| Author | Message | ||
| John that newguy Rating: |
Can anyone using the Trace Dr3624 provide some comments regarding what's being used with it, and it's overall quality? mucho' thankso. | ||
| gabby
Rating: N/A |
I have had a DR 3624 in my 4905 for 5 years and my 102A3 for a year. From what I understand they were made for residences. I have not had a problem with either one of mine. They run the frig, microwave and airconditioner when going down the road. I would use another one if I needed one. | ||
| Stephen Fessenden (Sffess)
Rating: N/A |
They were made for Dominican Republic. D. R. I believe there is a difference in the ground. In Dominican Republic, the ground is not tied to neutral at the pole or the house. I have heard they are tough units that do a great job. | ||
| Chuck Newman (Chuck_newman)
Rating: N/A |
John, I've studied the manual for this unit since it is half the price of a 4024 on sale, is simpler to set up, and the manual is reasonable -- 75 pages vs 350 for the latest version of the 4024. When I first asked about it several people said the step modified sinewave from the DR series would not run an A/C without overheating, and on and on. In two long posts I pointed out several facts about inverters, one of which is the sacred 4024 outputs a step function wave also. The 4024 was initially designed for the off grid and co-generation crowd. There is more to the story, but that is in the archives. At the time, I talked to Ray Lala who had used a DR3624 for several years as Gabby has done. Ray had used it to run his A/C and other loads also. No over heating or any other problem. The link below is the best prices I have found for any inverter. As you can see, you can get two 3624's for the price of one 4024, and you've only lost 400 watts in the deal and have a spare to boot. Stephen, it sounds like the ac system in Dominican Republic is just like an RV park here. http://www.wholesalesolar.com Chuck Newman Oroville, CA | ||
| John that newguy Rating: N/A |
Thanks guys! I only need an inverter to run the AC units or microwave, tv, etc while the engine's running. My battery bank will not exceed a bank of four (for nighttime TV and laptop w/out genset). The next big question..... The sw4024 can run both ac units from the bus alternator. Can I expect to do the same with the DR3624? I need to be able to run both rooftops while going down the road. | ||
| RJ Long (Rjlong)
Rating: N/A |
On a related note, what's the difference between the Trace and the Prosine units? (BTW, I'm working with a 12vdc system.) | ||
| John that newguy Rating: N/A |
Xantrex makes quite a few models: http://www.xantrex.com/web/id/2/type.asp The "DR" series is a modified sine wave model, while the Prosine model is a true sine wave type. I don't have any need for a "true sine wave", thanks to Xantrex having apparently built enough filters into their modified sine wave models to allow most all appliances to run efficiently. If my air conditioners can run, our TV set work, and a meal be made using our microwave, what more do I need? The DR3624 is about 1/2 the price of a SW4024 and contains almost all the features of the more expensive SW series.... And "refurbished" DR units are available for less than $800. Howzat? | ||
| Chuck Newman (Chuck_newman)
Rating: N/A |
John, Running 2 A/C's while going down the road brings up several issues. First, the conventional visdom for motor starting current is 1.25 or 1.5 times the running current. Some motors can be more, but 1.5 is probably safe for small compressor loads present in roof A/C units. Some roof A/C units run at 11.5 amps, some as high as 16 amps. The math will tell the tale. Second, it is not listed in the specifications but life expectancy of an inverter is extended if not run full bore. 50 to 70 percent of full load and adequate cooling (very important) will give maximum life. Third, using the general 10:1 formula, a 14 amp A/C unit will draw approximately 140 amps at 12 vdc or 70 amps at 24 vdc. Two units on a 24 vdc bus would draw around 140 amps DC into the inverter. Losses not considered. Just round numbers. A 50DN alternator will output about 250 amps at 24 vdc at speed. Much less at idle. I plan to run only the front A/C unit while driving with automatic generator startup and cutover when batteries get a little low in heavy traffic due to slow running alternator. If I wanted to run two roof A/C units on the road, I would get two DR3524's (for the price of one 4024) and load each DR with a separate A/C unit. This accomplishes two things: 1) You're not straining to the max any type inverter you purchase, which will result in longer service life. 2) If one inverter dies for any reason, you have another unit for backup. Use the second unit in the most critical application while the other is being repaired. Chuck Newman Oroville, CA | ||
| John that newguy Rating: N/A |
Chuck- Good points! I like redundancy, and having two inexpensive inverters seems better than one very expensive one. My main concern was all the talk about the benefits of a pure sine wave inverter, and how a modified one wouldn't run an AC unit. I'm happy to hear it's just a myth. After reading your comments, I realized that there's an RV after-market company that makes a switching unit that allows two air conditioners to run alternately from one power supply. That may be well suited to what I'm trying to do. I can still have a second inverter also, ready to go.. just in case the swapping device goes bad, or the other inverter quits... | ||
| James Maxwell (Jmaxwell)
Rating: N/A |
Does all this talk of redundancy lead us to an ultimate conclusion that we all need (2) buses? It is not a myth that modified sine wave electricity does not lend itself well to operating inductive loads, as compared to equal purely resistive loads. There is a lot more involved than just the basic calculation of the wattage load. Another significant factor is the number of steps of inversion utilized to "approximate" the pure sine wave, since even the SW models truly only "approximate" a true sine wave. However, they do it with many more stages than say a DR model. If u compare the modified sine wave and a pure sine wave form on a scope, or even a graph of the two, you will quickly discern the difference in the two. The modified wave form will have very large steps in it that build up to the peak voltage, while the SW model will have many more smaller steps building to that peak voltage. The problem arises in that the power, or amperage, of that form does not follow with the voltage stepping, but rather follows it's own curve. With the very large