Hi Yáll

I have been having a problem with an existing installation, where I replace 2 x gel batteries with a Lithium battery. The installation was a Riio Sun 3 Kw 24v inverter that was connected to 2 x 12V 105Ah Gel batteries. The system was used as a back-up for loadshedding, no PV panels connected. The inverter only runs a essential loads, with a base load of ≤500W. Everything on the original installation worked well for about a year, then the inverter was only able to supply current for about 5-10 mins. I tested the batteries, to find one battery to be faulty. I then installed a Pylontech UP2500 battery, as the UP2500 is fully compatible with the Riio Sun, using CAN for BMS comms with inverter. Did the installation and tested the system manually and everything worked according to plan, after changing the settings on the inverter as per the manual. The can cable pin-outs I also used according to confirmed diagrams. The inverter supplied power to essential loads in excess of 6hrs. Then a problem started rearing it's ugly head. Everytime loadshedding commences, the inverter immediately shuts down and needs to be manually re=started by pressing the on button. Once booted up, it operates normally and supplies current to the essential loads for the duration of loadshedding and when Eskom supply returns it switches back over to Eskom as primary supply. If I switch off the Eskom supply to the inverter manually, it works normally and supplies power from the battery. The second Eskom loadshedding starts, it shuts down totally.

I have attached the Riio Sun's manual just in case

I have gone through the settings many times, but can't seem to find the problem. I have even installed a Surge protector on the supply to the inverter, just to be sure, but earlier today the Eskom supply dipped and the inverter shut down and needed to be started manually again. Cab anyone offer some help with this problem please, as I am pulling out what little hair I have left. Thank you

RiiO Sun User Manual.pdf

 

Then a problem started rearing it's ugly head. Everytime loadshedding commences, the inverter immediately shuts down and needs to be manually re=started by pressing the on button.

My wild guess: capacitors are drying up in the inverter, and the power supply is marginal, and when not propped up by Eskom, the sudden load on the power supply is too much for the nearly dead capacitor to provide.

It sounds like the inverter is several years old; they don't use the longest life capacitors. If you know what you're doing, this can be done fairly inexpensively (less than US$10, say 150R). Details are on this very forum; see the "a journey started" topic. Even the labour should not be too expensive if you have to get it repaired. The hassle is the poor lifestyle while it gets repaired. Maybe you can post the relevant photo to the repair shop so that they can get spares in stock if needed before you arrive.

It sounds to me that your battery is fine.

What load is it supporting? If it's fridge/freezer then it's quite possible you're exceeding the battery discharge capacity for a brief moment causing the shutdown

 

What load is it supporting? If it's fridge/freezer then it's quite possible you're exceeding the battery discharge capacity for a brief moment causing the shutdown

You might be on to something, although he mentions if he manually disturbs the grid, then its working fine. 

I am scratching my head here. 

Edited October 3, 20232 yr by BritishRacingGreen

 

My wild guess: capacitors are drying up in the inverter, and the power supply is marginal, and when not propped up by Eskom, the sudden load on the power supply is too much for the nearly dead capacitor to provide.

It sounds like the inverter is several years old; they don't use the longest life capacitors. If you know what you're doing, this can be done fairly inexpensively (less than US$10, say 150R). Details are on this very forum; see the "a journey started" topic. Even the labour should not be too expensive if you have to get it repaired. The hassle is the poor lifestyle while it gets repaired. Maybe you can post the relevant photo to the repair shop so that they can get spares in stock if needed before you arrive.

It sounds to me that your battery is fine.

Thanks Coulomb, I am struggling to find a workshop/repair manual for this inverter. The inverter however is only just on a year old now.

 

What load is it supporting? If it's fridge/freezer then it's quite possible you're exceeding the battery discharge capacity for a brief moment causing the shutdown

It is only supporting led lighting and three plugs ( bedside light, cellphone chargers etc, no fridges no microwaves.

 

You might be on to something, although he mentions if he manually disturbs the grid, then its working fine. 

I am scratching my head here. 

