Semi Infinite Battery

[donob08]

Title includes a misnomer, misspelling or.. I'm thinking of making tribrid system out of my 2008 eZip Hybrid Trailz.

I commute to my weekly tasks by eZip. One day of the week my task is 20+ miles away. I have two 24V, 10AH battery packs on my eZip so 20 miles in the morning is no biggie. But some times they don't have enough stuff to keep me busy 8 hours, although my pay rate is 0.00/hr that can't afford to keep me. I get disruptive when I'm bored.

So, I'm thinking a bigbore model airplane engine, fossilish fuel, a generator head/alternator/dynamo to make cursing electrons, a dc to dc converter/charger to make 24V+ DC to charge my battery, on the go, as I go home. Four hours charge time "at the office" doesn't get it. All this stuff would ideally weigh about 16 lbs, the weight of the second battery I would leave home.

I'm an Electrical Engineer by education, but the last time I worked on "Electrical Machine Systems" was about 1962. Tell me there is better stuff now. All ideas will be appreciated.

 

[vanilla ice]

I'd prolly get a 2nd or even 3rd charger. I think you can hook them up in parallel to increase the charge rate since they are isolated. Your charger has got to be less than 2 amps, and the 10ah bats can take two or three times what it puts out. They are pretty cheap at tnc and elsewhere. The other idea could be great too if you get it to work. The noise and complexity would keep me away from it, but I'd love to see something like that run.

 

[dogman dan]

It's a cool Idea, and we have a thread on it somewhere in the ebikes section. As an experiment, I put a small generator in my trike and a 4 amp charger, and it did work. My stuff just weighed too much. The general conclusion was that a 20 lb generator of about 500 watts would do the trick, but I don't know if one ever got built by anybody.
Two Ping Lifepo4 24v 20ah batteries would weigh about 20 pounds and take you the 40 miles I think. Run one and then the other since the connectable bms is not out just yet. Of course you miss out on the fun of building a frankenbike that way though. The lifebatt lookalikes on ebay, or A123's can take a really fast charge so that may be another way to handle it, but then a 10 or 20 amp charger gets a bit heavy to tote around. It seems like a lot of money for lifepo4 but bear in mind that it could be a decade before you need another new one. mine was $450 including shipping and should go 20,000 miles on my ebike, by which time it's range will have dropped to 16 miles from the original 20. It could still be good for a 5 mile ride after 40 or 50,0000 miles.

 

[docnjoj]

Hey Dogman! Yer gonna be 180 years old by that time! Oops, that was in "dog years" Seriously, we dont know if these batts will last a long time! Nobody has tested them for more than a year or so! Definately buy Ping cause its good (and Cheep) but dont think for a minute these batts are gonna outlast, say, Nicads!
otherDoc

 

[donob08]

Thanks Dogman found the thread. All sounds logical. It gave me a worthwhile thought. I have a trailer and an 1000 watt AC generator that weighs about 45 lbs. I can put it in the trailer next trip and see if the concept is worth pursuing. Thanks!

 

[dogman dan]

True enough about battery life. I really don't expect a BMS to go forever but I belive the test specs Ping has put out, that say 80% capacity at 1000 cycles. For my bike a full cycle is 20 miles, and I usually go 15 or less. So I'm hoping to see 16 mile range 20,000 miles from now. I'm on track for 3000 miles a year at this point. When it gets real cold, I may bus to work and ride back though. So call it seven years. Some say the shelf life is five years so I'll be happy enough if I get that, riding 15,000 hassle free miles.

I know what you mean about nicads, I sure abused em enough for decades in makita drills. I'd get at least 5 years out of use that would kill a lead battery in a few weeks.

 

[StevenR]

I've got a bid in on a Ryobi 875 4-stroke motor ($25.00) and am looking at an...

