to some specific settings to check (solar before batteries, back to grid etc.)

Edited by introverter
added PV production dip

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been thinking a bit... that PV drop out is likely when the battery state of charge is communicated as full and the PV gets throttled to only cover the loads.

If the battery state is indicated as 100% by 14:00ish most days and on those same days after only 13kWh is used the battery state is reported as 13% it would seem like 1/2 the battery is unaccounted for.  If this happens more often than not then I would wonder about these things: All battery cables actually connected? Battery size etc. correctly specified in all required monitoring/inverter parameters (simplified example; if part of the system was told there is only a 100Ah battery even when there is a 200Ah battery it will use 90Ah and report that there is only 10% left even though there is more than 50% left). Unfortunately axpert, ICC and emoncms is way outside my wheel hosue so can't help with trouble shooting the exact issue.

But keep in mind it is not that difficult to use 24kWh - you do it on average everyday. So if the PV production is lower, and the battery gets used almost exclusively the whole day and night then by the next morning 13% left from 24kWh battery sounds about right. 

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11 hours ago, introverter said:

been thinking a bit... that PV drop out is likely when the battery state of charge is communicated as full and the PV gets throttled to only cover the loads.

If the battery state is indicated as 100% by 14:00ish most days and on those same days after only 13kWh is used the battery state is reported as 13% it would seem like 1/2 the battery is unaccounted for.  If this happens more often than not then I would wonder about these things: All battery cables actually connected? Battery size etc. correctly specified in all required monitoring/inverter parameters (simplified example; if part of the system was told there is only a 100Ah battery even when there is a 200Ah battery it will use 90Ah and report that there is only 10% left even though there is more than 50% left). Unfortunately axpert, ICC and emoncms is way outside my wheel hosue so can't help with trouble shooting the exact issue.

But keep in mind it is not that difficult to use 24kWh - you do it on average everyday. So if the PV production is lower, and the battery gets used almost exclusively the whole day and night then by the next morning 13% left from 24kWh battery sounds about right. 

This made me think... are the Pylons not limited to 8? The other four probably won’t be used? You need some type of Hub?

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13 minutes ago, jykenmynie said:

This made me think... are the Pylons not limited to 8? The other four probably won’t be used? You need some type of Hub?

You're right! Small details you miss. Indeed, you are limited to 8 per group. You can combine up to 5 groups (40 modules total) by using a "Pylontech LV hub". Can't provide a link, pylontech.com.cn is unreachable for me at the moment. That little hub is almost half the price of a battery module though...

But I'm not convinced this is the reason for his troubles. Or it could be... I don't know. If you connected all the batteries together, it may well be that the last 4 can't be addressed by the master unit and they open their master disconnect (a big old FET inside), so that they don't contribute to the whole. Then I would expect their SOC indication to be different from the others. Or.... they do contribute, because this is an Axpert system and the comms really isn't all that important.

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2 minutes ago, plonkster said:

You're right! Small details you miss. Indeed, you are limited to 8 per group. You can combine up to 5 groups (40 modules total) by using a "Pylontech LV hub". Can't provide a link, pylontech.com.cn is unreachable for me at the moment. That little hub is almost half the price of a battery module though...

But I'm not convinced this is the reason for his troubles. Or it could be... I don't know. If you connected all the batteries together, it may well be that the last 4 can't be addressed by the master unit and they open their master disconnect (a big old FET inside), so that they don't contribute to the whole. Then I would expect their SOC indication to be different from the others. Or.... they do contribute, because this is an Axpert system and the comms really isn't all that important.

Would a picture of the battery modules help? I suspect that the last four would only have their power lights on, but the "run" light won't flash or SoC lights won't light up. When I set up my Pylons, I start only the master battery who then in turn starts all the slaves (even though they are all "switched" on).

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Plonkster would like this suggestion.... 😀

Have you thought of installing a  Victron BMV (includes shunt) onto your system which would give you accurate and reliable data...

Am just busy ordering a BMV700 to connect to my ICC/Pi. Don't need the mid-point voltage monitoring or bluetooth so don't need the more expensive bigger models.

It is a small price to pay to add to your system which has already been a significant investment for you.

Oh yes to connect the BMV to the ICC and Pi you would also need the Victron USB to VEDirect cable.

What says Plonkie ?

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1 hour ago, GreenMan said:

What says Plonkie ?

Truth be told, the Pylontech battery has a very good BMS.  Of course I'd love to sell you a nice bit of kit, but I kinda feel like you already have enough kit, and I am concerned about warranty matters when you don't wire it up properly. My advice would be to get the LV hub. I believe ICC can read the Pylons.

Edit: The protocol from the batteries and from the LV-hub is the same. At least on the CAN-bms side. I assume ICC would have no trouble reading the hub instead of the master battery. But you may have to look into that...

Edited by plonkster

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Regarding the batteries, were there a reason you didn't go with 8xUS3000s? That should be cheaper and take up less space (and be compatible). If the system is still new and the LV hub is expensive, could the stuff be exchanged? Especially if someone ended up speccing and installing out of spec parts?

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39 minutes ago, introverter said:

@KallieDAlebout try to post a picture from ICC that indicates what the system says about the batteries. I know nothing about ICC but looking at this thread you should be able to get something like this:

ICC_Pylon1.jpg.bddbf251590160d7ec66c16e08970748.jpg

It could help to at least determine if your system knows how many batteries there are?

Oh this is really nice! I wish I could see that detail on my Victron system...

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38 minutes ago, jykenmynie said:

Oh this is really nice! I wish I could see that detail on my Victron system...

The support is there. What is missing is Pylontech support for the new CAN frames (the BMS has to send us that info). But apparently support for this feature is not far off...

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17 minutes ago, plonkster said:

The support is there. What is missing is Pylontech support for the new CAN frames (the BMS has to send us that info). But apparently support for this feature is not far off...

I eagerly await more numbers to look at. 😀

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5 hours ago, plonkster said:

You can combine up to 5 groups (40 modules total) by using a "Pylontech LV hub". Can't provide a link, pylontech.com.cn is unreachable for me at the moment. That little hub is almost half the price of a battery module though...

Here's a link to the Hub. It is on a reseller's website, and I'm not advising to use them, just for informational purposes. I remembered seeing it listed somewhere before.

https://solaradvice.co.za/product/pylon-low-voltage-communication-hub/

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On 2020/06/29 at 12:11 PM, KallieDAlebout said:

PS- I am a complete novice, have very basic knowledge, Had all installed for me, and open to being shown my "wrong way of thinking"..... 

 

3 hours ago, plonkster said:

Of course I am a tad bemused by the budget inverter paired with a sizeable investment in batteries, but to each their own 🙂

At the risk of pitch forks and flame throwers, while @plonkster's post is probably aimed at installers/"system sellers" it is potentially alienating to someone new indicating their interest to learn and wanting to figure something out?

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