That is what I am struggling to understand. I am clutching at straws, but I figured that there must be some feedback on the neutral or something. Oh, I forgot to mention that this house is fed by Eskom 3 fase power. One fase feeds the inverter. Could it be than when Eskom disrupts their supply, that there is some residual power on neutral that causes the inverter to read a critical malfunction and shut down? Would the surge protector I installed solve this? The inverter does not display any faults or error codes. It shuts down completely, but you can manually re-start the inverter immediately after that and it works perfectly until the next loadshedding.

 

I am struggling to find a workshop/repair manual for this inverter.

It seems to be a "look alike" or "work alike" to the Axperts. But the settings are different to those of Axperts. So unfortunately, much of the knowledge and experience that this forum has with Axperts may not apply to these.

Since the inverter is about one year old, hopefully my wild guess about dry capacitors is wrong. 

 

It seems to be a "look alike" or "work alike" to the Axperts. But the settings are different to those of Axperts. So unfortunately, much of the knowledge and experience that this forum has with Axperts may not apply to these.

Since the inverter is about one year old, hopefully my wild guess about dry capacitors is wrong. 

My confusion stems from the fact that when I disrupt the Eskom supply to the inverter, by manually switching off the isolator on the supply, the inverter switches over to battery mode immediately and carries the load without a problem. When Eskom disrupts the supply to the house ( and inverter) when loadshedding commences, the inverter shuts down immediately. Then I manually start the inverter and it continues to carry the loads, until either loadshedding ends or the battery is depleated. This is the most confusing that blows any theory I have, out of the water.

 

My confusion stems from the fact that when I disrupt the Eskom supply to the inverter, by manually switching off the isolator on the supply, the inverter switches over to battery mode immediately and carries the load without a problem. When Eskom disrupts the supply to the house ( and inverter) when loadshedding commences, the inverter shuts down immediately. Then I manually start the inverter and it continues to carry the loads, until either loadshedding ends or the battery is depleated. This is the most confusing that blows any theory I have, out of the water.

I am not an electrician so what I say may be total rubbish!

There is a total difference between manually switching off the isolator and an Eishkom power failure.

Switching the isolator breaks the circuit whereas a power failure still has the complete circuit to the local transformer in place.

Maybe an electrician  can weigh in as to what in a circuit can cause issues, e.g. capacitance.? Or maybe the inverter detects the unpowered circuit as a short circuit?

 

I am not an electrician so what I say may be total rubbish

I Understand your disclaimer, but your input is not rubbish, not by any stretch. 

 

There is a total difference between manually switching off the isolator and an Eishkom power failure.

Understood, correct. 

 

Maybe an electrician  can weigh in as to what in a circuit can cause issues, e.g. capacitance.? Or maybe the inverter detects the unpowered circuit as a short circuit?

Valid concerns here. Especially now that all modern gridtie and even offgrid inverters like Axperts are all build around a gridtied bidirectional topology. So typically when the inverter sync to the grid, then a number of relays actually ties the grid, the inverter output and the load together as one connection. 

Now when the grid fails away, the inverter senses this and isolates the grid via a relay. How fast this action responds to the grid falling away, is a valid question. And I for one dont know that answer. And I also dont know if the inverter will see a short or very low impedance on the grid network before that relay disengages the grid. 

I hope we can inpire an axpert like @Coulomb, amongst other, to shed some light on this. 

 

Now when the grid fails away, the inverter senses this and isolates the grid via a relay. How fast this action responds to the grid falling away, is a valid question. And I for one dont know that answer. And I also dont know if the inverter will see a short or very low impedance on the grid network before that relay disengages the grid.

I've often wondered this, but since I don't have an inverter that attempts to be grid tied, I can't do any experiments.

When load shedding starts, I assume that some giant switch or relay disconnects the high voltage feed to a set of transformers. So as BritishRacingGreen suggests, your DC-AC converter's output will suddenly be trying to power the entire area's load (along with some other inverters perhaps), and it's very likely that this will overload the DC-AC converter at least momentarily. How the inverter usually copes with this, I have no idea.

