toyotaboy

Took a long 8 weeks, but it finally came. I'm actually working on it during my lunch hours at work since I have better tools there. Here's what I have so far:


I had to grind the slot on the front fork quite a bit (wheel threaded rod was like .400", slot on my fork was only .340"), I managed to open it fairly quickly with some drilling. The kit I got has a mandatory headlamp (doesn't have to run), but it actually has a key to prevent someone from taking it for a joyride (which is rather nice), but I didnt' realize at first and thought I hooked it up wrong somehow. I still need a rear rack so I have somewhere to put the batteries (using four 9amp AGM cells at the moment). It's a 48v 800watt motor, so I'm hoping to get some decent speed once I finish it. I also have to flip the rim 180 degrees because at the moment it's running backwards :-)

nwmtnbkr

Nice bike, post more photos when you've finished assembling it. Did it come with torque arms for the fork? If not, you might want to consider adding them for safety. Congratulations, I think you'll love having an e-bike.

toyotaboy

No, the thread is oversized and has flats, so there's no way it can twist inside the slot.
I will post more pics as I get closer, having a tough time finding a rack in the store, might have to order online and wait for it in the mail.

ambroseliao

Hi Toyotaboy,

I know that you don't think the motor can spin out of the front fork, but at 48V and 800W, that is a very powerful motor and your front forks don't look particularly beefy. You've also reduced the strength of the dropout by grinding away some of it. It's much better to invest in a $15 torque arm than to risk falling at speed and possibly destroying the motor.

As for a rear rack, I recommend the Topeak Explorer rack. It's very solidly built, not expensive and has super strong welds. It also has 2 extra thick attachment plates with 4 solid screws to hold the rack to the seatstay. I've tried using a beam rack (can't stop it from swaying side to side with heavy SLAs) and cheaper rear racks (which loosen and shake over time) and the Topeak is a winner. The Topeak holds my 48V 12AH pack (roughly 30 lbs) very solidly.

Ambrose
(no affiliation with Topeak, just a happy customer)

crimsonsnake0

hi looks like nice kit. i have a 48v 1000watt kit looks similar to yours. for a rack search ebay and get a steel rack only alloy not strong enough. i tried 10ah sla batterys and found them to weak for my journey about 12 miles a day. changed to 4x 20ah purchassed on ebay for £92 delivered bit of a bargain really. do a search for 12v 20ah and you will find them on ebay.if you go with larger capacity batts you could also wire up a 12v spot light and switch to 1 batt for great night time riding. anyway have fun cheers.rob

toyotaboy

ambroseliao: I may do that longterm, there is a hole for a hook, though like I said the thread has two flats, so it would be very hard for it to twist.

Here's another photo with the tire mounted (which I found out today doesn't seal well, I think the new rim is slightly wider than the old one, so will probably have to get a new tire/innertube


I saw a schwinn rack that mounts directly to the seatpost, but it's only rated for 20lbs (and I don't trust it), so I'm going to build my own by bolting some aluminum tubes directly to the frame and add some aluminum strips for a platform. I modeled something up real quick in solidworks (I'm also an engineer, which comes in handy):

ambroseliao

Nice! That rear rack of yours looks pretty cool.

One more thing about the front fork. It needs to be steel or cro-moly. You've probably already verified that it is!

Ambrose

toyotaboy

ambroseliao: I would highly doubt the fork is aluminum, I'm thinking it's steel since it's a cheap bike, but I could stick a magnet to it to verify.

toyotaboy

Got the rack built, fits a little snug (didn't realize the welds poked out so far), hoping to at least get it mounted and the batteries mounted so I can attempt to take a short test ride

nwmtnbkr

toyotaboy,

Nice job. Please keep posting photos of your new ride. It must be looking good.

Jaydevil

toyota boy I also have that same kit, just 1000W. I just wanted to ask is how did you wire up your motor wires? green to green? green to red? green to yello and so on so forth. Also, did you charge your batts with a 48v charger? And what color does the throttle light up too when everythings connected? Thanks for the help in advance.

toyotaboy

@jaydevil: There's a lot of wires.. There's like 3 tube connectors (yellow, green, blue), and then there's like 2 molex-like connectors (power and motor). The kit seemed pretty obvious (cept there's like an extra yellow or green connector), and then there's two left-over connectors that I assume the brakes hook up to, but they don't seem to do anything (I know it's not for regenerative braking). This is the same kit I have:
https://cgi.ebay.com/NEW-Electric-bic...item3355c66a85

I precharged the batteries with a 12v charger before I wired them together (though my company is working on 48v chargers, so that won't be an issue soon). I believe all the blue LED's on top light up, and the lights on the throttle all light up. Keep in mind that you HAVE to have the key at least turned once (accessory?), not necessarily the headlights on, but if you don't have the key in, it cuts off power.

toyotaboy

Bike is finished
Empty rack:


Rack side profile:


Assembled (wires not as neat as I'd liked, batteries mounted with zip-ties)


Close-up of battery/controller:


Video of my co-worker doing a test-run for me:
https://www.youtube.com/watch?v=w_IxCuFIVjE

I must say I'm slightly dissapointed. I was whole-heartily expecting a little more oomph from a motor this size. In fact for equivalent weight, had I used a motor/chain/sprocket, I could have 2000-7000watts, so I'm thinking hub motors aren't so efficient (though convenient and easy to install). I'll probably have fun riding it around for a while, but I think now that I've gotten a taste, I want to build an electric trike with some fairings.

