| Author |
Message |
Eric Plourde (206.134.177.28)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 9:59 am: | |
I have been reading the old posts about 12V or 120 lighting. Here are my thoughts and questions:
I want to run off of batteries most of the time (boondocking) and one day plan on solar being added. Right now I have all the wire strung around the coach and am thinking 12v lights. I found fixtures at Home depot that are 20watt halogen 12v bulbs that work great. Super bright, but you still need multiple for the main sitting areas.
My question:
I have a converter/charger that is 13.6volts 60 watts. I will be rewiring the fixtures. Right now they are 120 dropped to 12v and 20 watts. So I did the math and if my convertor puts out 60watts I would need a 10ohm resistor in line and then I could add a pot. for the dimmer.
The same goes for the hockey puck lights that are often mentioned, if they were unstrung and added seperate but in a string under cabinets.
So, all you electro genius folks, am I on the right path. Bear in mind that I already own the convertor, plan on buying a invertor, but would be using almost all 12v and have a few 120v for appliance hookup and the things that suck when convertored to 12v.
With the resistors am I going to lose more then I gain with using 12v over 120v.
Any help, drawings, offers to come to Virginia and build it while I sit mint julips, would be a great help.
Eric
Cowboy Game 4106 |
DonTX/KS (66.82.9.18)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 11:15 am: | |
I went thru the same process with mine, and decided to use ONLY 120v lights. It worked out swell, and I enjoyed the simplicity and ease of use. I too bought a batch of those little halogen 12v lights, and decided the heat they produced was not what I wanted in the bottoms of my overhead cabinets.
With a modern inverter, you can have all the 120v items you wish, no "double" wiring requirements, and I tended to use a lot of the screw in flourescents for low consumption.
It seems to me that most of the 12/120v bus conversions are simply copies of commercial RV systems, and have no real function or value for doing it that way. |
CoryDane RTSII (66.155.188.126)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 12:11 pm: | |
I opted to have lighting available in many modes. The most economical lighting in my whole coach is a Marine flourescent bulb that uses 12vdc, puts out 60 watts of white lite and screws into a normal 110v type socket so converting a fixture is simple. The bulb uses 13watts and gives 60watt light, compact size. For the specs...
http://wmarine.mobular.net/wmarine/5/5/2/index.jsp
Enter Page 576 and then ENLARGE
For dimming I did install some "puck" style hallogen, though hallogen are fast losing favor due to load versus light output versus heat output. They are dimmed with a timer via X10 timer module and dimmer modules.
You are doing the right thing to look for the most energy efficient since you are looking at solar. Sounds like a good start, good luck
"Imagine Your Dreams"
cdcd |
Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 1:45 pm: | |
Be carful where installing Halogens to make sure they are not directly above a partially opened cabinet or passage door. I saw a luxury yacht burned to the water line as a result of this. There were halogens installed in the ceiling and one was directly above and just a few inches from the top of a door leading into the master suite. When the door was about half open, the top of the door was directly below the light. Apparently someone left the door partially open and the heat from the light ignited the door.
Richard |
jim mci-9 (209.240.205.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 4:51 pm: | |
i agree with don..... i'm gonna change the lights in the "man show" to 110ac....only plan on having a few 12vdc.... 2nd porch light... night lite for bathroom....closet lite...1 in kitchen...1 in bedroom.....i already have some small florescent fixtures.... |
BrianMCI96A3 (69.34.170.181)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 8:15 pm: | |
I'm going to be using 24V LED lighting throughout most of the coach, I've already built several lamps using circuits with 6 white LEDs and a 330ohm resistor.
Each of these circuits uses 14ma and the largest lamp I've built so far draws 42ma.
I bought enough LEDs to not only do the interior lights but I've already converted the two stepwell lights, the aisle light at the rear of the coach, both front turn signals, all four side turn signals and ALL the rear stop/turn/tail lights over to LED's.
Brian |
DonTX/KS (66.82.9.66)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 8:25 pm: | |
Now THAT is one idea that is hard to beat! They can provide plenty of light with minimal current draw, and have become very reasonable in price. The added plus is no super hot spots to ignite fires. |
Tom Caffrey (Pvcces) (65.74.64.127)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 9:51 pm: | |
Eric, all the heat produced in the resistor is wasted power. That is true of all the heat that the halogen or any other bulbs produce, as well.
