Tingling sensation when touching the battery negative pole

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South Africa
South Africa Solar Expert Posts: 295 ✭✭✭
in Advanced Solar Electric Technical Forum #1
Accidentally the other day I was checking my system.

The inverter was on, lights was working and when I brushed against the battery negative pole, I got a tingling sensation.

Yes, the ground cable was not properly connected ... inverter casing is plastic as was the controllers, so I never knew that.

So, I did a quick check. If I leave the inverter on and disconnect the lights cable, and touch the pole again, the sensation is gone.

I presume there is a problem somewhere within the lights circuit, or is this normal?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,445 admin
    #2
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    Re: Tingling sensation when touching the battery negative pole

    You could get some kick back from the AC side of the inverter to the DC side--Especially if it is a "non-isolated" MSW (modified square wave) type inverter.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • South Africa
    South Africa Solar Expert Posts: 295 ✭✭✭
    #3
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    Re: Tingling sensation when touching the battery negative pole

    Thanks Bill. That is then indeed the case. It is a temporary mod since wave I am using.

    Just to confirm, connecting to the batteries, properly this time, to ground will solve this problem for mod sine wave inverter?
    5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied.


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  • BB.
    BB. Super Moderators, Administrators Posts: 33,445 admin
    #4
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    Re: Tingling sensation when touching the battery negative pole

    Yes, as long as none of the AC outputs of the MSW inverter are tied to ground (in North America, we "ground" the AC neutral of our 120/240 VAC circuits--And with MSW inverters if you ground an AC output and the DC input from the battery, it effectively creates a dead short across the inverter).

    Most TSW (true sine wave) inverters have isolation from DC input to AC output--So DC and AC grounding do not affect each other.

    As always, read the manual closely to ensure that your wiring conforms to the inverter's requirements.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • South Africa
    South Africa Solar Expert Posts: 295 ✭✭✭
    #5
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    Re: Tingling sensation when touching the battery negative pole

    Thank you Bill.

    Manual was/is useless, being a cheap (temporary) inverter whilst waiting for the new one.
    5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied.


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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #6
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    Re: Tingling sensation when touching the battery negative pole

    Very high probability that with this inverter, if you ground one side of the AC output and also ground the battery negative - - the inverter will instantly emit smoke.
    Many, many MSW inverters have met with such a sudden death.
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  • South Africa
    South Africa Solar Expert Posts: 295 ✭✭✭
    #7
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    Re: Tingling sensation when touching the battery negative pole

    Out of pure curiosity.

    If you use a cheap UPS inverter (temp measure), one that can work when it is not plugged into a AC socket, can one disconnect the live and neutral in the 220v AC plug, leaving the earth wire connected, and plug it into the wall socket to give it a earth connection?
    5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied.


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  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    #8
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    Re: Tingling sensation when touching the battery negative pole
    South Africa wrote: »
    Out of pure curiosity.

    If you use a cheap UPS inverter (temp measure), one that can work when it is not plugged into a AC socket, can one disconnect the life and neutral in the 220v AC plug, leaving the earth wire connected, and plug it into the wall socket to give it a earth connection?

    Many UPS's will complain about the MSW power and not even turn on (or cycle on/off every second). Also, the "Building Site Wiring Fault" light might come on if it does not see a proper ground/etc and that might cause issues also.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
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  • South Africa
    South Africa Solar Expert Posts: 295 ✭✭✭
    #9
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    Re: Tingling sensation when touching the battery negative pole

    Yes, I am aware, although I have never had a UPS that cannot work complete disconnected from the mains.
    A "Building Site Wiring Fault" light ... that is a grand idea! Must ask the electrician if I can get such installed.

    Let me rephrase: Is it safe (to get rid of the tingling sensation) if I disconnect the live and neutral from the UPS, keeping the earth connected to a the AC plug and plug it into the wall socket?
    5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied.


