Senior Engineering Project - E-Trike - suggestions welcome!
- Thread starter SimpleCJ
- Start date
docnjoj
1 GW
The shame of it all is that apparently good engineers insist on putting the 2 wheels on the wrong end! It causes a world of trouble! Tadpoles rule!
otherdoc
otherdoc
diver
1 kW
lots of torque steer with one wheel driven with the etek powered bike. both wheels driven it handles like a charm. the Schwinn trikes are alu frame , make sure your ok with welding the alu. That peerless unit looks the nuts... 
My Schwinn is extended 18 inch's, axles came from Miami sun, along with there 24 inch wheels . i went with the 5/8 axel from them and upgraded the bearings. the Schwinn axles wont handle any weight as they WILL break at the step down to 15 mm. they just stepped it down with no radius and axel will break at the step down. My Schwinn's are front wheel drive and carry a total weight with me in excess of 450 lbs . I weight 175.. I use the maxis tires with the heavy duty tubes and wrap the wheel with cloth first aid tape several times. the velor tape don't seem to hold up as well for some reason. I have had no tire or rim failure with the maxis and Miami sun rims and spokes. yes the bikes are heavy with the lead acid batterys ,but you wont be charging them at 30 miles either. I have gone 70 miles with out a charge and plenty more to go. I set the CA to run a max of 25 amps.. They will get a work out next year as we a moving to maine, dont know how the shwinns will work on the steep hills ..
My Schwinn is extended 18 inch's, axles came from Miami sun, along with there 24 inch wheels . i went with the 5/8 axel from them and upgraded the bearings. the Schwinn axles wont handle any weight as they WILL break at the step down to 15 mm. they just stepped it down with no radius and axel will break at the step down. My Schwinn's are front wheel drive and carry a total weight with me in excess of 450 lbs . I weight 175.. I use the maxis tires with the heavy duty tubes and wrap the wheel with cloth first aid tape several times. the velor tape don't seem to hold up as well for some reason. I have had no tire or rim failure with the maxis and Miami sun rims and spokes. yes the bikes are heavy with the lead acid batterys ,but you wont be charging them at 30 miles either. I have gone 70 miles with out a charge and plenty more to go. I set the CA to run a max of 25 amps.. They will get a work out next year as we a moving to maine, dont know how the shwinns will work on the steep hills ..
diver
1 kW
fechter said:
I ended up with two rear axels on my etek bike with both rear wheels powered ( meaning as like i cut the axel in half and added extra bearings It, IS a blast to drive now. no pulling on accelration and one can spin it circles and that even to an old fart like me is a blast. I cant wait to take it on a frozen pond and give it hell lol.. My projects would not be possible if it werent for the help from this forum.. Ive built severl front wheel drive trikes for my friends and all love them. one guy is even 275 lbs. I put him on a 3/4 axel and worksman wheels..lol
AussieJester
1 TW
docnjoj said:
Theeere he is hehee... go Doc
Just wheel around in reverse for a bit Doc you'll see how much better the two wheels at the back is hehehe
I decided on a 300W smart charger/balancer unit powered by a 500W Pyramid benchtop PSU. The charging unit claims excellent acuracy of <10mV and over 90% efficiency!
iCharger - 300W - 10A max charge current - balancer - multi-chemistry compatible - USB port for firmware updates and LogView data analysis.
Cost ~$190 shipped
http://www.progressiverc.com/1010B+.html
Pyramid 6-15v 25A 500W Benchtop Power Supply
Cost ~$110 shipped
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=120352088942
With my pack at 8s, 3.6v charging voltage, and 10A max output, that means a maximum of 288W to the batteries. At 90% efficiency that means the power supply would only need to input 320W (21.3A @ 15v)
I'm guessing I'll have about a 2-3 hour charge with this setup on my 26.4v 18.4Ahr pack. Not bad... AND I can keep some alligator clips with it and charge off of a car battery if I ever needed to. Partial charges are fine with A123 batteries, so I could literally steal enough energy from someone's car to get home and then do a full charge with my benchtop supply.