We bought our coach with transit fluorescent 12 volt ballasts already installed. They use the same tubes as AC fluorescents. They produce a lot of light and are very easy on the batteries.
I don't know what the specs are on the ballasts, but they are very tolerant of voltage changes, and we have yet to replace any bulbs.
We really like them and have found no reason to use incandescents except for original coach lighting.
For what it's worth.
Tom Caffrey PD-4106-2576
Suncatcher |
BrianMCI96A3 (69.34.170.181)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 9:56 pm: | |
Thank's Don... also, the miniscule gauge wire needed saves money and weight. I'm going to put LED lights in every cabinet too.
Brian |
Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 10:37 pm: | |
Tom, according to my calculations the wasted heat in the resistor amounts to about 2.25 watts per each 42 ma light fixture and about 0.82 watts in the 14ma lights. I would hazard a guess that that is less than is wasted in a flourescent ballast.
Richard |
Terry Mac (67.233.188.112)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 11:48 pm: | |
I am looking at dc refrigerators.I am planning on 100% solar. Is the dc fridge worth the extra money? |
Peter Aduskevich (Slowslowpete) (206.216.178.37)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 12:52 am: | |
Am I missing something here. If you have all 120 lites, what do you do when your inverter dies. Or if you do not have a inverter, you have to be pluged in to a 120 source.(gen. or pole). Like the LED's. |
FAST FRED (65.154.177.31)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 5:51 am: | |
The latest version of the DC fridges IS very worth while . Tundra and others have finally done some smart engineering.
The best units will have a danfloss compressor that reduced the pulse of DC saving juice when little refrigeration is needed (keeping a cold box cold).
But the have a chip and two thermostats so when power is avilable {engine or solar) the unit will run at full power till a 33F thermostat is hit.
With only battery power the std 40 -42 thermostat is in charge as is the load saver feature of the Danfloss.
Many marine systems now work this way ,and some also have a eutetic plate to keep the unit silent at night.
It is a rull of "thumb" that with a good well insulated box 2 panels will do refrigeration, and 2 more will do most living coach systems , add one more for each person aboard.
2 folks = 6 solar pannels with a need for a good charge controller and also an E meter or similar in a sine wave inverter.
Large enough batts to run 3 days without going down to 50% charge and your all set for silent "forever" camping.
Great way to go only a bit pricy.
Home Power Mag FREE on line ,would be a GREAT place to research the batt set size , inverter use , solar panel purchases (now down to $2.50 a watt ) ect.
FAST FRED |
DonTX/KS (66.82.9.18)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 7:34 am: | |
Of course the flip side of the coin, if money means anything to you, is to buy a Home Depot 120v fridge, long time guarantee, decent size and cooling along with a decent price (couple hundred).
With the thousands of dollars you have now saved over the "half way almost refrigerator" that offers no easy way out when it quits and about zero guarantee, you can buy an additional battery or solar panel, AND a genset that will get you by when the sun don't shine for weeks at a time.. |
DonTX/KS (66.82.9.18)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 7:44 am: | |
For SlowslowPete: If the inverter dies, you simply get a new one. Meanwhile, you can park anywhere with a power cord and continue as normal, or use the 120v genset to keep the beer cold until replacement arrives and supplement with a candle or battery powered lamp. Inverter failure rate is almost zero. I had a spare along for a while until I decided it was silly, and there was no need. Kinda like the transformer on the pole beside the house, no spare is usually available for it either. The idea of both a 12 and 120v system comes from storebought RV, that did not have inverters, and with a bus you sometimes gotta think outside the limits of grandpa's Winnie. |
Doug Dickinson (Dougd470) (24.207.240.13)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 9:39 am: | |
I am using all 12V lighting in my coach. I could go either way, but this has the advantage of simplicity. I have to charge batteries anyway at some point under way or parked) , so no big deal here. Also - it has a couple of conveniences since I can wake up the coach (go to start it up and get ready for a trip) without regard to the 120V system until I am ready to deal with it.