As an experiment, and maybe as a lasting work around, you might consider switching the inverter from SUB output source priority (where the above scenario will happen), to something like SBU, so that the inverter will be in battery mode. If you know when load shedding is due and they are accurate with the timing, you might be able to do this semi-automatically a few minutes before it's due. That way, you won't be connecting to AC-in when load shedding happens, and hopefully you've only lost a few minutes of battery run-time. Presumably, the onset of load shedding will have no effect, and you keep the lights, computers, etc on.  Depending on various factors, this might or might not be a good compromise. For example, if they are very sloppy about the timing, you might find that you end up often wasting half an hour of battery run-time that way.

Having said all that, presumably this is still not normal behaviour, and you should usually see just a very brief period where the lights go out or dim, then the relay drops and the inverter is in battery mode. So it's possible that the power supply is marginal, and you can get "normal" behaviour with some sort of repair, e.g. replacing the "usual suspects" of electrolytic capacitors. Again, this is a judgement call; will it be worth the hassle and expense, and lack of backup power while this happens?

 

When load shedding starts, I assume that some giant switch or relay disconnects the high voltage feed to a set of transformers. So as BritishRacingGreen suggests, your DC-AC converter's output will suddenly be trying to power the entire area's load (along with some other inverters perhaps)

Another non-electrician putting in his 2.5C worth. This must surely compound? There will be an increasing number of inverters in that area, all connected for a brief period and either demanding or exporting power. 

@Ralf mentioned that all used to be well, but recently the system has started tripping as the load shedding starts. This may be an explantion: The ever growing number of inverters on the same grid segment, all reacting to the grid losing power. 

May an SPD on the grid side of the inverter is worth a try.

 

Another non-electrician putting in his 2.5C worth. This must surely compound? There will be an increasing number of inverters in that area, all connected for a brief period and either demanding or exporting power. 

@Ralf mentioned that all used to be well, but recently the system has started tripping as the load shedding starts. This may be an explantion: The ever growing number of inverters on the same grid segment, all reacting to the grid losing power. 

May an SPD on the grid side of the inverter is worth a try.

I have actually given thought to the very same scenario. It cannot be ruled out until its proven otherwise. 

@ralph  this calls for a bit of experimenting, its got my full attention, where are you located? 

Hi all

Thank you firstly for all the ideas and advice, much appreciated.

@coulomb I also thought the mode setting might make a difference, but unlike the familiar Axpert inverters, the Riio Sun differes in its mode settings and explanation of the mode functions. Setting are as follows:

0-AC First
1-BATT First
2-Time Ctrl
3-Ubat Ctrl/ SOC Ctrl
4-AC IN backup
Default:0

(AC in source priority
Note:
ACin First: The system will work in AC input first
mode (default)
When there is an AC input, the load will firstly be
powered by the AC input. When the solar panel is
sufficient to charge the battery independently and
there are still some surplus solar power, it will also
supply power to the AC load together with the AC
input.
BATT First: The system will work in battery first
mode.
When the PV power is more than the power of the
AC load in operation, the solar energy will charge
the battery and supply power to the AC load first.
When the PV power is less than the power of the
AC load in operation and the solar panel is
insufficient to take the AC load, the battery will
discharge to supply power to the AC load together
with the solar panel
When the battery is running low (lead-acid battery
under low-voltage protection or lithium battery
under SoC protection) and both solar and battery
are insufficient to power the load, the AC load will
be powered by the grid only, and the battery will be
charged by the grid as well as the solar panel until
the battery is charged at constant voltage and the
overload is removed, the system will disconnect the
grid power supply and restore to the battery first
mode.
Time Ctrl: Set the time period for the BATT First
mode, once it exceeds this time period, it will
automatically switch to the AC input to supply
power
In the ACin Logic Time Ctrl setting in the TBBLink
User Control interface, up to three valid periods
can be set
In the ACin Logic Time Ctrl setting in the TBBLink
User Control interface, you can turn ON/OFF Auto
Charge when U_BAT_LV Warning to choose
whether to automatically switch to AC input
charging when the battery voltage is low
Ubat/SOC Ctrl: Battery Status Mode
When the battery type is non-TBB SUPER-L, the
Ubat Ctrl will be displayed, and the ACin First
power supply can be turned on/off according to the
battery voltage.
0-AC First
1-BATT First
2-Time Ctrl
3-Ubat Ctrl/ SOC Ctrl
4-AC IN backup
Default:0