Not sure if my math is correct...
26.4v * 18.4Ahr = 485.7 Whr
485.7 Whr / 288W = 1.68 hours charge time IDEAL (constant 10A input to capacity)
More like 2-3 hours realistically since a lot of time is spent in the CV cycle of charge and Watts are slowly reduced to zero.
iCharger - 300W - 10A max charge current - balancer - multi-chemistry compatible - USB port for firmware updates and LogView data analysis.
Cost ~$190 shipped
http://www.progressiverc.com/1010B+.html
Pyramid 6-15v 25A 500W Benchtop Power Supply
Cost ~$110 shipped
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=120352088942
With my pack at 8s, 3.6v charging voltage, and 10A max output, that means a maximum of 288W to the batteries. At 90% efficiency that means the power supply would only need to input 320W (21.3A @ 15v)
I'm guessing I'll have about a 2-3 hour charge with this setup on my 26.4v 18.4Ahr pack. Not bad... AND I can keep some alligator clips with it and charge off of a car battery if I ever needed to. Partial charges are fine with A123 batteries, so I could literally steal enough energy from someone's car to get home and then do a full charge with my benchtop supply.
Not sure if my math is correct...
26.4v * 18.4Ahr = 485.7 Whr
485.7 Whr / 288W = 1.68 hours charge time IDEAL (constant 10A input to capacity)
More like 2-3 hours realistically since a lot of time is spent in the CV cycle of charge and Watts are slowly reduced to zero.
Ok, so I got a bunch of stuff now...
I tested every single cell I had and grouped into groups of 8 cells with similar capacities. I ended up with 9 packs of A123 cells, but the bottom 1 or 2 packs are pretty crappy. I'm trying to figure out what will happen when these lower capacity packs go flat before the others. They will all be connected in parallel, but have their own connectors for individual balance charging. I got a lockable/removable motorcycle trunk for the batteries and extra storage. Fits perfect between the rear wheels and looks alright too.
I got all the packs glued together, got my wire, shrink wrap and cut my battery tabs out. Just waiting on my zinc solder and flux for experimenting with soldering to the positive terminal because I don't really trust the welds I'm getting on that end. I also have balancing and power connectors coming soon so I'll be able to finish assembling the individual packs and move on to modifying the motorcycle trunk to house the packs and other electrical stuff.
Spent some time getting the spot welder worked over so everything's a bit cleaner, especially the wiring.
I just purchased the Cyclone 500W Brushless motor kit. I'm going to try mounting it with the included mount inline with the crank chain as they recommend. The kit also comes with the freewheel crank adapter and a wider crank shaft to fit around the motor.
I was toying with the idea of putting a multi gear sprocket on the rear with a derailer system, but then I stumbled across something even better!!
Shimano Nexus 3 Speed Trike Hub with internal gearing, a direct fit for my trike!!
Now I can have 3 speeds and get better efficiency from the motor! Ordered it yesterday, should be coming soon.
Everything seems to be comming together well. Main issue now is getting my extension brackets and steering brackets machined. My buddy said he'll be in the college's machine shop working on some stuff and that he could do it for me... if I pay him... $100 for four parts? Sounds reasonable for a friend right??
I tested every single cell I had and grouped into groups of 8 cells with similar capacities. I ended up with 9 packs of A123 cells, but the bottom 1 or 2 packs are pretty crappy. I'm trying to figure out what will happen when these lower capacity packs go flat before the others. They will all be connected in parallel, but have their own connectors for individual balance charging. I got a lockable/removable motorcycle trunk for the batteries and extra storage. Fits perfect between the rear wheels and looks alright too.
I got all the packs glued together, got my wire, shrink wrap and cut my battery tabs out. Just waiting on my zinc solder and flux for experimenting with soldering to the positive terminal because I don't really trust the welds I'm getting on that end. I also have balancing and power connectors coming soon so I'll be able to finish assembling the individual packs and move on to modifying the motorcycle trunk to house the packs and other electrical stuff.
