My UPS makes my TV and Decoder reboot with load shedding. But when I test the unit by turning off the main power at my DB board or unplugging the main power my Tv and Decoder don't reboot. The inverter kicks in and no rebooting of any devices. What is the reason for rebooting during load shedding and not rebooting when I turn off the power manually? Also interesting is that my pc and internet also do not reboot, only my tv and decoder, and everything is connected all time.

Edited April 1, 20231 yr by Shane1

Which inverter is it? It shouldn't cause them to restart. Theuxpower we got installed used to do that but we upgraded the firmware and it's not doing it anymore 

30 minutes ago, mzezman said:

Which inverter is it? It shouldn't cause them to restart. Theuxpower we got installed used to do that but we upgraded the firmware and it's not doing it anymore 

Hybrid Inverter 2 KVA 1600 Watt MPPT 12V- Sun Solar

Some sort of noise or spike coming down the line? 

1.  Check that Live & Neutral haven't been swopped at the 230VAC input to the inverter.

2. If you switch the inverter off at the DB, where do you switch it off?  At the Main Circuit Breaker or at one specific wallplug CB?  Whatever the answer, repeat the test but this time use the other breaker.  See if that makes a difference.

3. Is the inverter earthed?   Is it connected to the main DB earth?

8 minutes ago, Bobster. said:

Some sort of noise or spike coming down the line? 

No, nothing

 

@Bobster.'s  comment made me think...  There are two possible reasons why your TV/decoder might reboot.

1. Your inverter takes too long to switch.
2. As Bobster pointed out, a power spike could also let this equipment somehow fall over.

I tend to think (1) is the more probable cause.

29 minutes ago, Modina said:

1.  Check that Live & Neutral haven't been swopped at the 230VAC input to the inverter.

2. If you switch the inverter off at the DB, where do you switch it off?  At the Main Circuit Breaker or at one specific wallplug CB?  Whatever the answer, repeat the test but this time use the other breaker.  See if that makes a difference.

3. Is the inverter earthed?   Is it connected to the main DB earth?

If I switch the power off at the main or at the wall plug it does not restart the Tv.  It only restarts with load shedding. The inverter is not connected to the Main DB earth. Very strange that it only restarts the tv and decoder but not my pc and modem during load shedding. 

Edited March 31, 20231 yr by Shane1

50 minutes ago, Shane1 said:

Hybrid Inverter 2 KVA 1600 Watt MPPT 12V- Sun Solar

Looks like an Axpert clone. If your inverter has function setting 03 (AC input voltage range) and it's currently set to APL (i.e. 90-280Vac),  try changing it to UPS (170-280Vac) and see if there will be any noticeable difference.

 

3 minutes ago, Kilowatt Power said:

Looks like an Axpert clone. If your inverter has function setting 03 (AC input voltage range) and it's currently set to APL (i.e. 90-280Vac),  try changing it to UPS (170-280Vac) and see if there will be any noticeable difference.

 

Thank you. Will look into it

Power supplies always have bulk storage capacitors.  These are at the input and at the output of the power supply.  Some designers are conservative and also don't count the very last cent, and they fit bigger capacitors.  Also, equipment has widely differing consumption patterns.  So some equipment might be OK with 2000mS blackouts, while other might not tolerate more than 100mS.  So it's not really surprising that you find these differences.

I think you should at least wire a temporary earth and see if that makes a difference.  Check your manual.  The earth terminal is normally next to the L/N input.  Run the earth to the main DB earth.  Only connect the earth wire to a point provided by the manufacturer and that is clearly marked as such.  Don't connect it to something you **think** should be earth, such as the negative battery terminal.

The setting that @Kilowatt Power mentioned will definitely influence the speed at which the inverter decides to switch over.  But it doesn't explain why you have that difference.  This is really a strange one to solve.

7 minutes ago, Modina said:

The setting that @Kilowatt Power mentioned will definitely influence the speed at which the inverter decides to switch over.  But it doesn't explain why you have that difference.  This is really a strange one to solve.

