I would not rely on a battery gauge.. my mobile phones let me down all the time. my li-ion batteries performance are crap.. my hobby is electic rc cars. I know batteries. I dont like li-lon batteries. I have seen them burn all the time.. nimh dont do that.. li-lon have more power with less weight, but run out fast. and you can`t run them low like nimh.. they get to hot.. I have a hpi wheely king monster truck and a sportswerks raven buggy..
and what kind of discharge time are you looking for in those vehicles? Do you want batteries that go from full to empty in two hours? 1 hr? 30 min?10 min? 1 min?
Cells are optimized for different applications - the cells we're using were designed for cordless tools and do quite well for discharge times ranging from ten minutes to a few hours.
Cooling really isn't a problem for us - we're probably pulling substantially lower specific power than you. State of charge estimation is indeed tough.
yeah my rc cars go from full to empty fast. 4-10min on buggy, 15-40min on monster truck.. (with 3200mah battery). it is all about gearing and how many turn the engine have.. li-lon batteries still dont like it when you crash or jump .. my friends have brushless air-planes and helicopters.. they have burned lots of li-lon batteries.. even when they dont crash... never seen nimh batteries do that..
You won't find a lot of lithium-ion cells optimized for such rapid discharge. A 5-10 minute discharge (we call that 6C - 12C) is pretty fast - cells tend to be designed for more gradual discharges (e.g. in power tools) or very rapid but pulsed discharge (e.g. in digital cameras). The 15-40 minute discharge is more reasonably matched to the LiIon cells on the market, though you''ll find way more options with NiMH.
Li-Ion is definitely more susceptible to failure when crashed. Cells are internally protected so they won't burn, but they will likely be non-usable after an impact that causes damage to the case.
Since this is a manned vehicle, such severe crashes are less common.
We haven't seen any issues with ordinary vibration (cells are used without problems in hammer-drills and other (often dropped) tools).
We have a 19.6 A-hr battery at 336 V - we pull 300 A peak and typically 20-40 A continuous.
You are talking to the wrong people about E85 vs. electric...we've done both, e85 does have some benifits (renewable, can squeeze a little more power out if you modify the engine) and is possible to reduce some emissions. But for some people and applications, electric is the obvious choice. Don't hate on it just because it wouldn't work for what you do. At least we are trying different ideas, the best breakthroughs usually are a result of straying from conventional methods.
yeah. then you do it all wrong. saab cars work in the arctic circle.. and is it that hard for you to make a 5liter extra petrol thank for start up... electric is the obvious choice to not buy.. heavy, no power, short range, expensive if you dont drive them all the time.. long charge time+++++ it will not work. they say e85 dont pollute more than the organic circle.. okey maybe a bit more but still. only 15% of e85 is normal petrol..
are Saabs all E85 there? E85 is indeed a great fuel from the standpoint of building small high-powered engines, though I have great reservations about it having a positive global environmental impact if used on any large scale (especially in the US, where ethanol primarily comes from corn).
We're not suggesting electric snowmobiles replace IC-powered ones in anything but a narrow niche of applications - they are indeed heavy, expensive, and have limited range (but can have very high power).
not all. only if you buy them with biopower. they can run on e85 and gasoline.. I have seen new dodge cars with biopower engines.. dodge avenger or caliber.
E85 is pretty simple to do - we have a small flex-fuel sensor that gives a continual readout of the percentage of ethanol in the fuel. The target air-to-fuel ratio is adjusted based on that, and feedback from the O2 sensor is used to trim it. We also adjust the boost pressure based on the ethanol percentage - more ethanol allows higher pressure without knock.Starting at low temps is the big challenge - ethanol is significantly less volatile than gas and it's tough to get enough vapor to burn.
yeah. ther are lots of e85 conversion kits on the web now. but only in sweden can you realy drive your car only on e85.. they have like1200 e85 stations. more than rest of EU and more than USA I think. I have not seen one in norway.. but i know they will come. maybe in 2-5years.. sweden is the e85 king.. lots of dragracer even use it on snowmobiles..they even make a e85 super sport car in sweden..
