# reverse polarity question



## bazzal (Apr 15, 2006)

:roll: Hello all, just a question if anyone can help. I tried a generator 240 volt hooked up to my 2006 Autocruise Sarasota today and found that the reverse polarity light came on on the EC200 control panel so I unplugged the gene then switch the live-neutral wires over and tried again but with the same result Hmmm! again I unplugged the gene and used my site hook-up cable with 3 pin to plug into the house and this was fine. Could anyone throw a light on this prob or is it normal. Cheers Baz................


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## cabby (May 14, 2005)

this is an interesting one. obviously when you plugged your hook up cable to the house mains and all was well with the world, then the fault is not with the motorhome.were you using the same cable to connect to the genny. is the connection to the genny 3 pin or the blu 7 pin euro connection. have you used a mains tester on the output side of the genny.


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## 88724 (May 9, 2005)

Hi

First are you certain that the reverse polarity light is on for fault? I have seen these wired for ON means fault and on other units OFF means fault.

Next this is a fairly normal occurance due to the fact that the genny as a floating earth.

When you tried it afterwards with the house cable had you swapped the live neutral back? (or was that only on the genny wiring?)


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## bazzal (Apr 15, 2006)

*reverse polarity*

Cheers for the replys george/cabby. The cable is not the same one but showed the same result when unplugged from the house or in to the gene, the cable from the gene to m/h is a 3 pin and it was this that I changed the wires over in (live-neutral & back). The polaraty light does not come on when connected on normal house electric. I fitted a polarity change-over unit in my last m/h between input and mainboard and when in europe I plugged in checked to see if the light was green or red, if red I just flicked the switch and it changed polarity showing me a green light. I have never tried a generator before and was only trying this one to see if it would charge my batteries and what it would run ie; tv-dvd before buying one. It's a sinewave master 1kw. I have not tried a tester on the output, what would this tell me and what am I looking for. Cheers Baz....


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## 88724 (May 9, 2005)

Hi Bazzal

Depends on the tester you are going to use and what you are looking for.
If you feel nevous with a tester and mains, get someone else to test for you.

You will probably find that the voltage between earth and Live is 240 and between neutral and live is the same on the generator (hence its showing reverse polarity, when in fact its both reversed and normal hence when you reversed the wires it showed the same _fault_), on household mains it would only show 240v between Live and Earth, Neutral and earth have the same potential.

1 Kw will run TV DVD Hot water, allsorts, to run it for battery charging is pretty pointless *unless you have a good charger* on the normal stuff thats fitted (Zig Plug in etc) its ridiculous you would need to run for many hours to put a really pathetic amount of power in.


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## bazzal (Apr 15, 2006)

*reverse polarity*

Hi all, I called Sargents electronics today (they made the control unit fitted to my m/h) and told them about the light being on with the generator running and not on with the house mains hook-up, and they said that this is normal and theres nothing to worry about. The power that comes via the gene floats and will cause the light to come on and flicker and changing the wires over in the plug makes no difference. It's only when on mains hook-up that if the light comes on that I need to change polarity.

Cheers all, Baz.......................


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## 88724 (May 9, 2005)

Hi Bazzal

The earth that Floats not the power, its as per my first post

_*this is a fairly normal occurance due to the fact that the genny as a floating earth. *_

Glad you are all sorted

George


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## hymerbug (Jan 10, 2006)

hi george what sort of good charger are you talking about to make it wothwhile using with a 1Kwatt generator and how would you connect to the leisure battery / batteries.
colin


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## 88724 (May 9, 2005)

Hi Colin

Zigs and plug in systems efforts are pathetic as chargers, for continuos on-site use they are OK (this just uses the battery as a capacitor for smoothing and small reserve duties), a good charger would be something like DABurliegh as just bought a 50A Sterling, this will make use of the Generator's output and put worthwhile charge in rapidly, also cutting down the running time needed for the genny.


