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Old 01-12-2016, 05:24 PM   #43
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Let's sort out some other myths. LED bulbs are essentially current driven devices. Small changes in voltage have large changes in current at the operating voltage. The operating voltage is typically around 3 VDC. It is relatively simple to design a fixed voltage current limit as all it is is a resistor set to a value determined by the applied current and desired drop.

The problem with that is resistor dissipates a large amount of power compared to the LED as heat. To solve that problem some type of switching circuit is used to lower the applied voltage and limit the supplied current.

Both the LED and the switcher supply are polarity sensitive. The easy way to deal with that is to add a bridge rectifier to the input. That will run the power through the circuitry in the correct direction. It also lets the light run off of AC hence the AC designation.

With a 12 VDC nominal system the charge voltage of the battery can run from a low of 10.2 or so to a high of close to 15 VDC for charging and higher if there is an anti sulphation function. Depending on the design there will always be some ripple on the output but it will not be much as the battery acts as a very large capacitor filter. The more controlled designs also have better filtering as part of the control function. None of them are putting out AC in large enough amounts to be worth worrying about. OTOH things like big relays (solenoids) put out significant spikes when turned off. Ditto DC some DC motors that do it while running.

FWIW I think there is some possibility in the heat trapped idea and reason to go to the AC version of the bulb as it probably has a wider service range. Also be careful about how connecting what looks like common ground planes to ground. I would only connect the - pin to ground and insulate anything else metallic from the fixture.

Good luck with it. It somewhat sounds like the seller is also confused so I would be cautious. If they sold you the DC version I might be inclined to try one AC version and see what happened. Switching fixtures also looks promising as it takes all the problems into consideration. They blew enough up under warranty that I think they may have a clue by now. Be cautious of new old stock. ;-)
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Old 01-12-2016, 05:50 PM   #44
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The Amazon vendor says I should have used 12v AC/DC instead of 12v DC. Is this correct?

Thanks!
NO. it's not,, The lights should be DC, Now.. if you run a 12 volt DC LED on A/C it runs at reduced light level, but should suffer no damage.. If you run an AC led on DC. you won't be able to tell the difference.

A DC lamp, plugged in backwards, will not work AN AC/DC lamp will. that's really the only difference.

Some sockets are wired backwards since for an incandascent lamp who cares. I've never had a LED fail due to AC/DC issues.
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Old 01-12-2016, 05:53 PM   #45
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A more common issue (And I have had this) is that if they design the lamp assembly for 12 volt, using a resistor, as opposed to a voltage limiter/resistor or current limiter, (Active electronic devices, Resistors are passive) then you hit it with say 15.6 volts during equalization of batteries.. Bad things can happen.

My Door handle LED burned out very fast, So did the replacement, The 2nd Replacement I re-engineered and designed it for 14 volts give or take a bit.. Works well.. and works, and works Well.

I would chang suppliers.
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Old 01-18-2016, 11:29 PM   #46
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DC or AC/DC 12v G4 bulbs?

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If your lights are powered off of the house batteries, then the current is 12 v DC and a standard LED buld should work perfectly. If You're operating off of shore power that's been converted to 12 v and not the batteries, then it's AC power and a regular LED won't work, you need one that's capable of running on AC power. AC/DC bulbs will run on either DC or AC.

Everything after the first sentence is absolutely, totally, unequivocally, 100% WRONG.
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Old 01-18-2016, 11:44 PM   #47
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Bronccat
If you are using these to replace bulbs in halogen ceiling fixtures and the interior of the fixture is reflective, the LED bulbs with regulation circuits typically have that circuit on the rear of the disc. The reflective coating then reflects the heat generated back on to the rear circuit and if there is limited air circulation in the fixture, will cause premature failure of the bulb unit. On most ceiling fixtures I have seen, there is really no way to exhaust the heat from the rear.
The halogen fixtures in our rig had a very heavy cast metal reflector/heat sink. Even so they melted some of the lens carriers when using the halogen bulbs. When converting to LED's I broke the reflector loose and threw it away, then glued the socket to the remaining backing. I used the single sided round LED panels that plugged into the old socket. Luckily all my fixtures had the correct polarity too although a few of the 60 or so bulbs had polarity compensation built in but most didn't.
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Old 01-19-2016, 12:15 PM   #48
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Everything after the first sentence is absolutely, totally, unequivocally, 100% WRONG.
Actually it's not. If you simply convert 120v to 12v it's still AC until you rectify it. The only reason you would possibly have to have a 12v AC LED bulb is if you had 12VAC. That was my point. I didn't say that RVs have 12AV available; they don't. The converters contain a large transformer to reduce the voltage and then they have a rectifier circuit that changes the AC to DC.

I just stated by point poorly.
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Old 01-19-2016, 04:03 PM   #49
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This thread certainly highlights the difficulty of conversing via the written word.
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Old 01-20-2016, 03:22 AM   #50
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Actually it's not. If you simply convert 120v to 12v it's still AC until you rectify it. The only reason you would possibly have to have a 12v AC LED bulb is if you had 12VAC. That was my point. I didn't say that RVs have 12AV available; they don't. The converters contain a large transformer to reduce the voltage and then they have a rectifier circuit that changes the AC to DC.

I just stated by point poorly.
The reason they suggest AC bulbs is that the steering diodes in the rectifier compensate for any polarity problem. The current always goes through the LED in the correct direction. The manufacturer may also be adding in better current regulation. LED light brightness is all about current control once the voltage exceeds the turn on point.
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Old 01-20-2016, 10:52 AM   #51
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Your lights work on 12 volts DC. PERIOD! There is no 12 volt AC in your e ml RV. When you are plugged into shore power, your converter is charging your batteries and supplying 12 volts DC to your lights.
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Old 01-20-2016, 06:01 PM   #52
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Your lights work on 12 volts DC. PERIOD! There is no 12 volt AC in your e ml RV. When you are plugged into shore power, your converter is charging your batteries and supplying 12 volts DC to your lights.
On my coach, all 12vdc is supplied by the batteries and the power converter only keeps the batteries charged. So, if the battery sw. is off, then nothing having to do with the house works. There is an exception, as to this sw. and concerning the slide, as it still works with the sw. off, so I'm thinking that it's on the hot side of the sw. relay and maybe because of the heavy current draw concerning the slide.
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Old 01-20-2016, 07:40 PM   #53
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On my coach, all 12vdc is supplied by the batteries and the power converter only keeps the batteries charged. So, if the battery sw. is off, then nothing having to do with the house works. There is an exception, as to this sw. and concerning the slide, as it still works with the sw. off, so I'm thinking that it's on the hot side of the sw. relay and maybe because of the heavy current draw concerning the slide.
No, the slides work on the chassis battery.
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Old 01-21-2016, 08:50 AM   #54
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No, the slides work on the chassis battery.
Maybe yours, but not mine and they're not all the same.
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Old 01-21-2016, 07:35 PM   #55
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No, the slides work on the chassis battery.
Mine very definitely run off the house batteries.
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Old 01-23-2016, 12:17 PM   #56
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For those of you who have never played around with electricity, any filament style light bulb will work on either DC or AC. A 120 volt filament bulb, the kind we used to use in our houses (a few still do), will glow dimly when attached to 12 volt direct current. Remember that there is a 10 X difference between the two voltages. If you take a 12 volt filament light bulb, like those found in older RV coaches, and attach 120 volt alternating current to it, it will light up brilliantly for a second or two then burn out.

LEDs are whole 'nuther story. It is best to purchase your LED replacement bulbs from a source that supplies RV bulbs. M4 Products is a good one. You may find some replacements at Camping World.
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