E85 is excellent from a performance standpoint - the power output of engines is usually limited by the amount of air that can be sucked or forced into the cylinders. Since ethanol burns at 9:1, much more ethanol can be burned for a given volume of air, more than making up for its lower specific energy. Evaporative cooling also helps quite a bit in turbo engines by keeping charge air temperatures down and preventing knock. Unfortunately, it's not as great a fuel from an environmental standpoint.
your wrong there.. dead plants, organic stuff make lots of co2, metan gas,++ so if you burn e85 it is not a big deal. and when e85 burn that clean it not that bad for the enviroment.. and making e85 also take up co2,, and you get nice new fresh oxygen.. way better than bio diesel. that shit realy dont burn clean,, even vs normal diesel.. and you lose power.. hydrogen/hybrid cars would be nice..
That's fine if you were making your E85 from natural dead plants that would be otherwise allowed to decay normally. But in most of the world, ethanol is made from corn or other crops specifically grown for that purpose. To satisfy demand, much of the production takes place on poor land that requires energy-intensive farming. It ends up being an energy neutral or negative process. Producing biodiesel is way better for the environment from a greenhouse gas impact standpoint.
Indeed, but the US burns 140 Bgallons/year of gasoline. Producing even 10Bgallons.year of ethanol in the US will be a challenge - we make about 4 Bgal/year right now. There's a question as to whether there's enough good land to even use E20 nationwide. To do this from corn will require using a lot of energy- inefficient farming practices. Making ethanol directly from suger (i.e. as is done in Brazil) is far more efficient, but unfortunately not practical here.
they have to do more research. find all the best ways to make ethanol.. I did not say etanol alone will save the world.. why not use all the best technology on cars.. electric/ethanol/hydrogen hybrid. I bet hydrogen/electric hybrid will beat ethanol on cars. but not on snowmobiles.. hp/weight will always be a big problem on snowmobiles.. opel, volvo+++ have new electic cars for 2011. opel volt.. I bet they are nice. not like the stupid norwegian made smart think..
The main problem with hydrogen is that there its energy density is so low that there is no way to store adequate amounts of it on a vehicle to get a decent range. The only viable technique right now is high pressure cylinders (we'll see what happens with the metal hydrides), and the energy required to compress the hydrogen for storage means its greenhouse gas impact is larger than diesel. It's hard to beat liquid fuels for compact, light, and easily usable, energy storage.
Yes, but many of the processes are very energy intensive, and the sad truth is that we use so much fuel that there are few waste products that we have enough of to make a dent in our fuel consumption.
I've got a friend whose graduate research involves making ethanol from wood chips...
Some oxides of nitrogen (N2O, specifically) are greenhouse gasses (though it's more an acid rain issue and low-level ozone), but moving to diesel yields such large fuel economy improvements (30% ore more), that the net GHG impact drops significantly. While a diesel car might put out ~1 g/mi NOx (only some of which is N2O), it's putting out 100+ g/mi of CO2. The GHGi of NOx is ~300, so it's a wash now, but EURO IV limits NOx to 0.4 g/mi, and the US 2010 regs are 0.05 g/mi! Hence the move to SCR.
Diesel fuel is an oil, and as such is substantially cheaper to make from oil-bearing plants. Alcohols come from fermentation of sugar, which is a more energy-intensive process. Diesel engines are also much less particular about what they burn - fuel for spark-ignited engines must conform to more stringent criteria. I personally think biodiesel from algae is the best long-term hope for a sustainable transportation fuel. Ethanol from corn most likely is not.
I read about scr. they say 30-70% less nox. but that is still way over what a petrol car make.. I would not buy a diesel car. they sound bad, stink, hard to start in cold wether. and diesel are know to freez in -40celsius. less engine heat, and they dont rev that high, need to change gear more than a petrol car. diesel cars and fuel are more expensive in norway.. no need for webasto on petrol car.. and diesel exhaus make me sick..
