Help - should I build 2 slow bikes or 1 fast bike?

[auraslip]

So I got my financial aid coming in a week. It's enough for me to survive until summer and the lawn mowing business takes off again.

My current bike is a 9x7 9c powered by a 48v20ah ping. I want to upgrade it with a 72v10ah headway pack. That and some other upgrades to the bike like a DIY torque arm, ventilation of the hub, changes to the battery box, temperature sensors, and the tools to do this should run around $900

Or I could order 2 bike kits from cell_man or some used kits from members here, and make some slow SLA powered ebikes. I've been wanting to do this to loan some bikes to my friends, so they can enjoy my hobby. Also I think a great number of people in my trailer park would be interested in buying them. Some are illegal and can't get licenses, some are rednecks with DUIs, and some are just poor. I see a lot of people riding beat up old department store bikes, and I think that even if I break even selling these bikes it would be worth it. It could establish the viability of these ebikes as means of reliable transportation! The experience making these and selling them would be valuable too. Since I'm a member of a bike co-op, I can get bikes for really cheap. So a $200 kit, a $100 bike, and $100 for an SLA battery and charger. Also I'll build wooden battery boxes for these bikes, so add another $100 for materials, paint, and general repairs to the bikes. So around $500 per bike, and if I sell it for $600 GREAT. I don't have a job, and would enjoy building these! If I break even, that is fine too!

The problem is I REALLY want to upgrade my old bike because my commute to school is mostly on a two lane country road with out shoulders. The speed limit is 35mph, and people pass all the time. It's probably more annoying than it is dangerous! If I could get up to 40mph consistently I'd be happy! Maybe a 60v headway could do that, and be affordable enough.

The only thing I'm sure of is that I'm going to transplant my ping pack into a new bike built to tow my lawn care trailer around this summer. This bike doesn't need to go faster than 25mph, and a 20ah range is plenty. Especially when I charge my bike at customers houses like I did last summer.

Maybe I should just build up the lawn care bike, and then decide. Money burns a hole in my pocket for sure!

 

[adrian_sm]

I would build a single bike for yourself that can do the school commute and lawn-care job. So get a new 72V or whatever pack, and use a speed switch on your controller to dull things down when you don't want all out speed, and just need to tow things around.

Then put your old ping pack on a different bike, with a new motor/controller from wherever meets your budget. This can the be lent to friends, sold off or whatever.

But don't go SLA. If this is peoples first introduction to ebikes, they will miss out on how great ebikes can be.

 

[auraslip]

I would build a single bike for yourself that can do the school commute and lawn-care job. So get a new 72V or whatever pack, and use a speed switch on your controller to dull things down when you don't want all out speed, and just need to tow things around.

A few reasons for wanting two separate bikes. The fast bike is built for speed. Rear wheel, finicky brakes, expensive suspension. Battery box is painted black (heat in the texas summer!) Fitting the trailer hitch on the rear motor plus a torque arm for 72v = pain in the ass. It's also an xxl frame, so stand over height is an issue.

The lawn care bike is going to be front wheel drive, low stand over height for easy on and off while attached to trailer, and amenities for thermal control(like a white paint job!).

Basically a pick up truck vs. a sports car.......... but you are right. It is tempting! A lot cheaper too!

I could put the 72v battery on the lawn care bike for the summer, and use the pickup truck all summer. Then I could move the 72v kit to the sports car in the fall.
Then I could sell the ping now..... I could afford that...

But don't go SLA. If this is peoples first introduction to ebikes, they will miss out on how great ebikes can be.

Truth. For $300 I could get a headway 36v10a headway pack. A 36v14ah sla pack weighs about 30lbs and gets around 15-20 miles with pedaling @ 23mph. With the weight in the triangle of the frame it wouldn't be that bad. I just think most people don't understand the difference lithium makes! $600 vs $800. Plus since I'm selling these bikes, I want them to be super duper reliable. With SLA I know they won't come back with any problems. At least until the battery dies in 9 months. Maybe then they'll understand the value of a good lithium battery

 

[Lessss]

Help - should I build 2 slow bikes or 1 fast bike?

How likely are you to be arrested on the one fast bike? there is your answer.

 

[jag]

My advice: Rather than spending your money building a bike that someone might hypothetically buy, lend them your bike for short sweet rides (if you trust them), then have them pay first before you buy parts and build them a ebike.

Keep your financial aid in the bank account, and try to have a positive balance by end of semester. Too many of my friends started the semester rich, but by end could only afford eating pasta and catchup.

