12v leds in 6v system?
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Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=145039
Printed Date: 16 Jun 2025 at 8:52pm
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Topic: 12v leds in 6v system?
Posted By: mdm1
Subject: 12v leds in 6v system?
Date Posted: 03 Dec 2017 at 8:26am
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There was a post that I cannot find about using a 6 to 12v inverter to use 12v bulbs. My question is since it is positive ground how would you connect the inverter? I know the bulbs don't care if it + ground but what about the inverter? Also would led lights care? Sounds like it would be a good deal for lights. ------------- Everything is impossible until someone does it! WD45-trip loader 1947 c w/woods belly mower, 1939 B, #3 sickle mower 1944 B, 2 1948 G's. Misc other equipment that my wife calls JUNK! |
Replies:
Posted By: steve(ill)
Date Posted: 03 Dec 2017 at 8:52am
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MOST LED will work on a range of voltages. I would guess a 12 volt bulb would lite on 6 volts, just put out half of the watts. You should be able to see OK on a tractor. Might be a little dim for a truck moving 60 MPH. also, LED take very little power.. Before I installed an inverter, I would just buy a $19. lawn mower battery ( very small) and stick it somewhere hidden and use for the lights. Take it off once a month and put on battery charger. ------------- Like them all, but love the "B"s. |
Posted By: jaybmiller
Date Posted: 03 Dec 2017 at 10:11am
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I've actually got the parts ordered even though I don't have a 6V tractor... The 'trick' is that the LED will need 2 leads 'floating',simple to use. A 12 V LED should NOT work on 6V as all 'white' LEDs require 3.2V to run. Typically a 12V LED will be 3 LEDS in series + a current limiting resistor. BTW ALL the LED flashlights that run using 1 or 2 cells have 'voltage converters' in them. I was going to use one of them but real modules are dead cheap. The 'ground' might be an issue so when I get my parts I'll post my results. If I can find an 'isolated' DC-DC convertor then it's real,real easy... ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: bigal121892
Date Posted: 03 Dec 2017 at 11:37am
| Check Digikey, for a DC-DC convertor. |
Posted By: littlemarv
Date Posted: 03 Dec 2017 at 11:48am
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Sheesh, as soon as it gets dark around 4PM, everybody starts thinking lights! I bought two 4" square LED's, I am going to put them outside in the cold tonight hooked to a lawnmower battery and see how long it lasts.... cheaper and quicker than converting to 12V. ------------- The mechanic always wins. B91131, WC23065, WD89101, CA29479, B1, Early B10, HB212, 416H |
Posted By: theropod
Date Posted: 03 Dec 2017 at 12:25pm
LED’s are polarity dependent devices. They have specific positive and negative poles and will not work at all if reversed. The DIODE portion of these divices will block/stop current flow in one direction just like any other diode. LED’s that are designed for a 12 volt system may not light at all with 6 volts as most have built in resistors to drop the voltage to the voltage at which they are designed to operate. Resistors waste power as heat. A simple 3 pole transistor-looking fixed voltage regulator of the correct voltage will drive a load up to one amp. Variable voltage 3 pole regulators are available up to 5 amps and only require 3 to 4 external components to set the output voltage. An LM3940 fixed 3.3 volt 1 amp TO 220 package is about $2. An LM1084 fixed 3.3 volt 5 amp TO 220 package is about $3. Both would need a small heat sink if pushed to their limits. Pin one is input voltage. Pin two is ground. Pin three is output voltage. Pins left to right from front printed face. So simple it is silly. ------------- Put the bunny back in the box! 1938 B, 1977 Yanmar YM2200 No private messages: use email: theropod AT yahoo DOT com |
jaybmiller wrote:Posted By: theropod
Date Posted: 03 Dec 2017 at 1:51pm
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Since the forum software has some sort of issue with my permission to send private messages I am forced to respond here. Not real happy about this, but it is what it is. I just don’t feel like figuring it out right now. Responding to Ted J: Don’t worry about the tractor grounding setup or voltage. Both are irrelevant. The LED doesn’t care what the ground system of the vehicle is as long as the LED is fed the proper polarity. Think of them as lightbulbs that work as a one way valve. If the LED is fed positive voltage to the anode (+) and negative voltage to the cathode (-) wthin the maximum voltage of its operating ceiling it will light up. Voltage too high will cause immediate, and sometimes catastrophic, failure. Under voltage will cause the LED to either not light up at all, or at a lower output. LED’s work like any other diode as a one way current blocker, just like the rectifiers in an alternator. If the leads to the LED are reversed no current flows and they do nothing because the current is blocked. Of course if the reversed polarity, or input voltage, exceeds the “breakdown voltage” of the LED it will fail just like any other diode. Feel free to ask anything you like if you don’t get it. LED’s are not mysterious magic in any way. They work by a simple set of rules. Positive to positive, and negative to negative and within voltage limits. They don’t care about anyting else. As I said in the thread, a cheap voltage regulator will protect them from overvolt conditions and are cheap as dirt. ------------- Put the bunny back in the box! 1938 B, 1977 Yanmar YM2200 No private messages: use email: theropod AT yahoo DOT com |