I am using 12V rope light concealed in a shadow box in the living, bath, and BR areas for low level area lighting, and some florescents in the kitchen. For reading and so forth, I will have strategicly placed reading lights, like in the bedroom and next to the couch and chairs. A couple of lamps and I have light! I will use 120V for the things that make sense to me like a microwave, coffee maker, AC, etc. Fridge and stove are propane.
I could have gone with 120V only lighting, but figured I would delay the invertor for a couple of years since boondocking is more of an after-kids thing and I have a couple of years to go yet. Spreads the expense around a little.
\My way
Doug
St Louis MC9 |
CoryDane RTSII (66.155.188.86)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 1:47 pm: | |
I must have missed something. All the LED lights I have seen only give off a marginal amount of light. Not enough to read from with my eyes.
An article stated the problem with LED lighting is they have a very narrow, directed light, compared to incondesent or florescent which blast light 270 degrees. The LED's narrow patern will light a small tiny area of coach and does not have much distance.
I installed LED stop/tail lights in the bus and they reflect the article exactly. They are efficient because you look at the light so the magnified light source is bright but for projected light, the light source is poor.
I have seen the LED lights for boats at the Marine store and they too are limited, not what we are used to with florescent or incandesent.
Are we talking about the same lighting here???
When I started my conversion I was going to go with LED lighting because of how economical they are, but I could'nt find any that put any decent amount of light out, so I have gone with florescents and halogen. I am through with the DARK RV and inadequate lighting, as I learned with the RV, don't be cheap where it counts, you get what you pay for.
"Imagine Your Dreams"
cdcdcdcd |
Stephen Fessenden (Sffess) (65.154.177.52)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 2:39 pm: | |
I use LEDs for reading lights in the bed, 14 ultra bright amber LEDs in strings of 7 with a 500 ohm resistor for each string of 7 for 24 volts. The LEDs are aranged in a narrow circle that fits inside a regular brass light bulb base obtained by breaking out the original bulb. Brass is necessary because you can solder to it. The group of LEDs has a much wider beam than a single one, but still narrow enough so that someone nearby is not disturbed by the light. I made the original bulbs on perf board but future ones will be made with pieces of plexiglass drilled with 3/16" holes with the LEDs pushed throught the holes and epoxied in place after all connections are made. This accomplishes having all LEDs aimed the same direction, something that takes extra effort when mounting them on perfboard.
If you want diffuse light, don't drill all the way through the plastic and epoxy the leds in place first. The epoxy fills in between the rough hole and the LED, leaving a flat surface for a lens. Light is evenly distributed at a few inches to infinity. I plan to change all my cabinet lights to this syle. I currently have incandescent cabinet lights and they draw a lot of power and put out a lot of heat if the microswitch on each door fails to turn one each one off. LEDs could be used with no individual switching.
I also used 10 amber LEDs in each of three ceiling vents for aisle lighting. You can walk the coach at night without turning on another light and even see to use the bathroom.
I try to arrange my LEDs in arrays that only need ballast for 4 volts, a number I got from another post on this board. You use the same amount of electricity for one LED plus ballast as for 10 plus ballast, so might as well get all the light possible.
I have tried Ultra bright white LEDs and they are too glaring for general lighting.
Current costs from Hong Kong (see Ebay), in lots of 500 or 1000 are: Ultra bright white - 25 cents each. Ultra bright amber - 10 cents each, Ultra bright red - 5.5 cents each. |
DonTX/KS (63.154.16.94)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 7:47 pm: | |
Thanks for all that Stephen. I think the world of LEDs has progressed so rapidly many are not aware of what is really available, and still think of them as a feeble glow. |
BrianMCI96A3 (69.34.170.181)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 8:45 pm: | |
Yes Don, I agree, as little as a year ago white LEDs were fairly rare, and plenty expensive. Now, not only are LEDs being made of increasing brightness all the time, but the price for LEDs has obviously fallen at an incredible rate.
