Generator Trailer

[BozoShanks]

So what kind of setup would a person need if they wanted to put a gas generator in a trailer that
could supply 48 VDC @ 50 Amps continuous and say 80 Amps Peak?

This would be for directly running the DC motors as well as charging the battery packs on an electric
bike for long distance 200 mile plus runs.

Sounds counter productive, but I have sworn off cars and If I can run at 20-30mph I can allocate the
extra few hours. But that would take $$$ in batteries and weight.

ANY HELP --- Greatly Appreciated....

Thanks

 

[Pure]

I saw in your other post where you mentioned this.

I will be building a mid-drive e-bike with (current plans call for 2 1000 Watt 36 or 48 Volt Scooter Motors)
driving a nexus hub.

I'm not really sure how you could do a dual motor mid-drive bike, but the point is, it would really be a waste of time. People who put 2 motors (usually dd hub motors) do so for the added traction that having power in both wheels gives them. To do what you are thinking, you would really be better off just putting one motor with the right amount of batteries, that can produce enough power for your needs. It will be cheaper, and much lighter in the end.

You would be surprised just how much power some of the larger hub motors can produce, especially in a mid drive setup. As an example, my rig has no problems doing 25+ MPH with my large 250# ass towing a 2 wheeled 200 pound load on flats. Hills are an issue, but only because I'm limited as to how many amps I can feed my motor. If I had a better C rated battery, hills wouldn't be a problem.

Also, for your "long range" needs, you should treat this as 2 separate builds. First build your bike with enough battery to accommodation your normal needs. Most people do good at about a 20-30 mile range for daily commutes. This would roughly be about 20 ah of battery at 48Volts. Then build your trailer to give you the distance you want for your long range commutes. Pretty much everything you need to know how to do this has been beat to death in that other thread that you posted in.

 

[dogman dan]

As I have said before in other threads, it's nearly always better to just carry more battery to extend range. A lot less weight of battery can extend range to 60-70 miles.

There are places where you ride into mountains or desert, and won't have a plug for a lot further than 70 miles because you rode 60 miles up a dead end road. But for crosscountry use, you more than likely will reach a plug by noon, be able to recharge, and ride more till your ass has giant blisters on it.

Solar charging could be an option too, if you are riding into the wild and setting up a base camp.

If you do want to run a generator, carry the smallest one possible. On the commercial market, the Honda EU 1000 is not a bad choice at 50 pounds or so. As quiet as they come for one thing. It puts out 12v, or 110v AC. A lipo charger won't run directly from the 12v, so a daisy chain of some kind is required. Gen 12v+ lead acid batt+ lipo charger is one route. Or gen+ 48v charger that runs on 110AC is another way.

Even if your charger only puts out 500w, it will be doing it continuously, while you will take a break from riding from time to time. So you can greatly extend your range by having a charger than puts in only half what you are drawing. Start with a bigger battery as well, so that between the extra battery size and the genset, you have 100 mile range or whatever.

Forget the big generator, for one thing, you won't easily find one that outputs 48v. A 3000w generator is easy to find, and still cheap if your go with a china brand. But they are just too big and heavy to drag around. The tiny ones are bad enough. So buy at least 50 miles of range in battery, and then haul a smaller generator. Don't be in a hurry, stop when you need to, and let the charger catch up. You will not have infinite range, but you will have range equal to what your ass can tolerate, even if you ride a recumbent with a lawn chair seat.

So, you want 200 miles a day? You've pedaled further than 60 before right? You know what 200 miles on a bike does to your ass?

 

[Alan B]

Note that the 12V output of the honda generators is low power and specifically designed for charging a 12V lead acid battery - it is not regulated or filtered.

You should get a power supply / charger setup that will run from the 120V output of the generator, this is where the full power is available.

The EU2000 is under 50 pounds, the EU1000 is much lighter.

 

[dogman dan]

True, I think my older model honda 800w generator only puts out 7 amps of 12v. That's less than 100 w, from an 800w generator.

I wasn't thinking about that much when I typed that. The 12v is low amp so you can charge a car up, but not explode the battery too quick.

When I use a generator to charge, it's typicaly at the racetrack, where there are no plugs in the pits. Generator, to meanwell power supply, to lipo charger, to battery.

If you ran a 48v battery, then a large 48v power supply could be used to tap the full power of your generator through the ac side. Or one largish charger in your voltage.

 

[Alan B]

The original question in this thread was 48V 50-80A generator. That is a lot. That is 3-4KW. Probably more generator weight than you would want to tow. A Pair of 2000W Honda quiet generators would be about 100 pounds. Plus a power supply and charger to get to 48V at 4KW. Plus fuel. That is a lot of weight. Probably at least 150 pounds including trailer, more likely 200.