Posted By: mdm1
Date Posted: 03 Dec 2017 at 3:20pm
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Back to the original question. How would you wire the inverter? Maybe I will just stay in the dark! ------------- Everything is impossible until someone does it! WD45-trip loader 1947 c w/woods belly mower, 1939 B, #3 sickle mower 1944 B, 2 1948 G's. Misc other equipment that my wife calls JUNK! |
Posted By: bigal121892
Date Posted: 03 Dec 2017 at 3:37pm
| Original question. You would wire the inverter positive to positive, and negative to negative. In other words, if the system is a positive ground, the positive of the inverter would go to the frame, and the negative to the negative of the battery. Same way with the LED's, Anode goes to the frame, and the cathode, would go to the negative of the battery. |
Posted By: theropod
Date Posted: 03 Dec 2017 at 3:52pm
My question is why do you need an inverter? LED’s are EXCLUSIVELY direct current divices and inverters produce alternating current. Seems like a total waste of time, money and watts to and put an inverter into the system that only needs direct current. A voltage regulator matched to your LED array, like I cited above, is all you need. What am I missing here? ------------- Put the bunny back in the box! 1938 B, 1977 Yanmar YM2200 No private messages: use email: theropod AT yahoo DOT com |
Posted By: jaybmiller
Date Posted: 03 Dec 2017 at 4:16pm
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You actually need a DC to DC converter NOT an 'inverter'. An 'inverter' typically changes polatity of a power supply to the opposite. A 'converter' usually change voltage and a DC-DC converter changes an input DC voltage to a different output voltage. Clear as mud right ? welcome to my world and I design these things but NOT as cheap as the off shore stuff. I can buy premade modules for LESS than a handful of parts from Digikey BTW. You NEED an ISOLATED DC-DC converter IF the LEDs are say '1157' style ,with the shell of the light GROUNDED to the tractor or truck or whatever. Isloated means the output power is 'floating' ( NOT connected ) to the input power. Most DC-DC converter 'modules' I've seen to far SHARE a common between the -ve input and the -ve output which is fine IF the LED has 2 leads and NOT grounded. When I get time , I'll try to draw some 'pretty pictures' and post. I'm beat, spent all day ,sunup to sundown and then some, 'modifyig' a modified, replacement trailer axle to fit..it's almost done and I KNOW my back is..off to the shower... ------------- 3 D-14s,A-C forklift, B-112 Kubota BX23S lil' TOOT( The Other Orange Tractor) Never burn your bridges, unless you can walk on water |
Posted By: steve(ill)
Date Posted: 03 Dec 2017 at 4:54pm
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Guys, your making it too complicated for him... He is not asking how to build a 3.3 volt unit... He wants to BUY a 12 volt LIGHT BULB and connect it to a 6 VOLT BATTERY... He needs some type of DC- DC converter to INCREASE 6 volts to 12 v. I still say a very small lawn mower battery might be best....... I use a couple 12 v LED bulbs on the "outlands" that have no AC power supply... I bought a 60 watt EQUIVALENT output LED screw in bulb ( it uses 10 watts at 12 volts).... that's about 1 amp draw... I have a dry cell battery that is 26 amp/hour rated.. So it will run the LED at 1 amp draw for 26 hours......... 60 watt (equivalent) will light up and area 50 ft in diameter. ------------- Like them all, but love the "B"s. |
Posted By: HoughMade
Date Posted: 03 Dec 2017 at 5:04pm
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Ther are automotive style LED lights made for 6 volts. Old cars used the same bulbs as these old tractors. https://www.superbrightleds.com/moreinfo/tail-brake-turn/1156-led-bulb-19-led-forward-firing-cluster-6v-and-24v-dc-car-classic-car-bulb/511/" rel="nofollow - https://www.superbrightleds.com/moreinfo/tail-brake-turn/1156-led-bulb-19-led-forward-firing-cluster-6v-and-24v-dc-car-classic-car-bulb/511/ https://hidkitpros.com/shop/1156-ba15s-led-bulb-30w-cree-6-volt/" rel="nofollow - https://hidkitpros.com/shop/1156-ba15s-led-bulb-30w-cree-6-volt/ https://www.ledlight.com/g18-s25-6-24v-non-polarity.aspx" rel="nofollow - https://www.ledlight.com/g18-s25-6-24v-non-polarity.aspx Just make sure that they are hooked up in the right direction. ------------- 1951 B |
Posted By: mdm1
Date Posted: 03 Dec 2017 at 5:32pm
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Steve has got it right. I'm just a dumb drywall finisher. It just sounded like a good idea. ------------- Everything is impossible until someone does it! WD45-trip loader 1947 c w/woods belly mower, 1939 B, #3 sickle mower 1944 B, 2 1948 G's. Misc other equipment that my wife calls JUNK! |
Posted By: theropod
Date Posted: 03 Dec 2017 at 5:37pm