Brian |
Dale MC8 (69.19.171.40)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 9:24 pm: | |
Kinda down a side road, BUT, just how bright are LED's? I know they are good tail/signal/brake lights. How good a back-up light do they make? Dale |
Tom Caffrey (Pvcces) (65.74.64.127)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 10:18 pm: | |
Richard, I think you and I must be using different math. When I calculated the total power consumption for 42 ma. at 24 volts, I got about one watt.
The 330 ohm resistor looks like it must have been intended for the 14 ma. lamp, because 42 ma. would cause a 14 volt drop. It looks to me like the ballast resistor would waste about 20% of the total power if it dropped about 5 volts.
I don't think any of these lamps would produce appreciable heat if there weren't an awful lot of them in one bunch.
Don't fluorescents run something like 50% efficient? I know there is quite a bit of heat produced in the ballasts and lamps.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher |
Stephen Fessenden (Sffess) (65.130.11.252)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 11, 2004 - 11:40 pm: | |
There is an LED calculator program at the following web site:
http://trotto.zmoz.com/led_pro.htm |
BrianMCI96A3 (69.34.170.181)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 12:27 am: | |
Uhhhmm, since I'm not an electrical engineer, and the one circuit I am certain works well is: 6 white LEDs and a 330 ohm resistor, I used that circuit in parallel to make up the larger lamps!
Brian |
Stephen Fessenden (Sffess) (65.130.11.252)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 12:44 am: | |
Richard, your calculations were probably based on straight resistance. LEDs don't act that way. Each has a voltage drop of 1.7 to 3.6 volts. If the drop is unknown it is safe to use two volts. It looks like Brians calculations were based on 3.6 volts per LED as in some high power white LEDs, probably the specs that came with his LEDs. The 42ma circuit would have been 3 parallel chains of 6 series LEDs and a 330 Ohm ballast resistor for each chain. The total power draw by the 42 ma light would be 26 Volts X .042 Amps = 1.01 Watt. Tom is correct that the resistor would waste about 20% of the power as heat.
Remember in designing these bulbs that LEDs put out very good light at half their rated maximum voltage and milliamps. Since we may not want to build new light arays often, we can fudge with 2 volts instead of 3.6 and 20 ma. with a loss of light and an aray that will last greater than 100,000 hours even if exposed to more than 30 volts by a runaway charging system. The calculation can be checked with higher surge voltages to assure that the milliamperes never exceed 25 in overvoltage conditions. Or you can overdrive to 30 milliamps intentionally for more brilliance and less life. I prefer to buy the LEDs cheaply enough that I can get the increased brilliance with extra LEDs. I like a slightly softer light. For clearance lights and turn signals and tail lights, they need to be designed for 28 volts anyway and we don't want to give up much brilliance on brake and turn signals.
I noticed with my white LEDs with a maximum 3.6 volt drop I can only run 3 at full power or 4 at reduced output on a 12 volt circuit. With my amber ultra high output LEDs with 2 volt drop I can run 5 on a 12 volt circuit with full output. This suggests a way to test for the voltage drop of LEDs with unknown specs. Construct a chain of LEDs sufficient for a 2 volt drop per LED and add an appropriate resistor (around 150 to 200 Ohms for the test). Connect the resistor end to 12 volts and find the maximum number of LEDs that will light properly. Plug the numbers into the calculator in above post and you will have a rough idea of forward voltage. Buy LEDs cheaply enough that you can toast a few to find the right circuit. The first white LEDs I bought cost $2.50 EACH. Needless to say I did no tests with them. At 20 cents each, no problem. |
Stephen Fessenden (Sffess) (65.130.11.252)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 12:49 am: | |
If you are seriously going to use LEDs invest in an LED test / check device. Search Ebay "led test" or LED check". Not "LED tester": to many returns. Price is about $10 plus the usual high shipping. Also available from All Electronics and other sources. Device allows you to put up to 10 LEDs in a row at 10ma to be sure they have equal output and tests individual LEDs at 2, 5, 10, 20, 30 and 50 ma. |
Richard Bowyer (Drivingmisslazy) (24.196.191.70)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 7:23 am: | |
Tom, You are absolutely correct. Guess I have been out of school too long. I forgot to square the current.