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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #10
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    Re: Tingling sensation when touching the battery negative pole
    South Africa wrote: »
    Yes, I am aware, although I have never had a UPS that cannot work complete disconnected from the mains.
    A "Building Site Wiring Fault" light ... that is a grand idea! Must ask the electrician if I can get such installed.

    You can buy one that plugs in: http://www.canadiantire.ca/en/pdp/gardner-bender-gfi-3501-gfci-and-receptacle-tester-0520027p.html There is probably something similar for your power system there.
    Let me rephrase: Is it safe (to get rid of the tingling sensation) if I disconnect the live and neutral from the UPS, keeping the earth connected to a the AC plug and plug it into the wall socket?

    Yes. A strange way to connect ground perhaps, but a ground nonetheless. Over here we would use a wire with a spade lug on it screwed to the adapter plate of the outlet (which is a ground source). You have different outlets there; may not be grounded casings.
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  • South Africa
    South Africa Solar Expert Posts: 295 ✭✭✭
    #11
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    Re: Tingling sensation when touching the battery negative pole
    Cariboocoot wrote: »
    You can buy one that plugs in: http://www.canadiantire.ca/en/pdp/gardner-bender-gfi-3501-gfci-and-receptacle-tester-0520027p.html There is probably something similar for your power system there.

    Seems like a good idea. Going to find one locally.
    Cariboocoot wrote: »
    Yes. A strange way to connect ground perhaps, but a ground nonetheless. Over here we would use a wire with a spade lug on it screwed to the adapter plate of the outlet (which is a ground source). You have different outlets there; may not be grounded casings.

    Cool. Never seen wires with a spade lug connected to a earth of a plug socket here.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,445 admin
    #12
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    Re: Tingling sensation when touching the battery negative pole

    The answer (I am not sure it was clear)... If you have a DC negative ground battery bus (or positive ground, does not matter here), And you have a building with a Hot/Ground bonded Neutral, and have a transfer switch that only transfer the outlet's "Hot" wire between the Utility and AC MSW inverter's output--Yes, that will let the magic smoke out of the inverter.

    You must use a two wire transfer switch (transfer both hot and neutral) from Outlet to either Utility or AC MSW inverter to be safe.

    It is the physical tying of one of the batter connections to one of the MSW AC output connections that will kill the MSW inverter. It (more or less) creates a dead short through the H Bridge switching Transistors.

    That common connection is the battery to ground. and the "neutral" to ground connection (a MSW inverter cannot really have a ground bonded neutral connection--both leads must be floating).

    I have seen some UPS systems that will not start if their input does not have a ground bonded neutral (at least for US/North American 120 VAC units--The building wiring fault as mentioned by jcheil).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • South Africa
    South Africa Solar Expert Posts: 295 ✭✭✭
    #13
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    Re: Tingling sensation when touching the battery negative pole
    BB. wrote: »
    The answer (I am not sure it was clear)... If you have a DC negative ground battery bus (or positive ground, does not matter here), And you have a building with a Hot/Ground bonded Neutral, and have a transfer switch that only transfer the outlet's "Hot" wire between the Utility and AC MSW inverter's output--Yes, that will let the magic smoke out of the inverter.

    Yes, I understood that. Bill, yet again (!) I was saved from going for a smoke. :-) Thank you.

    The batteries are not grounded, temporarily, so if I was going to do this the only ground would have been the AC lead from the inverter, with live and neutral cut off with pliers, leaving only the earth wire connected via the AC plug into the socket's earth.

    Leaving the live and neutral in place would result in ... but wait ... simply leaving the plug in the wall, switched off position, would give me the ground, removing the tingling sensation.

    Let me go an try ... shoes off ... brb ...
    5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied.


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  • South Africa
    South Africa Solar Expert Posts: 295 ✭✭✭
    #14
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    Re: Tingling sensation when touching the battery negative pole

    Nope, did not work. New inverter better come quick.
    5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied.


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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #15
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    Re: Tingling sensation when touching the battery negative pole

    safrica,
    this was one of my points to you in a pm. just don't touch the battery - until you get everything proper.
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