Onboard generator

[PedalUma]

How about increasing the battery capacity like this one? I saw this advertised today in the SF Bay area.

"This is a custom built high-performance electric cargo bike it runs on Nissan leaf electric car batteries with an operating voltage between 72 and 85 V. It has a 100 amp controller which means it’s 7500 W or 10 hp. If you’re interested please send an email with your phone number no test drives you can ride at all you like after you buy it comes with a charger. Goes about 45 mph and has a 45-60 mile range."

 

[Dallant]

How about increasing the battery capacity like this one? I saw this advertised today in the SF Bay area.
View attachment 85519
"This is a custom built high-performance electric cargo bike it runs on Nissan leaf electric car batteries with an operating voltage between 72 and 85 V. It has a 100 amp controller which means it’s 7500 W or 10 hp. If you’re interested please send an email with your phone number no test drives you can ride at all you like after you buy it comes with a charger. Goes about 45 mph and has a 45-60 mile range."

Next we’ll see the Prius Traveller ebike! 100 miles per charge!

 

[Comfortably Numb]

How about increasing the battery capacity like this one? I saw this advertised today in the SF Bay area.
View attachment 85519
"This is a custom built high-performance electric cargo bike it runs on Nissan leaf electric car batteries with an operating voltage between 72 and 85 V. It has a 100 amp controller which means it’s 7500 W or 10 hp. If you’re interested please send an email with your phone number no test drives you can ride at all you like after you buy it comes with a charger. Goes about 45 mph and has a 45-60 mile range."

Eyesore. CN

 

[tomjasz]

Just stick a gas motor on the bike. Why futz around with electric drive? It adds a lot of inefficiency and weight. Kits are cheap through Amazon, but no guarantees of quality.

You do realize this is an eBike forum? Cheap and much more complex. Noisy stink pots. Every one I’ve seen disappears after 1 maybe 2 seasons.

 

[retiredNH]

How about increasing the battery capacity like this one? I saw this advertised today in the SF Bay area.

"This is a custom built high-performance electric cargo bike it runs on Nissan leaf electric car batteries with an operating voltage between 72 and 85 V. It has a 100 amp controller which means it’s 7500 W or 10 hp. If you’re interested please send an email with your phone number no test drives you can ride at all you like after you buy it comes with a charger. Goes about 45 mph and has a 45-60 mile range."

I don't think so. Imagine cooling such a motor! The fact that the controller can provide that power level doesn't mean the motor can handle, or draw, that much.

 

[Cyklefanatic]

Before you say “just buy a bigger battery”, well that’s no fun, is it?
I want to put a generator system on my eBike (will this actually happen? Probably not, but I still wanna get some opinions on it).
The two options I have are this:
1) Buy a Honda GX35 engine, it only weighs 7.6 lbs, and then find a way to generate power from the rotational output (probably have to generate a high amperage 12V power and then use a boost converter to take it to the 42V I need). It has a 1 kW mechanical output, which if we have (I’m guessing) 50% mechanical efficiency from shaft to charge, gives us about 500 watts, which is more than what I need (I probably could get by with 250W, so I could run the generator at half throttle?)
Additional info
.63 litre fuel tank
1.0 kW @ 7,000 rpm
1.6 Nm @ 5,500 rpm
0.71l/hr at full throttle
View attachment 85435
Advantages-
- Lighter
Disadvantages-
- Will require a lot of work (but that’s fun... right?)
- Probably louder
- I have no idea where to find a generator
- May have trouble fitting to bike

2) I own THIS
View attachment 85436
So what if I put it on one of THESE!
View attachment 85437
In theory, this would work, since it weighs 46 lbs, and a lot of these bike racks claim to be able to hold up to 60 lbs.
This thing is as quiet as “52 dBA” and can last “up to 12 hours” on a 1.2gal tank.
Advantages-
-Quieter
-More efficiency from fuel to battery
-Can always upgrade the charger if needed
-USB ports (my bike HAD a USB port, but now it doesn’t...)
-Cheaper (in my case, but only because I already own the generator)
Disadvantages
-Substantially heavier
-Messes up weight distribution
-Might break the mount if I’m not careful

So if you were to build a generator for your eBike, which one would you do?