The applied voltage to the overall circuit should not matter whether 12 or 24 volts since we know what the actual current is thru a known resistance. It is still a very small power loss in comparison to incadescent or flourescent lighting in my opinion.
Richard |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 1:59 pm: | |
This is all very interesting, but I don't think anyone has answered Eric's original question, which had to do with halogen lights, not LED.
Eric -- If you intend to use 12v halogen lamps on a 12v system, no resistor is involved. You simply wire the lamps directly to 12v, in parallel. In fact, resistors are never used with halogens or other incandescents -- only with LEDs. If you have those sets of 12v lamps with small transformers that plug into 120vac, you just throw the transformers away.
If you want to use a dimmer, I advise against just using a pot -- the heat and power dissipated in the pot will dictate a very large unit. There are several 12v electronic dimmers on the market that would be a better choice. A few manufacturers of 12v lighting that come immediately to mind that have dimmers are Hera, WAC, and Halo. You won't find that stuff at Home Depot, but their high-end sister store (Expo Design Center) carries them.
If you have halogens designed for 120v, they won't work on 12v at all. You'll need to use 120.
Lastly, a converter with only a 60w output won't run very much at all. If you have three or four lights on, you'll use it all up and then will be draining your batteries. If you're doing any boondocking at all, you'll need a much more powerful battery charger to recharge a decent size battery set. My charger, for example, puts out 3600 watts -- 60 times what you're talking about! (Are you certain that 60 watts is correct?)
-Sean |
Eric Plourde (65.177.96.12)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 14, 2004 - 8:25 pm: | |
Thank you Sean,
This is a good string and it got me thinking about a # of things. I am wondering if it is not better to build LED lights for the reading areas and bed.
The numbers I wrote were wrong. It is unfortunate that i get to do email often late at night or after a long day.
The converter/charger is 13.6V 1000Watts, 60 Amps. So my worry is that I need no more then 20 watts per bulb. THe bulbs are 12volts, 20watts max. How do I regulate the wattage?
Eric |
Tom Caffrey (Pvcces) (65.74.64.127)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 14, 2004 - 10:35 pm: | |
Eric, you don't. If you use a rheostat to dim these, the light will turn yellow and the lumen output will drop faster than the power consumption. In other words, you will lose efficiency when you actually want to increase it.
You will be much better off reducing the number of lit elements by switching when you want to save power.
Tom Caffrey PD4106-2576
Suncatcher |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 15, 2004 - 1:50 am: | |
Eric,
I think I see now what you are asking -- "how does one connect 20-watt lights to a 1000-watt converter?"
The answer is that you simply connect them directly. A 20-watt lamp that is made to run on 12 volts will draw only 20 watts, no matter how "big" the source is (as long as it is a 12-volt source). Now if you connected 50 of them all at once, you would use up the output capacity of your 1000-watt converter. The converter would either blow a fuse, or the output voltage would drop below 12. If the only thing connected is one lamp, then the converter will only be putting out 20 watts. The 1000-watt number is simply its maximum rating.
I hope that clears up any confusion.
To echo Tom's comments, and repeat what I said earlier, you definitely do not want to dim with a rheostat (a big potentiometer). If you really want to dim (for mood lighting, for example) use one of the electronic units I mentioned earlier. But I agree with Tom -- you're better off putting in more switches so you can turn more or fewer lamps on at a time to control lighting levels. That's what we did in our coach.
-Sean |
BrianMCI96A3 (198.81.26.45)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 15, 2004 - 11:12 am: | |
Hey Stephen, I couldn't get led_pro to run once I downloaded it onto my desltop, I got an error message saying I was missing a file that enables the program to run!
Brian |
CoryDane RTSII (66.155.188.96)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 18, 2004 - 1:22 am: | |
I have an error message too. The Program won't run??????
cd |
Stephen Fessenden (Sffess) (65.154.177.51)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 19, 2004 - 12:10 am: | |
I downloaded it as a file in MS Excel. I don't know if it will work in other spreadsheets, such as Lotus 123, but apparently it needs to be in a spread sheet file to work. It is a useful program, so if you can't get it to work, I suggest you email the program originator at the same web page. |