Now for your own needs, you could add a 24V 20Ah pack to your current ping.
10Ah Headways is a possibility but may not be that much of an upgrade over the ping in terms of internal resistance.
A123 is considerably better. A bit pricier for a built pack from cell_man (but you can tailor the capacity to your need). Can be built with less expense from used cells if you are handy.

Best would be if you could somehow borrow a 12 and/or 24V booster pack and see what voltage you need for 30-40mph, and also check the voltage sag of the ping for your riding at that speed. Then you would also get a feel for how your bike handles at speed, and how fast you really want to go.

 

[adrian_sm]

Yeah. I am running 6s LiPo boosters on my "48V" headway pack. Bit of a pain to have dual chargers, but was an easy way to up the voltage and get a taste for more power.
I also need to modify my controller to handle it.

 

[auraslip]

How likely are you to be arrested on the one fast bike? there is your answer.

Rural texas. Only sheriffs. Cops barely blink.

Keep your financial aid in the bank account, and try to have a positive balance by end of semester. Too many of my friends started the semester rich, but by end could only afford eating pasta and catchup.

Really good advice there that happened to me last semester. I could afford everything I wanted, but then I would be eating ketchup and ramen by the end of the semester. Hence the decision.

Best would be if you could somehow borrow a 12 and/or 24V booster pack and see what voltage you need for 30-40mph, and also check the voltage sag of the ping for your riding at that speed. Then you would also get a feel for how your bike handles at speed, and how fast you really want to go.

I did this with two 12v14sla batteries in series. Did around 40mph, but the sag was really bad. I also get the impression that the ping was getting slaughtered! Pings are rated at 2c continuous, but I think it's more like 1c. Don't want to melt the pack.

You don't think 10ah headways would be much of upgrade? I was reading the thread with doctorbass's tests it seemed to indicate 3c continuous is fine with proper cooling. 30amps @ 72v = 2160 watts. Much better than the 1500watts I have my ping limited to.

 

[John in CR]

Single guy, just one good bike. A multiple bike solution would be one for transportation and one for fun. In your case, make it both bikes in one. Get at 36v20ah Ping, mount a smaller wheel and be done with it till at least this time next year when batts are better and cheaper. Headways were good 2 years ago and now they're just ok.

Better yet for a bridge pack think about some Konions from DrBass and DIY a pack while it's still cold. 20 used Makita 3ah18v is probably all you need, but get 23 just in case, and build a 10s pack in whatever shape you want. That will probably give you an simple to assembly 16p10s pack with a number of left over oddball cells for lights and stuff well in excess of 20ah, so you don't have to worry about it in series with your Ping. Get home plug it to a Makita charger that auto cuts off at 40.5 volts...no BMS no LVC nothing but simplicity. About $350 plus shipping (maybe less), and you've got more performance and double the range you were looking at, and plenty of $ in your pocket.

 

[auraslip]

Get at 36v20ah Ping, mount a smaller wheel and be done with it till at least this time next year when batts are better and cheaper. Headways were good 2 years ago and now they're just ok.

I wish I went with headways originally because then I would feel good about a booster pack. I mean, I couldn't really put a 24v20ah booster pack with the ping could I? It'd be a higher voltage, but I'd still be limited to 25amps(what I have my pack limited too now). That's only 1800watts or 500watts more than what I'm running now. Plus I'd have to have two chargers which would be a pain as well. Seriously, though it might be worth it. The rate prices are dropping, and quality is improving!

I could do a 4s2p booster pack with the 8ah high C headway cells. It'd only be 8 extra cells, so it'd be cheap. Then I could break that pack down when it's time to upgrade. I could built a really powerful battery pack over time!

Get home plug it to a Makita charger that auto cuts off at 40.5 volts...no BMS no LVC nothing but simplicity.

I haven't researched those cells, but I'll check them out for sure.
Right now I have my battery and charger integrated into my bike. It's really nice because I don't have to worry about a thing. Just plug the charger in and walk away. I charge at school; I dragged the bike rack over to a power outlet
When I do lawns I bring my charger, and people are happy to let me plug into their power! They seem amused and curious about it. One of the issues I'll be having with the lawn care bike is cooling the charger and battery! Last summer the charger got REAAAAAAAAL hot in the 100 degree weather.

 

[dogman dan]

1 Keep the ping. You need a reliable battery for your basic needs.

2 using a diode, and a controller that is not too much amps for your ping, you can boost the voltage to 72v for the fast ride to school.

3 do the boost pack with lipo, Cheap, light, etc. Should be able to get going with 10 ah lipo boost pack, diode and slow charger for about $200-250.

4 let those neighbors pedal. I bet they can't even scrape up $600. If they can, offer to help them build a bike, using thier money.

5 Hard to go wrong, having a second motor handy, so maybe have the cellman kit too if it's in the budget, at the end of the semester.

