The electric GMC fully imagined -

For GMC motorhome was space age for the time. Could easily throw a 3800 with hybrid assist for your '75 and throw in an extra Onan RWD boost drive electric/Onan petrol 4k generator (heck my 4k Onan would fire up and be used to charge the starting batteries for my 455 all the time). Viracon out of Owatonna MN still makes the cool windshields plus the Series 3 3800 with 200 hp and near 300 torque can pull similar # to the Cadi 402 at the time. Heck the 'naturally aspirated' Series 3 3800 was probably used 3800 motor going away party in 2008. And with no axle plenty o' room to stack LifePos when vehicle wants to go all electric. If and when my Lacrosse body gives out (it has been 15yrs steady @269k but who's counting) plop that motor an drivetrain as is (performance has not dipped since driving off used car lot) and you got a pretty good camping setup.

From experience the 4k Onan genes would sip not more a gallon per day when powering a mobile dj setup
 
Gfmccann said:
First post. Hope you don't mind me resurrecting this thread. I found it via a google search. Fantastic conversation!

I do not yet own a GMC coach but I am a serious 'gearhead' and have been a fan of the GMC for a looong time. (I currently vacation in a Winnebago Brave -- don't hate me!) Anyway, I have collected all manner of drawings, etc. with the intent of determining whether my imagined EV-RV can square with reality. Regardless, EV conversion or not, I will own a GMC sooner rather than later. With that introduction, here is a specific question (after context)...

I've looked at the Tesla drive units, specifically the "large" drive unit. As these units have independent axles coming from a differential off each side, it would seem to be relatively straight forward to adapt the stock GMC drive axles and leave the front suspension otherwise unmodified. No need for the transaxle. Assuming, then, that fitment isn't an issue, here's where my question comes in. These units have a torque rating of 445 lb-ft. That's comparable to the 455 Olds but available from zero rpm, so acceleration would be just fine. It's the three horsepower ratings that need to be focused on. 536 max HP, but only for well less than a minute before overheating. There is a second rating of 215 HP for "up to twelve minutes". That would be more than enough for overtaking other vehicles. The key figure is the third, "continuous" rating of 61 HP. This one concerns me....

The details that have been shared about aerodynamic cd, etc. are really helpful. Although it would be nice if there was a definitive answer for HP required to keep the GMC at steady state highway speeds, I appreciate the well reasoned guesses that have been offered up... and, obviously, headwinds and grades are variable. At any rate, do you suppose 61 HP would be a sufficient bottom line for maintaining highway speeds.
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Nobody expects a ladderback to be going fast so there's no shame in going at a leisurely pace which burns way fewer electrons. I think a 80 kwHr battery would be enough. The New EV Hummer has a battery north of 200 kwHrs! Here in BC, 100kw fast chargers are appearing everywhere so a 30 minute stop, charge and walk is no big deal.
The TH425 bolts onto what appears to be a fairly separate differential. It appears that an EV motor would only need an adaptor to mechanically connect to the diff and away you go (plus a couple electrical mods LOL)
 
Matt Colie said:
Dreiachser,
While your single point analysis may be accurate, it is obvious that you have never done vehicle road load studies. That is no surprise as these do not happen outside of vehicle testing labs that are scrambling for a fractional more MPG. The road load of any vehicle at a steady speed on level smooth pavement is usually quite low. But as soon as you include acceleration and any grade at all, it is a whole new ball game.
Matt
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When I regen brake or go downhill, I recapture most of the energy used to accelerate or climb. EVs level out the energy to go over mountain passes so it's almost the equivalent of traveling on level roads.
 
GlenC said:
Another way to look at the math for this analysis, My '08 Cayenne S is about 5,000lb and gets about 20mpg on the road. With my 5,000lb Airstream attached, I get about 12mpg.

So, 455/TH425 ~1,100lb and 55 gal gas and tanks ~400lb = 1,500lb
Tesla Model S battery 1,200lb, Model Y 1,700lb Motor ~220lb
Model S motor and battery might be a 1:1 swap by weight....
You might get 180 mile range with the one "S" battery, however, using the "Y" or adding a second battery would exceed GVW
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Good math.👌
I think that any GMC is not the ideal vehicle for a fast coast to coast trip.
I try to keep the 'R' in RV so stopping for an hour to charge in a place you never heard of usually puts a bit of adventure into the 'R'.
 
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Billygoat said:
I’ve always wondered about hub drive for a temporary assistance for the front wheel drive. It would help in off road traction issues like grass.
I can now understand how full electric would be hard to reach for our RV’s. Just the weight numbers and potential elevation challenges for electric in mountain driving are near impossible to overcome without large money and charge times. I’m seeing GM and now Ford are pulling back from EV’s? Wht are they doing that? Is there other engine developments happening?
I wonder about the ammonia burning engines for our application.

TG
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Just am seeing some interesting stuff Toyota is doing with hydrogen. Not sure they’ll pull it off but interesting. I’m rethinking my next car purchase, not sure EV will be what I’ll do yet.


