| Author | Message | ||
| peff Rating: N/A |
Hi, I have read various posts on this board regarding using surplus small diesel (or even gas/LPG) engines and a 12V generator/alternator to construct a DIY genset. I'm curious to hear from folks who have actually done it--parts, costs and results of the project. I'm more interested in the 12V version since I'll have an inverter to do the 12VDC-120VAC conversion and battery charging management anyway. Doing 12V also seems like a way to simplify the shore/house/genset switching conundrum down to 2 options as well, with the tradeoff of inverter efficiency losses... thanks Peff | ||
| FAST FRED Rating: N/A |
"with the tradeoff of inverter efficiency losses... " Any inverter in efficency is made up for in spades by the batteries being Properly charged , and the ability of the noisemaker to operate at low rpm's when the load is minor. FAST FRED | ||
| bruce knee (Bruceknee)
Rating: N/A |
I think that you want to talk to Bill Glenn. He not only has a small diesel powered ac. compresser/12v power plant, but is will run on WVO also. The smell of french fries cooking is a bonus | ||
| JW Smythe (Jwsmythe)
Rating: N/A |
Doing it should be trivial. Just make sure you're spinning the alternator the right way. I'm not positive, but I know most automotive things don't like to be spun backwards.  You'll probably want to do a little research on the particular alternator that you plan to use, and find out what the optimum RPM's are for generating power. Then find your ideal engine speed (lowest fuel consumption, highest power output), and buy pullys accordingly. I've seen the kits. I always look at them and tell myself, "I can do this cheaper." I had a 50cc moped once that would run forever on a gallon of gas, and was almost silent. Something like that would seem to be ideal, except for the crappy automatic transmission that came with it. I wouldn't hope to power much with that, but it should spin a small car alternator satisfactorly. Sorry I can't say that I've done it before. I'll probably do one eventually, because it sounds like fun. It sounds like good camping gear. Drag a little beer fridge and generator, with my 6 man tent into the woods, and have ice cold beer for a week, without the ice. Was I forgetting something? Beer. Tent. Woods. Nah, don't need anything else. | ||
| peff Rating: N/A |
Yeah, I agree with FF that the inverter losses are covered by his comments plus other gains like being able to match peak engine RPM/Alt max power at minimum speed, etc as JW mentioned. Also if using a smaller diesel, loading it into it's happy working range would be a bonus too. Does Bill Glenn lurk on this board? | ||
| Tim Strommen (Tim_strommen)
Rating: N/A |
If you're going through the motions of putting in a secondary power plant (small engine) and a belt driven generator (or alternator/rectifier/regulator), you might consider what else you can power so that you make maximum use of the power the genset will produce (waste not...) If you're only running a powerplant at limited load you could conceivably attatch a belt driven air compressor to build up air while the batts charge. This, coupled with block heater that takes power from the alternator-fed inverter could heat up your block while the engine is warming up (not running). Your fellow campgrounders will thank you especially if it's a cold morning and you have a DD 2-stroke. If you add a compressor - make sure the air it outputs gets dried... Cheers! -Tim | ||
| peff Rating: N/A |
Tim, Good ideas. Also planned to plumb the water through the water heater to take advantage of that too. | ||
| TomNPat
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Why, at an overweight position, would I want to smell french fries cooking? What a stupid way to promote the corporate philosophy for waste oil! It seems that many consider this an advantage. I don't think so!!!!!!!!!!!! TomNPat | ||
| John MC9 Rating: N/A |
Hey peff - Get a load of this: Converting a lawn mower into a generator. | ||
| John MC9 Rating: N/A |
TomNPat - Regarding the wieght issues: No fears running french fry oil through injectors. The system's totally no carb! | ||
| John MC9 Rating: N/A |
(Oh gawd. Corn oil) | ||
| peff Rating: N/A |
Yeah, previously saw the lawnmower link--close but no cigar... Anyone have ideas where to look for a 300A alternators and used small diesel engines? Peff | ||
| truthhunter@shaw.ca Rating: N/A |
If price is not a consideration this site has very fancy and efficient DC diesel sets http://www.polarpowerinc.com/products/generators/index.htm , not to sure I would go with there engine choices , but they do sell just the super efficent,ultra expensive DC alternators. I think a better choice would be a used air cooled 50DN alternator out of a bus and perhaps one of those noisy little air cooled diesels if co-generation for heat recovery and noise was not a concern to you. | ||
| truthhunter@shaw.ca Rating: N/A |