 

[AussieJester]

I would build one fast bike after you finish the seimester and/or when your lawn mowing business takes off...always good to have money
in the bank.

Also I think a great number of people in my trailer park would be interested in buying them. Some are illegal and can't get licenses, some are rednecks with DUIs, and some are just poor.

[off topic]I would love to see pics of your genuine USofA 'trailer park! How big is it? is really like the ones i see in some
of the American T.V shows like 'My name is Earl" for example? or do they make them look ratty and shitty just for T.V?
We call them caravan parks in OZ and most of them (in W.A) anywayz are on the coast in holiday destinations, they
are all really nice and well kept. What is rent like in a US Trailer park generally? Can you buy the 'trailers' or are they rent only? [/off topic]

Best of luck with school, your new business and whatever project you decided to tackle e-bike wise...

KiM

 

[dogman dan]

Heh Heh, they have it looking extra nice in the Earl show. They exaggerate the dumbshits a tiny bit in that show, but any trailer park older than 20 years looks just like the grapes of wrath usually. Always at least one old muscle car in the process of a 10 year repair in the driveway, then a 500 buck turd car they actually drive. Turd car often has $2000 gold rims and tires though. :lol: :lol:

It works both ways though, ever seen a movie called Welcome to Woop Woop? Laughed my ass off on that one. Every country has it's stereotypes that get joked on.

 

[auraslip]

Always at least one old muscle car in the process of a 10 year repair in the driveway, then a 500 buck turd car they actually drive. Turd car often has $2000 gold rims and tires though.

NAILED IT SO HARD Lots of half built up Camaros, Mustangs, and Harleys!

my neighbors back yard. Probably the nicest lot. They are old, and have nothing to do but yard work though.

This used to be the laundry mat, but went out of business.
It's split about 50-50 between whites and mexicans here. I just asked my girlfriend if it looks like "my name is earl.", and she said it kinda does. She is also scottish and says caravans are R.V.s. Trailers are.......shit. So many problems with cheap construction. I'll try to take some pictures today.

4 let those neighbors pedal. I bet they can't even scrape up $600. If they can, offer to help them build a bike, using thier money.

Probably right. And they probably won't want a 15-20 mph kit for the price. More like a 25mph kit, but that's pressing $1000.

Keep the ping. You need a reliable battery for your basic needs.

That is good advice. The damn thing is just to damn utilitarian.

Anyways, I've gotten qoutes from two different sellers for a 72v10ah headway pack. It should be around $525 shipped. Not to bad. I'm gonna spreadsheet all my bills out as far as next semeseter to see how much money I'll need + money for food, known unknowns, and unknown unknowns.
I was thinking 6sp2 booster pack made with the 5-13 cell smart bms would be good. It would give me experience making a battery. Plus I could rewire it to 12sp1 using the same bms. Still, the issue is multiple chargers, and a higher c rate on the ping.

 

[dogman dan]

People used to ask where I lived, and I'd reply 1st trailer slum on the left, after the real houses on Elks Drive.

So glad to live in a house now, with walls that go all the way to the ground. Had one neighbor move out so he could go do his child molester jail time, on the other side, the Wife put two bullets in hubby's head and set the place on fire. I never had any muscle cars taken apart in the yard, just pickup trucks cut in half to make trailers out of the back half. :lol: And a pack of huge hound dogs, to keep the nice neighbors out of my yard. We lived in that shack of a trailer 18 years.

 

[auraslip]

I'm glad too. I like my neighborhood, but trailers have some serious health risks due to leaky old pipes and mold. Also heating and cooling is a bitch.

I did my spreadsheets. I budgeted for food, all bills for four months, and some various TRAILER REPAIRS I have to do. I got a lot less than I was hoping. I'm glad I took the time to figure out the REAL amount of money I have. I guess I'll just have to save up enough money this summer, or get a part time job.

In other news, I had a DUH moment, when I went to the store today. I had my 3 speed switch at 99% instead of the normal 120%. I thought the wind was blowing hard or something cause I was only doing 28-30mph, but then I realized I was only pulling 17amps. It cost almost 10 amps extra to get that 5mph speed boost from 120%! It's great news because it means I COULD keep the battery limited at 25amps, use a 24v booster pack, and run the bike at the much more efficient 99% speed.

If it only takes 1000w (17amps times 52v) to hit 30, I'm sure 1800 watts(25amps times 72v) would be a big speed increase.

 

[jag]

People used to ask where I lived, and I'd reply 1st trailer slum on the left, after the real houses on Elks Drive.