ARGORD CORP. Permanent magnet motor with brushes. Mounting bracket is designed for a pivot mount to tighten belt. Thermal overload protection.
SPECIFICATIONS
HP 2-1/2 at 130 VDC int.
1-1/2 at 95 VDC cont.
95-130 VDC
18.5 Amps
0-6750 RPM
...at...
http://www.surpluscenter.com/item.asp?item=10-1783-A
...to run as a generator. This would go in my Nashbar trailer. It looks like it should weigh in at about 15 pounds without bracketry and electronics. The voltage looks wrong though and I have further exploration to do on that side. I'm not sure about electronics - I'm an ME, not an EE after all. I was considering just running it to charge batteries and modulating the throttle to maintain a specific voltage output to avoid DC-DC or DC-AC-charger losses. The potential to have the generator act as a motor (it is one, after all) and start the ICE automatically or on command would be interesting. Other configurations like serial hybrid would also be worth exploring. I'm currently running a C'lyte 5303 with 48V 40A controller. I will be getting a YESA 48V 20 AH pack (although the 30 AH pack is supposed to be available soon) and would get two for this system - one to run and one to charge. I've looked at the Yamaha 1000W generator and it has potential as well but I think this may be lighter and have the potential for self-start with no inverter-AC-DC conversion issues.

Avoiding philosophical arguments about using an ICE, the point of this is to produce a system to give as long as my butt holds out range (175 miles). Does it make any sense? Is there something better for use as the generator (what do you think of this?
http://www.perm-motor.de/site/en/products/syn_generators.php?linkid=p&linkid2=3
...)? What are the consequences of charging a LiFePO4 pack this way? What about the series hybrid/LiFePO4 system battery issues? A $1000-$1500 pack is a terrible thing to waste...

 

[Jeremy Harris]

Sam,

If you can supply reliable cells, at a good price, that will deliver at 3 to 5C without massive voltage sag then I think there may well be a queue of people waiting to buy them.

There are quite a few of us looking for cells with a higher peak discharge rate than the normal LiFePO4 ebike packs can provide.

Jeremy

 

[Timbo]

Somewhere on one of my bookshelves I have some notes on how to rewire a brushless Fisher & Paykal washing motor to use as a wind generator or in a micro-hydro set up. I've wondered if it would be possible to apply the same idea to an e-bike motor for recharging or powering lights etc. I was just doing a bit of digging and I found all this stuff from Brett at solar bbq:

http://www.users.bigpond.com/solarbbq/bikeexp/bexp.htm

Gold

 

[Fumesucker]

A three phase BLDCPM motor will work just fine as a three phase alternator, just pick a motor that will have sufficient back emf to charge your battery pack at the rated rpm of the IC engine you choose to drive it with.

 

[lfairban]

I recall being in a discussion like this a couple weeks ago.

One of the poinst was that using a generator was a bit silly since you already have a motor that can act as a generator if you have re-generative breaking. The best way to do this would be by adding a 35-49cc gasoline bike motor to an e-bike with something like a Bionix rear hub motor. Most of the time, you will be better off using the weight and dollars to get another battery, until you get to a range of about 100 miles.

If you can get a dedicated generator that is only about 15 lbs or so, it might be a viable idea since you could remove it for shorter trips.

 

[docnjoj]

Maybe a moderator could shift the above message to the battery or sales section so it doesnt get buried!
otherDoc

 

[youreaspeedemon]

But some times they don't have enough stuff to keep me busy 8 hours, although my pay rate is 0.00/hr that can't afford to keep me. I get disruptive when I'm bored

I'm running 48v and I use a 24v Soneil (it's only 1.8 lbs) to charge my 4 18ah sla's in 24v parallel at work and it goes into float after about 3.5 hours, granted I'm only going 13.5 miles each way, my CA says I'm using about 400-450 watt hrs or a little over 30 wh/mi. I use the 8A one that is supposed to be the equivilent of a 16A standard charger in time. I got this one because If I have to leave at lunch it should be fully charged.

So, I'm thinking a bigbore model airplane engine, fossilish fuel

Do you ride solely on the street? If not and you ride on bike paths I don't think the other cyclists would appreciate the smell the noise and the cheating, and someone is bound to rat you out. Also do you really want to pull a trailer every where you go? I've got one for the kids to go on a short bike ride and that's enough for me. Granted if you are trying to do long hauls with this bike you would need something like this. Seems to me though car companies are beginning to see that this is where they need to go, run on batteries and charge when needed like the Chevy Volt and others.

Good luck and if you decide to put it all together definately document it, easily sourced parts and configuration would be nice for those who want to do the same.