Sofar hybrid inverter and pylontech batteries

[speculatrix]

wow. At that price it looks like the pylontech equipment beats out most other battery systems like the Powerwall. I hope that equipment will last the ten years for you to get the payback.

so do I . I've been watching and waiting for the price of storage to fall, and so once it hit the tipping point, went for it. Also, sales tax ("VAT") in the UK on renewable microgeneration installations is going to jump from 5% to 20% after September, which will increase the entire cost of PV + battery very significantly, and delay payback!

the Sofar links to the Pylontech with canbus, and so it knows all the operating params, which is nice.

on the subject of warrranties, yes, you do have to be careful because some have both a longevity/age warranty, and a throughput warranty. I once worked out that a Powerwall has a total throughput warranty which if you totally charged and discharged it every day, your warranty would expire in under 8.5 years. Their warranty terms might have changed now.

[ButchDeal]

the Sofar inverter does have a clamp sensor on the meter tail. I've had another play with the SolarMan graphs and generated this:
Screenshot from 2019-05-30 13-44-53.x.png

now, this is interesting because it suggests that the "Ac Output Total Power(Active)" does not include the battery power, because the charge/discharge is non zero when AC Output and Power Grid are zero, and the battery continues to be discharged.

I did discover, and fix, a loose wire on the inverter's cable connector to the clamp sensor, yesterday evening about 20:00, but it doesn't appear to have changed the Power Grid Total Power.

well it looks like it is doing a good job of trying to keep your grid usage low. It does seem that the loose connection improved the ability of the device to keep the grid usage low as it improved after 20:00

you are likely correct on the ac output as it seems to only be showing from solar. but not showing the total solar as some is being used to charge.
I would suspect that it has other things like solar input..
you may have to look at some of the other variables to get a better picture but it seems to be doing a decent job at reducing grid consumption from this graph.

[SunEagle]

Actually, my costs are in UK pounds and pence, but it's all relative. My pylontech battery packs came in at roughly 3000, for roughly useable 6kWh capacity.


IF I got, and I know it's a big IF, a full 6000 charge cycles, the value would be
6 kWh/cycle x 0.15 x 6000 = 5400

but if I only get ten years, 3650, that gives 3285

if I only just break even but in doing so benefit the environment in a useful way, I'm happy.

wow. At that price it looks like the pylontech equipment beats out most other battery systems like the Powerwall. I hope that equipment will last the ten years for you to get the payback.

[speculatrix]

the graph looks like a miss configured monitoring system


Your inverter has to sense the grid import in order to try to minimise it. Does the inverter NOT have any monitoring on this?
The Owl does not seem to be capable of reporting correctly.

You need an accurate way to monitor what is going on and to insure that things are configured correctly and working correctly.

the Sofar inverter does have a clamp sensor on the meter tail. I've had another play with the SolarMan graphs and generated this:
Screenshot from 2019-05-30 13-44-53.x.png

now, this is interesting because it suggests that the "Ac Output Total Power(Active)" does not include the battery power, because the charge/discharge is non zero when AC Output and Power Grid are zero, and the battery continues to be discharged.

I did discover, and fix, a loose wire on the inverter's cable connector to the clamp sensor, yesterday evening about 20:00, but it doesn't appear to have changed the Power Grid Total Power.

[ButchDeal]

yes, this would be the case if the inverter is not sensing the grid import correctly and trying to minimise it.

the graph looks like a miss configured monitoring system

The Owl can only measure the inverter output (including battery) and consumption. I think it therefore assumes that if the inverter is producing more than consumption, the difference is exported. It doesn't report negative export, i.e. import.

Your inverter has to sense the grid import in order to try to minimise it. Does the inverter NOT have any monitoring on this?
The Owl does not seem to be capable of reporting correctly.

You need an accurate way to monitor what is going on and to insure that things are configured correctly and working correctly.

[speculatrix]

This graph is wrong.
it is showing your imported power from grid increasing 1 for 1 with your generation. That is clearly wrong.

yes, this would be the case if the inverter is not sensing the grid import correctly and trying to minimise it.

You should have a device measuring your NET at the grid side and another measuring your generation.
The sum of the two is your consumption.

The Owl can only measure the inverter output (including battery) and consumption. I think it therefore assumes that if the inverter is producing more than consumption, the difference is exported. It doesn't report negative export, i.e. import.

[speculatrix]

I also think the expense of a battery will still cost more to generate a kWh then to purchase it for 15.5 cents/kWh. So based on the spec of 3.2kWh for each cycle and 6000 cycles that comes to 19200kWh. At 15.5cents/kWh that calculates to just under $3000. What did that pylontech system cost you?

Get back to us in 5 years and tell us how it is working for you.

Actually, my costs are in UK pounds and pence, but it's all relative. My pylontech battery packs came in at roughly 3000, for roughly useable 6kWh capacity.


IF I got, and I know it's a big IF, a full 6000 charge cycles, the value would be
6 kWh/cycle x 0.15 x 6000 = 5400

but if I only get ten years, 3650 cycles, that gives 3285

if I only just break even but in doing so benefit the environment in a useful way, I'm happy.

