Help with weird AC problem anyone?

[ditchcrawler]

 

But Psycloud's IS a PSW one, as is mine!

And centre tapped

[Theo]

Modified sine wave inverters generate loads of harmonics, which then flow to earth. This is what is lighting your LEDs and causing the earth loop hum. Unfortunately harmonics are made up of many frequencies which can make them difficult to filter out.

 

I don't think you can do anything to stop them lighting when switched off other than unplugging them or going for the drastic solution of replacing the inverter with a PSW one.

 

That is not really surprising when you consider that the MSW waveform is merely a square wave with gaps in it.

 

N

[cuthound]

That is not really surprising when you consider that the MSW waveform is merely a square wave with gaps in it.

 

N

Well the better ones do try to round the corners off a bit

[Theo]

Well the better ones do try to round the corners off a bit

 

Is there an accepted standard for when MSU becomes PSU?

 

N

[cuthound]

Is there an accepted standard for when MSU becomes PSU?

 

N

I don't think there is, but if there was it would have to be based on total harmonics under no load conditions.

[Loafer]

Well, my lack of progress so far: Re-established a proper earth link from inverter case to boat chassis.

 

No change- Hifi tripped the RCD after 40 mins.

 

Removed the earth wire from the hifi's mains plug. Tripped the RCD just the same.

 

Advice, from the eBay seller of the inverter, includes the following:

 

'Nearly all inverters are wired that way. The only way to cure the problem is to remove the RCD. They don't work properly with these kind of inverters'.

 

Or words to that effect.

 

Tomorrow I'm going to bypass temporarily the RCD, and try again, with a bit of judicious back-of-fingers tapping on all powered equipment.

 

If there's still anyone awake on this thread, I'll report back later!

[nicknorman]

Well, my lack of progress so far: Re-established a proper earth link from inverter case to boat chassis.

 

No change- Hifi tripped the RCD after 40 mins.

 

Removed the earth wire from the hifi's mains plug. Tripped the RCD just the same.

 

Advice, from the eBay seller of the inverter, includes the following:

 

'Nearly all inverters are wired that way. The only way to cure the problem is to remove the RCD. They don't work properly with these kind of inverters'.

 

Or words to that effect.

 

Tomorrow I'm going to bypass temporarily the RCD, and try again, with a bit of judicious back-of-fingers tapping on all powered equipment.

 

If there's still anyone awake on this thread, I'll report back later!

Seems odd that the RCD still trips without an earth on the hifi. The RCD trips with a mismatch between the live and neutral currents, but for this to happen the current must be going somewhere else ie via earth. Does the HiFi have anything else connected to anything that could be touching the hull, eg an aerial, some other metal to metal contact etc? Any bags of damp stuff touching it (eg human beings or other animals?

[Loafer]

Seems odd that the RCD still trips without an earth on the hifi. The RCD trips with a mismatch between the live and neutral currents, but for this to happen the current must be going somewhere else ie via earth. Does the HiFi have anything else connected to anything that could be touching the hull, eg an aerial, some other metal to metal contact etc? Any bags of damp stuff touching it (eg human beings or other animals?

 

That's now the next study in the morning, nicknorman. Ta for that!

 

Indeed, it is most logical that there's still an earth leakage somewhere, Captain.

 

I'm no mug with electrics, but this one is baffling to say the least.

 

Ponder, ponder. Drink.

[Iain_S]

(snip)

Removed the earth wire from the hifi's mains plug. Tripped the RCD just the same.

(snip)

 

That's interesting.

We had a similar thing on Gamebird. Set up was small invertor, centre tapped earth, plug in RCD and a laptop mains charger, which had a plastic earth pin, so no electrical connection. Tripped RCD every time. Never did work out how.

[Loafer]

 

That's interesting.

We had a similar thing on Gamebird. Set up was small invertor, centre tapped earth, plug in RCD and a laptop mains charger, which had a plastic earth pin, so no electrical connection. Tripped RCD every time. Never did work out how.

 

Bum. I was full of hope when I started reading your post! I'm at phase 3 of my investigation now, which is to bypass the RCD, and then go poking around with my meter on everything 240V. And see if the stereo stays on.

 

Is there anyone out there successfully using 12V stuff for their audio entertainment? (A £100 car stereo from Halfords just will not 'do'!)

[Dinz]

Why not just get a small puresine inverter dedicated solely for your hi-fi?

Clearly you want to keep your present kit but faffing around like this may well lead to damage to the kit you have.

End

[Loafer]

Why not just get a small puresine inverter dedicated solely for your hi-fi?

Clearly you want to keep your present kit but faffing around like this may well lead to damage to the kit you have.

End

 

I thought of that but would rather go all 12V. Plus the wife likes her Krupps coffee machine which needs a big inverter.