Diesel inherently will make more NOx than petrol, but that's because it's more efficient (i.e. lean mixture, higher combustion temperature and pressure => higher NOx) process. The same is true for direct injection (DI) gasoline engines - NOx is a problem when they are running in lean burn modes. The US Tier 2 NOx limit for passenger vehicles is currently be the same for petrol and diesel - the same will be true in Europe with Euro V.
they will not be more fuel efficient for long... mercedes have made a petrol engine with diesel technology. diesotto.. more hp and torque, better fuel economy than diesel cars. my friends all have diesel cars.. all have turble starting there cars when it drop under -15celsius.. need to heat engine up with webasto or electricity. I dont, even in -25c.. 1hour drive from where I live it can drop down to -50celsius.. belive me diesel can freez there.. lot of cars did last time they had -50c.
There is also some talk that NOx regulations may be relaxed, to allow for greater reductions in CO2. There's a tradeoff between improving fuel economy and cutting NOx - the increased focus on greenhouse gasses, higher levels of NOx may be tolerated. Modern diesels idle very smoothly and quietly (using pilot injection to smooth the combustion profile), start well in the cold, the fuel doesn't gel (with proper additives), can have adequate cabin heat on warmup (from the EGR cooler).
Diesels do need to be shifted more, but they are more efficient over a wider range of loads and speeds, and shifting can be handled by an auto-shift gearbox (e.g. DSG) if you're lazy. Diesel fuel is indeed more expensive, though not if you consider it on a usable-energy content basis (at least in the US). Part of the reason gasoline is so cheap now is due to soft demand - diesel is still in high demand and subsidizing petrol production. I don't really notice the diesel smell anymore with ULSD.
yeah. try to hillclimb that sled in deep snow on the mountains.. you will only get stuck. if you even get ther with your 6-10miles range.. it sucks to see a nice polaris chassis with a crapy electic engine.
First, its obviously not a mountain sled, second try doubling that range (still not that far, but give us some credit), and I'm pretty sure that "crappy" 150 hp electric motor in there is worth more than that stock fusion 900.
"150hp" yeah right. look more like 15hp to me.. I would scrap that electic engine and but the stock 900 back.. what ever it is worth, it no good.. you can make 2 strokes and 4strokes run on e85.
Vectra - I doubt anything I say will change your mind (considering the uninformed comments you posted to the McGill video), but I wanted to point out that our "crappy electric [motor]" puts out 100 kW, giving the 300 kg sled a top speed in excess of 120 km/hr and a 32 km range. Taking it into "deep snow in the mountains" would indeed be foolish, but that's not what it was designed for. It was made to support environmental research at Summit Camp, Greenland (600+ km north of the Arctic Circle).
not uninformed att all. they had to bull that mcgill sled back after a 10miles run.. and there top speed was30-32mph.. 300kg wow thats heavy.... my 60hp sled have 120km/h top speed.. and i use only 6-8liter of my 45liter on a 32km run... 240kg wet weight sled with 136track.. I live in the arctic circle. -20celsius and my car battery get to weak to even start my car.. battery and cold.lol
In case you haven't noticed, we're not McGill (Canada != USA). 300 kg is indeed very heavy (though comparable to many production four-strokes), but the weight is necessary for traction when towing cargo (500-1000 kg of scientific equipment on a towed sled).
The lithium-ion batteries used in the sled are quite different from the lead acid battery in your car. We notice little to no performance degradation at -20 C - hop on, turn the key and go.
you dont need that extra weight for traction. bullshit.. my friend had 3 sled behind a 174kg ski doo 300 freestyle. no problem.. you only need a good track and right gearing.. my lithium-ion mobile phone battery lose power even faster than my old ni-mh batteries in cold wether... just turn the key and go,, and rely on your friends to pull you home with there petrol sleds.... I would not trust my life with any thing electric on the mountains....
