# Idea that may upgrade EV mileage



## Raik (Jun 17, 2013)

I'm saving for my brand old to new EV and then solar panels but thats another story.
Researching all about EVs pros and cons I just had an idea to increase mileage and recharge anywhere with gasoline or propane but I know little of electricity and thats where you help!

The idea is simple, you have a modest EV with a range of about 60-100 miles per charge with lithium batteries, how about having a constant power source charging the batteries as you go (a power generator) making it maybe like an hybrid (if it works I'm calling it EVrid or something like that). I know it will not fully charge the batteries but maybe increase range.

Now picture this










A 4000 watt WITH 220V (important, faster charging) also 110v for convenience (camping maybe?).

Now this baby inside this:










Even spare space for luggage and additional fuel or camping goods

Now please help me with the math, I don't know how much power draws a charger (watts? amps?), in the specs sheet says 15A 110VAC or 220VAC, as far as I know 15x110= 1650 or 15x220= 3300, that means that can theoretically draw 3300watts and for charging I would need a 3500 or 4000 watts generator, is that true? or is way overkill? also I know nothing about charge times, how long would take to charge the usually 15 or so CALB batteries normally used, I know the charger plays the most important role so how about theoretical times of this which is one of the cheapest of-the-shelf chargers, and this http://www.diyelectriccar.com/forums/showthread.php/10kw-60a-diy-charger-open-source-59210.html posted here.

Disclaimers: Yes I know this would be terrible for the enviroment (if gasoline is used, maybe propane would be better?) and you spend more in gasoline than a combustion car, but the idea is avoid the need to purchase more batteries just for one round trip a year (hollidays trip) and the gas generator (I have one BTW  ) can be used for more aplications or even lend to another friend to use with his EV. Also I don't like the idea of using a combustion car because it may be great for long range travel but once you arrive the city you will wish you had your EV every day.

Any post will be thanked and doubts about what the heck I'm trying to explain. Pardon my poor english I'm not native.


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## steelneck (Apr 19, 2013)

Yes there is nothing technically wrong with your idea, i have thought about it too. A portable, well.., generator to put either in a small trailer or just putting it in the boot (with an exhaust pipe). Just to extend the range on occasion. For the normal everyday commute it is not needed, n that case it would be just dead weight, but on longer trips it can be useful. I can see myself have a stop for lunch after 100km or so and leave the generator generator going, giving me some extra clicks to go, and even have it going while driving depending on how long the trip is planned to be. I wonder how a "bad boy charger" (just a large capacitor in series with a rectifier bridge) would work with a generator like that you had a picture of, i really have no clue about that.

A 4kw generator wont drive the car on longer trips, just extend your range a bit, unless you take longer stops to let it charge up your batteries. You can expect to need at least something like 10-15 Kw to just maintain 50-60mph (depending on your car of choice of course), so 3300w is just around 1/3 of what you need to go way further than your normal range, unless you stop for extended periods to let it catch up. But yes it is doable.


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## Duncan (Dec 8, 2008)

Hi Raik
That is doable but as you say not very efficient
A cheaper and more efficient way is to build a "pusher trailer" - basically the front end off something like a Golf (Rabbit) diesel
You drive your EV and when you are on the highway fire up the trailer and let it push the car


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## Raik (Jun 17, 2013)

steelneck said:


> Yes there is nothing technically wrong with your idea, i have thought about it too. A portable, well.., generator to put either in a small trailer or just putting it in the boot (with an exhaust pipe). Just to extend the range on occasion. For the normal everyday commute it is not needed, n that case it would be just dead weight, but on longer trips it can be useful. I can see myself have a stop for lunch after 100km or so and leave the generator generator going, giving me some extra clicks to go, and even have it going while driving depending on how long the trip is planned to be. I wonder how a "bad boy charger" (just a large capacitor in series with a rectifier bridge) would work with a generator like that you had a picture of, i really have no clue about that.
> 
> A 4kw generator wont drive the car on longer trips, just extend your range a bit, unless you take longer stops to let it charge up your batteries. You can expect to need at least something like 10-15 Kw to just maintain 50-60mph (depending on your car of choice of course), so 3300w is just around 1/3 of what you need to go way further than your normal range, unless you stop for extended periods to let it catch up. But yes it is doable.


Well of course I knew this wasn't new or original, and I agree with you, I only wanted to knew the mathematics to see if that generator was enough and how far could extent the mileage.

