Using a lightweight generator to charge Bosch e-bike battery

[dnmun]

As to the question, no I'd ditch the idea and look to have a fast plug-in charging solution. Depend on people's outlets. Which are everywhere. Still pennies for a charge, so no one should object. Give you an opportunity to interact. Be willing to tell your story as the battery charges. People will love you for it.

i never had trouble talking someone into letting me plug in to an exterior socket when i ran outa juice on my range tests.

but if they are willing you can pay them the cost of the electricity and you have an accurate idea of how much because you know how much power your charger uses. so you can reimburse them based on the local rate for the length of time you are charging at the full power level.

 

[dogman dan]

Definitely, you can always find somebody willing to let you plug in, in any place where there are 100 people living.

The one time I had a problem, was at a state park campsite. Place where you pay even just to picknick. The camp Nazi refused to let us borrow a plug, then even refused to sell us a vacant camp spot with electric power. They weren't reserved or anything, he was just being a dick. Unfortunately the place was 25 miles from the nearest town. We made it back though, just by riding a bit slower home. Had there been any RV's in the camp, I'd have just chatted up one of them, and got a plug in. At other state parks, buying a camp with a plug was no problem at all.

Another time I got refused a plug at a National monument, But I did not need the plug. I was just scouting to see if I could plug in there on the return trip, when a headwind was forecast.

But any town of any size, you can always find a plug. Just ask nice, and often people are fine with you using 20 cents of power. Grindz rode from New York to Colorado and back last summer, and had very few problems finding a plug. Some of the camp sites were funky, but always he could get power.

 

[friendly1uk]

If your on a cycle tour, it would be really lazy to cycle 8 hours and have 16 off each day. That is as much time on foot as the bike. Presuming you really were that lazy though, and just needed that 80 miles a day, that is 10mph. If the battery voltage were reduced we could make the motor most efficient at that speed. Then 150kg should roll along on 100w. That 100w could be a solar panel maybe 400x750 and worth £100. That to me looks like great value... Because the solar won't perform. You do get more than 8 hours light though, and you could have a couple of panels. Trailer them or shelter under them. Maybe have one front and back on a pole so they swivel and you avoid shading both. Or charge in the day and cycle at dawn and dusk when it's cooler with less obstructions. No need to cycle and charge at the same time then.

Pedaling such a bike to 12mph would require 100w from you, but unload the motor so it takes 50w.
You may note the 100w required for 10mph increases 50% to 150w required to go 12mph. Just 20% faster, for 50% more energy. So solar soon meets it's technical limits. I'm sure attempts have been made by forum users in the last couple of years.


In a world record attempt, the motor efficiency at the speed your doing is of great concern. Your many gears will help you keep spinning it to it's limits and beyond I hope. Where efficiency usually lays. That is probably a good riding strategy. As most motors are at the most efficient just before they top out. Further assistance from you then lessens the effort they put in. At these motor rpm's you might see 80% efficiency. Run your motor at half speed, and you could expect to see efficiency down to 50%. I don't know how the bosch fare's but I bet it's well documented.


Who would of thought a square meter of solar would go 10mph. Is that even right? Meaning any lightweight structure covered in panels would do 10mph. 8 hours a day.

All numbers in this post won't be quite your bike, but are relative.

 

[dogman dan]

Definitely solar can work great when the riding speed is slow. You will pay a huge wind drag penalty for a large solar panel, or even a trailer large enough to have the panel on top, if you want to ride 25 mph+

But 200w can get you there, if you ride slow. My comically large cargo bike, with it's wind catching gigantic panniers, can travel 15 mph on the flat on just 300w. Usually just 50w on average from me, because I'm so weak.

So I'm using 250w on the flat from my battery, I average 25wh/mi, including over big mountains, or into some wind. Well, if you carry 100w of panel, you can still get at least 70w out of that. And if you pedal at 100w, well hell, you are half way there with 150w that's not from your battery.

The problem for the original poster though, is his tour won't be in the desert southwest, with few clouds. So his harvest from a 100w panel won't be so great.

I still think that for him, carrying 20 pounds more battery will benefit him more than 30 pounds of generator. He should be able to find a plug often enough. Just carry a fast charger.

 

[TotalConfusion]

Im planning a similar trip from the East Coast of Australia to the West Coast of Australia in a year or two and although ill be in the hottest parts of Australia for days on end Solar just wouldnt cut it because of the drag it would cause while travelling.
Carrying a 1000 Watt Generator is my only option as charging points will be more than 400km apart at some points and 250 km for most. Carrying around 3000 Watts of battery power should see me around a 200km range at 15 Watt hours per km if i can manage that.
To carry a generator and a 5 litre jerry of fuel will see me able to travel for 700+ kms without the worry of having to find somewhere to charge.

