Backup down under

[wattmatters]

Back in March I reported this:

Latest update:

My two year old clone PIP HS-4048 AIO inverter died. This was the one I replaced with the EASun 8kW unit, so it's no longer in service.

Plan is to remove it when I next get the chance and then attempt a repair. It'll be a while before I get a chance to do that but I'll share my experience.

Most likely some of the capacitors are cactus. It was cheap and a great learning tool. If I can revive it, then I have a few ideas on how I might use it.

Well I've now gotten around to having a crack at repair.

And it's back to life!

This capacitor (C79) was bad:

but it was recommended to me by a PIP inverter guru I should also replace a group of nearby capacitors (except the one marked with purple):

While I was able to disassemble and remove the main board, I tried and failed to do the capacitor remove and replacement, so got a local electronics repair dude to do that for me.

I put the inverter back together this morning and took a video of the first power up test.

I didn't have a spare 48 V battery to use, so I just connected a small power supply to simulate a battery, along with a small load (an old halogen globe desk lamp).

This is what happened:

It's ALIVE I tell you!

So while I had it working again I tested the Utility bypass function, which worked as expected:

and did one other quick test, to measure the no load / idle power consumption:

Approx 47 W, which is in line with the user manual which states it's less than 50 W:



So now to think about how I might use this unit.

 

[Nobodybusiness]

Back in March I reported this:


Well I've now gotten around to having a crack at repair.

And it's back to life!

This capacitor (C79) was bad:

but it was recommended to me by a PIP inverter guru I should also replace a group of nearby capacitors (except the one marked with purple):

While I was able to disassemble and remove the main board, I tried and failed to do the capacitor remove and replacement, so got a local electronics repair dude to do that for me.

I put the inverter back together this morning and took a video of the first power up test.

I didn't have a spare 48 V battery to use, so I just connected a small power supply to simulate a battery, along with a small load (an old halogen globe desk lamp).

This is what happened:

It's ALIVE I tell you!

So while I had it working again I tested the Utility bypass function, which worked as expected:

and did one other quick test, to measure the no load / idle power consumption:

Approx 47 W, which is in line with the user manual which states it's less than 50 W:

View attachment 176040

So now to think about how I might use this unit.

I think I could repair the discrete components on stuff like this.
It’s the proprietary firmware that makes me cringe.
If something goes wrong with the EPROM you kinda hosed.

It’s good to see it was only basic Caps on this one.

 

[wattmatters]

If something goes wrong with the EPROM you kinda hosed.

For sure. But for a US$300 bit of kit, I'm not going to be too concerned if/when that day comes.

 

[wattmatters]

So on a whim I just bought 24 x 275 W used panels via local FB marketplace. Local upgraded his grid-tied PV system to a 10 kW inverter with new panels.

US 14c / W delivered tomorrow, including railings, cables, clamps etc.

These will be deployed in tranches for our off-grid system. Plus have some spares.

 

[nezjnr]

So on a whim I just bought 24 x 275 W used panels via local FB marketplace. Local upgraded his grid-tied PV system to a 10 kW inverter with new panels.

US 14c / W delivered tomorrow, including railings, cables, clamps etc.

These will be deployed in tranches for our off-grid system. Plus have some spares.

Do you have more roof space or going for some ground mount?

 

[nezjnr]

I moved over the majority of my GTI strings to my off-grid inverters, somehow I'm still exporting a significant amount but according to my inverters my AC out is usually above what the GTI is making.

Head scratches here.

 

[wattmatters]

Do you have more roof space or going for some ground mount?

I large amount of SW facing rooftop. Eventually I will have space for another row of panels (10-12) facing NE, but that has to wait for a renovation which will remove one of our chimneys.



All the grid tied PV (40 panels) is on the roof facets on the other side.



Field array(s) would be nice but that's not going to be in budget or attain approval by the minister for the interior.

 

[nezjnr]

How is your off-grid inverters temperature on hot days?

One of my units is getting really hot, might take off the wire cover and see if that increases air flow.

This unit also has my combined strings from the roof so it sits at the current limit for one of the MPPTs for some of the day.