And if price is a object like it is for my MC 8 conversion: I have a military 24 VDC 4.2kw gas generator set that can be fitted into the spare tire compartment. It is powered by a Chrysler marine 4cyl opposed OHV (like a BMW bike engine only even less vibration and noise)32 CID derated to 6 hp. I suspect that I can safely get a lot more power out of this "lowered" compression engine, even if converted to propane. My hope is to also power a Air Conditioning compressor with it as well as the 4.2kw generator/starter that it came equipped with; and also run the same A/C compressor on a 120 or 240 volt AC electric motor when plugged into shore power. Maybe not the most efficient for A/C , but a compromise of one system. I am also toying with how to safely recuperate all the hot air from the engine cooling and exhaust for coach heat and hot water if this propane conversion pans out. With low noise/vibration and far less stink than a gas or diesel burning system (just as toxic though,so safe design is mandatory with heat recovery/co-generation )the effort could be worth it? I am fiddling with this as I have 4 of them to play with, they are only 230 lbs complete and when taken out of the roll cage they can be put in the spare tire compartment, if that is what I end up doing. There are lots of them around for cheap if you look and the engine was used in many military applications. . The big next question is how much can power can I get safely get out of this big/little 4 cyl engine when converted to propane, as they are de-rated to only 6 hp? While I have the military rebuild manual I have not been able to find any other information on these 32 CID Chrysler marine engines other than they were also made by Continental and Wisconsin under license. Would be good to here from anyone that has lots of first hand experience with these eheap & abundant engines | ||
| Richard Bowyer (Drivingmisslazy)
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The rule of thumb is one half kw (500 watts) per hp. Therefore you should be able to get at least 3kw from a 6 hp engine. | ||
| FAST FRED Rating: N/A |
"300A alternators and used small diesel engines? " The engine on most coaches spins a nice, reliable EZ to work on 200 -300A Alternator. Your local reefer dealer (those cold boxes on the back of 18 wheelers) will have nice Kubota or even better Yanmar 2 and 3 cylinder working takeouts for $300 or so. A couple of pulleys & matched belts , a welding set gov to operate the throttle and your done. IF you go this way its to rapidly and efficently recharge a large bat set. If NOISE is the concern remember AGM batts can be recharged at 75% of their capacity (with a GOOD temp sensative charger) , where the 100+ year old wet cell style will live longer at 20 or 25% inital charge rate. Trojan makes excellent AGM (in series 27) that could be worth while if noisemaker run times are any concern. FAST FRED | ||
| Tim Strommen (Tim_strommen)
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Prestolite (the company that bought Leece-Neville), has 300 Amp and down 12/24 volt Alternators spec'd. on their webpage (the "VLF" series - advertised as a 50DN replacement unit, and can output 325Amps@12Volts or 300Amps@24Volts depending on the model). If you're going to go "Crazy" and match one of these to an engine, you can do the same basic thing that Polar Power is doing by setting the engine RPMs to match the driven DC load. You would need to have some form of current detection (shunt?) and a look up table driving a servo on the throttle. To make this work correctly you'll need to match the engine's power curves to the alternator's power curves (adding a little headroom, should help with surge loads and prevent alternator stall) - plus you need to de-rate the alternator based on temperature. If you're going to add a belt driven Air compressor as well - you can predict the load by looking at the system pressure and whether or not the compressor's governor is driving or freewheeling the cylinders. Also, If you add a "logical rule" by switching off a soleniod for the air copmressor's govenor - you can lock out the air generation source during high electrical demands. Really if you're going to get this involved you may as well add either a microprocessor, or a very expensive EEPROM (Electronically Erasable Programmable Read Only Memory) that has the input sensors attached to the address lines and the output data lines attached to the servo driver (then some form of data "strobe" sequencer to trigger latches). It's easy enough for an uber-geek like me (and I probably should do it and sell it - but I digress), but it may be more than you're willing to commit to. Do it your way. Cheers! -Tim Strommen | ||
| Gary Carter Rating: N/A |
Most small engines have a KVA rating, so this will tell you have much you need to get the current you want. Somewhere in my failing memory I seem to remember something about 5hp to generate 150 amps at 12 vdc. I think this equals 1.8KV. | ||
| Tim Strommen (Tim_strommen)
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The KW to HP conversion is: 1 kW = 1.341 HP The actual math is easy but that does not include the efficiency of the alternator, the efficiency of the belt, gear, or direct coupling, DC line loss - etc. As with other algebra, you'll need to work backwards (known values first) with how much power you will actually need to get your enigne HP. Doing this correctly can be the difference between a succesful DC power pack and a (expensive) mistake. Cheers! -Tim Strommen | ||
| Tim Strommen (Tim_strommen)
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Cool little Google feature... Type in 1KW in HP - They built in a calculator function with conversions into the search engine... See the details on how to use it HERE. Cheers! -Tim | ||
| Richard Bowyer (Drivingmisslazy)
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Hey guys, believe me, it will take a two hp engine to run a one kw alternator. Richard | ||
| peff Rating: N/A |