My Question is why do so many people think it is so wrong to use a generator when all our power comes from huge power sources like Nuclear or Coal powered generators anyway, this power is NOT a clean source of power anyway so i think this guy is on the right track for his goals.

How is the power from a generator any different from the power from a plug in terms of how clean the energy is ?

 

[diggler]

I still think that for him, carrying 20 pounds more battery will benefit him more than 30 pounds of generator. He should be able to find a plug often enough. Just carry a fast charger.

Yes this is the rout I will be going now too because I found out that up 50cc on a bicycle is NOT considered a gas peddle assist, it's considered a moped! (at least in Minnesota) So that means I would have to have a license, title and liability insurance! But then I could legally go 30mph and right on the road or on the shoulder.
When ever I think of touring with a fast charger I always think of the Adapto controllers as the way to go.

 

[999zip999]

The charger that comes with the bosch bike is very robust and is thought to be able to travel much better than most chargers. I read it's a 4amp charger.

 

[quuxman]

Also thinking about this, instead of blowing a huge amount on a large battery pack. Here's a decent looking option you can buy now, weighing in at an impressive 20 lbs while providing 800W peak power and around 500 W (not clear) continuous:

https://www.amazon.com/Porta-Source-Portable-Invertor-Generator/dp/B00P2FOX4C
https://www.amazon.com/Earthquake-11613-Starting-Portable-Compliant/dp/B00FL89I2W

And here's an even more impressive and intriguing option who's availability isn't entirely clear, that's several times more expensive. It runs on alcohol, and there's a 12 lb 800 W continuous version, and 1500 W 16 lb version, 2000 to 3000$:

http://www.generatorsmart.com/?page_id=197

If you're thinking of around 1 kWh or more of power, I think it makes sense to start thinking about these options. I've done quite a bit of searching on fuel cells in this weight range, and unfortunately they basically don't exist. There are now some impressive miniaturized fuel cells on the market for cell phone size loads, and also 60 lb propane fuel cell systems designed for RV use, but nothing in between that's not specifically for military applications with unknown (most likely horrific) pricing, like this:

http://www.ultra-fuelcells.com/D350

For now, seems the best option for serious long range is the 4 stroke Porta Source / Earthquake gas generator. UPDATE: Here's what looks like the same thing from Alibaba for only 200$

http://wholesaler.alibaba.com/product-detail/lightest-800w-portable-camping-gasoline-power_1830681806.html

 

[quuxman]

I think my dream machine is a tilting trike with a mid-drive system, about .5 to 1 kWH of battery, and a trailer set up with one of those little 200$ portable generators. Ideally top speed would be 30-50mph, and range would be practically unlimited, mileage probably 200-300 mpg.

 

[bionicdan]

Has anyone ever thought of rigging a small cc motor that can spin your back wheel for two hours at your destination while upside down or on a stand. Use the motor as the generator? Seems silly to carry two lumps of metal\copper around and your not gassing out fellow riders on the move.

 

[dogman dan]

Not heard of that one, but have seen bikes that have both gas engines and electric. That could also charge just while riding. Or just ride to a plug.

 

[parabellum]

Has anyone ever thought of rigging a small cc motor that can spin your back wheel for two hours at your destination while upside down or on a stand. Use the motor as the generator? Seems silly to carry two lumps of metal\copper around and your not gassing out fellow riders on the move.

Problem is to create reasonable mechanical connection, between them. When you did it already, then why just not ride on gas to the plug as DD mentions. You will hardly save any gas or money with 4 additional conversion stages.

 

[bionicdan]

I thought it was for some ebike electric record attempt not hybrid? Plus as discussed petrol powered things need insurance and tests etc. So my idea would be purely for static recharging avoiding unwanted attention and fumes.

 

[cavallo pazzo]

solar rig could be below 4 kg all in all for 100 W peak, 400 Wh/day average. This coupled to a 1000 Wh minimum pack to harvest all available energy even during a day off, and that's it.
My last setup was 150 W panel on 1850 Wh pack, for a cross Europe tour of 7500 km in two month. Worked fine, max daily distance around 300 km.
More than 1/3 from sun, around 1/3 from muscles and a bit less than 1/3 from plug.
Fuel cell would be another option, as it's silent and respect the idea of e-bike.