You are correct - the additional weight is not "necessary" for traction, but is helpful, especially for the snow conditions seen at Summit (10,000 ft altitude and very windy, so it's packed and icy).
When pulling $50,000 of fragile scientific equipment, very controlled power delivery and high drawbar torque at low speeds are desired, and the extra weight is helpful with that.
I would never suggest that you take our electric sled out into the mountains - that's not what it's for.
A bit of reading about battery technology might help you become better informed about low-temperature performance of various cells. NiCd did have an edge several years ago (and still do over NiMH), but some modern Li-Ion designs can operate down to -40.
As for avoiding having to rely on your friends to pull you home, the rule is simple and the same as on an IC-engine powered sled - turn around and head home before your "gas gauge" gets to 1/2.
I would not rely on a battery gauge.. my mobile phones let me down all the time. my li-ion batteries performance are crap.. my hobby is electic rc cars. I know batteries. I dont like li-lon batteries. I have seen them burn all the time.. nimh dont do that.. li-lon have more power with less weight, but run out fast. and you can`t run them low like nimh.. they get to hot.. I have a hpi wheely king monster truck and a sportswerks raven buggy..
vectraB97 3 years ago
and what kind of discharge time are you looking for in those vehicles? Do you want batteries that go from full to empty in two hours? 1 hr? 30 min?10 min? 1 min?
Cells are optimized for different applications - the cells we're using were designed for cordless tools and do quite well for discharge times ranging from ten minutes to a few hours.
Cooling really isn't a problem for us - we're probably pulling substantially lower specific power than you. State of charge estimation is indeed tough.
ethanbrodsky 3 years ago
yeah my rc cars go from full to empty fast. 4-10min on buggy, 15-40min on monster truck.. (with 3200mah battery). it is all about gearing and how many turn the engine have.. li-lon batteries still dont like it when you crash or jump .. my friends have brushless air-planes and helicopters.. they have burned lots of li-lon batteries.. even when they dont crash... never seen nimh batteries do that..
vectraB97 3 years ago
You won't find a lot of lithium-ion cells optimized for such rapid discharge. A 5-10 minute discharge (we call that 6C - 12C) is pretty fast - cells tend to be designed for more gradual discharges (e.g. in power tools) or very rapid but pulsed discharge (e.g. in digital cameras). The 15-40 minute discharge is more reasonably matched to the LiIon cells on the market, though you''ll find way more options with NiMH.
ethanbrodsky 3 years ago
Li-Ion is definitely more susceptible to failure when crashed. Cells are internally protected so they won't burn, but they will likely be non-usable after an impact that causes damage to the case.
Since this is a manned vehicle, such severe crashes are less common.
We haven't seen any issues with ordinary vibration (cells are used without problems in hammer-drills and other (often dropped) tools).
We have a 19.6 A-hr battery at 336 V - we pull 300 A peak and typically 20-40 A continuous.
ethanbrodsky 3 years ago
You are talking to the wrong people about E85 vs. electric...we've done both, e85 does have some benifits (renewable, can squeeze a little more power out if you modify the engine) and is possible to reduce some emissions. But for some people and applications, electric is the obvious choice. Don't hate on it just because it wouldn't work for what you do. At least we are trying different ideas, the best breakthroughs usually are a result of straying from conventional methods.
midgy5604 3 years ago
yeah. then you do it all wrong. saab cars work in the arctic circle.. and is it that hard for you to make a 5liter extra petrol thank for start up... electric is the obvious choice to not buy.. heavy, no power, short range, expensive if you dont drive them all the time.. long charge time+++++ it will not work. they say e85 dont pollute more than the organic circle.. okey maybe a bit more but still. only 15% of e85 is normal petrol..
vectraB97 3 years ago
are Saabs all E85 there? E85 is indeed a great fuel from the standpoint of building small high-powered engines, though I have great reservations about it having a positive global environmental impact if used on any large scale (especially in the US, where ethanol primarily comes from corn).