Jaydevil

Ok I have a problem. I have that same battery setup as you toyota. Only difference is when I power the system and look at my throttle light indicator the "POWER" lights up red and stays constant but the "EMPTY" lights up yellow and blinks off and on, sort of like a blinker. Does this mean my batteries arent fully charged? Too low voltage? Faulty throttle? Also the "FULL" light has never comes on. I really hope its just Low Voltage Cutoff.

toyotaboy

@jaydevil: I would connect a volt meter to your battery pack (if you don't have one, get one, they are cheap). Does your system also have a light and a key?

Jaydevil

Yes, my system has the light and key, but its a grey one. If it matters, the horn doesn't work and when I power the system and look very very closely at the small LEDS on the top of the headlight unit surrounding the batt meter I can see one of those LEDS glowing a faint glow. Its like its getting power but very little. No I dont have a volt meter but I will try and get one.

toyotaboy

@jaydevil: yea if your getting one LED faintly glowing, then you have very low voltage. Could be bad batteries, could be a bad connection at one of the terminals, only way to find out is a volt-meter at each lead to see if your getting 48 volts. I think even radio shack should have a basic analog meter for around $10.

Jaydevil

I just ordered one online. Will give you the results in about 4 days. Till then...thanks.

crimsonsnake0

hi i have a similar kit but mine is 1000watt motor. i tried 10ah batts and found bike very slugish and only got about 5 miles distance. i changed to 4x 20ah batts quite heavy but the change in performance is very noticable. i now get at least 22 miles distance thats with throttle all the time and bike has more pulling power. somthing to think about ? cheers rob.

toyotaboy

@crimsonsnake: u have a good point, I assumed agm cells could deliver full output, but if it's only 1c that would mean 9amp output at best, which at 48v is barely 500 watts. I will have to check the specs, perhaps I'll invest $300-$400 on a lithium phosphate pack

toyotaboy

Ok after some digging, AGM is very similiar to lead acid, so it's not the batteries (they typically have 200 cranking amps, and 20-30 amp continous draw).

I stuck an ammeter on the battery wire to see what draw was during full throttle (granted there was no load since it was up in the air), but it was very low. I got about 2-2.5amps, which is way lower than it's supposed to be rated at (48v @800watts implies 16amp draw). One thing I noticed is that there is only 18awg wire coming out of the motor leads, which can only carry about 2amps.. So either the wires get hot, or the controller drops down the voltage and is not putting out what it's speced at.

So here's my logic, I am going to replace the wires with 12AWG wire (just fits if I don't include a jacket):


Then I'm going to try hooking up the batteries directly up to the motor to see if there's a speed difference (starting out at 12v, then 24, 36v, 48v). If there's a noticeable difference, I've convinced my co-worker to build me a custom PWM controller for cheap. I've heard crystaline controllers can handle 48v@20amps, but I can't even find a place that sells them, or pricing?

JinbaIttai

That rack looks completely awesome! I wish I had those kinds of fab skills.



You're right that chain driven motors are considerably more efficient and can go faster using less power.
AGM batteries behave like other lead acid batteries. Both are susceptible to Peukert's Law

But 200 cold cranking amps or not, that voltage is sagging under load because it's a lead acid battery. A 48 volt lithium-iron-phosphate battery is really more like 53 volts under load (59 off the charger) giving a higher top speed. It has a very flat discharge curve which gives like double the capacity. An example is while riding at top speed, 9ah of lead acid will get you 5 miles, but 9ah of lithium will get you 11 miles.

toyotaboy

@jinbaittai: lithium packs are also 1/2 to 1/3 the weight of AGM, but also 3 times the price. Still, I think I still want to tinker and get the motor running faster as it is, then any battery upgrade is just icing on the cake.

toyotaboy

I tried swapping out the 20awg wires for 14awg, didn't make a lick of difference as I figured. I forget that because it's pulsing (3 sections of transformers), it's actually 2amps x 3, but only one section at a time. I think I'm going to start over with a separate mounted motor and use a chain system so I can use the gearing.

BroadwayJoe

Those Chinese (Golden?) hub motors are pretty lame and remember that the controller will limit oomph as much as wire size. If you want a hill climbing hub motor you need to use a Crystalyte Phoenix Brute. 48V should climb most reasonable hills.

Yes, going with gearing setup is attractive but also has it's limitations. Some folks have converted Golden Eagle belt and/or Staton chain - gasoline setups to electric with good results. Chains can be noisy and belts might not like the torque of electric motors.

I've got years commuting experience with eBikes and eScooters and the Phoenix motors are probably the best way to go IMO. I don't work for any company - simply a guy trying to get back/forth to work without lining the pockets in the Middle East.