steps of the modified waveform type (DR) it can be considerably out of sync with the voltage form. Inductive loads do not like that and tend to overheat under such a condition. Therein is the problem and the hugh difference in inverter waveforms. Several yrs. ago I bought a DR when I 1st built my Grumman (motivated purely by saving money). It was a 2412 model, intended to run a 1700 watt A/C roof unit while running and nothing more. It didn't work--the roof air compressor overheated and tripped off on internal thermal overload. I sent the unit back to the dealer as defective, he replaced it, same results with the replacement. I then called Trace, spoke w/ a guy I only recall as Steve now. His comment, we did not build it to operate heavy inductive loads for any period of time; they will overheat and trip off. He gave me a quick lesson on waveforms, explained that the DR had 13 stages of inversion and I should get a U series, which had 25 stages. The SW was new on the market then and priced well above the value of my entire bus! so that was not in the picture then. We can discuss and debate these differences in inverters all we want but there is one in-escapable fact. The sine wave inverters are far superior to the modified sine wave type and that is the reason why the DR is the cheapest thing Xantrex sells under the Trace line while the SW is the most expensive. If u want a DR to run your roof air then u had best OVERSIZE it tremendously (as in shopping 3600 watts for 1500 watt loads) and u may well find that even then, it won't do the job for hours on end like a 2400 SW model will. FWIW | ||
| FAST FRED Rating: N/A |
The big problem (if melting isnt enough) with "modified sine wave" (Chop chop power) is weather the item will perform with a useable percentage of what it would do with Power Pole juice. Sure many things will run , but the performance is usually considerably reduced . A simple test is to get a measured amount of water and place it in the microwave. A quart of water in a Pyrex jug is fine. After say 10 min measure the temp rise , do the same test on inverter power . The difference is the loss of power from the Chop chop . The power (cooling ability) of the air cond is reduced , just as the microwave. Will Chop chop work , sure , will it work WELL? U decide. Caviat emptor, FAST FRED | ||
| Stephen Fessenden (Sffess)
Rating: N/A |
The surge rating on a DR3624 is an unbelievable 12000 watts, twelve thousand watts. It should be able to handle starting current on a second AC just fine. | ||
| John that newguy Rating: N/A |
Xantrex may have made some changes, Jim.. DR3624: http://www.xantrex.com/web/id/57/p/200/pt/18/product.asp http://www.xantrex.com/web/id/1040/info.asp The quest among us regarding the need for "redundancy" is often humorous... It can become a sort of phobia; a mania. Lossphobia? Redundamania? Is Luke a shrink? I need an oil change and some Quaalude... I'd like to insure that I'll have two ways to cool the bus, and our food. Two sources for power, and two ways to heat the bus. In my opinion, being able to run the bus to generate electricity via an inverter, or using a genset for power, would be enough power supply redundancy for me. If I need two inexpensive inverters to run both airs at the same time, I will have a degree of built-in redundancy if one inverter fails, versus having only one (expensive) inverter doing the job of two. It's inadvertent redundancy... I had been concerned that the modified sine wave type would not run an rooftop air conditioner. I'm hearing that there are a few busnuts now using them successfully. That's good 'nuff for me! There's no better information, than from those that have tried the device being considered! The 2412 model appears to be a little too light duty for running a rooftop ac unit. http://www.xantrex.com/web/id/57/p/197/pt/18/product.asp The 3624 seems quite a bit beefier: http://www.xantrex.com/web/id/57/p/200/pt/18/product.asp I'm hoping your right about using the "oversized" model. Mucho' gracias. | ||
| John that newguy Rating: N/A |
Chuck- Actually, my need to run both AC units going down the road may not be as necessary as I first thought. I'm leaving our Welch auxiliary AC unit intact. That supplies enough air conditioning to cool the bus on a moderately hot day. Since it's in the back (I haven't figured out how to tie it into the driver's air yet), I'll need the front rooftop working once the walls are up. You're right, though... having a second inverter running that rear rooftop would be a good addition. Gabby- Thanks for the info! Personal experience weighs heavy. Egads, I@n..... what would I do without this website? | ||
| Sean Welsh (Sean)
Rating: N/A |
Stephen, My data sheet on the DR3624 says the surge is 7500 watts. It will handle 100 amps (12,000 watts), but only for one millisecond. 100 millisecond rating is 72 amps. It takes longer than one millisecond of surge to start an air conditioner. JTNG -- the 3624 will probably work fine for what you want to do. But J. Maxwell and FF's comments bear consideration. There WILL be a performance penalty running inductive loads, and there MAY also be a life-cycle issue with them (by which I mean you may very well end up shortening the life of motors running them this way). Following up on Chuck's comments, the DR was designed for strictly off-grid applications, whereas the SW was designed for off-grid or grid-tie applications. A lot of what you are paying for in a SW4024 is grid-tie functionality that you will never use. However, grid-tie quality output is the best you can get, and will be kinder to your appliances than any modified-sine output. Only the Outback is a comparable product. Like everything else, it comes down to a tradeoff, and it's a decision only you can make: initial purchase price, versus operating costs. Depending on how much you use it, and for how long, the operating savings of an SW may never make up for its higher initial cost. BTW, we have no trouble running two A/C's on our SW4024. FWIW. -Sean | ||
| RJ Long (Rjlong)
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JTNG - Welch Industries is just outside Atlanta - not really that far away from you. Lamar Welch could probably easily help tie that rear unit to the driver's HVAC, after all, it's his specialty! FWIW, RJ | ||
| ohn that newguy Rating: N/A |
RJ- Thanks. I talked to someone at Welch last year.regarding hooking up the driver's a/c to it. He said that they didn't do it, but know it can be done, since a few of their customers have said it works. He said he didn't have any info to provide.... Maybe someone here can..... ? |