If its really a 1/3 then it means a 30% increase, not bad, not too shaby, but how long whould take to charge the batteries with that boy in 220v? you know a pit stop, I can travel say 12:00pm and then rest at 2:00pm, go to a grab a meal, wait say 3 hours 5:00 pm (hopefully reach the quick charge level of up to 80% battery) then travel another few hours say 7:00 pm and rest in a motel to go in the mornig with full charge, rense and repeat.

 how long do you think it will charge to full?

 my second idea was to use a DC generator, but they are uber rare and expensive... then again I haven researched throughfully.



zsnemeth said:


> They're called range extender trailers. Just do a search.


Wow, they even have a name, thank you, will do.



Duncan said:


> Hi Raik
> That is doable but as you say not very efficient
> A cheaper and more efficient way is to build a "pusher trailer" - basically the front end off something like a Golf (Rabbit) diesel
> You drive your EV and when you are on the highway fire up the trailer and let it push the car


Great idea, but I think its a really hard execution; the problems I see is unless you're a mechanic you need to pay quite a few bucks for the job.
I see it this way, I got a car converted to electric, I got the engine to spare, then I use a teardrop trailer and try to make the "pusher trailer", I need to electronically turn on the engine (easy part), then transfer the power of the engine to the axis of the wheels (hard part) because I need a transmition and its in the EV so I need to make a gear set, if I go cheap only 1 gear with a proper ratio to a 60-75mph speed, not a cheap job but hey there is more, even with 1 gear you still need a neutral and/or cluch and a way to shift because you will need to brake and prevent the engine to spin, now I don't know but now you need an electric engineer, or someone that can do the job (I know I can't), also you need a way to accelerate (not hard, not easy, a steel wire like a motorcycle will do).

I think its a nightmare to make one, let me hear what you thought


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## Duncan (Dec 8, 2008)

Raik said:


> Great idea, but I think its a really hard execution; the problems I see is unless you're a mechanic you need to pay quite a few bucks for the job.
> I see it this way, I got a car converted to electric, I got the engine to spare, then I use a teardrop trailer and try to make the "pusher trailer", I need to electronically turn on the engine (easy part), then transfer the power of the engine to the axis of the wheels (hard part) because I need a transmition and its in the EV so I need to make a gear set, if I go cheap only 1 gear with a proper ratio to a 60-75mph speed, not a cheap job but hey there is more, even with 1 gear you still need a neutral and/or cluch and a way to shift because you will need to brake and prevent the engine to spin, now I don't know but now you need an electric engineer, or someone that can do the job (I know I can't), also you need a way to accelerate (not hard, not easy, a steel wire like a motorcycle will do).
> 
> I think its a nightmare to make one, let me hear what you thought


You are making it too complex
You cut the entire front end off a front wheel drive car
Engine, gearbox, drive-shafts gears front suspension
bodywork
(need to remove or cover the headlamps
Then you need to be able to remotely operate
Clutch,
Gearbox (one gear) - in/out
throttle
ignition

You will also need to lock the steering

Attach it to an A frame with a trailer receiver - hook it onto your car's towbar


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## Raik (Jun 17, 2013)

Duncan said:


> You are making it too complex
> You cut the entire front end off a front wheel drive car
> Engine, gearbox, drive-shafts gears front suspension
> bodywork
> ...


You mean this










I'm afraid to get pulled by a cop, and guess what  if cop doesn't like me or the little monster I'm in BIG trouble unless I register the "push trailer" as a motorbyke or something because it has an engine and wheels. A more camo terdrop will pass unnoticed... but you're right is easier BUT more expensive, at least in my country, here in the 3rd world we recycle anything and everything, I think its cheaper to re use my old ICE engine and build everything than buy a used car with good working engine and transmission (hopefully automatic) and pay around 1500 bucks, with my old engine working I think I can make this










With 500 dolars,  mucho cheaper, better looking, smaller, lighter, stealthier 

-----------------

Researching around I found something that sounds B S

"The unit can be attached to an electric car while it drives and fully recharge the electric car’s battery three times with six gallons of gasoline in the engine."
Source: http://blogs.wsj.com/drivers-seat/2...ates-novel-way-to-unshackle-the-electric-car/

I don't think the math works, what do you think? not only has a gasoline generator that can charge the EV 3 times over with only six gallons (and the engine can also used to pull the EV) but the little teardrop ALSO has 70kwh!!! battery pack... I mean it looks it all can be fitted but charging 3 times over with a small gas engine...


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## Siwastaja (Aug 1, 2012)

Raik said:


> I don't think the math works, what do you think? not only has a gasoline generator that can charge the EV 3 times over with only six gallons (and the engine can also used to pull the EV) but the little teardrop ALSO has 70kwh!!! battery pack... I mean it looks it all can be fitted but charging 3 times over with a small gas engine...