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## gromett (May 9, 2005)

GeorgeTelford said:


> Hi Colin
> 
> Zigs and plug in systems efforts are pathetic as chargers, for continuos on-site use they are OK (this just uses the battery as a capacitor for smoothing and small reserve duties), a good charger would be something like DABurliegh as just bought a 50A Sterling, this will make use of the Generator's output and put worthwhile charge in rapidly, also cutting down the running time needed for the genny.


Just a quick question George, I have a Victron 12/1600/70. By my calcs 
70(A) * 12 (V) = 840 VA.

Q) Allowing for losses, charging voltages etc a 1KW Genny should be able to put maximum current into my batteries?
Q) As I understand it the 70A charge will only happen for a short period when on Bulk charge?
Q) How long would it take for the Genny to bring the batteries up to say 90-95% charge (2 X 200AH) if the batteries were down to say for example 55%
Q) Am I correct in assuming going to a 2KW Genny would not help at all.

Thanks in advance.

Cheers
Karl


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## 88724 (May 9, 2005)

Hi Karl

The Charger wont ever be putting out 12v so the wattage would be higher 13.8 to 14.6 Volts from memory 

VA (KVA) is usually used to express "Phased" power factor, not applicable here.

Yes it should be able to Max Charge your batteries, a 1 KW genny is being used to the Max by the victron charger.

Niot sure but would Imagine the Victron follows a similar regime to Sterlings IUoUo pattern, in which case the First part would be constant current, then an absorbtion phase where the current tapers down

The absorbtion Phase is adjustable in time terms and I am not familiar with Victrons reccomended best settings.

Going in between 90-95 % means putting back 150 Amps, allowing for battery inefficiency in accepting charge lets guess 15% means you need to put in 172 Amps at a straight run that would be 2.5 Hrs, but in the absorbtion phase the ampage is constantly dropping so I would estimate 3.5 Hours

But would you be using that much per day? if this is a few days usage saved up, I think better results would be achieved by charging daily for 1 + hours

Trying to put the same amount back via Zig etc would take weeks........... 

Tired post, hopefully I wont think it looks dumb when I check back later today....


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## DABurleigh (May 9, 2005)

I have the same Victron integrated mains charger/inverter/UPS as Karl. The Sterling I have bought is the 50A battery to battery charger for rapid charging from the alternator. A 1kW Honda EU10i is also available for aircon or charging at ~50A but I would hope only needed for the former once I have the Sterling installed.

What is your battery capacity, Karl? Charging at a rate greater than a fifth of that (as a ruile of thumb) adversely affects battery life.

And George, you missed the opportunity to point out Karl won't be able to charge at 70A when it warms up  Which is why I got the 1600/70A and not the 1200/50, which otherwise would have been sufficient for my needs .....

Dave


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## gromett (May 9, 2005)

Thanks for the answers George.



GeorgeTelford said:


> The Charger wont ever be putting out 12v so the wattage would be higher 13.8 to 14.6 Volts from memory


I realised that which is why I mentioned charging voltages, I was just working it to the nearest figures for convenience sake.



GeorgeTelford said:


> VA (KVA) is usually used to express "Phased" power factor, not applicable here.


Yup, got my terms wrong there, I was thinking of Generator output which is going into a toroidal transformer (inductive load) and could'nt be bothered with Power Factors etc. The output is DC so I should have used Watts. Well spotted.



GeorgeTelford said:


> Yes it should be able to Max Charge your batteries, a 1 KW genny is being used to the Max by the victron charger.


Great, that will save me some dosh then. I was wondering due to charging voltages, gennie efficiency, charger efficiency etc if the power required would go over the 1Kw of the generator from the 840 Watts roughly indicated.



GeorgeTelford said:


> Niot sure but would Imagine the Victron follows a similar regime to Sterlings IUoUo pattern, in which case the First part would be constant current, then an absorbtion phase where the current tapers down


It has a 4 stage charger built in, Bulk, absorbtion, float and I forget the other one. I will look into it and find out what the charge rates are.