[ButchDeal]

I've grabbed a graph from Owl Intuition which shows power draw for part of yesterday. It measures the output of the inverter, and the consumption, and estimates grid import or export from those.
Screenshot from 2019-05-29 16-03-43.x.png

I've got an iBoost with Buddy, which measures grid export or import, but there's no data port to capture the readings, and it seems quite inaccurate.

I've tried connecting my CurrentCost to different cables to confirm what I see on the Owl and iBoost, which is how I know the iBoost is inaccurate.

thanks
Paul

This graph is wrong.
it is showing your imported power from grid increasing 1 for 1 with your generation. That is clearly wrong.

You should have a device measuring your NET at the grid side and another measuring your generation.
The sum of the two is your consumption.

[SunEagle]

check the link I posted to the product - "ensures more than 6000 cycles with 90% DoD" - 6000 cycles is nearly 16.5 years.

I think it's reasonable to be able to drain it 80% every day and still have 80% or better performance, which is 3650 cycles!

If the battery is exhausted by midnight, I want to set things up to get an additional late night top-up from really cheap electricity, about 1.5kWh for breakfast period.

I pay 15.5/kWh at peak, but could pay 5/kWh at cheapest time.

I saw that claim by the battery system mfg. What I would like you to understand is that some claims are not worth the paper they are written on or shown on a webpage.

Maybe I am wrong or being a doubting Thomas but any battery chemistry being able to go > 80% DOD on every cycle and last 6000 cycles is pretty high in expectations.

I also think the expense of a battery will still cost more to generate a kWh then to purchase it for 15.5 cents/kWh. So based on the spec of 3.2kWh for each cycle and 6000 cycles that comes to 19200kWh. At 15.5cents/kWh that calculates to just under $3000. What did that pylontech system cost you?

Get back to us in 5 years and tell us how it is working for you.

[speculatrix]

So your expectations is that you will get more than 4000 cycles out of a battery system that has been drained 50% each cycle?

check the link I posted to the product - "ensures more than 6000 cycles with 90% DoD" - 6000 cycles is nearly 16.5 years.

I think it's reasonable to be able to drain it 80% every day and still have 80% or better performance, which is 3650 cycles!

If the battery is exhausted by midnight, I want to set things up to get an additional late night top-up from really cheap electricity, about 1.5kWh for breakfast period.

I pay 15.5/kWh at peak, but could pay 5/kWh at cheapest time.

[SunEagle]

BTW, I expect our batteries to still be useable in 12 years, at which point the cost of replacement will be significantly less, and the entire system will have paid for itself by then, the panels will still have more than half their life left.

So your expectations is that you will get more than 4000 cycles out of a battery system that has been drained 50% each cycle?

[speculatrix]

I've grabbed a graph from Owl Intuition which shows power draw for part of yesterday. It measures the output of the inverter, and the consumption, and estimates grid import or export from those.
Screenshot from 2019-05-29 16-03-43.x.png

I've got an iBoost with Buddy, which measures grid export or import, but there's no data port to capture the readings, and it seems quite inaccurate.

I've tried connecting my CurrentCost to different cables to confirm what I see on the Owl and iBoost, which is how I know the iBoost is inaccurate.

thanks
Paul

[ButchDeal]

Hi,
we average about 750W from 4pm to 11pm, excluding kitchen appliances, which is peak electricity use.

The PV system came with an Owl Intuition, but I previously used a CurrentCost to track power usage for a long time, so I know we're using a good 5 or 6kWh. The pylontech batteries hold 7.2kWh before the 20% reserve, which brings it down to a bit under 6kWh usable.

You can see when the solar kicks in and starts charging about 0830 at the moment as the battery charge starts to rise.

750w is a generalization for consumption but you have an exact graph with time plot for the battery here.
These should be set up to offset your consumption with some meter and likely has a way to present a consumption graph as well.

As for the charging, it looks like it starts charging around 6:30 am from the graph.

You seem to be questioning why there is still a charge on the batteries in the morning which SHOULD be because the system is working correctly and offsetting only what you used.
Do you have a graph or something showing that you were using more than the battery put out?

[speculatrix]

Hi,
we average about 750W from 4pm to 11pm, excluding kitchen appliances, which is peak electricity use.

The PV system came with an Owl Intuition, but I previously used a CurrentCost to track power usage for a long time, so I know we're using a good 5 or 6kWh. The pylontech batteries hold 7.2kWh before the 20% reserve, which brings it down to a bit under 6kWh usable.

You can see when the solar kicks in and starts charging about 0830 at the moment as the battery charge starts to rise.

[ButchDeal]

Sorry, I should explain. After about 11:30 we're all in bed, and the power consumption drops to just a few hundred W (phone chargers and things on standby), and I've been finding that by 7am the next day we still have 50% charge left, and soon after the batteries start charging again (we're in the UK and sunrise is 5am at the moment)!

So instead of running off free* energy, we're paying for grid power in the evening. I want to run off battery as much as possible until it hits the programmed limit of 20% reserved charge.

Screenshot_20190529_000647.png

* ok, I know it's not strictly free because it wears out the battery.

I assume these batteries are trying to offset your consumption. what is your consumption during this time?
When is your solar kicking back on in the morning to start recharging?
Do you have consumption metering to see your actual home consumption?