Spent some time getting the spot welder worked over so everything's a bit cleaner, especially the wiring.
I just purchased the Cyclone 500W Brushless motor kit. I'm going to try mounting it with the included mount inline with the crank chain as they recommend. The kit also comes with the freewheel crank adapter and a wider crank shaft to fit around the motor.
I was toying with the idea of putting a multi gear sprocket on the rear with a derailer system, but then I stumbled across something even better!!
Shimano Nexus 3 Speed Trike Hub with internal gearing, a direct fit for my trike!!
Now I can have 3 speeds and get better efficiency from the motor! Ordered it yesterday, should be coming soon.
Everything seems to be comming together well. Main issue now is getting my extension brackets and steering brackets machined. My buddy said he'll be in the college's machine shop working on some stuff and that he could do it for me... if I pay him... $100 for four parts? Sounds reasonable for a friend right??
JEB
100 W
If you do any heavy peddleing the cyclone freewheel on the crank will not hold up, a friend did a double freewheel on the motor shaft (split chain) this is working out better for him- (after the 2nd replacement of the crank freewheel)
I did the jackshaft, 2 freewheel rear drive to the wheels, I have no problems with it. (as another poster suggested)
I did the jackshaft, 2 freewheel rear drive to the wheels, I have no problems with it. (as another poster suggested)
Update:
I've got all my battery packs assembled.
The removable trunk/battery storage is pretty much done.
I also got the motor mounted with the chain, extended peddle crank and Nexus 3 speed hub.
I'm waiting on the machine shop to get my extension and steering brackets done, but it sounds like I could be waiting several weeks for that, so I'm about stuck.
What I need to focus on now it building the headset that will mount into the seat post with an offset bracket like in a picture I posted a few pages back.
Here's some updated pics of building the batteries, trunk and the mounted motor etc..
I've got all my battery packs assembled.
The removable trunk/battery storage is pretty much done.
I also got the motor mounted with the chain, extended peddle crank and Nexus 3 speed hub.
I'm waiting on the machine shop to get my extension and steering brackets done, but it sounds like I could be waiting several weeks for that, so I'm about stuck.
What I need to focus on now it building the headset that will mount into the seat post with an offset bracket like in a picture I posted a few pages back.
Here's some updated pics of building the batteries, trunk and the mounted motor etc..
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MidniteTweeker
100 W
- Joined
- May 16, 2008
- Messages
- 121
If I understand the drive layout correctly, it appears that the bottom run of chain is where motor tension will be applied. Doesn't this double the rearward force applied to the crank/crank bearings? That is, because of this layout there will be tension in both the top and bottom run of chain? If so, this doubles the frictional losses.
I suspect with a solid axle it will very much want to go in a straight line. At low speeds it may be OK. At higher speeds it could get real interesting, especially on surfaces where the traction if variable. I would call anything over 10 mph high speed. As docnjoj pointed out, tadpole trikes eliminate a lot of this struggle.
Also, it appears the chain wrap on the motor drive sprocket is only 90 degrees. I'm very skeptical this is enough.
MT
I suspect with a solid axle it will very much want to go in a straight line. At low speeds it may be OK. At higher speeds it could get real interesting, especially on surfaces where the traction if variable. I would call anything over 10 mph high speed. As docnjoj pointed out, tadpole trikes eliminate a lot of this struggle.
Also, it appears the chain wrap on the motor drive sprocket is only 90 degrees. I'm very skeptical this is enough.
MT
This setup is almost exactly as specified by Cyclone, only difference is that the motor is slightly farther from the peddles and is tilted at about 30 degrees. I think there's enough contact. I understand what you're saying, but I don't think there's a good way to mount it on the top run because peddling would put too much stress on the idler pulley. It seems to be working ok. I will probably put the bike together until I get the extensions brackets machined, just temporarily so I can test it out.
Ideally I won't be going over 20mph on this trike once I get the frame extended and the seat and steering moved back and down.
I could have just ran the motor on it's own sprocket to the rear axle, but then I wouldn't be able to take advantage of the 3 speed hub.