"Gasoline contains about 36.6 kWh/US gal" says Wikipedia. 6 gallons is 220 kWh. Assuming 30% efficiency (which might be optimistic), that makes 65 kWh - approx. one recharge of a 70 kWh battery pack. Certainly not three.


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## Woodsmith (Jun 5, 2008)

Duncan said:


> You are making it too complex
> You cut the entire front end off a front wheel drive car
> Engine, gearbox, drive-shafts gears front suspension
> bodywork
> ...


Use one with an auto box, that will make controlling it easier.

However, it may not be legal in some parts of the world, the UK for instance.

There would also be a little bit of a safety issue should the trailer begin to push too hard when cornering as it will cause the car to 'tail slide'.




I think, personally, I would only use a powered trailer to reduce the load on the car when pulling a cargo trailer, most likely in an off road situation. The throttle and brake on the trailer would be controlled directly by the amount of 'pull' and 'push' on the hitch respectively so that the trailer is only following the car and not pushing it.


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## steelneck (Apr 19, 2013)

Raik said:


> If its really a 1/3 then it means a 30% increase, not bad


No not really. I was comparing to a steady speed of 50-60mph. In real traffic your car will use more than 10-15kW, acceleration takes a lot more than just keeping speed, the same goes for climbing a hill. Then it also depends on how efficient your car is, it is a big diff between a small, light and aerodynamic car compared to a 3 ton small truck. You have not told us anything about the car you are thinking of, that is important to give you a bit more precise numbers. You can expect something between 20-30 kWh/100Km drawn from the batteries at normal driving, for a quite normal car.

As for the time it takes to charge up it is also hard to tell you anything, we have no clue about the size of your thought battery pack.


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## ken will (Dec 19, 2009)

A pusher trailer with an automotive engine would be more efficient than a generator-battery charger-electric motor. 

A pusher trailer would increase your acceleration.

A pusher trailer can push the car sideways...but when making sharp turns I fed most the power to the main engine and only a little power to the pusher.

Pusher trailers are illegal in a lot of places.

A generator trailer can also be used if you loose electricity at home or go camping.

You can buy generators that run on Propane.

You can remove the generator and use the trailer as a trailer.


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## dragonsgate (May 19, 2012)

Shortly after I finished my conversion I started thinking about ways to extend the range. The front wheel drive pusher trailer at first looked like a good solution. Then some short comings became apparent to me at least. If anyone builds a petrol engine pusher trailer there are a couple of things to consider. (1) Throttle sticking in acceleration mode; this could be as bad or worse than having the motor controller blowing in a full on mode. A provision for a kill switch to the engine should be made. (2) The possibility of the momentum of the trailer making the rear end of the car spin out. Ever see any videos of the cops tapping the rear end of a car they are chasing and causing it to spinout? It is possible that the thrust of the trailer could do this. I don’t know if this should be under number two or be a separate category but trailer breaks would be a must. These reasons had nothing to do with my decision not to do a pusher trailer. It is just that I didn’t want to ruin the cool feel of pure electric propulsion.


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## frodus (Apr 12, 2008)

With the time, money, space and complication limitations..... why not just spend that extra money on more batteries?

I've been looking around at how to provide myself emergency power. The weight and inefficiency of an engine sucks, and putting that through a charger decreases it even more to where an engine (whether gas or propane powered) isn't a good choice. I decided it will be better to get 1-2kwh worth of batteries + an inverter and just charge normally. I'm limited on space because it's a motorcycle, so it'll likely be an emergency rescue pack, but there's no reason you couldn't just build the car with more batteries to begin with.


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## fotajoye (Nov 28, 2011)

If you own a Leaf, now is the time of your discontent...if you can wait, I think within the next couple of years, when the Leaf batteries start reaching "end of life," there will be an after-market for upgraded batteries. I expect some enterprising company to offer higher density, lower-cost, battery packs at a reduced price than the current Nissan packs. Hopefully you can have your choice of only buying battery packs based on your mileage needs so you don't carry around the extra weight and hopefully if you need to go out of range, there will be a fast-charge station along the way.

Nissan cannot compete in this market because of the ridiculous prices their dealer's charge for parts and service. Remember, the dealer is really in the repair business since he makes most of his money from the service bays by charging sky-high prices.

If you own a Leaf, it's to your long term advantage for Nissan to sell as many commuter cars as possible with the current low-energy density batteries. This will help assure a good market for the improved future battery packs that will allow the car to be classified as a true freeway cruiser.

