Single Speed Mini-Velo Ebike - Advice Please

[lowspark]

Hello all. I’ve come close to building my first ebike before but ended up not going forward - got cold feet on the two speed motor as it seemed more experimental than I wanted to go with. But this time, I have a fun little project that I am ready to move on, if it can come together as I hope.

I have three bicycles (well, one is a tandem shared with my wife, so maybe that should be 2-1/2) as I really enjoy cycling and want the ebike to be more about supplementing my power, rather than replacing it. Living in hilly Seattle, I am looking for some help on the hills, valuing torque over speed.

I am intrigued by mini-velo bikes which essentially have a full size frame with smaller wheels. I am looking at a steel frame / steel fork bike with 20” wheels that will fit tires up to 2” wide. I figure the 20” wheels will help with torque.

My goal is a very simple lightweight ebike, preferably with a front hub motor. The mini-velo is single speed (I’ll ride freewheel, not fixed) and weighs 20 lb. My plan is for the hub motor to help me up the hills - I’ll take care of the flats and descents, which I usually coast down. My cadence is usually about 90 but I am comfortable going from 60 to 120, can go less that 60 as needed. I can swap out the rear cog to find the ideal gear to work with the motor. I weigh about 170 lbs and will carry little on the bike. In a perfect world battery, motor and controller would add about 10 lbs to the package making 30 lbs total for bike, 200 lbs total for bike and rider. Total cost would be about $1000, with $350 of that going for the bike.

I’m okay with 12 mph climbs but I would prefer a little more speed but not if it means moving from a 5 lb motor to a 10 lb motor. I have been reading about the small hub motors from Bafang, Cute, etc. and looking at batteries. I really like the idea of this 52V mini battery from Luna:

http://lunacycle.com/batteries/packs/52v/52v-mighty-mini-cube-ebike-battery-pack-panasonic-ga-7ah-3-pounds/

Can I use it to power a Q100H? I was thinking of using the 201 rpm version instead of the 260 rpm version even though I am just putting it in a 20” wheel, assuming I’ll get more torque and the speed would be acceptable for my purpose. Would running 52 volts give me more speed than the 201 rpm rated value? Would there be a better motor choice in the 5 lb weight range? What should I limit amperage to? Can you recommend a controller? I was thinking of just a thumb throttle - I’ll pedal to get moving a little then add the electrical power.

The main reason I want a front hub motor is that one future tweak might be to fit a Sram automatix two speed hub in the rear (modify shift point as desired) to get an extra gear without adding a shifter. This would increase cost to $1100 - $1200 range.

Can this be made to work well without going to a bigger motor or bigger battery? If no, what would be best? I really want to keep the weight down. Thanks for your thoughts, comments and advice!

 

[electrocats]

I expect the system you describe to work well if you're accustomed to biking those streets on leg power. I'd avoid most Lunacycle batteries. That is perhaps their worst one but they have a number of issues and poor support. Unless you use it sparingly and limit to 15A I'd expect that battery to give you problems within a few months with a year max lifespan in Seattle but YMMV. I explored Seattle with a large DD MXUS 3k in 16" rim running a lowly 52V30A controller (with Luna 52V10Ah 25R pack). Only one hill really bogged me down but I don't care about weight and don't pedal much at all. I prefer regen braking, but for your weight budget you might consider a friction drive.

Oh, brother ...I'd also avoid taking any of eTrike's posts beyond a grain of salt in regards to Luna products. He's just upset about their business tactics.

 

[lowspark]

Thanks for your thoughts eTrike and electrocats.

I am sure that powerful motor in a 16" rim could handle about anything - must have been a fun trip to Seattle. I had not considered a friction motor. I looked into it a bit and found a very interesting option, not quite available:

http://www.velogical-engineering.com/velogical-velospeeder.en

I thought Luna batteries were supposed to be good but have zero experience in the matter. Has anyone else had recent experience with them - good or bad? I guess I should do a search...

It looks like a Bafang G01 might be easy to get my hands on, sold by Grin Technologies, not far from me up in Vancouver. I ran a Standard Wind version and 48V battery through their simulator with a 20A and 25A and a "custom" 15A controller (15A was not on their drop down list, but it comes packaged with their kit). Each looks like it would perform very well - way better than what I was hoping for actually. Maybe the simulator is a little optimistic, but I don't know.