We're not suggesting electric snowmobiles replace IC-powered ones in anything but a narrow niche of applications - they are indeed heavy, expensive, and have limited range (but can have very high power).
ethanbrodsky 3 years ago
not all. only if you buy them with biopower. they can run on e85 and gasoline.. I have seen new dodge cars with biopower engines.. dodge avenger or caliber.
vectraB97 3 years ago
E85 is pretty simple to do - we have a small flex-fuel sensor that gives a continual readout of the percentage of ethanol in the fuel. The target air-to-fuel ratio is adjusted based on that, and feedback from the O2 sensor is used to trim it. We also adjust the boost pressure based on the ethanol percentage - more ethanol allows higher pressure without knock.Starting at low temps is the big challenge - ethanol is significantly less volatile than gas and it's tough to get enough vapor to burn.
ethanbrodsky 3 years ago
yeah. ther are lots of e85 conversion kits on the web now. but only in sweden can you realy drive your car only on e85.. they have like1200 e85 stations. more than rest of EU and more than USA I think. I have not seen one in norway.. but i know they will come. maybe in 2-5years.. sweden is the e85 king.. lots of dragracer even use it on snowmobiles..they even make a e85 super sport car in sweden..
vectraB97 3 years ago
kønigsegg biopower. 1025hp I think...
vectraB97 3 years ago
E85 is excellent from a performance standpoint - the power output of engines is usually limited by the amount of air that can be sucked or forced into the cylinders. Since ethanol burns at 9:1, much more ethanol can be burned for a given volume of air, more than making up for its lower specific energy. Evaporative cooling also helps quite a bit in turbo engines by keeping charge air temperatures down and preventing knock. Unfortunately, it's not as great a fuel from an environmental standpoint.
ethanbrodsky 3 years ago
your wrong there.. dead plants, organic stuff make lots of co2, metan gas,++ so if you burn e85 it is not a big deal. and when e85 burn that clean it not that bad for the enviroment.. and making e85 also take up co2,, and you get nice new fresh oxygen.. way better than bio diesel. that shit realy dont burn clean,, even vs normal diesel.. and you lose power.. hydrogen/hybrid cars would be nice..
vectraB97 3 years ago
That's fine if you were making your E85 from natural dead plants that would be otherwise allowed to decay normally. But in most of the world, ethanol is made from corn or other crops specifically grown for that purpose. To satisfy demand, much of the production takes place on poor land that requires energy-intensive farming. It ends up being an energy neutral or negative process. Producing biodiesel is way better for the environment from a greenhouse gas impact standpoint.
ethanbrodsky 3 years ago
search:Making Ethanol from Office Paper - CopyEthanol : DigInfo
you can realy make ethanol of almost any thing..
vectraB97 3 years ago
Indeed, but the US burns 140 Bgallons/year of gasoline. Producing even 10Bgallons.year of ethanol in the US will be a challenge - we make about 4 Bgal/year right now. There's a question as to whether there's enough good land to even use E20 nationwide. To do this from corn will require using a lot of energy- inefficient farming practices. Making ethanol directly from suger (i.e. as is done in Brazil) is far more efficient, but unfortunately not practical here.
ethanbrodsky 3 years ago
they have to do more research. find all the best ways to make ethanol.. I did not say etanol alone will save the world.. why not use all the best technology on cars.. electric/ethanol/hydrogen hybrid. I bet hydrogen/electric hybrid will beat ethanol on cars. but not on snowmobiles.. hp/weight will always be a big problem on snowmobiles.. opel, volvo+++ have new electic cars for 2011. opel volt.. I bet they are nice. not like the stupid norwegian made smart think..
vectraB97 3 years ago
The main problem with hydrogen is that there its energy density is so low that there is no way to store adequate amounts of it on a vehicle to get a decent range. The only viable technique right now is high pressure cylinders (we'll see what happens with the metal hydrides), and the energy required to compress the hydrogen for storage means its greenhouse gas impact is larger than diesel. It's hard to beat liquid fuels for compact, light, and easily usable, energy storage.
ethanbrodsky 3 years ago
search:Overview: 2011 Chevrolet Volt
looks like a car I would like to own in 2011.
vectraB97 3 years ago
searchEthanol from Garbage and other waste:
vectraB97 3 years ago
Yes, but many of the processes are very energy intensive, and the sad truth is that we use so much fuel that there are few waste products that we have enough of to make a dent in our fuel consumption.