Need to reverse the fans as well, pulling air from the top and blow out the bottom doesn't seem all that great.

 

[wattmatters]

How is your off-grid inverters temperature on hot days?

We had some hot days a couple of weeks back but otherwise it seems mostly OK.

It's seasonal - here's a temp measurement every three hours since 21 Feb this year:



Zooming in on that period with the peak:



If we look at what was going on the day with the peak inverter temp measurement (22 Oct) can see temp rose with some solid loads when supplied by the battery:



It was a pretty warm day with max of 36.4°C:

 

[nezjnr]

It's been cool days since so haven't been too stressed about heat, I took one of the filter pads off my inverter and the temperature showed a really large drop, will need to keep an eye on that one.

Impressed with my SCC so far, the lower string voltage seems to work pretty well for me as I have shading issues.

Thinking about putting my 10kw Goodwe GTI inverter on the output side of my off-grid inverters with it's export limit set to 0% and the 5kw Almost 600V string that I can't run on anything else, I always have at least 7kw of load running I just wonder if it will think something is off with Voltage/Frequency and go off on anti-islanding.

 

[Hedges]

It's been cool days since so haven't been too stressed about heat, I took one of the filter pads off my inverter and the temperature showed a really large drop, will need to keep an eye on that one.

Seen that before. A product we developed had a fan at one end, as wide as the enclosure, with filter on the input.
Mechanical designer removed his filter and it ran much cooler.

I saw photos of interior, and there was a lot of dust built up. Especially on high voltage DC terminals (electrostatic precipitator).

How about using a large furnace fan filter, ducted to the input? Much more surface area, less pressure drop for more airflow.
Could take up space the width of inverter, height from just below display to below bottom, only a couple inches deep.

Very well done study on myocarditis shows very high rates.

Still so sure? No. He has no studies. He has one anecdotal case where he thinks that is what happened. He is then referring to the mice cases but he has not looked at those studies and so he is just guessing that the method, dosage, and impact of giving mice these injections means there is a...

diysolarforum.com

Corsi–Rosenthal Box - Wikipedia

en.wikipedia.org

 

[wattmatters]

When I disassembled my other smaller AIO inverter for repair, I was actually pretty surprised at how little dust was inside. I was sort of expecting a filthy mess.

One idea I have for using it is as an emergency charge controller for my battery, powered by my EV's V2L capability.

 

[nezjnr]

Seen that before. A product we developed had a fan at one end, as wide as the enclosure, with filter on the input.
Mechanical designer removed his filter and it ran much cooler.

I saw photos of interior, and there was a lot of dust built up. Especially on high voltage DC terminals (electrostatic precipitator).

How about using a large furnace fan filter, ducted to the input? Much more surface area, less pressure drop for more airflow.
Could take up space the width of inverter, height from just below display to below bottom, only a couple inches deep.

Very well done study on myocarditis shows very high rates.

Still so sure? No. He has no studies. He has one anecdotal case where he thinks that is what happened. He is then referring to the mice cases but he has not looked at those studies and so he is just guessing that the method, dosage, and impact of giving mice these injections means there is a...

diysolarforum.com

Corsi–Rosenthal Box - Wikipedia

en.wikipedia.org

This is the filter, can clearly see through it and it really doesn't look that blocked.

Because it's sucking heat in from the top I guess it might be pulling heat from the SCC next to it...could also be a fan issue I heard it spinning up and down the other day and there is no control or information available about the fan.

 

[nezjnr]

I didn't start work until this afternoon so was having a look at my system and realised the battery charge from the inverters was well below available solar, and then I took a reading of my grid in and the power draw was way lower.

I'm in Utility mode but it's can't push all power to the battery and just starts diverting power to the loads.

I had my Inverters at 53.6 CV/Float.

I changed it too 53.8V and it began pushing a lot more to the battery but is still diverting a lot too loads instead of charging.

I have 3 SCC and when I had set at 53.6 they would just clip severely like this so I have them set at 54.1V and clipping didn't seem to be happening but I did see a drop after raising my inverter voltage.



Batteries at the BMS are now reaching 53.8V, was hoping to really long life them at 53.6~V but I'm losing so much money if they can't receive enough power at that voltage while the sun is out.