Then what he needs is one of those gel cell 12 volt batteries used with automatic deer feeders and such. I have one I use to drive what’s called a barn door tracker for taking pictures of stars so there are no star trails. It will run the Arduino microprocessor, stepper motor and driver all night with power to spare. I can’t see his LED drawing more power. mine is a 4.5 amps at 20 hours rating. These batteries can be oriented in any position and are cheap. Mine is about 4” X 6” X 3” and weighs about 2.5 pounds. Recharges in a couple hours. The use of the term inverter had me thrown. Considering I live with the power from an inverter 24/7/365 one can see why. What he is talking about is a buck/boost converter, and none I am aware of changes polarity. ------------- Put the bunny back in the box! 1938 B, 1977 Yanmar YM2200 No private messages: use email: theropod AT yahoo DOT com |
Posted By: mdm1
Date Posted: 04 Dec 2017 at 5:13am
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Sorry about using the term inverter instead of converter. My mistake. I also have solar power so I should have known better. I think I may just leave everything as it is. But thanks for all the replies as I did learn some things. ------------- Everything is impossible until someone does it! WD45-trip loader 1947 c w/woods belly mower, 1939 B, #3 sickle mower 1944 B, 2 1948 G's. Misc other equipment that my wife calls JUNK! |
Posted By: theropod
Date Posted: 04 Dec 2017 at 6:51am
No problem for me. I was just thrown, and misunderstood. A little 12 V battery easily removed and charged would be easy peasy. An alternative to all this would be a rechargeable LED flashlight with a magnet base. Stick in where you need it. ------------- Put the bunny back in the box! 1938 B, 1977 Yanmar YM2200 No private messages: use email: theropod AT yahoo DOT com |
Posted By: Jordan(OH)
Date Posted: 04 Dec 2017 at 6:54am
| Why go though all this instead of converting the tractor to 12v? |
Posted By: drobCA
Date Posted: 04 Dec 2017 at 7:34am
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hey mdm - don't give up. here's 3 choices off of amazon - local auto supply should have same or similar.  hookup should be 1 black to whatever is neg on your tractor, red to pos & other black to neg on light, yellow to pos on light. directions with converter may say different but that would work. hope this answers your actual question  ------------- 3 Ford 8N's I loan to neighbors, but the '52CA, '41B and little B1 I do not. |
Posted By: Ted in NE-OH
Date Posted: 04 Dec 2017 at 5:54pm
Do they make 6V replacement bulbs, if so just turn the battery around (polarity wise) repolarize the generator. Does the cut-out relay care about polarity if so use a diode. ------------- CA, WD, C, 3 Bs, 2 Gs, WC, I-400, 914 |
Posted By: Gerald J.
Date Posted: 04 Dec 2017 at 7:07pm
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Some voltage regulators have a short life with reversed polarity because of minimal contact sizes. When changing the polarity of the battery and generator the ammeter needs its leads reversed and the ignition coil needs its primary connections reversed for good ignition. Gerald J. |
Posted By: Ted J
Date Posted: 05 Dec 2017 at 9:43am
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To make this SIMPLE, on a 6v system, is there a replacement (LED) bulb(s) out there that will fit the bullet taillight and a replacement for the headlight bulb? Numbers? Thanks Guys!  ------------- "Allis-Express" 19?? WC / 1941 C / 1952 CA / 1956 WD45 / 1957 WD45 / 1958 D-17 |
Posted By: HoughMade
Date Posted: 05 Dec 2017 at 9:47am
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If only someone would post links to 6 volt LED lights. ------------- 1951 B |
Posted By: Gerald J.
Date Posted: 05 Dec 2017 at 10:25am
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Checking a catalog from Jameco ( http://www.jameco.com" rel="nofollow - http://www.jameco.com ) I see high output white LEDs have voltage drops of 2.5 to 5 volts, so it would be easy to make a simple 6 volt lamp replacement with either a series resistor or a switching regulator. Many a 120 volt LED lamp uses that switching regulator and some make so much radio frequency noise that they prevent radio reception in the neighborhood. As for powering a 12 volt LED from 6 volts, there are at a couple circuit possibilities. One is to use a DC to DC converter with 6 volt input and 12 volts output. That requires the converter to handle all the LED power in and out. Best if the output is isolated so the 12 volt side can be negative ground as the LED lamps expect. A bit more efficient scheme is to use an isolated 6 volt to 6 volt converter and connect the floating output in series with the 6 volt power source so the converter has to handle only half the LED power. Lamp socket and LED polarity might be a problem. Jameco has some converters but none rated for lower than 9 volts input in their 2016 catalog. Bigger distributors like Mouser and Digi-Key probably have a wider selection of DC to DC converters, I haven't looked recently. A 6 volt battery wired in series with the tractor 6 volt battery could supply only half the power for the 12 volt LED too. If the same size as a handy 12 volt lamp battery it could run the LEDs twice as long. Gerald J. |