Inverter and microwave/toaster

[blackrose]

For the first time today I ran my automatic washing machine with a full 30C cycle from my new inverter (Sterling ProPower SB 2200w PSW) which I fitted a couple of months ago. The sun was shining so I didn't start the engine as I had up to 28 amps going into the batteries from my solar panels and the batteries were at a decent voltage (between about 12.8v - 14v during the cycle). I had no problems running the machine.

 

Yet if I try to run my microwave from the inverter it sounds like it's only running at half power and takes twice as long to heat anything up. The small toaster is the same and the elements seems to hardly get red. I don't really understand it. The inverter also tripped when I tried to run a 1200w wet vac recently. My batteries are always well charged and I've got 70mm2 cables from the batteries to the inverter about 1.5m long one way. All the terminals and connections are clean & tight.

Edited January 2, 2023 by blackrose

[nicknorman]

I think the wet vac is not too surprising as the sorts of motors in these things have a very high startup transient power demand.

 

But as to the toaster, being a resistive load that does seem odd. Are you sure you haven’t bought a 110V inverter by accident? The washing machine might be designed to run on 110 - 230v.

 

The inverter has a power output display, with the toaster on what does the power output display show and what is the power rating of the toaster?

 

 

Edited January 2, 2023 by nicknorman

[blackrose]

The inverter says 230v and it runs the other mains appliances on the boat like the fridge and the TV, etc. 

 

The toaster is 900-980w and the inverter is displaying about 620w with the toaster switched on.

Edited January 2, 2023 by blackrose

[matty40s]

I'd get some old kit if I were you. My old(30 years old this year) chunky wave Heart Interface (thanks Gibbo) runs my microwave no problem, and also my wetvac(1800w ancient thing).

I have only 6x 110ah batteries.

[blackrose]

3 minutes ago, matty40s said:

I'd get some old kit if I were you. My old(30 years old this year) chunky wave Heart Interface (thanks Gibbo) runs my microwave no problem, and also my wetvac(1800w ancient thing).

I have only 6x 110ah batteries.

 

Well it's a pretty basic PSW inverter. My old 1800 MSW inverter didn't run the microwave very well either. Perhaps the microwave and the toaster are just a bit old and worn out. They're both about 17 years old 

Edited January 2, 2023 by blackrose

[TheBiscuits]

Have you tried the microwave and toaster on a different AC socket, or even directly to the inverter?

 

I was previously wondering if you had a complicated digital/wifi/bluetooth controlled toaster but that's unlikely at 17 years old!

[blackrose]

Ok I'll try that tomorrow.

[GUMPY]

9 hours ago, matty40s said:

I'd get some old kit if I were you. My old(30 years old this year) chunky wave Heart Interface (thanks Gibbo) runs my microwave no problem, and also my wetvac(1800w ancient thing).

I have only 6x 110ah batteries.

Hearts were great, well ahead of the time.

From memory they are MSW but still ran most things without problems, I never did work that one out. Unfortunately the one that was on Loddon when I got it had already lost it's smoke and it was cheaper to buy a new combi.

 

[blackrose]

It's the same when I run the microwave and toaster direct from the inverter.

[blackrose]

I visited Sterling this morning as I'd arranged to take the inverter there for testing. I took the toaster there too so they could see the issue for themselves.

 

They found that the output voltage of the inverter was low (around 220v). They said this was a very rare occurrence related to the voltage regulator and swapped my inverter for a new one - tested first to make sure it was ok. 

 

One could make the criticism that Sterling's QA should be testing their products before they go out. I'm not sure how viable it is to test every unit of every product going to all their distributors in this country and around the world as I'm not in electronics manufacturing. However, they're not the only manufacturer to have issues reported about their products on this forum. 

 

What I do know it's that their customer service is excellent. I took the inverter there myself because I was sort of passing the area for work this morning and it just saved me sending it. I don't think many marine electronics suppliers would let you into the testing/repair workshop and make you a coffee and test your returned item while you wait with you watching and asking questions. They were just a little annoyed that I hadn't brought any bread with me to make some toast!

 

Edit: just don't turn up there without an appointment.

Edited January 9, 2023 by blackrose

[Tracy D'arth]

I have always found Sterling to be brilliant if you have a problem.

[IanD]

17 hours ago, blackrose said:

I visited Sterling this morning as I'd arranged to take the inverter there for testing. I took the toaster there too so they could see the issue for themselves.

 

They found that the output voltage of the inverter was low (around 220v). They said this was a very rare occurrence related to the voltage regulator and swapped my inverter for a new one - tested first to make sure it was ok. 

 

One could make the criticism that Sterling's QA should be testing their products before they go out. I'm not sure how viable it is to test every unit of every product going to all their distributors in this country and around the world as I'm not in electronics manufacturing. However, they're not the only manufacturer to have issues reported about their products on this forum. 

 

What I do know it's that their customer service is excellent. I took the inverter there myself because I was sort of passing the area for work this morning and it just saved me sending it. I don't think many marine electronics suppliers would let you into the testing/repair workshop and make you a coffee and test your returned item while you wait with you watching and asking questions. They were just a little annoyed that I hadn't brought any bread with me to make some toast!