46 added pounds makes the idea a non starter. However you could add two batteries and a quality charger like a Satiator for a total weight of around 20 pounds. Put one battery in each pannier to get the weight lower in the frame.
It would give you triple the range and not require any wiring. If you have a 40 mile range now that would go up to 120 miles probably more than your butt can take. When you stop to eat or sleep you can charge your battery. Add a trailer with a large solar panel and you never have to stop to charge.

 

[Bitmugger]

You do realize this is an eBike forum? Cheap and much more complex. Noisy stink pots. Every one I’ve seen disappears after 1 maybe 2 seasons.

They are cheap (2-stroke engine kits). They are quite simple to install though. I still don't recommend them. They are fun machines but are not ridable in the same way as an ebike. They are 100% throttle driven, you don't pedal at all. You CAN pedal with the clutch in (yeah it has a clutch lever) but you're still turning a second (heavier) chain and front sprocket when pedaling. I enjoy riding my son's motorized bike but it's a different experience

 

[retiredNH]

They are cheap (2-stroke engine kits). They are quite simple to install though. I still don't recommend them. They are fun machines but are not ridable in the same way as an ebike. They are 100% throttle driven, you don't pedal at all. You CAN pedal with the clutch in (yeah it has a clutch lever) but you're still turning a second (heavier) chain and front sprocket when pedaling. I enjoy riding my son's motorized bike but it's a different experience

This whole thread seems like a bit of a joke. Lighten up!

 

[Mike_V]

I would build Tiny Mad Max:
A '3D printed' additive machined titanium alloy micro turbine powered; DC micro super magnet ' gen set ' running >50K screaming RPM, fueled by
'Aunty's homemade bottled gas'.

Before you say “just buy a bigger battery”, well that’s no fun, is it?
I want to put a generator system on my eBike (will this actually happen? Probably not, but I still wanna get some opinions on it).
The two options I have are this:
1) Buy a Honda GX35 engine, it only weighs 7.6 lbs, and then find a way to generate power from the rotational output (probably have to generate a high amperage 12V power and then use a boost converter to take it to the 42V I need). It has a 1 kW mechanical output, which if we have (I’m guessing) 50% mechanical efficiency from shaft to charge, gives us about 500 watts, which is more than what I need (I probably could get by with 250W, so I could run the generator at half throttle?)
Additional info-
.63 litre fuel tank
1.0 kW @ 7,000 rpm
1.6 Nm @ 5,500 rpm
0.71l/hr at full throttle
View attachment 85435
Advantages-
- Lighter
Disadvantages-
- Will require a lot of work (but that’s fun... right?)
- Probably louder
- I have no idea where to find a generator
- May have trouble fitting to bike

2) I own THIS
View attachment 85436
So what if I put it on one of THESE!
View attachment 85437
In theory, this would work, since it weighs 46 lbs, and a lot of these bike racks claim to be able to hold up to 60 lbs.
This thing is as quiet as “52 dBA” and can last “up to 12 hours” on a 1.2gal tank.
Advantages-
-Quieter
-More efficiency from fuel to battery
-Can always upgrade the charger if needed
-USB ports (my bike HAD a USB port, but now it doesn’t...)
-Cheaper (in my case, but only because I already own the generator)
Disadvantages
-Substantially heavier
-Messes up weight distribution
-Might break the mount if I’m not careful

So if you were to build a generator for your eBike, which one would you do?

 

[Tars Tarkas]

That's a really good idea, I'll have to look around and try mine out!

Try this. It makes about as much sense as mounting a generator on an ebike.

 

[MartsEbike]

I've taken inspiration from Back to the Future and installed a Flux Capacitor... I don't charge my bike any more, I just go back in time to when it was full again.

 

[TWB503]

46 added pounds makes the idea a non starter. However you could add two batteries and a quality charger like a Satiator for a total weight of around 20 pounds. Put one battery in each pannier to get the weight lower in the frame.
It would give you triple the range and not require any wiring. If you have a 40 mile range now that would go up to 120 miles probably more than your butt can take. When you stop to eat or sleep you can charge your battery. Add a trailer with a large solar panel and you never have to stop to charge.