I've got a friend whose graduate research involves making ethanol from wood chips...
ethanbrodsky 3 years ago
bio diesel in not better. nox is a greenhouse gass. 5--25times more nox gas from diesel cars will not help.. bio diesel are also made form crops..
vectraB97 3 years ago
Some oxides of nitrogen (N2O, specifically) are greenhouse gasses (though it's more an acid rain issue and low-level ozone), but moving to diesel yields such large fuel economy improvements (30% ore more), that the net GHG impact drops significantly. While a diesel car might put out ~1 g/mi NOx (only some of which is N2O), it's putting out 100+ g/mi of CO2. The GHGi of NOx is ~300, so it's a wash now, but EURO IV limits NOx to 0.4 g/mi, and the US 2010 regs are 0.05 g/mi! Hence the move to SCR.
ethanbrodsky 3 years ago
Diesel fuel is an oil, and as such is substantially cheaper to make from oil-bearing plants. Alcohols come from fermentation of sugar, which is a more energy-intensive process. Diesel engines are also much less particular about what they burn - fuel for spark-ignited engines must conform to more stringent criteria. I personally think biodiesel from algae is the best long-term hope for a sustainable transportation fuel. Ethanol from corn most likely is not.
ethanbrodsky 3 years ago
I read about scr. they say 30-70% less nox. but that is still way over what a petrol car make.. I would not buy a diesel car. they sound bad, stink, hard to start in cold wether. and diesel are know to freez in -40celsius. less engine heat, and they dont rev that high, need to change gear more than a petrol car. diesel cars and fuel are more expensive in norway.. no need for webasto on petrol car.. and diesel exhaus make me sick..
vectraB97 3 years ago
Diesel inherently will make more NOx than petrol, but that's because it's more efficient (i.e. lean mixture, higher combustion temperature and pressure => higher NOx) process. The same is true for direct injection (DI) gasoline engines - NOx is a problem when they are running in lean burn modes. The US Tier 2 NOx limit for passenger vehicles is currently be the same for petrol and diesel - the same will be true in Europe with Euro V.
ethanbrodsky 3 years ago
they will not be more fuel efficient for long... mercedes have made a petrol engine with diesel technology. diesotto.. more hp and torque, better fuel economy than diesel cars. my friends all have diesel cars.. all have turble starting there cars when it drop under -15celsius.. need to heat engine up with webasto or electricity. I dont, even in -25c.. 1hour drive from where I live it can drop down to -50celsius.. belive me diesel can freez there.. lot of cars did last time they had -50c.
vectraB97 3 years ago
There is also some talk that NOx regulations may be relaxed, to allow for greater reductions in CO2. There's a tradeoff between improving fuel economy and cutting NOx - the increased focus on greenhouse gasses, higher levels of NOx may be tolerated. Modern diesels idle very smoothly and quietly (using pilot injection to smooth the combustion profile), start well in the cold, the fuel doesn't gel (with proper additives), can have adequate cabin heat on warmup (from the EGR cooler).
ethanbrodsky 3 years ago
search:Water freezes instantly in mid air turning into snow
not the video I was talking about. but you see..
vectraB97 3 years ago
Diesels do need to be shifted more, but they are more efficient over a wider range of loads and speeds, and shifting can be handled by an auto-shift gearbox (e.g. DSG) if you're lazy. Diesel fuel is indeed more expensive, though not if you consider it on a usable-energy content basis (at least in the US). Part of the reason gasoline is so cheap now is due to soft demand - diesel is still in high demand and subsidizing petrol production. I don't really notice the diesel smell anymore with ULSD.