 

Edit: just don't turn up there without an appointment.

 

All equipment like inverters should (must?) have 100% outgoing test, it's easy to have a bad connection or assembly fault which doesn't show up until build is complete -- and for something generating mains voltage I would have thought this is essential, maybe even legally compulsory along with checking things like earth leakage and insulation resistance.

 

Doing all this is quick and simple, you plug it into the test equipment, turn in on, press a "test" button (possible on a computer) and get a good/no good result in a few seconds. If there's a manual voltage setting to exactly 230V then this would need adjusting, but these tend to be avoided nowadays as a potential cause of output voltage problems if the adjustment pot later moves -- or is moved by someone...

 

However there can always be occasional rogue units which even if they were correct when built drift afterwards, and at least Sterling fixed yours without complaint 🙂

[Chewbacka]

21 hours ago, blackrose said:

I visited Sterling this morning as I'd arranged to take the inverter there for testing. I took the toaster there too so they could see the issue for themselves.

 

They found that the output voltage of the inverter was low (around 220v). They said this was a very rare occurrence related to the voltage regulator and swapped my inverter for a new one - tested first to make sure it was ok. 

 

One could make the criticism that Sterling's QA should be testing their products before they go out. I'm not sure how viable it is to test every unit of every product going to all their distributors in this country and around the world as I'm not in electronics manufacturing. However, they're not the only manufacturer to have issues reported about their products on this forum. 

 

What I do know it's that their customer service is excellent. I took the inverter there myself because I was sort of passing the area for work this morning and it just saved me sending it. I don't think many marine electronics suppliers would let you into the testing/repair workshop and make you a coffee and test your returned item while you wait with you watching and asking questions. They were just a little annoyed that I hadn't brought any bread with me to make some toast!

 

Edit: just don't turn up there without an appointment.

Just an observation, most of the EU is 220v and we are 240v, but the EU standardised everything to 230v but with a tolerance that meant that the actual voltage at the wall is unchanged.  So it’s possible that an inverter when built could be tested to check it’s output is say 230v +/-10v which is well within the EU specified tolerance of 230v +10% -6%.

Edited January 10, 2023 by Chewbacka

[IanD]

Just now, Chewbacka said:

Just an observation, most of the EU is 220v and we are 240v, but the EU standardised everything to 230v but with a tolerance that meant that the actual voltage at the wall is unchanged.  So it’s possible that an inverter when built could be tested to check it’s output is between 220~240v which is well within the EU specified tolerance.  

 

True, but of course it depends what happens to the inverter output on and off load, and it's not clear under what condition it was 220V -- if this was no-load then it could drop considerably when the toaster is switched on, especially with any voltage drop in the boat wiring.

 

Whatever the reason, good service from Sterling -- though of course better still would be if the inverter didn't have a fault to start with, so maybe their quality control isn't all it could be... 😉

[Chewbacka]

8 minutes ago, IanD said:

 

True, but of course it depends what happens to the inverter output on and off load, and it's not clear under what condition it was 220V -- if this was no-load then it could drop considerably when the toaster is switched on, especially with any voltage drop in the boat wiring.

 

Whatever the reason, good service from Sterling -- though of course better still would be if the inverter didn't have a fault to start with, so maybe their quality control isn't all it could be... 😉

I was saying that possibly the inverter was not faulty as it’s output may have been within spec, however it was not suitable for your toaster, so well done to sterling for swapping it rather than telling you to get a new toaster.

[blackrose]

2 hours ago, IanD said:

Whatever the reason, good service from Sterling -- though of course better still would be if the inverter didn't have a fault to start with, so maybe their quality control isn't all it could be... 

 

I think the criticism that Sterling tend to use their customers as their quality control might be valid. I've got 2 of their battery chargers, 2 inverters and 2 alternator regulators. Years ago I had an issue with one of the alternator regulators not charging at 14.8v on the absorption phase and again they put it right without any questions. The unit was over a year old but they never even asked me for proof of purchase.

[GUMPY]

3 hours ago, Chewbacka said:

Just an observation, most of the EU is 220v and we are 240v,

No we are not, haven't been for many years.

Both us and Europe are now nominally  230v 

Tolerances are 

UK 230v +10/-6%

EU is 230v +6/-10%

230v is normal at our mooring but it varies from 214 to 245

235v at home and stable.

Edited January 10, 2023 by Loddon

[David Mack]

13 minutes ago, Loddon said:

Both us and Europe are now nominally  230v 

Tolerances are 

UK 230v +10/-6%

EU is 230v +6/-10%

But 220v and 240v are within both of those sets of tolerances.So when the UK changed from a nominal 240V to 230v, did any  equipment in service actually get changed? Or did we just carry on knowing it was within tolerance, with the voltage only being adjusted (closer) to 230v as equipment was replaced?

[GUMPY]

At the time nothing was changed, however stuff has obviously been changed as its been replaced. Voltages in the UK have generally come down it wasn't unusual to see 250v now its more likely to be 235.

I did once have to get EME, as it was then, out to lower the voltage at a previous home as it was getting to 255v o a regular basis.

Cue loads of people measuring their incoming mains just to show its still high.