At present it is set to 0-AC First. I don't know which of the other settings will possibly correct this and the system needs to be automatic for various security reasons.

I have installed an SPD on the AC supply side of the inverter, but since then Murphy has postponed loadshedding 🙄🤯 so I have not been able to test if this has fixed the problem.

 

 

Another non-electrician putting in his 2.5C worth. This must surely compound? There will be an increasing number of inverters in that area, all connected for a brief period and either demanding or exporting power. 

@Ralf mentioned that all used to be well, but recently the system has started tripping as the load shedding starts. This may be an explantion: The ever growing number of inverters on the same grid segment, all reacting to the grid losing power. 

May an SPD on the grid side of the inverter is worth a try.

 

 

Another non-electrician putting in his 2.5C worth. This must surely compound? There will be an increasing number of inverters in that area, all connected for a brief period and either demanding or exporting power. 

@Ralf mentioned that all used to be well, but recently the system has started tripping as the load shedding starts. This may be an explantion: The ever growing number of inverters on the same grid segment, all reacting to the grid losing power. 

May an SPD on the grid side of the inverter is worth a try.

Thanks Bob, the system is currently installed in a rural area on a farm that is supplied by a 11KV line stepped down to 380V 3 Fase and according to our knowledge there are no Grid Tied installations on this same feed, but we could be wrong. This inverter is single fase and is only supplied by one fase.

 

@ralph  this calls for a bit of experimenting, its got my full attention, where are you located? 

Hi BRC, thank you for your interest. The installation is outside a small village called Wolseley, near Ceres (where the fruit juice comes from😉) in the Western Cape, South Africa.

News just in:

Murphy has moved on and we are scheduled to have loadshedding this evening from 20H00-22h30. So we should be able to see if the SPD has resolved the problem. Keep your fingers crossed.

I will update once we know.

Holding thumbs. It would be interesting to know the reason for it working if it does. 

 

Hi BRC, thank you for your interest. The installation is outside a small village called Wolseley, near Ceres (where the fruit juice comes from😉) in the Western Cape, South Africa.

Ouch that is out reach by far for me as I am in the Republic of Germiston 😊  . Wolseley is in a beautiful part of our Country. I grew up in Somerset-West and Paarl .

Edited October 5, 20232 yr by BritishRacingGreen

 

News just in:

Murphy has moved on and we are scheduled to have loadshedding this evening from 20H00-22h30. So we should be able to see if the SPD has resolved the problem. Keep your fingers crossed.

I will update once we know.

Good , I have a particular interest in this mode failure , as there are a number of users in the wild that may experiencing this problem.

 

Thanks Bob, the system is currently installed in a rural area on a farm that is supplied by a 11KV line stepped down to 380V 3 Fase and according to our knowledge there are no Grid Tied installations on this same feed, but we could be wrong. This inverter is single fase and is only supplied by one fase.

This I know: something has changed. According to the time line you gave at the top of this thread, you made some changes and everything was working fine. Then at some later time the system started tripping as load shedding started. 

So something has changed since you reconfigured the system. 

And then it's either external to you or internal (on your side of the inverter). 

This is large chunks of my working life, looking for the "something". 

 

This is large chunks of my working life, looking for the "something

True.

And as U2 says :"..... I still havent found what I'm looking for.... "

20 hours ago, Bobster. said:

So something has changed since you reconfigured the system. 

 

 

Did the issue arise immediately after installing the new battery or later? It's not quite clear in the original post.