GeorgeTelford said:


> Going in between 90-95 % means putting back 150 Amps, allowing for battery inefficiency in accepting charge lets guess 15% means you need to put in 172 Amps at a straight run that would be 2.5 Hrs, but in the absorbtion phase the ampage is constantly dropping so I would estimate 3.5 Hours
> 
> But would you be using that much per day? if this is a few days usage saved up, I think better results would be achieved by charging daily for 1 + hours


Thanks, so 3.5 hours if I leave it to get down to that state. I will probably top it up more regularly than that. But some sites I just don't want to use a generator on, or can't tolerate the noise some days. I am a bit of a v meldrew when it comes to noise



GeorgeTelford said:


> Tired post, hopefully I wont think it looks dumb when I check back later today....


Thanks George, much appreciated an no never dumb


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## gromett (May 9, 2005)

DABurleigh said:


> What is your battery capacity, Karl? Charging at a rate greater than a fifth of that (as a ruile of thumb) adversely affects battery life.


I have 2 x 200AH AGM batteries. So thats 400AH/5 = 80A which is above the 70 or 50 A of charging available , Georges post seemed to cover that I think.



DABurleigh said:


> And George, you missed the opportunity to point out Karl won't be able to charge at 70A when it warms up  Which is why I got the 1600/70A and not the 1200/50, which otherwise would have been sufficient for my needs .....


I think thats why he added an hour from 2.5 to 3.5.

What batteries do you have Dave please? How long does it take to charge yours up with your Gennie from say 55%?

Cheers
Karl


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## 88724 (May 9, 2005)

Hi Dave 

do you mean the temp sensing on the Victron charger part? lowering the charge rate for temperature?, in reality at higher ambients a battery accepts charge easier so in effect the same actual charge is being achieved, they lower it to avoid the easy "overcharging" that can occur at temperature (this statement is a simplified explaination) 


Grommet

Beware when buying a genny that it is Actually 1 Kw and not KVA the Honda EU 10 i for example is a Power Factored 1 Kva genny but actually in reality it is only a 900Watt continuous power (1 Kw for spurts/surge)


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## gromett (May 9, 2005)

GeorgeTelford said:


> Hi Dave
> Grommet
> 
> Beware when buying a genny that it is Actually 1 Kw and not KVA the Honda EU 10 i for example is a Power Factored 1 Kva genny but actually in reality it is only a 900Watt continuous power (1 Kw for spurts/surge)


Are you saying I should go for the 2Kw one then? I am definately looking at the Hondas.

Cheers
Karl


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## gromett (May 9, 2005)

Just done a search for specs on the Honda's
EU1 1Kw, Rated output is .9Kw Max output 1Kw £500 exc vat (roughly)
EU2 2Kw, Rated output is 1.6Kw Max output is 2Kw £750 (roughly)

So EU1 is £555/Kw (rated) (£500/.9Kw)
And EU2 is £468/Kw (rated) (750/1.6Kw)

I think I will go for the 2Kw, as I will want to continue to use equipment in my van while the batteries charge and the 1Kw one would then be split between charging and operating equipment. With 2Kw, I can run my equipment and charge at full speed.

Decision made, Thanks George and Dave much appreciated.

Cheers
Karl


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## DABurleigh (May 9, 2005)

Karl - Certainly when the Victron is wacking out ~50A an EU10i won't have much left. With stuffing in as much as 200Ah (50% capacity) then you'd be talking 5-6 hours to replenish fully. Only you can judge whether you'd do this much that often to justify the extra weight, size and cost of an EU20i to do other things at the same time.

George regarding the temperature bit I was merely referring to the Victron spec drop-off above ~25deg.

I currently have 2*100Ah Elecsols under the driver's seat, though I am thinking of putting the Sterling b2b 50A alternator charger where they are and having Squadron FLA semi-traction (dependent on price) as big as I can get (at least [email protected]) next to the Victron box further back.

Dave


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