Having said all this, I can only hope this after market battery upgrade will be the case. EVs don't require the maintenance that ICE cars require, perhaps changing brake pads and batteries will be all that is required in the future. I like Elon Musk's approach when he says "Dealer's are not needed." EVs and Elon Musk are certainly disruptive to the current ways Dealers screw the ICE car buying Public.

And, BTW, do you really want to spend all that time on an extender mule science project?


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## Raik (Jun 17, 2013)

Woodsmith said:


> However, it may not be legal in some parts of the world, the UK for instance.
> 
> There would also be a little bit of a safety issue should the trailer begin to push too hard when cornering as it will cause the car to 'tail slide'.
> 
> I think, personally, I would only use a powered trailer to reduce the load on the car when pulling a cargo trailer, most likely in an off road situation. The throttle and brake on the trailer would be controlled directly by the amount of 'pull' and 'push' on the hitch respectively so that the trailer is only following the car and not pushing it.


Illegal as in banned? or illegal as unregistered, here is an example

http://www.nestofdragons.net/media/13670/dsc03813_small_500x375.jpg

Markered as a microcar, has cruising speed and able to travel the highway, registers (France, Switzertland, Belgium) as a Quad motorcycle (quadbyke) so yeah, I think an engine inside a trailer could be registred as a byke, maybe they will not want to making excuses like the lack of seats and lights (you WILL need to add lights, even teardrops trailers need them) also add brakes, as for the seat you can tell its a new concept already being used in the world (and registered) and by not allowing you to register it feels like your country is living in the medieval times.  smooth talking can help you in almost every ocassion.

Offroad pulling, another fabuolous use, thanks  the more reason to make one.

Tail slide shouldn't be an issue at least in highways they have an inner angle in curves so you don't get toss out of the road because of centrifugal force also if taking proper cautions, like neutral the engine while you brake your EV, brakes in the pusher trailer and as an advanced emergency system you can program the breaks to lock in case of more than 3G or one wheel losing contact with the ground... just an idea, I'm no engineer or car designer.



steelneck said:


> You have not told us anything about the car you are thinking of, that is important to give you a bit more precise numbers. You can expect something between 20-30 kWh/100Km drawn from the batteries at normal driving, for a quite normal car.
> 
> As for the time it takes to charge up it is also hard to tell you anything, we have no clue about the size of your thought battery pack.


Sorry, I think I did something about the batteries, oh well; as for batteries someting as 60kwh LifePo4 whould seem ok (limited by space, not by money* or weight). So how you think a 4000 watts generator in 220v will take to charge? if you can tell me the 100% and quick charge up to 80% whould be awesome.

*but I'm not rich enough to buy a second battery pack

As for the vehicle I will buy an used VW Bug (a.k.a. old beetle, scarab, sedan), but I will overhaul it to a buggy, I will toss the car body (100kg less weight or more, I haven't found an exact number anywhere, I only know the VW bug weights 850kg) and replace it with a fiberglass body (waaay lighter, with tail and side windows made of acrylic/polycarbonate/persperx or whatever they do lightweight windows today), here a few pictures

http://bimg1.mlstatic.com/carroceria-fibra-de-vidrio-buggy-nuevo-diseno_MLM-F-4358499731_052013.jpg
http://bimg1.mlstatic.com/carroceria-fibra-de-vidrio-buggy-nuevo-diseno_MLM-F-4358497508_052013.jpg

Racing lightweight front seats, fiberglass rear seats, full body and dashboard made of fiberglas... light as a feather  and fragile .

Thank you for your time.



ken will said:


> A pusher trailer with an automotive engine would be more efficient than a generator-battery charger-electric motor.
> A pusher trailer would increase your acceleration.
> A pusher trailer can push the car sideways...but when making sharp turns I fed most the power to the main engine and only a little power to the pusher.
> Pusher trailers are illegal in a lot of places.
> ...


I agree, you got advantages on both sides (more fuel efficient in the pusher trailer but harder to make and legal issues to tacle), I don't think a tail drag is an serious issue, highways have an inner angle in curves so you don't get toss out of the road because of centrifugal force.




frodus said:


> With the time, money, space and complication limitations..... why not just spend that extra money on more batteries?
> 
> I've been looking around at how to provide myself emergency power. The weight and inefficiency of an engine sucks, and putting that through a charger decreases it even more to where an engine (whether gas or propane powered) isn't a good choice. I decided it will be better to get 1-2kwh worth of batteries + an inverter and just charge normally. I'm limited on space because it's a motorcycle, so it'll likely be an emergency rescue pack, but there's no reason you couldn't just build the car with more batteries to begin with.