Ideally I won't be going over 20mph on this trike once I get the frame extended and the seat and steering moved back and down.
I could have just ran the motor on it's own sprocket to the rear axle, but then I wouldn't be able to take advantage of the 3 speed hub.
I couldn't resist seeing it running and not riding it, so I put the bike together with just a single battery pack taped on the rear, front brake cable attatched and the twist grip throttle on the handlebars.
For just being on a single pack it really moved nicely. Even riding in 1st gear only, I had a good top speed (not speedometer yet). Almost thinking I need to gear down at the rear axle a bit or 3rd gear will be too fast.
Also, while it did run fine on a single pack, when accelerating hard the voltage would drop on the battery meter down to red or orange then back to green once I let off it or got up to cruising speed. I found this was easily avoided by simply pedaling a little bit to get the bike moving, then engage the throttles and it stayed solid green. With 8 packs connected I should have no problems accelerating or going up a hill.
So far so good!
For just being on a single pack it really moved nicely. Even riding in 1st gear only, I had a good top speed (not speedometer yet). Almost thinking I need to gear down at the rear axle a bit or 3rd gear will be too fast.
Also, while it did run fine on a single pack, when accelerating hard the voltage would drop on the battery meter down to red or orange then back to green once I let off it or got up to cruising speed. I found this was easily avoided by simply pedaling a little bit to get the bike moving, then engage the throttles and it stayed solid green. With 8 packs connected I should have no problems accelerating or going up a hill.
So far so good!
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etard
100 kW
WOW, your build is turning out to be alot similar to my desired setup. I love your battery compartment, very trick! I have the 3 speed too, let me know how it shifts under load, and if you want more speed or torque, just change sprocket sizes. If you have a source for different sprockets sizes, let me know. Can't wait to see the final pics.
SOOO>.... Today I put the rest of the doo-dads on the bike!
I installed the shifter for the hub, the cycle analyst, and the connector and mount for the battery compartment.
Runs excellent with all batteries connected, was peaking up around 800W, 500W average full load. It does ok with electric only, but if you pedal with it, that's when it accelerates very fast! I clocked my top speed at about 23mph!! :wink: Of course there are people who will say that's too fast for a trike, but really as long as you only use 2nd and 3rd gear on straightaways you should be fine. Also, when I get the frame extended and move the CG down it should improve stability greatly. For now I'll just make sure I slow way down before attempting to turn. I also will probably gear it down a bit in order to get a bit more torque from the motor. With an estimated load of 300 pounds, I probably need the torque!
The Nexus hub worked great, but I had some problems getting it set right. I tried to use the little window on the hub end of the cable to adjust it, but I couldn't get it line up with anything. So I resorted to just tipping it on its side and adjusting it till I had all 3 gears shifting properly. On the road it performed very nicely. I could shift it under load with almost no noticeable lag in the shift, but once or twice I heard something pop, so I'm guessing it's best not to shift while still accelerating.
Another problem I had was that my handlebars are too short before the bend, so I don't have enough room to mount the controls properly and have to hold onto just the end of the bars practically. I cut the stock bar down cause I want it smaller for when I move it back, but I'm going to have to get a different bar that's not bent that far out.
I only have the front brake shoes to stop me, but they stock breaks seem to be plenty adequate, I can always add a disk brake to the front if I want to. Also, braking on the rear at higher speeds could be dangerous since only one wheel is locked to the axle and could pull you to one side if you were on loose or slippery ground. The extended frame would probably counter some of that force though, so I may still consider a disc brake on the rear axle, but that's near the end of my list of things to do.
If you look at the picture, imagine the rear assembly shifted back by 14 inches, the seat moved down to the trunk level and the handlebars mounted on the seat post like in this picture, but offset towards the front... http://www.lightfootcycles.com/txlsteer.jpg
That's one of my biggest issues right now is designing and building that offset headset for the steering extension. Like in that pic, I'm going to use ball joints and connecting rods with custom brackets, that is, I'm doing a dual-link steering set-up. Not that it's necessary, but that I think it will look nicer that just on one side. I have the headset bearings and caps, I just need to figure out what size pipes I need and where and what to thread them to. Also, how to connect the headset to the pipe that will slide into the seat post. This should be an interesting challenge...