What Voltage are you aiming for on your packs?

 

[wattmatters]

What Voltage are you aiming for on your packs?

56.4 V for mine.

 

[crossy]

Our rather worn (400Ah x 48V of used LiFePO4 golf-cart cells) top out at 54.7V when charging at 60A. They relax to 53.8V when the charge finishes.

I don't think there are any hard and fast rules, I just plotted the voltage and decided that the charge should end just as the upper "knee" started to appear. Similarly for the discharge end although that knee is rather less well defined.

Experiment is the key to match your pack/BMS with your charge controller.

Also, don't rely on the SCC/inverter metering, get a decent multimeter.

 

[wattmatters]

Also, don't rely on the SCC/inverter metering, get a decent multimeter.

I use a Victron Smart Shunt.

 

[nezjnr]

I use a Victron Smart Shunt.

I have Shunt/Monitor under each inverter and then on each battery at my Busbar and some of the BMS have a screen that shows voltage.

Want to try and integrate all the shunts into Home Assistant.

 

[Hedges]

This is the filter, can clearly see through it and it really doesn't look that blocked.

Because it's sucking heat in from the top I guess it might be pulling heat from the SCC next to it...could also be a fan issue I heard it spinning up and down the other day and there is no control or information available about the fan.

You're right, no obstruction yet. How long did it take to get this bit of dust?

Yet, when you removed filter, you observed it ran cooler. Maybe something else happened to change at the same time. A/B A/B test, repeat filter/no filter a couple times, see if operating temperature is correlated.

Check temperature of inlet air. If it is too hot due to discharge of other equipment, could add a baffle to duct them.

 

[wattmatters]

Grid voltage issues.

In recent weeks our grid tied system has experienced issues with excessive grid voltages. It all started back on 25 October. It was a very hot day (40°C+) and sometime that morning our grid voltages increased.

While it's hard to make sense of voltages in the daytime (as solar PV and loads all have their say), overnight voltages are a good guide as we have no PV output, do not export from our (off-grid) battery and typically have very little load either since the home runs from the off-grid battery. Occasionally we might use the ducted aircon overnight which only uses grid for power.

Here's the midnight to 6AM voltages at our grid feed-in point on 22 October:



Situation normal.

For reference I include lines at:
- 230 V, our nominal delivery voltage standard, although we've generally operate as if the standard was 240 V,
- 253 V, which is the upper voltage of the standards for delivery here (230 V +10% / -6%) above which our inverter will begin to derate output with volt-watt mode and use volt-var mode to inject reactive power, both in an effort to reduce feed-in point voltages, and
- 258 V, above which, if sustained for long enough, out grid-tied inverter will shut down.

Then after 25 October I see this for the midnight to 6AM period:



RED phase voltages jumped up a lot.

With unloaded voltage so high, ultimately I would experience inverter shut downs in the daytime, with 11 November being a prime example but it was not alone, these shutdowns were happening reasonably regularly:



and the voltage trace for that day:



Many forays up to 260 V - and check the overnight voltages - also high.

A few days after the initial voltage rise I lodged a ticket with the DNSP and they sent someone out the next day. He was going to do a check on my main supply board but once I described to him what was going on with voltages he said - "no need". He had received the exact same report from another local energy nerd located some 5+ km from here - which told him the issue was more likely a problem with their high voltage supply.

He asked if I could send him our voltage data, which I did attaching 30 days of data in a spreadsheet. Following that I sent more data and screen shots like these to show the issues.

Indeed it was an issue on the HV side. After a few weeks they replaced some HV supply equipment on 15 November and since then our overnight voltages have returned to normal:



We haven't quite had one of those perfect solar days since to really test the system but so far the daytime voltages haven't been so high as to threaten an inverter shutdown:



Looking at the last 45 days, and focussing on the RED phase as that was the most problematic, we can see the clear step change up in grid voltage, and the more recent step change down again:



In years gone by I've had similar high voltage issues cause problems for my grid-tied inverter but I did not get as good a response from the utility as I did this time.

One difference this time was being able to supply a clear data log, along with another local nerd being able to do the same thing.