Excellent suggestions, everyone. As the motivation for this project is simplicity and cost, I think I'll heed FF's advice and try to snag a used reefer engine. Tim, I have enough 8051s and other parts lying around to play with "smart" load regulation--good to idea think about. thanks Peff | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Peff, yup the reefer engine is a great source. I built a 15k genset (although it was 120v) out of a Kubota from Carrier and it's really sweet. One of the nice features of that style engine is that their injector pumps are usually set up to self-govern an whatever RPM you set them to, making that part of the equation a no brainer. That could be a real hassle with most other diesels... Also very easy to make very quiet. I use this stuff for sound abatement- it's cheap and amazingly good at shutting up ALL sound- part #5692T49 from www.mcmaster.com Interesting as you look at all their noise products, the "Noise Reduction Coefficient (NRC)" is published for all their various materials. This particular stuff is better than almost all the others except laminated lead sheet, and it's one of the least expensive of them all. It works amazingly well. I wouldn't mess with 8051's or any other DIY means of "load regulation" when there are already alternators out there with decent built in regulators, and inexpensive ($85) AVR's avaliable ( http://www.solesco.com/AVRmenu.html ) that do the job very well, without you having to beat your head against the wall just to reinvent another wheel... unless you enjoy that... spend your extra time doing work on your bus instead!! And last, as Richard said, plan on getting almost exactly half the KW as you have horsepower. That's how it works in the real world, at least up to about 50kw, where it finally starts getting to be a bit more efficient. | ||
| Tim Strommen (Tim_strommen)
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Yup - a good V-Reg is a critical part of the system when you use a Prestolite "VLF" alternator (they don't have built-in v-regs). The Solesco part you recommend has some interesting features in itself (namely overload field coil step down and start-generate delay). However the additional functions I was describing are not included. Namely engine speed adjustement to step down the engine revs when the alternator load is really low - and the ability to decide to run an air compressor when there is Horsepower to spare. The v-regs also will not monitor the engine's temp, oil level, fuel supply, exhaust temp, heat exchanger temp, etc. Either way if you want to put in this many functions in one power unit - you'll need to expect to put forth the planning to add these sources to the existing sytems without causing damage - and without choking the engine... I.E. if you add a secondary air compressor to the genset - it's a >>good idea<< to run the compressed air throught the air dryer, and if you use a little more planning (use a Bendix inversion valve to pipe in the govenor's "unload" control so that the dryer functions correctly and the compressor free-wheels when not needed) the original functions of the air system can be included in your new circuits. Plus this compressor will take about 1-5 HP from the engine while making air. I'd wonder if the Solesco V-reg would be "faked-out" by the eninge revs reducing due to low demand. The method it sounds like it's using for overload control is a tach pulse. If you had a shunt on the output of the alternator, and the load looked like it was reducing (and stepped down the engine speed) the v-reg might think the alternator is overloading the enigne and step down the field pulses to allow the engine to pick up speed. The shunt would then have less power drawn, and step down the enigne more... Just based on this, I'd want to very carefully pick what functions are automatic - and some of these functions can be "relocated" into a microprocessor that has a better (sensory) picture of what going on. Some times the wheel needs bearings... Cheers! -Tim Strommen | ||
| Gary Stadler (Boogiethecat)
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I dunno Tim, nothing like good old stewart warner gauges and a few emergency switches, like overtemp and low oil pressure. I've been in the electronics design business too long to trust microprocessors entirely for things I really care about, especially home brew stuff. It's WAY too easy to overlook a little unused register in your software that you forget to reset upon startup, and have it overflow and throw an interrupt or reset at seemingly random times, causing the whole system to burp at best, destroy itself at worst. Homebrew code, no matter how good it seems to be or how good a programmmer you are, never gets the rigorous reviews and pre-production beating that decent commercial stuff does... and for that matter there's just as much commercial stuff out there that has NO business doing what it does. For instance if you want a real eye opener, check out the real world of microprocessor fire-control systems that run most highrises. Much of the professionally used firmware in those systems is total bunk, marginal at best, has no process of review before putting it into the field, the companies (at least one big one that I know of) does NOT listen to field people when they point out major problems (ever hear that before?) and the fact that it's job is to protect lives is amazing, considering how close to "not working" many currently installed systems are. I live with a guy who installs this stuff and the manufacturer horrer stories are amazing. Just my opinion from listening and knowing. To a great degree I agree with David Hartley when he says, "Thanks, I will keep my antique MUI engine and Hydraulic transmission please and thank you"... microprocessors do a lot for us but they take a lot of work to make reliable, and that doesn't happen in the real world as much as it should... | ||