I really want to just add more batteries, but they’re expensive, and I don’t have a good mounting system. I have a 15Ah “kettle” battery on my frame held in place by hoseclamps, and while the hoseclamps do an exceptionally good job of keeping the battery mount in place (I’m using 3 clamps), for some reason the mount for my battery is whack, so it takes a lot of force to unlatch it, and it’s really hard to get it to properly latch for some reason. I had a 10Ah kettle battery on the top part of the frame as well, and it was great! But one day I hit a bump too hard and the mount just snapped off. I tried contacting the makers of the battery, but since it came with my conversion kit, and there‘s no branding anywhere on the battery, I can’t get in contact with anyone who has any idea where to get a replacement mount. Here’s a picture of my eBike charging at an EV charger (before you yell at me, the place was closed, so I wasn’t blocking anyone from charging)

You can see the two batteries, and also my laughable wiring skills (I’m a mechanical engineer, not an electrician.)

 

[TWB503]

Everyone seems to think this is a joke thread. This is why I do not enjoy using forums.
I’m asking a genuine engineering question because I want other peoples opinions on which method of this would be most effective, in theory. Will I actually end up building an on-board generator for my bike? Probably not. But I enjoy having things mapped out and knowing the reasons why certain things would/wouldn‘t work.

 

[TWB503]

View attachment 85489

Just stick a gas motor on the bike. Why futz around with electric drive? It adds a lot of inefficiency and weight. Kits are cheap through Amazon, but no guarantees of quality.

My idea was a sort of thing I could use for longer drives that’s modular to some degree and easily refuelable, that way there’s almost no downtime when I have to do long trips. But then if I’m just going to the shops, I could unbolt it in 10 minutes, and go without it. A gas motor mated directly to the wheels would not only make the pedals quite useless, but would ruin the e-bike thing (what, and a 46 lb engine wouldn’t?). Also the engine mated to the wheels may be subject to different laws

 

[Bitmugger]

Try this. It makes about as much sense as mounting a generator on an ebike.

I am unsure why you'd say that. Carrying or towing a generator will let him recharge his battery every night or even if he stops for a couple hours. What's nonsensical about that? Sure a generator might not be as "good" as a spare battery but cost wise a generator works, is super cheap, gives you extended range when you can't find an outlet and ultimately gives you more freedom if your use case is right. Plus you then have a generator which is useful for all kinds of stuff. He's not planning to run it while he's biking (I hope).

A generator wouldn't work for me without a trailer to tow it but I certainly considered it. I ordered a spare battery as I had the cash and decided that my original long range use case of occasional camping might have expanded into Credit Card Touring and long day trips too so a battery made more sense.

 

[TWB503]

I am unsure why you'd say that. Carrying or towing a generator will let him recharge his battery every night or even if he stops for a couple hours. What's nonsensical about that? Sure a generator might not be as "good" as a spare battery but cost wise a generator works, is super cheap, gives you extended range when you can't find an outlet and ultimately gives you more freedom if your use case is right. Plus you then have a generator which is useful for all kinds of stuff. He's not planning to run it while he's biking (I hope).

A generator wouldn't work for me without a trailer to tow it but I certainly considered it. I ordered a spare battery as I had the cash and decided that my original long range use case of occasional camping might have expanded into Credit Card Touring and long day trips too so a battery made more sense.

if charging as we stop is the question, i think the big generator would be better, since i can get more power out of it. But if i wanted to charge as i went, the Honda might work better

 

[Mr. Coffee]

My $0.02.

What problem are you trying to solve here? I've made multiple long trips (ten days or more) continuously riding fairly long distances. It has worked just fine having two or three 500wH batteries, which would weigh less and be simpler than the proposals described (though likely more expensive in terms of up-front cost). I need to charge up at night (and very rarely over the course of a day) which restricts where I can stay, but in practice that hasn't proven to be a problem.

There are lots of developed campgrounds in the PNW (Oregon, Washington, and British Columbia) where a biker can stay for $10 per night and where you will be able to charge up. Stealth camping and continuous long-distance travel isn't really feasible with an e-bike under my configuration. That presents a bit of a planning challenge and there are some bucket list rides I'd like to make where that isn't appropriate technology, but for the vast majority of tours that system works just fine.