I installed the shifter for the hub, the cycle analyst, and the connector and mount for the battery compartment.
Runs excellent with all batteries connected, was peaking up around 800W, 500W average full load. It does ok with electric only, but if you pedal with it, that's when it accelerates very fast! I clocked my top speed at about 23mph!! :wink: Of course there are people who will say that's too fast for a trike, but really as long as you only use 2nd and 3rd gear on straightaways you should be fine. Also, when I get the frame extended and move the CG down it should improve stability greatly. For now I'll just make sure I slow way down before attempting to turn. I also will probably gear it down a bit in order to get a bit more torque from the motor. With an estimated load of 300 pounds, I probably need the torque!
The Nexus hub worked great, but I had some problems getting it set right. I tried to use the little window on the hub end of the cable to adjust it, but I couldn't get it line up with anything. So I resorted to just tipping it on its side and adjusting it till I had all 3 gears shifting properly. On the road it performed very nicely. I could shift it under load with almost no noticeable lag in the shift, but once or twice I heard something pop, so I'm guessing it's best not to shift while still accelerating.
Another problem I had was that my handlebars are too short before the bend, so I don't have enough room to mount the controls properly and have to hold onto just the end of the bars practically. I cut the stock bar down cause I want it smaller for when I move it back, but I'm going to have to get a different bar that's not bent that far out.
I only have the front brake shoes to stop me, but they stock breaks seem to be plenty adequate, I can always add a disk brake to the front if I want to. Also, braking on the rear at higher speeds could be dangerous since only one wheel is locked to the axle and could pull you to one side if you were on loose or slippery ground. The extended frame would probably counter some of that force though, so I may still consider a disc brake on the rear axle, but that's near the end of my list of things to do.
If you look at the picture, imagine the rear assembly shifted back by 14 inches, the seat moved down to the trunk level and the handlebars mounted on the seat post like in this picture, but offset towards the front... http://www.lightfootcycles.com/txlsteer.jpg
That's one of my biggest issues right now is designing and building that offset headset for the steering extension. Like in that pic, I'm going to use ball joints and connecting rods with custom brackets, that is, I'm doing a dual-link steering set-up. Not that it's necessary, but that I think it will look nicer that just on one side. I have the headset bearings and caps, I just need to figure out what size pipes I need and where and what to thread them to. Also, how to connect the headset to the pipe that will slide into the seat post. This should be an interesting challenge...
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Update: Took the bike to the store yesterday, hit 26mph on the way back. I think I need to drop the rear sprocket by at least two or three teeth. Probably need to set up a spreadsheet calculator to figure out what gear I need for 20mph top speed.
Also, as part of my design project I will probably be doing CG calculations for structural analysis as well as determining safe cornering speeds.
I of course will also be doing efficiency calculations, which will be used to compare to a possible later part of the project involving a solar trailer of about 50W @12v. I've heard a few people say that a solar trailer adds too much weight and air resistance to make it worth the trouble, but I feel it is worth putting to the test. If I can get some good high efficiency and lightweight panels in roughly a 3x3 foot square, I don't see why it isn't a reasonable means to add extended range and mobile charging capability. We'll see if I can get some panels donated, at this point I've got too much money already into building the trike and batteries, but I suppose it's worth it just for the experience. I've learned A LOT already!
Also, as part of my design project I will probably be doing CG calculations for structural analysis as well as determining safe cornering speeds.