 

At the moment the RCD has been temporarily bypassed and so far everything is working properly. Hifi has been on 20 mins now, but it used to do that anyway before the RCD tripped. I'm sitting nervously waiting to see what happens in another 20 mins' time!

[Paul C]

 

 

 

Is there anyone out there successfully using 12V stuff for their audio entertainment? (A £100 car stereo from Halfords just will not 'do'!)

 

Why not, are your ears somehow different to normal? A decent car stereo brand/model such as an Alpine will quite reliably play CDs, MP3, radio just like a home hifi, happily on 12V (and cope with wide variations in the input voltage too......) I'd say 85% of the quality comes from the speakers anyway, if your hifi speakers are 4 ohm and you can make the connections (how many speakers are you using?) you'd never tell the difference. All Alpines have at least 2 line outs, the better ones have three; and decent equalisation contols (mine has 3 band parametric EQ). If you wanted to get fussy there's more options available such as using a DSP with it too etc

 

I can't help thinking its down to the inverter - would it be worth finding another boater with a PSW inverter and powering your stereo from their electricity, as a check?

[Loafer]

 

Why not, are your ears somehow different to normal? A decent car stereo brand/model such as an Alpine will quite reliably play CDs, MP3, radio just like a home hifi, happily on 12V (and cope with wide variations in the input voltage too......) I'd say 85% of the quality comes from the speakers anyway, if your hifi speakers are 4 ohm and you can make the connections (how many speakers are you using?) you'd never tell the difference. All Alpines have at least 2 line outs, the better ones have three; and decent equalisation contols (mine has 3 band parametric EQ). If you wanted to get fussy there's more options available such as using a DSP with it too etc

 

I can't help thinking its down to the inverter - would it be worth finding another boater with a PSW inverter and powering your stereo from their electricity, as a check?

 

Thanks for your answer, Paul C. I agree that the sound would probably be adequate - but I don't need the amp to have sources of its own. I only need 2X RCA inputs (although I can get away with just one) to use the sound sources I already have, e.g. a Bluetooth device to play thousands of MP3 tracks from 'pooter, TV sound output for movies and concerts, stuff like that. I'm not looking for a CD player or tuner - I have all that in other forms. I use just a standard pair of Dali 'Lector' bookshelf speakers which are good enough for me.

 

Most of the 'car stereos' that I have seen in boats aren't good enough, hence my dislike of them. I confess to having been an audiophile all my life and like quality, full sound. Maybe I ought to look at some Alpine models as you suggest, perhaps they are good enough.

 

Even then, though, I'm unlikely to embrace a car stereo, with all its silly lights flashing away, where my Cambridge Audio amp used to be!

 

 

 

I can't help thinking its down to the inverter - would it be worth finding another boater with a PSW inverter and powering your stereo from their electricity, as a check?

 

Not really - it would be a colossal faff.

 

It's all working now and hasn't tripped because I've removed the trip. There's nothing live to the touch anywhere.

 

This brings me to the BSS due next spring. If I just remove the inverter that day, like I do all the stuff from my gas locker, then I have no AC system on board, do I?

[Paul C]

Alpine are one of the better ones when it comes to a sensible display/buttons, rather than "silly flashing lights" etc.

 

They also have line inputs and the slightly dearer ones have bluetooth too. And if you don't want a CD player they now do something called a "media receiver" - although you seem to pay for NOT having a CD player, bizarrely. Also bear in mind that the CD player will read a data CD with MP3s and other audio formats on it - freeing the computer for something else, or not being used (save power etc).

 

If the stereo/hifi is the ONLY mains item on the boat, then it makes a lot of sense to "convert" to 12V only. But its up to you.

[GUMPY]

Why are you worried about the quality of the system if you are using MP3 and streaming Bluetooth? Both are sonically crap.

[ditchcrawler]

 

to use the sound sources I already have, e.g. a Bluetooth device to play thousands of MP3 tracks from 'pooter,

 

. I confess to having been an audiophile all my life and like quality, full sound.

 

 

I am not quite sure how those two go together

[Loafer]

I am not quite sure how those two go together

 

They don't really, I simply want to make the best of what I have, which is a good-sounding stereo. If I go round to the average mate's boat and listen to music there, it is almost ALWAYS sadly lacking in quality. Almost always a car stereo. Dull, boxy, tinny, all seemingly fine with the owner! All my MP3 and AAC stuff was recorded at the best possible settings, and when played through 'proper British HiFi' it sounds most acceptable.

 

I downgraded from a very good Linn and Meridian system to my present Cambridge Audio stereo tuner-amplifier when living aboard.

 

I agree with all of you in that I can't get total satisfaction on a narrowboat, but I am very happy with my system when it doesn't trip off.