 

[DAND214]

Buy a Motorcycle if you are going to tow that much.

If you do tow 200+ lbs you better put some good brakes on it. the BIKE and the TRAILER need good brakes.

Dan

 

[Kingfish]

Short Story: It doesn't make any sense to create a trailer with an ICE generator(s) and tow it behind an electric bike. I agree with DAN: Better to buy a motorcycle. No offense

Interesting to study, though beyond that - not practical.

~KF

 

[ZOMGVTEK]

I snagged a few super cheap Chinese 1000W generators a few years ago, and partially attempted to attach one to an e-bike.

http://www.youtube.com/watch?v=rE2oFrpP3nU

It would 'work', but its really not something thats nice to ride. The generator is about 48Lbs with fuel, and its tricky to mount. With a lot more time invested, it could have worked, but it wouldn't have been practical.
I basically ditched the idea, but I do have the mount laying around somewhere. It sure is a cheap and easy way to get good range. I tested this generator to put out about 700W for just over 5 hours on 1 Gallon of premix 87 octane w/ 10% ethanol. It only puts out about 800W max, but its happy doing that all day, and it was $50 new. That's hard to beat. Assuming you can get 600W into the pack, out of the 700W load on the generator, that would be 3kWh of electricity in 1 gallon of fuel. These figures are all conservatively low. However, assuming you have 2kW on the bike, and 3kWh in fuel (The generator holds 1.1+Gallon), you can get over 175 Miles out of the bike, at 20 MPH. Thats more than enough range, since it would take almost 9 hours to run out of power. When you arrive at the destination, you can idle the generator for a few hours and fully recharge the battery again. Refuel as needed at any gas station, keep a jug of 2T oil on hand. It would take <1 minute to refuel, pour some oil in, and shake the generator.

The 50A@48V you want is entirely unreasonable. That would be a large, heavy, expensive generator.

 

[deVries]

Go back to the Extreme Range E-bike thread where I posted all about NOT using a pre-made manufactured generator... you need to build your own to do this AND save weight.

You can get a $225 4 stroke Honda motor to output 1800wh at 12-lbs... then you have to add either an RC motor or alternator to charge your battery pack including some voltage regulation electronics and/or a rpm governor for the motor.

Unfortunately, I don't think ES has a thread showing how to do this in detail. So, if you don't have the skills to rig this, then we're at the mercy of finding that info online somewhere or get an expert ES member to help... :wink: 8)

 

[SamTexas]

I snagged a few super cheap Chinese 1000W generators a few years ago, and partially attempted to attach one to an e-bike.

http://www.youtube.com/watch?v=rE2oFrpP3nU

That's quite a setup. If I were to do it, I would use an AC motor instead and completely bypassing the AC to DC conversion. Of course the only reason for such a setup is to claim that I'm running an ebike. Otherwise, a 50cc moped would do a job many times better. In fact, even a bicycle with a bolt on ICE is still a better choice.

 

[dumbass]

I have to agree with the guys on the motorcycle idea. The ebike is great but like everything has limits. And trying to ride 200 miles at 20mph is 10 hours with the seat up your butt. Even if the gen idea were to work and if you search around ES I think there is a guy that did pretty much what your talking about.

I use my ebike for short fun type rides of less then 25 miles. And I use my 250cc motorcycle for longer or faster rides. Running at 65 to 70mph I get 65+ MPG. And the comfort and safety of the ride is without question. On this think I could do the 200 a day at 65mph and arrive without my butt hurting. Hell, that's only a 3 hour ride.......And I can carry things in a trunk or add saddle bags if needed.

Go cycle......... BTY, The cycle I have now is a 2006 CF Moto V5. I bought it with 600 miles on it and only cost me $550 in Aug. of 2011. So you might find it a lot cheaper in the long run.

 

[ZOMGVTEK]

That's quite a setup. If I were to do it, I would use an AC motor instead and completely bypassing the AC to DC conversion. Of course the only reason for such a setup is to claim that I'm running an ebike. Otherwise, a 50cc moped would do a job many times better. In fact, even a bicycle with a bolt on ICE is still a better choice.

There sure are better ways, but this is CHEAP, proven to be reliable, and ready to go out of the box. The efficiency of the conversion isn't terribly important, since these generators tend to get more efficient at higher loads. The difference between 700W consumption, and 800W consumption, might only be 15 minutes more runtime. The runtime tests were performed with the high speed needle fully backed out, and the hole blocked. The generator was running quite rich, as compared to the quite lean it runs out of the box. If you tweaked it to run slightly lean, it should give you around 30 minutes to an hour more runtime, but it would cause issues if the ambient temps dropped significantly.