ethanbrodsky 3 years ago
yeah. try to hillclimb that sled in deep snow on the mountains.. you will only get stuck. if you even get ther with your 6-10miles range.. it sucks to see a nice polaris chassis with a crapy electic engine.
vectraB97 3 years ago
First, its obviously not a mountain sled, second try doubling that range (still not that far, but give us some credit), and I'm pretty sure that "crappy" 150 hp electric motor in there is worth more than that stock fusion 900.
midgy5604 3 years ago
"150hp" yeah right. look more like 15hp to me.. I would scrap that electic engine and but the stock 900 back.. what ever it is worth, it no good.. you can make 2 strokes and 4strokes run on e85.
vectraB97 3 years ago
In case anyone reading this is interesting in learning, the torque/speed curve for our 100 kw (134 hp) electric motor is here (see page 3):
mtukrc.orgXdownloadXmadisonXmadison_ze_design_paper_2008.pdf
Of course one can make an IC engine run on E85 (though starting at -30 C ambient is challenging) - we also build flex-fuel four-strokes.
The electric snow machine was built in response to a specific request for a utility sled with 10 mi range and zero emissions at the point of use.
ethanbrodsky 3 years ago
Vectra - I doubt anything I say will change your mind (considering the uninformed comments you posted to the McGill video), but I wanted to point out that our "crappy electric [motor]" puts out 100 kW, giving the 300 kg sled a top speed in excess of 120 km/hr and a 32 km range. Taking it into "deep snow in the mountains" would indeed be foolish, but that's not what it was designed for. It was made to support environmental research at Summit Camp, Greenland (600+ km north of the Arctic Circle).
ethanbrodsky 3 years ago
not uninformed att all. they had to bull that mcgill sled back after a 10miles run.. and there top speed was30-32mph.. 300kg wow thats heavy.... my 60hp sled have 120km/h top speed.. and i use only 6-8liter of my 45liter on a 32km run... 240kg wet weight sled with 136track.. I live in the arctic circle. -20celsius and my car battery get to weak to even start my car.. battery and cold.lol
vectraB97 3 years ago
In case you haven't noticed, we're not McGill (Canada != USA). 300 kg is indeed very heavy (though comparable to many production four-strokes), but the weight is necessary for traction when towing cargo (500-1000 kg of scientific equipment on a towed sled).
The lithium-ion batteries used in the sled are quite different from the lead acid battery in your car. We notice little to no performance degradation at -20 C - hop on, turn the key and go.
ethanbrodsky 3 years ago
you dont need that extra weight for traction. bullshit.. my friend had 3 sled behind a 174kg ski doo 300 freestyle. no problem.. you only need a good track and right gearing.. my lithium-ion mobile phone battery lose power even faster than my old ni-mh batteries in cold wether... just turn the key and go,, and rely on your friends to pull you home with there petrol sleds.... I would not trust my life with any thing electric on the mountains....
vectraB97 3 years ago
You are correct - the additional weight is not "necessary" for traction, but is helpful, especially for the snow conditions seen at Summit (10,000 ft altitude and very windy, so it's packed and icy).
When pulling $50,000 of fragile scientific equipment, very controlled power delivery and high drawbar torque at low speeds are desired, and the extra weight is helpful with that.
I would never suggest that you take our electric sled out into the mountains - that's not what it's for.
ethanbrodsky 3 years ago
A bit of reading about battery technology might help you become better informed about low-temperature performance of various cells. NiCd did have an edge several years ago (and still do over NiMH), but some modern Li-Ion designs can operate down to -40.
As for avoiding having to rely on your friends to pull you home, the rule is simple and the same as on an IC-engine powered sled - turn around and head home before your "gas gauge" gets to 1/2.
ethanbrodsky 3 years ago