So glad to live in a house now, with walls that go all the way to the ground. Had one neighbor move out so he could go do his child molester jail time, on the other side, the Wife put two bullets in hubby's head and set the place on fire. I never had any muscle cars taken apart in the yard, just pickup trucks cut in half to make trailers out of the back half. :lol: And a pack of huge hound dogs, to keep the nice neighbors out of my yard. We lived in that shack of a trailer 18 years.

Trailer parks don't have the best reputation, but not all are bad. I lived for a year with a high school friend and his mum in one next to Conesus lake, New York. Beach and docks across the road. Used to go swimming, boating and have camp fires on the beach. Here's google map link. Our trailer was the one up the road off East Lake Road where the google maps marker "A" is, in the lower left corner lot.

http://maps.google.ca/maps?q=4430+E...code_result&ct=image&resnum=1&ved=0CBYQ8gEwAA

 

[dogman dan]

No, there are very nice neighborhoods in town that are entirely made of decent double wide mobile homes. Not to be confused with living in the trailer slum though. We all had 1/2 acre lots with a MH on it. I was the only owner on the street that didn't put an illegal second trailer on the land, and rent to scum. Hence the designation trailer slum, vs trailer park.

With my lyens 20 amp 9 fet 78v controller, I breifly see 34mph and then get a solid 30 mph most of the rest of the ride. Pulls about 1400 watts since it seems to actually limit closer to 17amps. Great controller for piggybacking a lipo on a ping. 9c 2807 motor.

 

[auraslip]

That's strange. You run a 9c 9x7 at 80v and only get up to 30..... I run the same hub at 52v and get around the same..... maybe the smaller 24 inch wheel is quicker because it is more efficient. (I know people typically think of smaller wheels as slower, but I've found my bike to be just as quick with a 24")

Or maybe the wind blows harder or something in AZ I weigh about 200 lbs ~ hrmmmm

 

[jag]

Best would be if you could somehow borrow a 12 and/or 24V booster pack and see what voltage you need for 30-40mph, and also check the voltage sag of the ping for your riding at that speed. Then you would also get a feel for how your bike handles at speed, and how fast you really want to go.

I did this with two 12v14sla batteries in series. Did around 40mph, but the sag was really bad. I also get the impression that the ping was getting slaughtered! Pings are rated at 2c continuous, but I think it's more like 1c. Don't want to melt the pack.

Now from this experiment going 40mph with your ping and booster you could measure and learn important things:
1. What was the actual voltage and current to the controller. This will determine what battery you need. (Voltage, current capacity and Wh needed for your commute)
2. What was the voltage sag of the Ping? From this we can determine the internal resistance losses in the ping.
3. What temperature rise did the Ping experience? If under 10C it is not a problem. If temp increased a lot it would be a problem.

Edit: B.t.w. I liked your heat capacity calculations in the other thread. I also did some power calculations on what power one might need into a 9C to go 40mph/65km/h (came out to 3688Watt), but the calculations are very sensitive to input data being correct. Both manufacturer battery and motor data as well as heuristic guesses for air resistance coefficients etc are notoriously inaccurate. Let me add this from the signature of other ES members: "Besser probiren als studieren" and "Experience is the best teacher"

 

[auraslip]

Edit: B.t.w. I liked your heat capacity calculations in the other thread. I also did some power calculations on what power one might need into a 9C to go 40mph/65km/h (came out to 3688Watt), but the calculations are very sensitive to input data being correct. Both manufacturer battery and motor data as well as heuristic guesses for air resistance coefficients etc are notoriously inaccurate. Let me add this from the signature of other ES members: "Besser probiren als studieren" and "Experience is the best teacher"

Yeah, that's been my experience. All the simulators I've tried have been off a bit or a lot. It's difficult to tell what will really happen!

I wish I had kept better track of what was happening to the batteries when I was making those test runs. All I had at the time was a CA, so I don't know what was sagging; the ping or slas :/

 

[dogman dan]

You get more speed out of 72v when you use a 40 amp controller and 10 ah of 30c lipo. The ride I was refering to used the 9 fet 20 amp Lyens controller. It seems to spend most of the time only supplying 17 amps. So as voltage fades on the lipo, you stop seeing 34v mph, and drop to the 30 mph ballpark by the time voltage is in the seventies. More watts can overcome wind resistance, but at 1400 watts, you get about 30-32 mph. Very upright ride position on that particular bike. http://endless-sphere.com/forums/viewtopic.php?f=6&t=25167

Voltage fade on that bike is pretty fast, since I mostly ride it with 20s 5 ah 20c zippy's. Does much better on 20s 10 ah 30c turnigy. With the big battery, it goes 33 mph for quite a ways. With a ping and a booster, I expect you'd get about 30 mph most of the ride using that lyens controller.