The 20A controller is rated 24V-48V and 25A rated 36V-72V. Would 52V be a problem for the 48 max rating of the 20A controller? The kit comes with a 15A mini-controller rated 24V-48V. I think that would be my preference if it could handle 52V, especially with eTrikes advice to keep amps down to that level. Thanks again for your help!

 

[electrocats]

I thought Luna batteries were supposed to be good but have zero experience in the matter. Has anyone else had recent experience with them - good or bad? I guess I should do a search...

Yes, lots of people have. He's just being a dick. Look through his post history to find a massive argument between him and the owner of LunaCycle. (GreenMachine)

He'll claim he's done the "facts" but he's just being nothing more than a massive overreactive twat trying to sway customers from Luna because of the way they do business.

Let's not go OT Mr. 9-posts. I've used and dissected Lunacycle batteries and can link to half a dozen problems with their packs. I'm a battery lover

Nice strawman argument. I only have 9 posts so therefore my opinion is worthless to you right? You clearly have acknowledged Luna's batteries as being quality products, but you seem to have a major issue with the specs of the battery being provided and and the "truth" around it's range and performance.

OP, do your own research and be careful who you believe around these areas. There's a lot of cut throat competition and any one of these jerks will jump on the opportunity to sway your opinion for a sale the first chance they get.

 

[nutnspecial]

Hi OP, it does sound like a low rpm 5lb hub set in a 20" wheel should be adequate for your description of use. If the calculator confirms this too that's excellent.

Would 52V be a problem for the 48 max rating of the 20A controller? The kit comes with a 15A mini-controller rated 24V-48V. I think that would be my preference if it could handle 52V

Usually, 14s is no issue for a '48v' controller- their limit is likely a little over 60v fully charged. Grin has great support and I'd confirm with them just to make certain. I'd recommend getting the hub and controller as a set. A 20a programable controller would be nice (and usable @ 15a also), but if it comes from a different seller it might be alot more difficult to get mated to the motor.

I personally am also not interested in luna products.

Perhaps consider my latest battery purchase: a tool battery.

They call it '58v' but it's the same 14s 2p of the small luna packs. I've been running it on a definitely lower efficiency (and higher draw) 1kw hub setup, and a single 4ah battery is acceptable for the >25a draws and a few miles of WOT with no pedalling. One pack would be certainly be sufficient depending on your range preference per charge, and two (making 8ah) should easily be added onto a bike. Or you could just swap between two batteries halfway in the ride.

The echo 4ah is likely smaller and lighter than the luna pack, it is far cheaper and holds up to the same currents, and best of all you can buy them with up to a FIVE YEAR warranty!! I imagine these larger production packs are far more well built and dependable- I was very impressed with the quality of build, and a warranty that can back it all up.

Just search ebay and forum for 'echo 58v'. I got my 4ah pack and charger for 75$ "used-like new", and they sell new for 130$ with a 1 yr warranty.

 

[lowspark]

Thanks again electrocats and nutspecial. Sounds like there are some differing opinions with regard to Luna.

Yes, I would much prefer to get battery and controller as a set. Would like to get the battery from the same vendor, too, but I can't seem to find the right combo.

I sent an email message to Grin. At the time I was not aware of the 15A controller with the kit and so inquired about 20A 24-48V vs 25A 36-72V when using 52V. When they respond I'll see what they think about running the 52V to the G01 through the 15A 24V-48V controller. From what I have read it seems doable, as you say, but I hope to get confirmation from Grin even if it is heavily qualified.

I had no thoughts about trying a tool battery, although I have have read of people doing this, using RC motors etc. But it sounds like a great battery, small in size. If the rule of thumb range numbers are in the ball part that would mean 58V x 4 ah / 20 rule of thumb factor = about 11.6 mile range, correct? I see they are available from home depot for $170 and a charger will cost another $80. One battery would probably do the trick for me 90% of the time. At 4.5 x 3.875 x 7.5 it is bigger than the Luna 52V 7ah pack @ 3.25 x 2.75 x 6, but maybe that include package size for the ECHO - I may check 'em out tonight they have a couple in stock. Can't find anything about weight.

So the Echos work well and are easy to hook up? Just have to adapt the connections, I guess?

 

[lowspark]

Oh yeah, and the echo 58V - 4ah goes for $85 new on ebay now

 

[electrocats]

Hi. Until a few months ago I blindly recommended Luna as well since they seemed like a great new choice. In the end I had their charger and a pack in hand-- I discovered amateurishly sub-par pack construction and started looking at their websites and specs. Their info is copy/pasted and broadly misleading. Comparing them to other vendors the discrepancy in quality was quite obvious.

