I'm new here, and I'm trying to decide on my first bike.

[ultralight001]

Hm.
I accidentaly charged one pack to 45v. They charge quickly.
It's been completely fine.
But I'm not doing that again.

On another note, I'm starting to hate xt60 connectors... They're really tough to solder even 16ga wire into. Whats a good connector for my pack and charger?

 

[nutnspecial]

If they're actually charged to 4.5v /cell you should get them discharged strait away man!

I use 5.5 mm bullets because that's what hobby king lipo comes with. For soldering large stuff look up 'torch soldering' on utube. It works good for bullets, tho still tricky.

 

[ultralight001]

If they're actually charged to 4.5v /cell you should get them discharged strait away man!

I use 5.5 mm bullets because that's what hobby king lipo comes with. For soldering large stuff look up 'torch soldering' on utube. It works good for bullets, tho still tricky.

Ok, I'll take care of that.
XT60 connectors should be fine. My soldering iron just wasn't working well. I found some smaller solder and another iron. It's only 30 watts though... looks like i need to invest in tools for yet another hobby. But this one should last.

I'll be ordering a kit next monday (paycheck). I have to decide if I should put the kit on my mountain bike, or buy a cheap mountain bike that I can sell. Because I want to keep my current bike.
I feel like, if retail 36v 500w bikes go for $1900, I could make a small profit on a cheap bike with a good kit and battery (Say $66 for 10ah battery, $150 for wheel kit, and $120 for bike, sell it for $600-$800 and... maybe use that to buy a 72v wheel kit.)

I built my first pack, a 10ah one. I'm not proud of my soldering jobs though. I'll order some parallel connectors of ebay for safety on the next pack. I wrapped it in duct tape. I need to order some shrink wrap to make it look better and less like a bomb...

 

[dogman dan]

I hate to be so negative, but you just primed your battery to do this to your house.

That's my house.

Keep those suckers outside from now on!!! You did ruin them.

 

[ultralight001]

Ouch, dog man. That was a loss. In sure the whole forum felt pretty bad for you on that...
Oddly enough it discharged itself to 42v overnight.

 

[markz]

If I were you I'd discharge them to storage voltage, and leave them there for a bit, then baby sit them to 41.5V or 4.15V if you can set that parameter. You literally gotta baby sit them until everything is kosher. My LiPo's did their fireworks show, but I babysat them. I drained them into the discharge valley without a LVC on the controller, then thought I was being cautious in charging them at a very low C-rate. Once I started hearing a pop here and a pop there, I put them outside. Neighbors called the fire trucks.

You need to be careful with batteries, no matter if they are in a ziplock bag aka pouch or in a metal can. You need to know what you are doing.

 

[ultralight001]

The batteries are taken care of and are all between 41 and 41.5 volts.

I'm beginning to realize that I could just take packs like these apart and solder together pre-welded packs without a spot welder to build my own pack... right? RIGHT?! And of course with a new bms.
If i wanted to build a 72v pack that would save me the trouble of charging 4-8 36v packs separately every so often.
Also, good news. I talked to someone at my church (kingdom hall) and they have a 48v kit they'd like to give me. It was a mom and son with a cargo bike, and they'd ride around on it. It didn't have enough power for both of them going up hills (of course). They upgraded to a mid drive and have all of the electronics and the wheel sitting in their garage. It should be plenty for a 120lb teenager.

I want to buy a 20-30A 72v controller, somehow figure out the wires (they're all different connectors, like always) and run it at that. So around 1500-2000w I imagine. I don't think it'd overheat if babied slightly.

That's why I'm thinking about 72v packs. These cells are genuine (LG) and it would be much cheaper to build a pack (around $250 for 8 packs and a bms) than buy one. And if I solder the groups together I don't need a spot welder.

Edit:
Possible 72v BMS? http://www.ebay.com/itm/72V-74V-84V-20S-45A-20x-3-6V-3-7V-4-2V-Lithium-ion-Li-ion-Li-Po-Battery-PCB-BMS-/172619655689?hash=item2830eeea09:g:bUgAAOSwd~RZQU9c
Possible 72v controller rated for 1000w? Should be low enough amperage http://www.ebay.com/itm/48-72V-1000W-Electric-Bicycle-E-bike-Scooter-Brushless-DC-Motor-Speed-Controller-/371813859405?hash=item5691d5404d:g:q7sAAOSwA3dYUPnd

 

[dogman dan]

Discharged itself to 42v overnight? And you call that OK?!!!! They have internal shorts now, after going to 45v.

Hope they are f---- outside.

 

[ultralight001]

I returned the overchagred batteries. I took apart the rest and kept the LG cells for the future. I may sell them.
I got a good deal on a chinese lifepo4 pack (won it for $197 on an auction). 48v 15Ah. It came and of course it's a 16s, so it's a 52v pack that charges to 58v. I've read that these are good packs but the chargers are crap. I'll be replacing that ASAP.
View attachment 1
This is my bike:
Its a craigslist wide-tire mountain bike. $40. Steel frame, walmart shock, upgraded seat, rim, pedals, and handlebars.
The kit was from a friend who recently upgraded her cargo ebike to a mid drive. It has a shengyi 48v 500w motor, contoller, lcd display, throttle, and brakes.