My advice would be to buy a second battery and learn how to e-bike tour with it. If you start finding places you want to go or rides you want to do where that mix isn't going to work, you can then start evaluating other options like a third battery, solar charging, or an on-board generator. Or even an acoustic bike.

With careful planning, running at low levels of assist, and reasonable skill you can manage to do long-distance rides with two 500wh batteries.

 

[TWB503]

My $0.02.

What problem are you trying to solve here? I've made multiple long trips (ten days or more) continuously riding fairly long distances. It has worked just fine having two or three 500wH batteries, which would weigh less and be simpler than the proposals described (though likely more expensive in terms of up-front cost). I need to charge up at night (and very rarely over the course of a day) which restricts where I can stay, but in practice that hasn't proven to be a problem.

There are lots of developed campgrounds in the PNW (Oregon, Washington, and British Columbia) where a biker can stay for $10 per night and where you will be able to charge up. Stealth camping and continuous long-distance travel isn't really feasible with an e-bike under my configuration. That presents a bit of a planning challenge and there are some bucket list rides I'd like to make where that isn't appropriate technology, but for the vast majority of tours that system works just fine.

My advice would be to buy a second battery and learn how to e-bike tour with it. If you start finding places you want to go or rides you want to do where that mix isn't going to work, you can then start evaluating other options like a third battery, solar charging, or an on-board generator. Or even an acoustic bike.

With careful planning, running at low levels of assist, and reasonable skill you can manage to do long-distance rides with two 500wh batteries.

The big problem would probably be range, because with a second battery you'd have to stop and switch out the battery, which adds time to your trip (albeit only five minutes at most, which isn't really enough time to justify a 46 lbs generator instead, but oh well...). With a generator, the battery remains at a high charge (and since my bike pulls a constant amperage, since the battery charge is higher, it gets more power due to the higher voltage), and once I've gone long enough to burn all the fuel, i still have a full charge, which is good for about 20 miles. Plus, sometimes people (myself included) forget to plug in before they leave.
I will say that a second battery is probably more practical, but come on, that's no fun, is it?
(and also with a second battery you don't get the quick refuelling of the petrol generator, plus you're getting less range for the money [subject to disagreement]. But if I'm totally honest, i just think having a generator is cool, even if it's impractical)

 

[Bitmugger]

if charging as we stop is the question, i think the big generator would be better, since i can get more power out of it. But if i wanted to charge as i went, the Honda might work better

Ok if you're planning to run it while biking to power the bike that's a different kettle of fish. You'll likely want an inverter generator for that at minimum. I've not used an inverter generator but the typical AVR generators (the normal ones most people buy) struggle to supply a consistent constant voltage when the loads are variable. They don't spool up or down very instantly and you end up with surges and sags in voltage. They also inherently generate AC voltages so getting them to be 48v DC will require more electronics. ProTip: Generators with a 12v DC supplementary output can only usually push a couple amps through the 12v circuit (like 30-50watts). I was assuming you were going to run a 120v charger with it while stopped or at worst maybe had an extra battery already so would be charging one while using one.

I think you'll find using a generator to directly power your ebike motor (or attempting to charge/supplement your battery while it's in circuit) will be un-even and require more engineering/parts than you figure to smooth out the loads and voltages. Towing a genny to recharge batteries while stopped seems very practical to me and only requires one of those small 900w generators. On a trailer you might even be able to charge a battery while biking if you have a spare (based on your pics I think you do have at least 2 already and just need even more power). Lol.

 

[MartsEbike]

Can't see any chance in recharging it as you're riding it. No charger can charge faster than the battery can output, so you'll still deplete the battery. Plus I'd say the battery wouldn't last very long either.

To directly power the motor, skipping the battery, your bike would need a generator capable of around 50 amps output to sustain a steady 25-30amp supply (running it around 50% of available rpm)....These are not small and not light, and use a lot of fuel.

Its more something like this.... Its a good two man carry. Even if you had a Bafang M620, you wouldn't want to lump this weight around with you...