| Author | Message | ||
| truthhunter@shaw.ca
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Found a little more vague information on the Chevy hybrd pcikup truck with generator that might be a good toad and a generator on PDF at http://www.gm.com/company/gmability/adv_tech/images/fact_sheets/pht.pdf Both 2WD($32,000 stock) and 4WD ($36,000 stock)versions are reported (by sorces other than GMC) to be fully towable as is, just add the toad equipement (towbar brakeing and lights).It can be used to tow up a trailer to 10,000 lbs. (with optional tow package I am guessing). Still have not gotten the real question answered on the generator capacity. While it does generate 14 kw from a "flywheel alternator" at 42 Volts (not very handy for coach conversion) and has a invertor to provide 20 amps at 120 VAC. I still am not sure about the total available invertered 120 VAC power, it may be only 20 amps (2400 watts). Still do not know the engine rpm required to produce either the full 14 kw or just the inverted 120 VAC 2.4 kw. From the evasive brochier and lack of boasting it may be that any reasonalbe idle speed will only produce 2.4 kw and burn the entire 23 gallons fuel tank in 31 hours. If this guess is correct then it is not enough power output, fuel efficentcy or engine wear rate to be cost effective for my conversion needs. As far as this pitaful excuse for a hybrd goes, the fuel milage cost-effective goes like this = $3,000 extra for hybrd equipment to save (at best in city stop and go driveing)10% fuel/ over 100,000 miles life = gas savings of $500 ??? lets put that a different way cost of a 2.4 kw generator is mush less than the $2500 extra cost of hybrd + how much "wear and tear" will it cost to idle the hybrd truck as a generator on a regular use. Does not look very economical if this unit can not be use for the full 14 kw potential without extra invertor parts added and reving the snot out of that big V-8 truck engine at 5,500 rpm. Well that is the best I can do so far "facts". They are not selling this hybrd model up north yet. Maybe if someone down south is board they can stop&window-shop at a Chevy dealership and get some real specifications on the generator performance for all our product education. Looks like the old expression still holds- If you want it just right, modify it yourself. Now if I could just find the right parts in my junk piles out back! | ||
| CoryDaneRTS Rating: N/A |
(" flywheel alternator" at 42 Volts (not very handy for coach conversion) and has a invertor to provide 20 amps at 120 VAC ") Hmmmmm Odd voltage, though, since it was GM that put the idea together, I am not surprised. But the theory is there. What exactly are you after, to place a gen on the toad? Best bet might be to changeout the alternator and put in a 200 amp 12v, then the biggest inverter that the 200v 12vdc can supply. If there is room, put in a 24v alternator with appropriate inverter. GM uses some off the wall stuff, You would have to talk to the engineers to understand what they do, sometimes its just because GM is CHEAP and buy lowest bid. But the idea is sound, and probably better then carrying around a generator. In this case, the inverter can stay on the bus, and you can use a disconnect (2 contacts) like the towing companies use, to connect to the alternator(or batts). I am not sure if just pulling the Pos lead would be safe for travel when using the toad. I'd have to look more into this but if you put a load, light bulb maybe, the alt volt control would keep the voltage at proper level. On the theory that the alt requires voltage to power up, I thought the alt had residual magnetism to fire up the voltage coils. If not, 12v sensor from the vehicle might do it. It does'nt take much to flash the field. Then a relay could switch from the 12v batt to the 24v output. GEES it can get complicated, can't it. Probably best to connect to the house batt and invert from there. That would keep a load on. If all else fails, just take the belt off when using the toad. I kinda like the idea of using the toad. Not a lot of problems there, Generator feeds batt or inverter. Most of the problems are gone. cd | ||
| Richard Bowyer (Drivingmisslazy)
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Cory, It is my understanding that all the new vehicles are going to a nominal 42 volts. Richard | ||
| CoryDaneRTS Rating: N/A |
Rich You mean 42 volts for the battery supply? Or the Alt will supply 42v then be converted to 12vdc? Seems I had heard there was a change coming, however the news was not very explicit so I didn't get all the dirt on it. cd | ||
| truthhunter@shaw.ca
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It seems both battery and flywheel altenator are 42 volt system. Like I said can you get anymore difficult in the design and planing of obsolecence. It appears that the 14 kw output is only achived at top engine rpm and the 120 VAC output in inverted generator mode is only good for 2400 watts 20 amp 120vac, 3/4 gallon per hour fuel consumption (and of course the expenisve wear and tear on a idleing V8 engine). It would not even be easy to add a large battery bank as it is at 42 VDC. I guess someone is just going to have to go do a test drive to get the strait facts, as GMC sure ain't advertising them. Ever hear of the old mechnaic that said "these engineers ought to be sentenced to a eternity in hell, using there own off the shelf design's"? | ||