At the end of the day, this is basically a 40LB 3kWh battery that costs $3.5-$4 every 100% DOD cycle. It's roughly equivalent to getting 350 cycles out of a 3kWh (Useable) Turnigy LiPo pack. The size is more substantial than the weight, since it is tricky to find a place to mount it. It's not like you can tip it over or tape it to the frame.

The key to a setup like this, is the ability to charge your high capacity battery without an outlet. The generator isn't required for the bike to run, and you should be able to get 80+ miles out of a 2+kWh battery mounted to the bike, then you can run the generator when appropriate to charge back up. A little odd setup, but its good for over 100 MPG with enough room to possibly eek towards 200MPG.

 

[amberwolf]

I considered borrowing a small generator that could supply enough power to run a variant of CrazyBike2, where the gen would be behind the seat but in front of the back wheel. This would let me ride to Tucson for the DeathRace and still arrive with fresh batteries.

Then I unbolt the gen and frame extension, so the bike can be ridden pure electric for the race.

But it's a lot of work, and I'm not convinced I'd make it all the way down there anyway, what with the many other possible problems along the way. I definitely wouldn't want to ride it in city traffic all the time.

 

[sangesf]

If you ran two 36v 25Ah Dual motor setup, you could easily get 100 miles at 20mph...

I've done such a thing on two 36v 20Ah batts on my dual motor setup doing 18mph...
My best was 116miles at 16 mph (an entire day's trip)...

If you've never done long rides on a bicycle frame (or even a moped or small motorcycle, for that matter) you'll know that after about 50 miles your butt definitely NEEDS a break...

The longest one trip I've done without stopping was 57miles.. Took 3 hours and let me tell you.. That is NOT fun.. My ass hurt like you wouldn't believe!

P.S. The old subaru/robin/Coleman "Ultimite" generator would put out 24v at about 40a (regulated) and only weighed 40lbs... Put that output into a buck convertor and you could use it to charge up your batteries.
Throw that in a small trailer and you're done...

 

[deVries]

So what kind of setup would a person need if they wanted to put a gas generator in a trailer that could supply 48 VDC @ 50 Amps continuous and say 80 Amps Peak?

This is not realistic or needed, imo.

You can do 48v @ 20-30a with the 1800wh Honda I mentioned at 12-lbs, otherwise you'll need a 50-lbs generator & still not get anywhere near 50amps continuous -which you don't need to go 20-30mph on a bike with trailer anyway.

Going w/moped or motorcycle for 200 miles will require the trailer-generator or lots of recharging on the grid along the way... you already stated you did not want to carry enough batteries to do this. A heavier motorcycle setup will need a bigger generator unless you just want to do 25mph instead.

 

[REdiculous]

If you can get 1500w from a 12lb engine, I think that's light enough you could double the recipe if you needed more power. That's up to 3kw for about 40lbs (fuzzy maths). Since we're assuming it's all going on a trailer anyway, 40lbs is nothing as long as it's not the size of a fridge.

 

[sangesf]

Where do we find this Mysterious 12pm engine that generates 1000+ Usable DC watts?

 

[REdiculous]

Without trying too hard I found a 2.5HP/1800w horizontal 4 stroke Honda engine at 16lbs. *shrug*

edit...I found a 1.1HP 4-stroke Subaru engine for $200 that weighs just 6lbs dry and measures roughly 6"x9"x9".

 

[sangesf]

Do either of those have a 12v or 24v regulated output? If not, how would one go about making one?

 

[sangesf]

Here's the old Ultimite Generator... Took me forever to find the pic...

24v 40a output at "full throttle".. (Always at full throttle)...

Can power a 24v 40Ah battery / bicycle (with a 40a max controller) at 25 mph and keeps the battery charged while running.
Just keep extra gas... 1 qt tank lasts about an hour...

 

[SamTexas]

And you'd be deaf after an hour ride. I couldn't stand near it for 5 mins. Yes I have one too, brand new no less.

 

[REdiculous]

Those were just the engines.

 

[sangesf]

And you'd be deaf after an hour ride. I couldn't stand near it for 5 mins. Yes I have one too, brand new no less.

Wanna sell it to me?

Also, have you tested output voltage (on the 24v side)?

 

[SamTexas]

No. Not for sale.

It's one of my toy and I might actually use it when power is down. I have no use for the 24V side, so no testing.