More batteries is a bad idea, it means more time (looong shipping time, I'm not in USA), the other 2 options are also WAY cheaper, even more because if I convert a car to electric it means I already got an ICE engine!, also I already own a 6000 watts coleman gasoline generator (I work in construction bussiness, they're a necessity). 

The reason I won't go for more batteries is one, I don't have extra space in the car also don't want extra weight for every day city rides, I won't buy batteries just to use them twice a year, also you needto use each pack of batteries isolated from eachother (never mix new batteries with old batteries), a teardrop can be used for more than carring an engine/generator specially useful with my compact car with little trunk space (see picture), and the last is I can use my generator in work/camping or lent/rent the range extender to another EV user, not doable with batteries.




fotajoye said:


> And, BTW, do you really want to spend all that time on an extender mule science project?


I'm my own boss also I really work like 3 hours (throught the day), so instead to sit and scratch my belly I can do this proyect. So don't worry about my time, leave that to me .
I may be one weird science project, but hey electric cars started this way, there won't be no DIY EV if it wasn't for guys with time to work in wacky science projects, see it this way, whatever happens I will post pictures and step-by-step process and hopefully will help one or two people that have the same ideas, doubts or plan to also do it.


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## frodus (Apr 12, 2008)

Raik said:


> IlleMore batteries is a bad idea, it means more time (looong shipping time, I'm not in USA), the other 2 options are also WAY cheaper, even more because if I convert a car to electric it means I already got an ICE engine!, also I already own a 6000 watts coleman gasoline generator (I work in construction bussiness, they're a necessity).
> 
> The reason I won't go for more batteries is one, I don't have extra space in the car also don't want extra weight for every day city rides, I won't buy batteries just to use them twice a year, also you needto use each pack of batteries isolated from eachother (never mix new batteries with old batteries), a teardrop can be used for more than carring an engine/generator specially useful with my compact car with little trunk space (see picture), and the last is I can use my generator in work/camping or lent/rent the range extender to another EV user, not doable with batteries.


You need batteries anyway, so shipping them is a bad argument. Adding a few more batteries will make almost no difference in shipping cost. You just need to order more of the batteries to begin with.

A 3kw generator, running for an hour, is 3kwh. 3kwh of batteries is just over $1000. A generator + controls + trailer will be more expensive than just buying an extra few batteries with 3kwh worth of energy in them. Realize that even with a 3kw generator, you still have to go through the charger and into the battery.... so you still get at best 2700W out of the system. That's not to mention the extra weight and drag that a generator trailer would take to even run it. I'd be surprised if you get more than 1500W of energy into the pack when you consider inefficiencies and drag!

If you just install more batteries into the car, they're already there, and you've already charged them at home. 3kwh is like 4 or 5 extra 200Ah lifepo4 modules and negligable weight. Having more batteries also means you stress out the rest of the pack less to begin with, and get a longer life from cells (assuming the same power use between the two). I'm not saying have an extra battery pack to hook to it.... I'm saying just install an extra 3-4kwh of batteries in to begin with! And if you add on an inverter, you can get 120VAC easily.


Or you could consider what I'm doing. Building a 1-2kwh pack of lifepo4, hook to a 1500-3000W inverter, and use as portable 120VAC power. In an emergency, I can use as a portable charging station. I can also take camping or lend to someone who needs power. It's more efficient, lighter and will have a longer lifetime without any maintanance than its 3000W generator counterpart. Also, it won't matter if the pack I'm "charging" is old or not. It's isolated from my portable pack with the inverter/charger in between them.


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## Raik (Jun 17, 2013)

frodus said:


> You need batteries anyway, so shipping them is a bad argument. Adding a few more batteries will make almost no difference in shipping cost. You just need to order more of the batteries to begin with.


 Dear lord, please tell me you didn't read my post... well again, unfortunately I don't live in USA, shipping costs varies with size and weight, also just by importing you also need to pay taxes, guess what we don't pay 9%, we pay 18%!!!, and they ADD, I'm going to fly to USA personally to buy all the stuff I need (electric motor, batteries, controller, etc.), buy a cheap old excellent conditions used car and drive my way back (will not be the first time doing it  ), and re-sell the car here, I can even make a profit around 100-300 bucks, that almost covers half the trip, another awesome thing is USA government gives me back part of the taxes I paid for the used car and the EV parts, just because I don't live in USA and have to prove I'm taking them with me (god bless America!), and by taking the stuff with me I can fend off the greedy bastards at customs and avoid the 18% taxes wich otherwise whould charge me (importing through shipping the customs office hold your stuff hostage!, they say pay or pay, and pay what WE think your stuff is worth %18), so no thank you.
Buying more batteries for a range I only would need twice a year are a waste I think, also they won't cover all the range.



frodus said:


> A 3kw generator, running for an hour, is 3kwh. 3kwh of batteries is just over $1000.