You can find my post history suggesting Lunacycle batteries as a good option more than electrocats' now 10 posts-- 20% of which were important enough for him to deflect the conversation away from Luna battery quality, let alone his fallacy fail... FWIW, the thread he mentioned is one wherein a user had a problem with a 52V14Ah GA pack. I pointed out that he should see ~12.7Ah and that the site's info is misleading (as we'd discussed in another thread where greenmachines admitted this mistake), and the owner of LunaCycles showed his true colors, threatening me for speaking the same truth ~6 other members reported on how his 14Ah GA pack would not deliver 14Ah despite Luna's claims they test at 14Ah@20A (until once later he admitted 12.5Ah was closer... then one minute later repeated the same 14Ah falsehod)... several users including OP pm'd thanks and support since the info I was giving was spot on-- I'm one willing to call BS when I see it and always have facts to back me up


Everything I've shared about their cells come from an intrinsic study of battery behavior. GA cells struggle with anything more than 2C and will die much more rapidly as a result. You'd get a little over ~6Ah out of that pack. You're paying over $1/Wh for that Luna pack. For a Q100 ran at 52V/10A it would work.

+1 on tool pack batteries. They are high power cells, not high energy cells (like GA) so they are better suited for our uses. FWIW I still use the same tool pack cells I bought over 6.5 years ago for my daily driver. Can't beat the warranty either

It's not that you're wrong, It's that you're being such a weenie about it and acting like slight overexaggeration of the facts is the complete end of the world.
(As if no other company would do such a thing /s)

I wouldn't have normally commented on this post but I've seen you do this in like 5 other threads like it's your active mission to tear down a legitimate business that's liked around here. Not every business is perfect either, as evident by Samsungs recent battery controversies so it's a little silly to have such high expectations, especially for a newer growing business.

It's not like people buy Apple products for their specs.(I know some do but most don't) They buy them for their design and constant need to change the industry, something Paul and the other vendors are failing to do. Luna might not be "there" yet but they're working on it and there's no reason to discredit them over some slightly over exaggerated facts that you seem to get so worked up over.

Honestly, this argument was of no use to OP, but seeing you going around and purposely distorting new users looking for simple information is just as scummy as exaggerating facts. I'm just a simple customer who's lurked here for awhile and usually I have no reason to comment but enough is enough with you.

What's even more scummy is, you didn't even tell him any of that information about Luna's batteries, you just outright said "I'd avoid most Luna batteries", misleading the customer into thinking they were buying from some super shady website with only bad history.

Unbelievable...

 

[Marin]

Glad someone said it, too bad so many wankers here these days.

 

[bowhunter29]

I highly recommend Luna. I've spent quite a bit of money with Eric and won't hesitate to spend more. I have the Luna cargo frame, a 52v battery, and a bunch of odds and ends. My experience has been great. Eric has given top notch customer service.

Jeremy

 

[nutnspecial]

Luna is a hot topic around here. Mention disapproval, on topic, and see some real weeny thread devolution. It is what it is and has been covered already. Argument is not for this thread, so people shouldn't get all worked up over disapproval. I appreciate posts like the last one, and posts like eTrike's. People are gonna either recommend stuff or not.

Please let us know any questions moving forward OP.

Btw, I'm not sure where you came up with ~11 miles on the 4ah packs I mentioned?

Even if the echo is larger, I'd recommend keeping it in the nice protective case. As eTrike said, they aren't as power dense but that helps with longevity at more reasonable ebike draws.
To get real world distance you'd have to use a sim to calculate WH for your motor under conditions, then subtract what you want to pedal in, then apply it to the pack WH capacity. It's possible to get 10mi I'm thinking, but I only got 4.3mi (avg resting cell @ 3.5v) with all WOT no pedalling, numerous starts, and a total of >150ft incline using a 1kw hub- GVW of 220lb.

 

[lowspark]

Hey - thanks to all for the comments and I really don't mind the dust up over Luna working it's way into this thread, but I certainly understand that many have heard enough about it. I appreciate hearing from both sides on it and in the end I think that I would be comfortable buying the battery that I was considering from them. But the tool battery is intriguing.