Sure. There shouldn't be any observable difference between LS and turning off the main CB. Both are power outages, real or simulated.

16 hours ago, Kilowatt Power said:

Sure. There shouldn't be any observable difference between LS and turning off the main CB. Both are power outages, real or simulated.

Observable is a strong word I rate,many device power supplies find the difference between 10ms and 20ms changeover to basically be a lifetime

17 hours ago, Modina said:

@Bobster.'s  comment made me think...  There are two possible reasons why your TV/decoder might reboot.

1. Your inverter takes too long to switch.
2. As Bobster pointed out, a power spike could also let this equipment somehow fall over.

I tend to think (1) is the more probable cause.

My thinking was that when you turn off the power at the DB, it's just the power going down. But when load shedding happens there's a surge from somewhere else near to you but from outside your property, and the equipment responds to that. I have heard lots of stories about DSTV decoders not liking surges that happen because of load shedding (and quite a few have been true).

I could be way off the mark here. I can hardly spell ehlektrishan. I could be very wrong. If I'm right then some surge protection on the input side of the inverter might be money well spent.

@Bobster.  Yes this is indeed a possibility.

If the inverter looks back into the power feeding circuit, things will look substantially different with Eskom disappearing or someone just unplugging or switching off the CB that feeds the inverter.

Don't ever attempt confirming with a multimeter what I am about to say now, this is only an academic exercise to try and explain what I mean:

If one were to measure the input impedance of the inverter (think of the impedance being the same as resistance) one would get a highish value.  With the inverter disconnected or the CB switched off, the impedance one would remain the same.

However, if Eskom drops away and the inverter is connected, one would measure literarily a few ohms.  All the small loads as well as potentially some big loads such as the geyser element, pool pump, etc, would all be connected in parallel.  Not only that, but the neighbours loads (if connected to the same phase) would also be measured.  Plus the impedance of the Municipality step-down transformer. 

It is not possible for an AC circuit to somehow store AC.  Due to it's alternating nature, an AC net needs to be driven.  DC is different.  A capacitor can hold DC for days.  (That's why things like CRT TVs and microwave ovens can be lethal, even after being off for many hours).  It is possible that some AC powered device, when loosing power, creates a small residual DC voltage (maybe due to a back-EMF) that takes a few 100 milliseconds to completely bleed away.  It is conceivable that such a small DC voltage on the AC bus could affect the mains-detection circuit within the inverter.

It is very difficult to figure out if the TV/decoder reboot is due to a too long power interruption, or a transient spike.  One would need to hook up an oscilloscope to a small conventional mains stepdown transformer and monitor it's low voltage output.  That way one could confirm or reject transient spike activity as the cause and also measure the blackout period.

47 minutes ago, Modina said:

@Bobster.  Yes this is indeed a possibility.

If the inverter looks back into the power feeding circuit, things will look substantially different with Eskom disappearing or someone just unplugging or switching off the CB that feeds the inverter.

Don't ever attempt confirming with a multimeter what I am about to say now, this is only an academic exercise to try and explain what I mean:

If one were to measure the input impedance of the inverter (think of the impedance being the same as resistance) one would get a highish value.  With the inverter disconnected or the CB switched off, the impedance one would remain the same.

However, if Eskom drops away and the inverter is connected, one would measure literarily a few ohms.  All the small loads as well as potentially some big loads such as the geyser element, pool pump, etc, would all be connected in parallel.  Not only that, but the neighbours loads (if connected to the same phase) would also be measured.  Plus the impedance of the Municipality step-down transformer. 

It is not possible for an AC circuit to somehow store AC.  Due to it's alternating nature, an AC net needs to be driven.  DC is different.  A capacitor can hold DC for days.  (That's why things like CRT TVs and microwave ovens can be lethal, even after being off for many hours).  It is possible that some AC powered device, when loosing power, creates a small residual DC voltage (maybe due to a back-EMF) that takes a few 100 milliseconds to completely bleed away.  It is conceivable that such a small DC voltage on the AC bus could affect the mains-detection circuit within the inverter.