I can make the "pusher trailer" with only $500 bucks or less  and gives me more range, 3kwh is kinda meaningless in a 350km/218miles trip, where a pusher can take me the whole trip without skipping or a power plant can recharge on the go and breaking for lunch.



frodus said:


> A generator + controls + trailer will be more expensive than just buying an extra few batteries with 3kwh worth of energy in them. Realize that even with a 3kw generator, you still have to go through the charger and into the battery.... so you still get at best 2700W out of the system. That's not to mention the extra weight and drag that a generator trailer would take to even run it. I'd be surprised if you get more than 1500W of energy into the pack when you consider inefficiencies and drag!


They are not more expensive, batteries ARE expensive, check your numbers, there is almost no air drag, just look, yes its more weight, but 250kg its like 3 more people in the car, wich can handle perfectly.



frodus said:


> If you just install more batteries into the car, they're already there, and you've already charged them at home. 3kwh is like 4 or 5 extra 200Ah lifepo4 modules and negligable weight.


Yes, almost no weight, but I will fit as many batteries as I can and not a single one more (take in account I will install A/C), take a look, its a VW bug made buggy, very limited space unless I get rid of the back seats... I'm seriously considering that option, but only will do it for A/C and kick ass sound system.



frodus said:


> And if you add on an inverter, you can get 120VAC easily.


 already own a 750watt inverter and with DC-DC it will work.




frodus said:


> Or you could consider what I'm doing. Building a 1-2kwh pack of lifepo4, hook to a 1500-3000W inverter, and use as portable 120VAC power. In an emergency, I can use as a portable charging station. I can also take camping or lend to someone who needs power. It's more efficient, lighter and will have a longer lifetime without any maintanance than its 3000W generator counterpart. Also, it won't matter if the pack I'm "charging" is old or not. It's isolated from my portable pack with the inverter/charger in between them.


Well, I guess different people have different needs, 2kwh pack of batteries will last 1-3 hours deppending on whats hooked, a power plant (gas generator) can work up to 8 hours (at least mine does, with several lights, 5 laptops, 3 printers, and sometimes hardware like drills or slegehammers). In the extended trip it means a 6000watt $500 gas generator will run 4 hours with no stop giving 4kwh, someting $1000 batteries can't do.

I think that covers it, I just can't use more batteries for a range extender especially since I will own an ICE engine and already own a gas plant... and even if I didn't it would be still cheaper.


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## frodus (Apr 12, 2008)

This same topic been hashed out on dozens of other threads by dozens of other members over the last few years. Maybe search those threads and see what they did.

I mean, Good luck.... it sounds like a fun project... but I have doubts that you can do what you say (either pusher trailer, or genset trailer) for under $500.


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## Woodsmith (Jun 5, 2008)

Raik said:


> Illegal as in banned? or illegal as unregistered, here is an example


As far as I can remember (and things may have changed, though I doubt to make it easier), having considered an ICE powered trailer for use with a Land Rover....
Illegal as in unregisterable (if that is a word). It would need to be subject to a Vehicle Inspection and would not meet the requirements. Even if it did it would then need its own MOT, insurance and road fund licence, might as well have a second car with sufficient range for when needed. 
Then you wouldn't be able to 'tow' it with the engine running (except in an emergency, as in getting the trailer off the road after a breakdown if the engine is needed to ensure safe operation of the trailer's steering, brakes etc.). 
If it is driving the wheels then it would be considered a separate vehicle and would need its own driver in the vehicle.

I could be wrong and there are no actual laws against a powered pusher trailer but the systems in place now would make it very unlikely that it could be made legal or used legally in the way it is being discussed.


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## Ziggythewiz (May 16, 2010)

Raik said:


> I won't buy batteries just to use them twice a year


If you just want to drive on gas twice a year, why not get a rental? Piping your gas through an EV doesn't make it more efficient or cleaner.

A high mpg rental can easily pay for itself on a road trip.


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## Ampster (Oct 6, 2012)

Ziggythewiz said:


> If you just want to drive on gas twice a year, why not get a rental? Piping your gas through an EV doesn't make it more efficient or cleaner.
> 
> A high mpg rental can easily pay for itself on a road trip.