I have looked into the tool battery a bit more and realize the appeal. Saw an interesting article that highly recommends a tool pack - specifically from Ego - and also mentions the Luna mini as it had just come out. I would like to know what he thinks about it now. In case any are interested:

https://electricbike-blog.com/2016/04/18/use-your-cordless-power-tool-batteries-to-power-your-ebike-what-could-possibly-go-wrong/

Regarding the 11 mile range - just a wacky rule of thumb I heard somewhere. VxA/20 = range. Pretty useless really as there are sooooo many variables involved, but it seems to always result in a more realistic (lower) estimate of range compared to the vendor's claim. Good of you to provide some real word numbers, nutspecial, I value it, and no doubt your method of predicting range would be far more accurate.

The info I am getting here and my trials with the simulator make me think that this could work out really well and I am getting very close to pulling the trigger and ordering the bike that I will add power to - probably do so this weekend.
I'll update everyone when I hear back from Grin regarding more volts thru the controller but it sounds like it would be fine.

In the meantime, if anyone cares to suggest a hub motor alternative to the Bafang G01, or relate their experience with it, or have any thoughts that it might not be the best choice, I'm all ears, or in this case, all eyes. Thanks again.

 

[lowspark]

I took another look at that article I linked and also looked at the Echo and Ego battery packs at Home Depot yesterday. The author, Karl, preferred Ego packs but I must say that the Echo packs look like good quality to me, as well. I didn't view the Ego promo video that disses the Echo packs but with the much lower price of Echos available on Ebay they would seem a good option - at the same price I would take the Ego, maybe would pay the premium. Haven't seen the Egos priced as low but my search was very brief. I think either would be a good choice. But the bottom line is i think I need to get a new string trimmer!

ETrike - thanks for weighing back in on the Luna packs and your "endorsement" of the 30Q version of the mini pack. While I would prefer the additional range of 7ah GA pack I guess it is trumped by the better reliability of the 30Q pack. 20A seems to be the border line between these packs and since i will be using throttle, although I plan to be deliberate in applying power, the safer bet at 20A would seem to be the 30Q pack. If i go with the mini-pack I think I will either run the 30Q with a 20A controller or the GA pack with a 15A controller as you suggested in your initial post.

Also, I heard back from Justin at Grin Technologies, who said "The 20A controller will work fine with the 52V nominal batteries, it has 60V mosfets and capacitors on it so even when your pack is fully charged to 58.8V it will work fine." This addresses my caution about going with a 52V battery - so no problem, as nutspecial predicted.

This project is officially a go for me - I will keep you all updated. Thanks for all of the outstanding help.

 

[lowspark]

Okay, bike has been ordered. I ordered a Respect Cycles Mini Velo V3 direct from their site as a pre-order for $349 with free shipping and no tax. Their website isn't great for getting good profile images of the bike, but Performance Bike also sells the bike and gives a better view so I linked it here:

http://www.performancebike.com/bikes/Product_10052_10551_1173954_-1___

The Respect site is here:

http://respectcycles.com/

Scotty from Respect said in an email that they expect the bikes to ship around Halloween.

Meanwhile, Justin at Grin had recommended that with the 20A controller this thing could pull around 1000W which, if held long, could make the little motor hot and so I might want to get the CA3 and thermistor wire so temp could be monitored and have the CA do an automatic temperature rollback. I have sent him a follow up question to see if he feels that would necessary with the 15A controller. I may go that route, giving up some power, just for the sake of simplicity, but I am open to any advice.

 

[lowspark]

Sorry that I didn't post a picture with the last post but I haven't posted one before. Hopefully this will work...

 

[LewTwo]

Meanwhile, Justin at Grin had recommended that with the 20A controller this thing could pull around 1000W which, if held long, could make the little motor hot and so I might want to get the CA3 and thermistor wire so temp could be monitored and have the CA do an automatic temperature rollback. I have sent him a follow up question to see if he feels that would necessary with the 15A controller. I may go that route, giving up some power, just for the sake of simplicity, but I am open to any advice.

Please post his response. I have a Bafang motor of similar characteristics running on a fixed 14 amp controller at 36 volts. I have wondered if a few more amps might not be safe or if it would offer any advantage. I ordered a Grin Phaserunner and CA (v2) to test that theory but that project is on hold until I finish my current build. I plan to use 'old school' temperature monitoring, "Ouch - That is hot!" Note also that EM3EV have a small programmable controller (much less expensive that the Phaserunner). http://em3ev.com/store/index.php?route=product/product&path=41_38&product_id=77

 

[lowspark]

Thanks for your opinion on the CA eTrike. It seems like money well spent, especially if I make the move to electrify another bike I have that has 700c wheels and just swap the battery and controller between the two bikes. I assume the CA would work with the two different set ups.