It is very difficult to figure out if the TV/decoder reboot is due to a too long power interruption, or a transient spike.  One would need to hook up an oscilloscope to a small conventional mains stepdown transformer and monitor it's low voltage output.  That way one could confirm or reject transient spike activity as the cause and also measure the blackout period.

I am not going to dispute what is said but I would like you to hold a AC powered capacitor that has been disconnected from AC even minutes later(not 100 milliseconds) if the capacitor has no discharge resistor. Easy to demonstrate the spark when you discharge it long after being disconnected from the mains. 

@Scorp007   Yes, you are 100% correct.  However that is a DC charge.  There are many resistive and inductive leakages in a typical house's mains distribution system.  I doubt if such a DC charge will stick around for long. All those loads will act like that discharge resistor you mentioned.   But I admit that it could take several seconds, or longer.  It really depends on the specific systems connected.  It is different with the caps in microwaves and some other devices where rectifying diodes, etc. can result in a very high impedance that might take hours or even days to dissipate the charge.

3 hours ago, PsyWulf said:

Observable is a strong word I rate,many device power supplies find the difference between 10ms and 20ms changeover to basically be a lifetime

@PsyWulf  Not really. The bulk storage electrolytic capacitors at the input and output of your typical power supply can be thought of as miniature batteries. In small appliances such as radios, cellphone chargers, etc. they can literally take many seconds to discharge.  Even in larger equipment such as HiFi power amplifiers, there will be substantial rail voltage for a number of seconds.  I am sure you must have witnessed this yourself.  You switch something off and the power LED remains lit for 2 or 3 seconds longer before fading away.  These days you even get Super-capacitors that have a few farad of capacitance.  These are made as battery replacements in certain applications.

There are even super-capacitor based batteries that can be used to replace your 48V 50Ah LiFoPO4s.  Advantage is they can be charged very, very quickly and have a far longer life expectance than lithium.  They are still rather expensive.

23 minutes ago, Modina said:

@PsyWulf  Not really. 

Oh riiiiiiiiiiiiiiiiiiiiiiiight

 

That's why my DSTV decoders,PC Power supplies,Audio Amplifier and CCTV system handles a 10ms changeover fine but 20ms causes reboots

Because reasons

 

Next excuse!

Edited April 1, 20231 yr by PsyWulf

41 minutes ago, Modina said:

@Scorp007   Yes, you are 100% correct.  However that is a DC charge.  There are many resistive and inductive leakages in a typical house's mains distribution system.  I doubt if such a DC charge will stick around for long. All those loads will act like that discharge resistor you mentioned.   But I admit that it could take several seconds, or longer.  It really depends on the specific systems connected.  It is different with the caps in microwaves and some other devices where rectifying diodes, etc. can result in a very high impedance that might take hours or even days to dissipate the charge.

I would not mention it if the charge whatever you want to call it AC or DC does not stick around for long. It was part of the learning process decade's ago to charge it and over 30min or so shock young trainees long after we left the wiring. Those days before you could get locked up or helping yourself to neighbours low hanging fruit and being called a thief. 

Yes, I was told by technicians how they as apprentices charged capacitors to a few hundred volts and then threw them around, shouting catch.

7 hours ago, Modina said:

A capacitor can hold DC for days.  (That's why things like CRT TVs and microwave ovens can be lethal, even after being off for many hours). 

I found your post very intersting, thanks, @Modina.

The passage I quote here reminds me of a job I had many years ago, fixing computer hardware in the days of CRT monitors (and physically massive disk drives with removable platter packs). 

There was, of course, an HT circuit in those monitors, with capacitors involved. Us appies were taught to always discharge the HT using a screwdriver before sticking our fingers inside. But, of course, we all promptly forgot this lesson until we relearned it the hard way. 

On 2023/03/31 at 10:13 PM, Shane1 said:

Thank you. Will look into it

Also: Test your earth leakage when load shedding happens and the inverter takes over, see if it works?