New Member, Advice Guidance on first e-bike build, Chinese kit...

mikeyuf

New Member
So I received a birthday present for a ebike conversion kit, https://www.amazon.com/Aosom-Electr...=1476463715&sr=8-1&keywords=electric+bike+kit

I have very little/no experience with bike mechanics or electrical work. I am hoping to tackle the project slowly and simply because I enjoy learning new things.

So, my plan is to use my old beach cruiser as a donor bike. It is a cheap Schwinn Jaguar bike from a big box store. I think I found a link to it, http://ratrodbikes.com/forum/index....-schwinn-jaguar-build-badly-chronicled.93036/

The kit itself came with the motor wheel, all assembled, the controller, throttle, 2 hand brakes, hand grips. It also came with a battery bag, and a rack. The rack came with no mounting hardware so I plan on buying a better one.

I decided to go with SLA battery pack that I will assemble due to being new and not wanting to double my budget. This doesn't seem too difficult, I figured I would do 4 batteries in a series, similiar to what this guy did,

The batteries I went with are this model: 2x https://www.amazon.com/gp/product/B007QW7T2M/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
I will also need to buy a 48v battery charger I assume.

The scariest part is the fact that the instructions are so darn poorly written and vague, I hope I can figure it out. If not I may try to call some bike shops in the area. Take a look, https://images-na.ssl-images-amazon.com/images/I/915KesWjD-S.pdf .

I think the hardest part will be the connections and wiring the bike.

I am just looking for tips and any advice you could give a new builder. Any tools you think I will need? Does anyone know any good guides or articles regarding building out one of these kits?

I will post plenty of pictures as I go. Thanks ahead of time!
 

MLB

Well-Known Member
Hey Mikey,
Good luck! It's not that complicated. Buy a soldering iron if you don't have one and practice a little before you work on the bike connections. A good connection with shrink wrap over it means not having to worry about it failing at some point like all clips seem to do.
 

harryS

Well-Known Member
It's not hard, but a couple of cautions. That's a big motor. Lots of power. It can easily spin the rear nuts loose on the axle. Although the axle is machined with a straight sides to sit tight in the bike frame w/o turning, the motor will tear the sides out if it is loose, twist up the power cord, and be ruined. Keep those nuts tight, and consider buying some torque arms which are just reinforced plates to keep the axle from spinning loose.

If this were a front wheel kit, torque arms would be almost required. It's a lot easier to spin the wheel out of the front fork and then crash. People have done that.

Those SLA batteries are heavy. Probably wobble on any rack. Maybe they are better mounted on pannier baskets to get the weight lower.

I consider those instructions pretty good, by the way. Actually, they're the same as what I got on my first bike kit, although it was made by a different company. I guess they just pirate these things.

Did you get an LED control or is it an LCD? The PAS sensor is not easy to install. You need tools to remove the pedal and crank. They are not expensive. I really wonder if anyone ever was successful using glue like it says in the instructions. I like PAS, pedal assist, so I've always put it on. and had to use clamps and brackets, not glue.
 

mikeyuf

New Member
Thanks for all the replys,

Soldering iron is on the list, harbor freight has a cheap one, like 4 bucks :) I have been youtubing soldering videos and it doesn't look to complicated, I will definately practice before "going for it". I will also shrink rap, thanks for the tips!

I guess with the pannier basket, I would have to divide the batteries up in two right? Probably need to get creative.

I have an LED I think, just 3 lights on it, not like a screen, battery FULL, MEDIUM, LOW, it also has a thumb accelerator.

I watched a video of crank removal, definately used a special tool, maybe I will get a bike shop to do that bit :)

dm nelson, that is an awesome link, thanks so much!
 

Ann M.

Well-Known Member
Spend a little more than $4, @mikeyuf and get a decent soldering iron that can heat to higher temps than what you'll find at Harbour Freight. Sears, Amazon and your local electronic shops, like Frys, etc. will have a more reliable product that you can control better. @George S. should have some good suggestions for this tool; he's very knowledgeable about electronics :)

And definitely torque arms; consider 2 made by Grin Technologies, Ebikes.ca. They have several options of size & shape and are built with the best materials. Cheap insurance to prevent motor wires from spinning loose & ripping.
 

George S.

Well-Known Member
Those batteries are OK. I've used several of them. It used to be an off brand, but now it is just a fairly low cost sealed battery. But you can't push these batteries very hard if you want them to last. Trying to get 1000 watts, the motor rating, is not a good idea and it probably isn't going to happen. The voltage will sag, a lot, especially if the battery is not fresh off the charger. I think I've used 4 of these batteries, and at least one of them was weak. If one of them is weak, it will bring down the 4 in series. Lead acid batteries are rated by discharge rates in hours, like a 20 hour rate. You will be drawing 10x that rate, so the capacity is pretty low.

The other problem is that you have a rear motor and then 40 pounds of battery on the back of a cruiser, which tends to be a little back heavy. You just want to be careful and get to know the bike. You don't want bad tires.

You'll help protect the batteries by pedaling as much as you can. You might get some months out of the pack, if you don't push it too hard. You might want to buy a better battery pack, at that point, but you can have some fun with what you have.

The Harbor Freight soldering iron is OK. I have one in the tool box for my camper. It's OK for connectors and fairly light stuff. You can get some XT60 connectors, which are reasonable to solder and heat shrink.

With an upgraded battery pack, you could probably run that motor at 1000 watts. That would get your speed into the 20's. I would take a very long look at the bike before going that fast for very long. It's not really what the bike was designed to do. Brakes are a real week point. What people have said about motors spinning out is true. Take a magnet and see if the frame is steel, which is stronger.

For the bike you have, a 350 watt motor would be a safer choice. You don't need to push things, and you want to protect your battery.
 

Thomas Jaszewski

Well-Known Member
And definitely torque arms; consider 2 made by Grin Technologies, Ebikes.ca. They have several options of size & shape and are built with the best materials. Cheap insurance to prevent motor wires from spinning loose & ripping.
I've stubbornly refused to help anyone in my shop that won't invest in quality torque arms. Grin are simply the most solid unless you go to something custom made. Ann is spot on. I keep a couple currently 4 in my parts box for when someones cheap stamped metal arms fail. And they do. Amped cycles had a design that was pretty cool but it seems to have gone away. I have an aluminum fork with two Grin ams and it's now got a couple thousand miles. It makes me nervous but the owner is happy and so far so good, BUT it's only pulling 20A 750W motor. I'd call 500W my safe spot for a alloy fork and two torque arms. I like getting older. I'm so over the speed thing.

I've done a bunch of work with a $15 solder iron from Amazon and it came with a few tips too.