TG
 
daver said:
When I regen brake or go downhill, I recapture most of the energy used to accelerate or climb. EVs level out the energy to go over mountain passes so it's almost the equivalent of traveling on level roads.
Click to expand...
Thats some creative physics there. Of course it depends on the definition of most
 
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Keith V said:
Thats some creative physics there. Of course it depends on the definition of most
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I go over a lot of passes here in BC with my plug-in and as long as you don't use the brakes but regen your speed away, I find I can recapture most of the extra energy used to climb. (turning potential energy into kinetic and then into electrical that charges the battery.) Friction brakes just waste kinetic energy by turning it into heat,
There are probably 5% losses every time you convert energy but it's way more efficient than an ICE vehicle where 25% of the gasoline energy gets to the road on a very good day.
 
I agree now with some here that are saying all electric on our GMC’s are not practical for all our scenario's of use. I do agree maybe a subframe platform change might be helpful on weight reduction. I’m not understanding yet the function of recent hydrogen conversions for combustion engines? When and if that technology is ready for prime time is when I would look at the conversion possibilities.
 
GM is building their BrightDrop electric delivery van at their CAMI plant just a couple of miles from where I live. It has a GVWR of 11,000lbs with 300Hp/390ft-lbs rating. The battery is 165Kwhr for 250 miles of range so about 1.5 miles per Kwhr.

It's designed for last mile delivery applications with FedEx being the first major customer to receive units. This is a great application for EV technology due to the recovery of energy in stop'n go courier delivery.

Our GMC's (at least mine anyway) are usually driven highway at highway speeds for 200-300 miles/day.

I mention this vehicle only because its about the same size/weight for battery sizing vs range.

The CAMI plant previously built our beloved GMC Tracker, GEO and Suzuki Toads.

I'm not sure why the URL shows up as "site maintenance" but clicking on it will take you to the Brightdrop website for more info.

 
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RF_Burns said:
GM is building their BrightDrop electric delivery van at their CAMI plant just a couple of miles from where I live. It has a GVWR of 11,000lbs with 300Hp/390ft-lbs rating. The battery is 165Kwhr for 250 miles of range so about 1.5 miles per Kwhr.

It's designed for last mile delivery applications with FedEx being the first major customer to receive units. This is a great application for EV technology due to the recovery of energy in stop'n go courier delivery.

Our GMC's (at least mine anyway) are usually driven highway at highway speeds for 200-300 miles/day.

I mention this vehicle only because its about the same size/weight for battery sizing vs range.

The CAMI plant previously built our beloved GMC Tracker, GEO and Suzuki Toads.

I'm not sure why the URL shows up as "site maintenance" but clicking on it will take you to the Brightdrop website for more info.

Click to expand...
There was a notice on this that GM has put that project and other EV projects on hold due to costs. They have already anounced that their EV's are selling at a loss of $38K per unit sales. Ford has made similar press releases. I suppose if you are the one that won the lottery Monday this would be a interesting project.

Of course, my personal objection to EV's is their detriment to the environment, and useless waste of energy. I do however base my objections on science and math.
 
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RoadWarrior said:
There was a notice on this that GM has put that project and other EV projects on hold due to costs. They have already anounced that their EV's are selling at a loss of $38K per unit sales. Ford has made similar press releases. I suppose if you are the one that won the lottery Monday this would be a interesting project.

Of course, my personal objection to EV's is their detriment to the environment, and useless waste of energy. I do however base my objections on science and math.
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They were still working on the new battery plant and lots of employee cars in the parking lot at the CAMI plant when I was last by there just before Christmas. I heard they changed the corporate structure to bring the Brightdrop subsidiary back under GM and the CEO is leaving.

I don't doubt they are "losing money" on each unit built since they are not in full production. Cost of that plant & retooling divided by only a few units built. I think this is a good application for EV, but I don't see myself buying an electric car. Zero emissions is BS. The whole environmental impact from cradle to grave must be considered. Hopefully a cleaner battery chemistry will be invented sooner than later.
 
RF_Burns said:
They were still working on the new battery plant and lots of employee cars in the parking lot at the CAMI plant when I was last by there just before Christmas. I heard they changed the corporate structure to bring the Brightdrop subsidiary back under GM and the CEO is leaving.

I don't doubt they are "losing money" on each unit built since they are not in full production. Cost of that plant & retooling divided by only a few units built. I think this is a good application for EV, but I don't see myself buying an electric car. Zero emissions is BS. The whole environmental impact from cradle to grave must be considered. Hopefully a cleaner battery chemistry will be invented sooner than later.
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Unfortunatly the whole environmental movement has become a sad situtation that revolves around government subsities. GM looses a huge sum for each unit produced even after huge government grants and subsidies. "Protecting the Environment" used to extend from "Cradle to Grave". Now we have politicans pushing whatever they can make sound good, and forget the big picture. Our children and grandchildren are now being left with a huge environmental disaster on a massive scale, that History will mark as a low point. The hydraulic mining and water contamination are all environmentaly sound and "Green" because they are blessed as part of the "Green" energy movement. Mining the Cobalt necessary for the batteries is done by children where they are expendable and they measure their success by how many pounds of Cobalt (which is a very poisnous metal) a child can recover before they become to cripled and die. This is part of the whole picture of vehicle batteries.
 
There are other battery types coming along, and two are no environmental issue at all. They still have to be recharged with utility electric power. When you can select to only car your car with wind/solar/hydro (US Hydro is not the same as Canadian), then it will be honestly environmental Matt_C
 
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