questions on a first build with limited understanding

[Diosky]

Ok not sure if these questions have been answered somewhere else and if so please don't flame me and provide the thread links and I will happily do the reading.

1. Is it possible to use ultracapacitors to power an e-bike? There doesn't really seem to be a definitive answer to this

2. would it be possible to use a solar array on a bike to help generate energy to sustain longer trips if so...or could you use solar power to charge the a123 lithiums?

3. using the above methods if possible, what would be the best setup for range/power? I plan to use the bike for traveling through both europe and asia if that helps.

I am not experienced in any of this technology or electrical engineering at all but am considered by most a very intelligent (though albeit poor spelling) individual and learn fast so any and all help will be greatly appreciated. I am planning on using a tadpole style recumbent tricycle that I am building with a friend and would really like it to be assisted mainly for hill climbing but if its possible to get enough range I will also use the electrical assist for flat roads/paths as well. The bike I am building has an average of 25-30 mph without assist on level ground so if it was to be assisted it would need a motor capable of similar speeds, though I am sure this can be solved through gearing. Thank you in advance for any help or pointing me in the right directions. Also try to use layman's terms because as I said I do not really know much about how all of this works though I have been doing alot of research myself for awhile, its just I understand more when I actually work on something in regards to science/mathematics than just reading formulas with no real thing to reference. Oh and forgive my poor spelling as I know it can be atrocious.

 

[kbarrett]

Depends on what you mean by "ultra-caps".

You want about 10 or 15 Amp-hours of battery to travel for an hour or so at 36V ... more hours can be added by pedaling more, or less hill climbing.

If you are evaluating a particular cell to make a battery, you need to decide how many volts and how many amp-hours you need, then use that to figure out how many individualcells you have to buy. When you know how many, you can figure out "how much?" and "how heavy?". For a solar powered vehicle, do the same, treating the panel arrays as individual cells.

As for solar cell recharging .... look at how many Amp-hours you need to recharge, and then divide that by the amp rating of the solar charger to determine how many hours a given array will need to recharge your battery.

 

[Diosky]

I mean the ultra caps like maxwell sells. I have read both good and bad about using them in EV's so I am curious if anyone here has any experience using them on a bike or similar build. Thanks for the info on amp hours for hour of time on 36v...nowhere have I been able to see anyone saying they were getting anymore than 15-20 minutes off of their setups even one guy with 6 Dewalt a123 36v packs (which seemed rather odd to me, but maybe there was something I was missing). I do know that at 20 MPH you run into wind resistance being a majoy facter, which is why I choose to do the tadpole recumbent and will have a windshield to help reduce that problem (I ran across a company that build the windshields for around $300 a piece which I think is a rather decent price). I plan on using a 36v motor as from what I have read it seems to be enough to do the job, especially if I use a more powerful controller (like a 48v for example) though with the need for more cells. I also am thinking somewhere along the lines of the crystallyte hubs (cant remember the number but its the one built for recumbents with great torque and decent speed) and 4 to 6 dewalt packs. I figure my total cost with the whole setup will be around 2,000 which includes all parts and the possibility of having to pay someone to help with setting up the cells and such. Again any help in this would be appreciated. Thanks again

 

[Link]

1. Is it possible to use ultracapacitors to power an e-bike? There doesn't really seem to be a definitive answer to this.

While you "can" power a bike with ultracaps, they won't get you very far. Only the EEStor ones will do you good, but those aren't available yet (if they become available at all). Plus they run at 3.5kV. The current-gen supercaps won't come close to even lead.

2. would it be possible to use a solar array on a bike to help generate energy to sustain longer trips if so...or could you use solar power to charge the a123 lithiums?

It would be difficult and expensive. Solar cells in general aren't very efficient, so you'd need a fair number of them. And their not cheap; I saw one at fries that was like $200 for like 40W or something. My cheap $30 48V charger does 60W, and still takes about two hours to charge my tiny 4.5A SLA pack.


Best you can do really is plenty of lithium and an onboard speed charger. Opportunity charging FTW 8).

A Crystalyte X5 will handle whatever you throw at it. A 5304/5 in particular would be a good choice, but they'll want more than 36V to be happy.

 

[Diosky]

Alright thanks alot for the info and will keep all of that in mind. WIll probably just go with a good lith set up then and a small diesel generator to help when not near a grid to connect to.

 

[dogman dan]

I need to learn to use the quote thingy. Responding on the solar power idea, the smaller sizes of photovoltaic modules are usually 12 volt, so getting 40 watts at 48 volt will take several of em. Still a great Idea to charge up solar, especially if you can do it more cheaply by having multiple battery packs, allowing you to ride while others charge. The savings would be in charging slower with a less expensive collector. A bunch of 12 volt lithium packs that could be combined to make the desired voltages of a variety different ev's is one of my fantasies. You'd charge at 12 volt using a 12 volt bms to make it more compatible with small solar cells , and then ride with the bms from the ping pack or better ones if avaliable. The item we need though is a photovoltaic charge controller that would be compatible with the lifepo4 batteries. That may take awhile to come, since most off the grid guys use lead acid for economic reasons. Carrying the solar collector around would be hard to make worth it, since a collector big enough to really charge the battery would cost too much range with it's weight and wind drag. A small one could take weeks to charge a big battery. Still, if parking the thing with a solar cell attached helped raise awareness, that is a dang good reason to do it. Soon enough there will be lots of parking structures that have solar collectors. There is one at our local colledge, NMSU and they are planning one for the new city hall. In both cases the power won't be avaliable to ev's, but that too will change.

 

[Dr. Shock]

Although it wouldn't do you any good for a cross country ride, solar charging seems very compatible with ebike commuting. The panels put out low watts over a long period, while your commute uses large watts over a short period. Set up a couple of panels to charge stationary batts at home all day, then charge your bike batts from those.

I found that the panels are too expensive to devote to a single use. Better to have them pumping into storage batts all day and then draw off those for all the things you need electricity for.