I of course will also be doing efficiency calculations, which will be used to compare to a possible later part of the project involving a solar trailer of about 50W @12v. I've heard a few people say that a solar trailer adds too much weight and air resistance to make it worth the trouble, but I feel it is worth putting to the test. If I can get some good high efficiency and lightweight panels in roughly a 3x3 foot square, I don't see why it isn't a reasonable means to add extended range and mobile charging capability. We'll see if I can get some panels donated, at this point I've got too much money already into building the trike and batteries, but I suppose it's worth it just for the experience. I've learned A LOT already!
diver
1 kW
looks real nice,,,i like it
diver
1 kW
were can the trunk be bought, thanks
I'm also looking at possibly using a motorcycle trunk that will serve as cargo, battery & electronics storage, brake & turn signals, lockable security, and also can serve as the backrest. Something like this...
[/quote]
Don't mean to double post, but this got left on the bottom of the other page and I thought it was important...[/quote]
I'm also looking at possibly using a motorcycle trunk that will serve as cargo, battery & electronics storage, brake & turn signals, lockable security, and also can serve as the backrest. Something like this...
Don't mean to double post, but this got left on the bottom of the other page and I thought it was important...[/quote]
Look on eBay for "motorcycle trunk". Most of them are not removable though. I think being able to remove the batteries from the bike is a major plus. That way you can bring them in in cold whether or for charging etc. Also, if you noticed, I've installed a 12v converter with a lighter outlet to power anything that can be plugged into a car. This means that the trunk also doubles as a portable power station. I could take it camping or whatever and charge cell phones, power portable CD player, whatever works with a 12v DC source can be adapted to be powered from the case.
One problem I had was that during hot summer days I know that the trunk will easily reach temps over 100F which isn't really very good for the batteries. That's what the fan is for. It draws air from the very bottom center of the case, goes up through each battery box, joins in the electrical box in the center, out through the fan and then out through the top vent on the case for total ventilation. I'm confident that this will keep the box at acceptable temps even on hot days. The fan also is a smart fan with a thermistor, so at normal temps it runs fairly slow, as it heats up to 100+ the fan increases speed. It only pulls about 30mA so I'm not worried about it running the batteries dead. I've also got a separate switch on the fan for cooler days when it's not needed.
One problem I had was that during hot summer days I know that the trunk will easily reach temps over 100F which isn't really very good for the batteries. That's what the fan is for. It draws air from the very bottom center of the case, goes up through each battery box, joins in the electrical box in the center, out through the fan and then out through the top vent on the case for total ventilation. I'm confident that this will keep the box at acceptable temps even on hot days. The fan also is a smart fan with a thermistor, so at normal temps it runs fairly slow, as it heats up to 100+ the fan increases speed. It only pulls about 30mA so I'm not worried about it running the batteries dead. I've also got a separate switch on the fan for cooler days when it's not needed.
Trike looks great.
Maybe you could attach a snow plow to the frame :wink:
For your next version, you might consider a leaning frame, which would help a lot with high speed cornering. Much more work though.
Maybe you could attach a snow plow to the frame :wink:
For your next version, you might consider a leaning frame, which would help a lot with high speed cornering. Much more work though.
Here's my initial efficiency and cost comparisons along with my charge and discharge logs. Note that this is only based on 2 complete charge/discharge cycles and 15 miles of travel, but I think it's pretty indicative of what I can expect with this set-up.
15 miles, average speed of 10mph, only cost me about 10 cents with a 621MPG Equivalent after factoring in losses from the AC outlet to the motor!!
This is something you may want to note when people state MPG equivalents for electric bikes is that they are usually not factoring in inefficiencies, just doing raw conversion from the vehicles rated efficiency and energy in a gallon of gasoline, but this isn't an accurate measurement because, as you can see from my figures, I loose roughly 44% of energy from AC outlet to the motor (30% lost in power supply, 20% lost in the charger, another 20% lost between charge and discharge cycles that isn't counted towards the reported Wh/mile on the Cycle Analyst (losses probably in battery cells themselves, balance charging waste & some from wire resistance). If I ignored these losses, I would say I'm getting about 1200MPG, but it's actually only half that much.
EDIT: I fixed my efficiency and cost chart to show both energy equivalent MPG, and the more realistic Cost Equivalent MPG which figures in actual expenses per both gasoline and electricity and uses an average car's economy of 30mpg to equate the "REAL" MPG equivalent. If gasoline prices go up, then this rating goes up as well, just as it will if the cost of electricity goes down. Opposite of that, if gasoline becomes a lot cheaper, then the electric equivalent MPG will actually go down.