That is what I do for the 2 or 3 trips I take to San Francisco to see my relatives. My insurance rate is based on miles driven so I save whatever on 3, 000 miles not driven. When I return from renting a high mpg rental I appreciate my EV's even more. LOL


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## Siwastaja (Aug 1, 2012)

For only 1-2 long trips per year, it's indeed clear; rent a car.

But there is a gray zone where designing some kind of hybrid module makes sense. For example, 1-2 long trips per month.

My standpoint is that it really makes sense, but you have to design it carefully to avoid the pitfalls mentioned in this thread. It _is_ green because you mostly drive by using electricity. If done right, the mileage would be very close to a normal car.

People are often mistaken that a series hybrid (ICE + generator + battery pack + electric motor) is somehow very inefficient. It is not. It may have 10-30% efficiency penalty compared to a parallel hybrid, but it's still very close to a traditional car.

If the choices are having two full cars, one electric one gasoline, or one electric car and a neat little generator trailer, I understand why someone would choose the latter.

I'd say just forget commercial off-the-shelf gensets. They are too small, or the powerful ones are both too heavy for the power and too expensive. You need 10-15 kW, unless your "long trip" is only a bit (<100%) longer than your battery range.

I'd search for a very small car engine (something below 1.0 liter; they are usually pretty efficient) and add a generator. I'd do it with an AC induction motor, but there are brushed DC generators very similar to the DC motors most people use.

For example, our donor car (Suzuki Alto) has a nice little 1.0 liter ICE which weighs a bit over 50 kg. Couple it to a 7.5 kW 4-pole ACIM weighing another 50 kg, run it at 3000-4000 rpm and get 15-20 kW out of it. Enough even for a larger car to run highway speeds. This is one of the options we are thinking about for a hybrid pickup conversion.


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## Raik (Jun 17, 2013)

Woodsmith said:


> Illegal as in unregisterable (if that is a word). It would need to be subject to a Vehicle Inspection and would not meet the requirements. Even if it did it would then need its own MOT, insurance and road fund licence, might as well have a second car with sufficient range for when needed.
> If it is driving the wheels then it would be considered a separate vehicle and would need its own driver in the vehicle.
> I could be wrong and there are no actual laws against a powered pusher trailer but the systems in place now would make it very unlikely that it could be made legal or used legally in the way it is being discussed.


Agree, it may need a driver if it is considered a vehicle... also is very state and country specific, the state I'm going insurance is not mandatory, in my state only cars, pickups and motorbykes need 3rd party protection insurance, quad bykes, go karts, and trailers do not need insurance. Yeah, kinda messed up laws we have. 
I got the idea of register the teardrop pusher as a normal teardrop, my car would be registered as an ICE normal car, if I get pulled AND get checked I will say thats the engine, it outside the car but provides same funtion and its an school project I'm a teacher.  hopefully I will get my speeding ticked and go my merry way.



Ziggythewiz said:


> If you just want to drive on gas twice a year, why not get a rental? Piping your gas through an EV doesn't make it more efficient or cleaner.
> 
> A high mpg rental can easily pay for itself on a road trip.


It may work pretty well in your country, but here almost no one rents a car, hence they are expensive, how about $ 60 dollars per day, vey limited mileage and if you drop the car in another city you get charged a lot. My plan is 15 days a year, so $ 900 per year, "pusher trailer" for $500 doesn't sound so bad now does it.



Ampster said:


> That is what I do for the 2 or 3 trips I take to San Francisco to see my relatives. My insurance rate is based on miles


 You so lucky, our insurance companies offer their insurance based on risk and nothing else, all prices are flat, only standard price, old senior price and fleet price, thats it, if you haven't used your insurance for 10 years they don't give a sheet, not even thank you, much less a discount, but if you use insurance more than twice in 3 years it gets more expensive .



Siwastaja said:


> My standpoint is that it really makes sense, but you have to design it carefully to avoid the pitfalls mentioned in this thread. It _is_ green because you mostly drive by using electricity. If done right, the mileage would be very close to a normal car.
> People are often mistaken that a series hybrid (ICE + generator + battery pack + electric motor) is somehow very inefficient. It is not. It may have 10-30% efficiency penalty compared to a parallel hybrid, but it's still very close to a traditional car.
> If the choices are having two full cars, one electric one gasoline, or one electric car and a neat little generator trailer, I understand why someone would choose the latter.
> 
> ...


I hope I get similar or a little above a normal ICE car, but I highly doubt to get that high, I mean more than half the road will be electric.
My engine would be a VW bug, small and doesn't need oil, but I don't think it can make highway speeds.