LewTwo, Justin said that the 15A controller would work with the 52V battery but be aware that this 15A controller only works in sensored mode, it does not have sensorless capabilities. But since the Bafang G01 motor has halls on it this isn't an issue really. As for the need for the CA and thermistor wire, he said that I am correct that it would make it less necessary to monitor motor temperatures, but I would still putting in 750 watts to a motor that is nominally meant for 250-500 watt operation, so on long sustained hill climbs the hub will still get pretty toasty inside.

Since I am now well aware of this limitation, I think I could manage without the CA, using the "Ouch" monitor, but the CA would greatly reduce risk for me. I'll ponder a bit more and gladly consider any additional advice.

 

[Warren]

Whoa! Flashback. Thanks for posting the Respect picture. Took me back over twenty five years. Formula One bike racing was the coolest idea ever!

http://grinderswheels.blogspot.com/2007/03/formula-one-bicycle-madness.html

There was a builder, and several active racers around Charlottesville back then. I think one of those guys is still riding his.

 

[lowspark]

ETrike - I forgot to mention that, yes, the Bafang G01 and the 20A controller are on the simulator. The 15A controller is not but one can model a "custom" controller, inputting 15A and other info that would be a guess for me. I used a 48V 9ah LiFe battery in the simulation. Here is a link to the simulator but I am sure that you are already familiar with it:

http://www.ebikes.ca/tools/simulator.html

Warren - I have never heard of Formula One bike racing. Thanks for posting the link - pretty cool. On the Respect site they have pictures of the way different people have set up the bikes and some look quite a bit like that low handlebar, stretched out riding position like the orange bike in the article. I'm hoping for a more upright position and hoping that I'll be comfortable with the stock stem and handle bars but if not, a stem / handlebar upgrade might be in the works, but I don't really want to go there. Did you have a F1 bike and did you race?

 

[lowspark]

Warren - I forgot to mention that Respect has two main offices. One in Santa Barbara and one in...

Charlottesville, Va.

 

[LewTwo]

... I assume the CA would work with the two different set ups....

I am making that assumption as well. The CA can take the place of a 'display' that is normally shipped with many of the controllers or used to 'upgrade' a controller that does not have display. AND it gives you the added functionality of a watt meter that is a heck of a lot more accurate than those (dare I say useless) LED battery gauges. It would need to be reset when swapped from one battery to another and might need to be reprogrammed when moved from one bicycle to another.

I got the DPS model and standard shunt. My bikes are all low power (less than 25A nominal) so I use XT60 connectors for all the power connections. By equipping the shunt with XT60 male/female connectors I should be able to easily move the CA from one machine to another. I am also planning to take advantage of the 1/4-20 screw on the bottom so that I can use GoPro camera adapters to mount it to the stem(s) via a simple thumb screw. You can do that with the standard CA mount but the GoPro mounts are somewhat more versatile.

 

[Warren]

lowspark,

"Warren - I forgot to mention that Respect has two main offices. One in Santa Barbara and one in...Charlottesville, Va."

Wow! That can't be a coincidence. I wonder if Nick Nichols of Rockfish Cycles is somehow connected.

http://www.leys.com/basic/rockfish/sales.html

I never raced, but knew several guys who did. The idea was to get young BMX racers interested in road racing. The races I saw were held in shopping center parking lots, with the short twisty courses laid out with traffic cones. They only ran a single front chainring, as there was barely enough time to shift a few gears in the back, sprinting the short straights from one corner to the next. Many guys wore real crash helmets, and elbow, and knee pads. Lots of contact on the tight courses. It was as much roller derby as road racing. Way more interesting for spectators than road racing, where you wait long minutes for the pack to roll by, and then nothing.

http://bmxmuseum.com/forums/viewtopic.php?pid=5173221#p5173221

 

[lowspark]

Very cool Warren. I had absolutely zero awareness or knowledge about F1. Those are some very cool bikes and the racing sounds insane. Yes, I think crash helmets and pads would have been a good idea. I haven't seen Nick's name mentioned in relation to Respect Cycles, but I agree, the Charlottesville connection can't be a coincidence.