 

Now that I have no RCD protection for the time being, am I right in assuming there's no risk to passers-by with my floating earth on the hull? If the 240VAC is produced entirely within the hull and earthed to it, anyone aware of potential dangers to those not on the boat?

Why are you worried about the quality of the system if you are using MP3 and streaming Bluetooth? Both are sonically crap.

 

But they are still better than any car stereo set-ups I've heard, and the CD storage would be an issue. Maybe I haven't heard enough 'good' car stereos, but I haven't liked what I've seen so far. More research, I guess!

Edited November 16, 2015 by Loafer

[Loafer]

Alpine are one of the better ones when it comes to a sensible display/buttons, rather than "silly flashing lights" etc.

 

They also have line inputs and the slightly dearer ones have bluetooth too. And if you don't want a CD player they now do something called a "media receiver" - although you seem to pay for NOT having a CD player, bizarrely. Also bear in mind that the CD player will read a data CD with MP3s and other audio formats on it - freeing the computer for something else, or not being used (save power etc).

 

If the stereo/hifi is the ONLY mains item on the boat, then it makes a lot of sense to "convert" to 12V only. But its up to you.

 

I will take a look, Paul, Ta. Yes, it would suit to have 12V audio on board. Maybe I'll have to accept a car stereo in a box!

[ditchcrawler]

 

 

 

Now that I have no RCD protection for the time being, am I right in assuming there's no risk to passers-by with my floating earth on the hull? If the 240VAC is produced entirely within the hull and earthed to it, anyone aware of potential dangers to those not on the boat?

 

If you dont have any shore connection it should be fine, also you will have a maximum of 120 volts to earth. Your earth is not floating its tied to the center point of the supply, you just dont have RCD protection to disconnect the supply if you have an earth fault.

[Paul C]

Most car stereos are hampered by being in a car...with the engine running, and road/wind noise too. Sit in a modern luxury car and the stereo is naturally better. Boat, without engine running, will naturally be better still. I suggested dsp or paying particular attention to the tone controls to tweak it if its a little off, but at the end of the day there's nothing wrong with decent car stereo s and its down to the standard speakers fitted in cars mainly. People seem to forget to upgeade these but its the best upgrade for the money.

[Loafer]

Most car stereos are hampered by being in a car...with the engine running, and road/wind noise too. Sit in a modern luxury car and the stereo is naturally better. Boat, without engine running, will naturally be better still. I suggested dsp or paying particular attention to the tone controls to tweak it if its a little off, but at the end of the day there's nothing wrong with decent car stereo s and its down to the standard speakers fitted in cars mainly. People seem to forget to upgeade these but its the best upgrade for the money.

 

That's all true. I'm going to have to go this route anyway, as I can see no decent 12V stuff that doesn't look like it should be in a car dashboard.

 

Either that or move back to dry land. Ugh, no.

[Paul C]

 

That's all true. I'm going to have to go this route anyway, as I can see no decent 12V stuff that doesn't look like it should be in a car dashboard.

 

Either that or move back to dry land. Ugh, no.

 

Economy of scale.......nobody is going to make a 12V powered stereo specifically for an application other than a car/truck, it would be commercially daft. And yes, I know there's specialist marine stuff, but these tend to be speakers (and for some reason, amplifiers too). The DIN-sized format makes a lot of sense on a boat too.

[Loafer]

If you dont have any shore connection it should be fine, also you will have a maximum of 120 volts to earth. Your earth is not floating its tied to the center point of the supply, you just dont have RCD protection to disconnect the supply if you have an earth fault.

 

Thanks DC. Any idea how I'd fare with a BSC examiner? Especially if I removed the inverter and 'declared' no AC system operational?

 

I'm happy at the moment with the safety of this arrangement, knowing the limited 240V stuff we use, but would like to make it completely safe.

 

I'm reluctant to buy any more Victron stuff since I've lost two of their combos, all out of warranty and out of range. Hence the purchase of a cheap one. It shouldn't matter that it's cheap though, should it? It should at least provide a suitably clean PSW output safely, like it says on the box?

 

ETA: Well it doesn't actually say 'safely' on the box!

Edited November 16, 2015 by Loafer

[ditchcrawler]

Hence the purchase of a cheap one. It shouldn't matter that it's cheap though, should it? It should at least provide a suitably clean PSW output safely, like it says on the box?

 

ETA: Well it doesn't actually say 'safely' on the box!

May be it does. I will have to go back and start reading the thread from the beginning, but from my conversation with a BSS inspector if you dont have a "Shore Supply" then for BSS you don't have to have a RCD. but I am not sure this is 100% correct.

Do you have a second RCD on the shore supply to the battery charger?