| Tim Strommen (Tim_strommen)
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Granted, I agree on the MUI engine and the hydraulic transmission (my rig will feature a 6V92TA and a 740HT 'till I can't find parts any more). I also did large commercial security, access control and fire systems for Apex Communications a while back (now part of Netversant), I do tend to agree with the evaluation that most of the cheap (cheaply built?) commercial hardware leaves a lot to be desired - example: I reverse engineered a Pelco D CCTV joystick camera controller for about $12 in parts and 5 minutes in time (they sell these for about $1,000 - and mine actually is reliable). I also currently work for a technology company in the S.F. Bay Area, and some of the things the industry does defies logic... That said (and having been on the inside) - the biggest factors that caused "blunders" to turn into commercial/consumer products are cost savings and time restrictions. I've seen some very solid and overbuilt engineering designs get stripped down to the bare minimum (while deep six-ing reliability and functionality) - and this is acceptable to manufacturers because everyone else in the industry is doing it. Point is, if you are willing to shell out the cash to do something right, and are willing to invest the time to make sure it's right before you drop it into your rig (and don't have a project manager breathing down your neck) - you'll likely enjoy it more. When dealing with electronics, I've run across two cardinal truths: 1) Start-ups have great ideas, vales, and make great products. 2) Investor driven companies don't (but enjoy destroying companies that do - and they usually lessen the user experience for the larger audience that consumes their product...) The best part about using a >>well designed<< hardware system with a microprocessor is that you can change the character of a system without re-defining its function. This covers even systems that are deemed life critical (think about this the next time you ride a modern elevator in a building with more than 10 floors). Correct hardware design will save you if your software does something it shouldn't (I.E. the pressure relief valves in your air system are there in case the automatic governor doesn't off-load your air compressor at 125psi...) By applying a safety conscious state of mind and ensuring that the hardware system is rock solid, and the microprocessor only controls the logic functions, there is less of a chance that the system will destroy itself (chances always exists - but if your 2-stroke was going to throw a rod anyway - there's nothing you can do about it with a piece of silicon...) Cheers! -Tim Strommen | ||
| Gary Stadler (Boogiethecat)
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Hee hee! WELL SAID Tim! Now where did the wife hide our microprocessorized blender... I want a margarita... | ||
| Tim Strommen (Tim_strommen)
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Heck - for margaritas I like a good 'ol fashioned mid '50s hand crank ice crusher... After a few drinks I can't figure out how to make more (self regulating sobriety...) I initially thought of using Stewart Warner gauges in my rig - but the more I looked at how the dash was going to work out, the less I liked it. I am using the Stewart Warner senders, but I'm piping them into my own dash cluster. It just looks better so far, and I like the extra control over the sytem I can put into it (and I added data logging). I should recant my two cardinal electronics truths. They should read: 1) Start-ups have great ideas, values, and make great products (if they get enough money to finish them) 2) Investor driven companies don't - but rather buy out start up companies that directly compete with them (then destroy the purity of the original concept and company - while lessening the user experience for the larger audience that consumes their product...) I see modern technology investors as more of an equalizer for new technology development. I've actually been doing a lot of thinking about this DC generator and aux air source idea as it was originally one of the ideas I intended to use in my rig. The main sticking point is that if you want to crank up the efficiency of the set, you need to control both the alternator field and the engine speed. This would suggest that a new voltage regulator design is in order (it tickles me to think of it). If you're going through those motions, it's only a few more steps to add sequencing, and some system safety features (low oil, high water temp, engine fire, etc.). I almost think I could make a tidy little bus-converter side business out of it... Whatda think? All in one water heater, DC generator, Air compressor? Probably do it for around $3500 or less if I got the costs right... Cheers! -Tim Strommen | ||
| FAST FRED Rating: N/A |
"All in one water heater, DC generator, Air compressor? Probably do it for around $3500 or less if I got the costs right..". The cost will go out of sight IF the camper needs to ALSO purchase an invereter big enough to run a couple of air cond sets. The reverse is also true if the owner needs air while at the power pole , a big battery charger will also be expensive if DC air cond was selected. Having the gen set operate a freon comprressor for air cond or eutetic plate fridge & freezer would be fantastic , but few would go to the hassle of rolling their own reefer boxes. Catch 22? Most folks usually NEED the noisemaker for air cond . FAST FRED |