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## Duncan (Dec 8, 2008)

_People are often mistaken that a series hybrid (ICE + generator + battery pack + electric motor) is somehow very inefficient. It is not. It may have 10-30% efficiency penalty compared to a parallel hybrid, but it's still very close to a traditional car._

I have not seen this anywhere! 

_but it's still very close to a traditional car. - _possibly close to a 1960's gas guzzler


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## Siwastaja (Aug 1, 2012)

Duncan said:


> I have not seen this anywhere!
> ---
> possibly close to a 1960's gas guzzler


For example, see:

http://en.wikipedia.org/wiki/Chevrolet_Volt

Hope this helps.


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## Duncan (Dec 8, 2008)

Hi Siwastaja

Doesn't help the Volt is a parallel hybrid - the engine drives the wheels


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## Siwastaja (Aug 1, 2012)

Duncan said:


> Hi Siwastaja
> 
> Doesn't help the Volt is a parallel hybrid - the engine drives the wheels


Actually, it's both series and parallel hybrid. It's beyond me why the design is so complicated; it combines the worst of the two worlds. Maybe it also tries to combine best of the two worlds. But at least it shows that the series hybrid mode is usable, contrary what is usually claimed on DIYElectricCar.com.


Series hybrid has extra losses from one extra generator (10%) and one extra motor (10%). Parallel hybrid has extra losses from the more complicated mechanical gearbox and less flexible ICE usage (runtime, warmup, optimal RPM and torque). It seems that in the end, parallel has a tad better fuel economy in a "traditional" hybrid design. But, the "traditional" hybrids, for example, used small NiMH battery with inferior efficiency compared to large li-ion. You have to use recent data because everything's changing so fast.

Also, it doesn't make sense to use series configuration when the ICE is relatively large, due to the need of both large generator and electric motor. But if it is "only" a "range extender" with a small engine, then the generator is small too. And because such vehicle is mostly driven by electricity, the more complicated gearbox wouldn't make sense.


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## subcooledheatpump (Mar 5, 2012)

A diesel freight train is a series hybrid as well. (sort of, most don't have batteries)

So are many other industrial machines like mining carts and mobile cranes, excavators/shovels, and large dump trucks. The dump trucks are where it gets interesting, because there are traditional engine and mechanical transmission systems, as well as diesel electric (and may even have battery storage for regenerative braking) in the same size of truck. The diesel electric dump trucks are thought to be more efficient. They claim that by optimizing the engine speed for the required load there are fuel savings. These systems are also in some cargo ships

Not sure if this applies to a normal road car but seems to be popular in heavy equipment


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## Ziggythewiz (May 16, 2010)

Siwastaja said:


> Actually, it's both series and parallel hybrid. It's beyond me why the design is so complicated; it combines the worst of the two worlds. Maybe it also tries to combine best of the two worlds. But at least it shows that the series hybrid mode is usable, contrary what is usually claimed on DIYElectricCar.com.


It's complicated because it's OEM greenwashing. They have no interest in electric cars, and their 'EREV' is guaranteed to need more dealership maintenence than any mainstream vehicle ever made.

DIY has never said series hybrid is not usable, just not very practical. Obviously a DIY hybrid is not likely to be as efficient as a $40k OEM one, and the $40k OEM one is far less efficient than the equivalent $17k ICE.


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## Karter2 (Nov 17, 2011)

subcooledheatpump said:


> A diesel freight train is a series hybrid as well. (sort of, most don't have batteries)
> 
> So are many other industrial machines like mining carts and mobile cranes, excavators/shovels, and large dump trucks.
> 
> ...


 Those DE trains, dump trucks etc are not "Hybrids" since they dont have traction battery packs.
They simply use the electric drive as a "transmission" to avoid having enormous mechanical gearbox's & torque convertors with all the maintenance that would require.
The dump trucks do use "regen braking" .. but burn off the regen braking power as heat through large resistor banks.


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## Siwastaja (Aug 1, 2012)

Karter2 said:


> Those DE trains, dump trucks etc are not "Hybrids" since they dont have traction battery packs.


Yes, but it still proves the point that the generator -- electricity -- motor drivetrain is perfectly feasible and does not increase losses _so much_, in fact in some cases it may reduce losses while working as a torque converters / variable electric transmissions (as you say).

More importantly, in large machines, it is easy to transfer electricity to different parts of the machine where it can be turned back to motion using motors, so that it allows separate torque control for every wheel. This would be very difficult and lossy mechanically.

Also, as you mention, the motors provide braking, replacing huge mechanical brakes (or leaving them mostly for emergency use) which are a huge noise source and have vast service requirements.


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