I run (8) 120 volt 50 WATT LED's and ran for about 6 months,and started to notice some pitting or electrolysis indications on the hull,so started looking for a possible source.Disconnected all 12 volt batteries and Read .03 volts DC sitting on the trailer from hull to the trailer which from what I found on internet is normal voltage range for aluminum with zinc anodes. I then plugged the LED lites and read 42 volts from hull to earth ground,actual meter leads to hull and in dirt. The lites are mounted to the lite rail,which is mounted to the gunwales on the hull,and are grounded thru the cord plug.I checked the LED housing and is grounded to the chassis of the lite,as a test removed the chassis ground and still read almost 7 volts with one lite from the hull to earth ground.reinstalled chassis ground. As a test,ran a wire from the hull grounded to a screw to earth ground rod and measured zero or no current draw thank goodness,but with all (8) lites on are reading 42+ ac volts which is alot of potential floating around the boat,and with more than (8) lites would keep increasing.Are we inducing stray emf thru the fixture into the hull with the driver rectifier? We ran halos for 2 years and never noticed a problem.Has any one checked the 12-24 vdc LED's to see what or if any voltage is being transfered thru the hull? Anyone notice similar or any problems with hps or mh ? I am definitely gonna change and beef up the boat anodes.Maybe try insulating the fixtures and lite rail from the hull with rubber washers and pads...Any ideas or suggestions ? Have a new boat supposed to get this weekend and want to get figured out before switch everything over to the new boat,was gonna do the same lites but may reconsider if is a potential problem. I also wanted to get it out there for others to check and possibly prevent someone else from having issues....thanks
Help from the electrical gurus ? LED's electolysis issue
garpwacker
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Will double check,I know cords are grounded under strain relief nuts,will check for ground wires off the driver itself.
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Just double checked and cords are grounded under strain relief nuts to the housing as posted. The cord to the driver has the green/yellow ground factory cut off and check for continuity from that cut ground wire to outer casing on driver or housing and read open / no continuity so it appears to not be grounded internally.
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Just got to see the video. I need to think on this. I do question your ground, with the little contact in the dirt you may have more voltage than your reading on the meter. If you can find a known ground like a steel pipe or house ground. You need an accurate reading.
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Thanks Istickem I figured someone on here would chime in, can you put it in simple country boy terms and is it anything to worry about and could it be a cause for possible electrolysis,and anything to do to correct it if it is a problem.
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I havent seen the inside of the driver box so I making some assumptions. Definately get a second opinion. I think the pc board is shorting to the housing after the line voltage. Im guessing they use half wave rectification to get about 50v then a voltage regulator to get the 25v to 30v needed to drive LED chip through the current regulation circuit, since transformers cost more. Instead of troubleshooting the board without a schematic, electrically isolate the pc board from the case, mounts and green wires. . Just let it hang for now of rest on insolated blocks. Check it with an ohm meter. Should be just a couple of ohms. Then test again. Without it mounted in the case there should be now where to short to the case. If the stray voltage goes away then mount the board with nonconducting fastners or bed it with silicon. The board is hot anyway and will be sealed inside of the case so there will be no hazard there. Attach the green wire from the plug wire to the case, really really good and cover it with sealant. This connection must stay clean. So white wire to the board, black wire to the board and green wire to the case. Now if the light floods or the pc board falls loose in the case and touches something, the green wire will carry the current back to the genny.
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Well its not simple, riverrocket nailed it, lots of assumptions have to be made not being there.
Is the earth you tested to close to the ground rod for the panel feeding that cord?
Have you tested with the generator?
Could be neutral to earth voltage happening made worse by a short in the neutral.
If you are near powerlines, a substation, or big electric installs its more likely.
Is the earth you tested to close to the ground rod for the panel feeding that cord?
Have you tested with the generator?
Could be neutral to earth voltage happening made worse by a short in the neutral.
If you are near powerlines, a substation, or big electric installs its more likely.
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Thanks for reply again. Power lines and transformers are overhead across the street over 200 ft away,house ground rod and electric box is about 75 feet away, I will drag out the gennie and retest since is how we use everything on the water. Everything is/ was grounded thru the cords that plug into the gennie. Have continuity from ground prong on all cords to all housings or fixtures and are all grounded to rail and boat except the one I have insulated with nylon bolts and washers...
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Just for grins since the driver housing is just laying inside the fixture why don't you attach the green wire to the driver housing and see if that makes any difference in your voltage readings??
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8/4/12 update-Did OBG suggestion and ran ground wire from driver chassis to strain relief nut on fixture where cord was grounded ,there was no continuity from driver chassis to fixture housing where was mounted in the fixtures.Plugged in and basically no change in voltage readings thru hull,was pretty much same as before. Next took LED array loose and temporary insulated (insulated with couple pieces paper under arry) to keep it away from the housing as DVF said and sent me a pm about,plugged that one lite in and voltage readings thru the hull dropped dramatically to around just under or around 1 volt,I am going to try a bead of hi temp silicone around outside edge of array with heat thermal compound under array in center,and try find small nylon screws to mount the array to try and keep it insulated. This seemed to work and seems to be the solution to our problem, my next step is to try modify a couple lites and try with gennie and try on water and see if I get any voltage readings....thanks and will keep everyone posted. I think this is interesting with the popularity of LED's I knew dvf noticed an issue and so did I so am sure there will be others caught in this learning curve.
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This is so complicated and I don't understand any of it. Will one of you knowledgable guys please PM me your phone # so i can call you when I am ready to install my LEDs? I'll be using either a 12 or 24 volt system...don't know which at this time. Thanks!
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Insulated everything light brackets and light rail from hull with nylon bushings and different bolts and eliminated my findings as seen in video. Also had suggestion if had same readings on genny vs house power and didn't see it with gennie. Might of been chasing my tail a bit thatz why postex the thread. Was crazy for sure. Noticed some pitting spots on the hull along waterline area, is an older unpainted hull 1989 basstracker. Another thing was light rail was made from stainless and stainless bolted solid to aluminum and have since found out is a big no-no as far as dissimilar metal and electrolysis is concerned . The new 2072 Seaark is all aluminum light rail welded to hull, have aluminum bolts and brackets for "NEW" led's,and have (2) zincs or anodes on the back of the new boat. Trying to eliminate all or as much stainless as possible out of the boat. But will check everything with meter when get lites mounted.
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Not sure..would take a DC voltmeter and check hull to earth ground possibly.And check from battery + to hull and battery- to hull should get no voltage readings. Also NEVER use the hull as conductor for positive or ground/ neg. from the battery or load ex.(lights). Always run back to a terminal block with wires from battery or loads. And when bought our new boat, the dealer is from saltwater area and advised very anal about keeping stainless and other non aluminum screws, bolts, hardware off the boat for dissimilar metal electrolysis reasons. Also we had aluminum brackets welded on transom to mount the zinc anodes so when get eaten up they dont eat the aluminum transom with permanent damage. I actually noticed the problem first,did some research and calls as far as what could be cause, then started checking everything with meter a/c and d/c noticed this.
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