Cost Equivalent MPG is a far more useful and meaningful comparison. With these considerations made, I came out with 242mpg cost equivalent efficiency. That's more reasonable and still very very good! :wink:
15 miles, average speed of 10mph, only cost me about 10 cents with a 621MPG Equivalent after factoring in losses from the AC outlet to the motor!!
This is something you may want to note when people state MPG equivalents for electric bikes is that they are usually not factoring in inefficiencies, just doing raw conversion from the vehicles rated efficiency and energy in a gallon of gasoline, but this isn't an accurate measurement because, as you can see from my figures, I loose roughly 44% of energy from AC outlet to the motor (30% lost in power supply, 20% lost in the charger, another 20% lost between charge and discharge cycles that isn't counted towards the reported Wh/mile on the Cycle Analyst (losses probably in battery cells themselves, balance charging waste & some from wire resistance). If I ignored these losses, I would say I'm getting about 1200MPG, but it's actually only half that much.
EDIT: I fixed my efficiency and cost chart to show both energy equivalent MPG, and the more realistic Cost Equivalent MPG which figures in actual expenses per both gasoline and electricity and uses an average car's economy of 30mpg to equate the "REAL" MPG equivalent. If gasoline prices go up, then this rating goes up as well, just as it will if the cost of electricity goes down. Opposite of that, if gasoline becomes a lot cheaper, then the electric equivalent MPG will actually go down.
Cost Equivalent MPG is a far more useful and meaningful comparison. With these considerations made, I came out with 242mpg cost equivalent efficiency. That's more reasonable and still very very good! :wink:
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As long as the laden weight distribution is 2/3 aft and less than 20" above the ground, you should be fine (i'd need the rear track width to determine the ideal CoM location, but suspect it may even be lower than 20").SimpleCJ said:
Not really. The yaw torquing caused by single rear wheel braking isn't enough to disrupt the grip at the remaining wheels. At lock-up, the vehicle will track perfectly straight. If you have 66% of the laden weight on the rear axle, the rear brakes will be the dominate (and most effective) brakes so you'd be wise to invest in brakes on both rear wheels. This is especially true when lowering the CoM because less weight will transfer to the front wheel during braking.SimpleCJ said:
Here's my updated and corrected efficiency with another cycle added. Also some new pics of the trike.
Cost Equivalent Efficiency: 361 MPG
Energy Equivalent Efficiency: 569 MPG
Cost Equivalent Efficiency: 361 MPG
Energy Equivalent Efficiency: 569 MPG
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BLUESTREAK
1 kW
- Joined
- May 10, 2009
- Messages
- 470
HI SimpleCJ,I tried to send you a second PM but not sure it went through,I am still working on my two SCHWINN TRIKES but it has rained here in TAMPA all week so not much progress on making new battery boxes for the trike rear end.I just finished making a rear suspension for my blue trike and it workes well,I know that you were interested in doing this to your trike also you do not have to change your stearing you can just get a longer handlebar to reach back and lower your seat down to about 26in.from the ground.I streached my trike rear back about 12in.and it looks good.This computer thing is all new to me and i have a lot to learn i am 65 years old and until about 7 mounths ago i had never touched a computer but i am learning fast.I have been reading all that i can and these groupe of guys on here like MR. DOGMAN and all others have been very helpfull.When i learn how i will post pictures of my project on here.This is my 3 posting on the sphere the other two were on the for sale section where MR.VPOWER battery guy opened up the chance for me to tell him that i felt that i was cheated by CAMMYCC AND V POWER OUT OF ABOUT 5 AMP-HR ON A 48 VOLT 20 AMP-HR BATTERY.I dont think i made much progress with them.sorry that i am rambling on and if i get out of line someone let me know i can take a hint. more later about the trikes. THANKS FELLOWS "BLUESTREAK"