| Richard Bowyer (Drivingmisslazy)
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Nope. What I read was that the nominal battery voltage would be 42 volts. The alternator would probably put out about 48 volts. This system is not designed for an auxiliary power plant, so do not knock the design. Will probably work great for what the engineers designed it to do. Just like I really appreciated the engineers that finally put a six volt starter and battery in the Model T. LOL Richard | ||
| truthhunter@shaw.ca
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48 volts and a battery bank could be useable with a little modification. Would be happy to have read it wrong. Have you found the real output(watts) /rpm ratings? | ||
| CoryDaneRTS Rating: N/A |
It sounds like it is intended for small loading, saw, drill, some lights, thats it. If you are after a power supply from the toad for the bus, I think you need to build it as I mentioned above. Perhaps you could get a air con type cluch for when you are driving the toad. Plug into the coach when you need a charge. the bats would used the coach inverter and batts. the coach could charge when underway from the bus generator. It all sounds good. Run low on fuel, run the toad to the BP station. You know the gen will start because you drive it all the time. All you need is the alternator on the toad, cable and heavy duty plug like the tow guys use. I would think most toads are 6 cylinder and I don't think I would be too worried about running it. Think of it this way, you sure don't have to worry about the noise the genset makes. with a little imagination, you could put in remote start also and maybe remote stop. All the convenience of home(so to say). 2400 watts isn't a lot, though it will run a (1) air con unit and a few lights. by itself, I suppose it could charge a battery alright but the more you use for the coach, the more is taken away from the charger. A home grown version could be helpful. You pick a larger alternator for your needs and go for it. hmmm sounds good CD | ||
| Tim Strommen (Tim_strommen)
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There is a major shift in the automotive world about to take place with the voltage change from 12VDC to 42VDC. This is just like the change from 6 volts to 12 volts that some of you guys were around for...  The major advantages that the auto guys/gals are looking at is that with higher tension (voltage) the wires can be smaller because the currents are smaller for the same amount of power (less negative effect with line loss too). This is also evident in the design of motors and generators that are being designed for the new cars. Oh yeah, BMW has had Flywheel/Alternator/Starter stuff in some of their newest cars for the past two years (to my knoweledge). GM thing was never intended to be used for any real loads, just little "neat-toy" loads Tim | ||
| truthhunter@shaw.ca
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Gee Whiz I would of guessed that the logic for to choose 42 v rather than 48v advantage would be to make all existing "aftermarket components obsolet and unadaptable, therefor you would be buying ultra overpriced 42 volt OEM during the survice life. Perhaps I just need to have more trust in the manufactures wisdom and stop being so paranoid (fear in the unreal) about being held captive with each new technological advancement. Thanks for the insite. | ||
| Ian Giffin (Admin)
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If you think 42 volts is going to mess you up, you'd best not think about the part where, when you come to a stop at a traffic light, the engine turns off, then when you press on the "gas" pedal the engine magically starts back up again. Seamlessly. Ian www.busnut.com | ||
| truthhunter@shaw.ca
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INCREDABLE, SURELY YOU JEST FOR SUCH A THING COULD NOT BE! | ||
| CoryDaneRTS Rating: N/A |
Gee IAN either the car manufacturers have done some exceptional technology or it is a real pretty dream, even if it does sound fantastic. I am sure they are thinking this is the way to lessen polution, but can they really do it?? NOT WITHOUT BLOWING A TON OF MONEY!!! cd | ||
| truthhunter@shaw.ca
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I was trying to be sarcastic towards GM, the concept is a stupid & ancient notion from the mid 70's that reduces idol time to a few seconds at stop lights for minor pollution reduction and a fuel savings that does not balance out economically with the thousands of extra start/additional engine wear factored in. It might be cost neutral if equiped with a pressureized oil accumaltor for start-up prelube. To the flywheel altenator inovation's merit it replaces the starter so that should reduce starter wear and tear if it is a brushless flywheel altenator. I am already getting the feeling this gmc design will be a very high maintence/cost design that has no possiblitly of being paid for with the small fuel savings (only in city driving), so if it can not doulbe as a primary generator for the conversion . ..Well if you want it just right expect to buy it from many shelves and assemble/adapt it your self. Perhaps one day our conversion coaches will counted as a economic force and not just a speacialty neice market associated with marine and RV vacationers. Where are those GMC factory reps when you need them . |