I got my battery, tested the voltage, and it was at 58v, so I assumed it was charged enough for a test. I twisted the wires together from the controller (the thickest ones that are obviously not for anything else)...
And...
Nothing.
I don't see an on-off switch, I played with the display, throttle, brakes, and checked and rechecked all of the wire connections. Either twising the wires together is not a stable enough connection, or this kit sensed that it was a 58v and won't accept it. There is no pedal assist hookup, I think it was cut off. I don't need PAS anyway. I tried the kill switch on the throttle too.

I want to use this battery. Maybe this controller won't accept it? It's a 48v peak 19a controller much similar to this one: https://lunacycle.com/replacement-controller-for-hub-motors/
I'm thinking maybe I could replace the controller? The hard part would be wiring. I'd have to cut the color-coded connectors off and figure things out myself.

For now I'll be charging the battery to make sure it's fully charged and balanced, soldering on connectors, and trying to figure out what is going on.

Help?

 

[nutnspecial]

A 48v should be fine up to at least 60v iirc. What I'd do when there are no obvious on/off switches missed on battery, controller, or controls: Apply battery to controller. Test other wires for pack voltage. That one wire will have a mate which needs to see pack voltage too. This will help identify the ignition switch wires and rule out if there's a problem with them or the switch.
All else fails, ask the person who the kit belonged to. It should be simple since they just removed the (assumed) working kit.


I don't follow much battery stuff 'cept lipo, but that sounds like a good deal on the lifepo. The bike looks cool too, you'll be having some fun brother!

 

[ultralight001]

A 48v should be fine up to at least 60v iirc. What I'd do when there are no obvious on/off switches missed on battery, controller, or controls: Apply battery to controller. Test other wires for pack voltage. That one wire will have a mate which needs to see pack voltage too. This will help identify the ignition switch wires and rule out if there's a problem with them or the switch.
All else fails, ask the person who the kit belonged to. It should be simple since they just removed the (assumed) working kit.


I don't follow much battery stuff 'cept lipo, but that sounds like a good deal on the lifepo. The bike looks cool too, you'll be having some fun brother!

Well I did something amazing.
I found the On/Off switch.
I got to ride the bike today, then something interesting happened. The phase wires got wrapped around the axle and sheared. I think this bicycle is meant for 3" rims. I couldn't pedal it and alignment kept going off even with the axle well bolted and locked in.

Now this motor won't work. The wires are sheared very close to the axle, and I'd have to pry apart the hub (each side is connected to the spokes) to replace the wires. It seems like a lot of hassle now. An ebay kit is tempting meeee, especially since I just want to get this thing running. I've already got a problem child project dirtbike. Guess I found something new to dump money into.

The battery works great. I just need to get a rack to mount it ( i had tested the bike with it crudeley mounted in the frame ) and maybe a new motor or kit.

 

[markz]

You might as well open it up and fix it and learn something.
They are quite easy to fix the wires. Hopefully your halls havent broken.
Just need a soldering iron, some large wire for your phase wires 12 or 14awg, some smaller wire for your hall sensors 22+ guage and some connectors. Bullets work well with phase wires, your halls could just be soldered and taped together. Otherwise some computer molex connectors, just cruise up and down alley ways for electronic shit. Even Value Village Thrift store might have some gadget for $2 in their electronics corner with a connector that would work. If not the The Source, perhaps Home Depot/Lowes/Rona may have something, order online through ebay would be good. If you go with Fast Tech and ship ePacket is comes quickly, not sure what Fast Tech has in terms of connectors.

 

[Chalo]

I got to ride the bike today, then something interesting happened. The phase wires got wrapped around the axle and sheared.

You know how whenever there's a new build thread, there are seasoned members telling n00bs that they need to use torque arms?

Now you know why.

If you inspect the dropouts of your frame, I think you'll find that they're damaged.

 

[ultralight001]

You might as well open it up and fix it and learn something.
They are quite easy to fix the wires. Hopefully your halls havent broken.
Just need a soldering iron, some large wire for your phase wires 12 or 14awg, some smaller wire for your hall sensors 22+ guage and some connectors. Bullets work well with phase wires, your halls could just be soldered and taped together. Otherwise some computer molex connectors, just cruise up and down alley ways for electronic shit. Even Value Village Thrift store might have some gadget for $2 in their electronics corner with a connector that would work. If not the The Source, perhaps Home Depot/Lowes/Rona may have something, order online through ebay would be good. If you go with Fast Tech and ship ePacket is comes quickly, not sure what Fast Tech has in terms of connectors.

Thank you. I'll see what I can do.

 

[ultralight001]

I got to ride the bike today, then something interesting happened. The phase wires got wrapped around the axle and sheared.

You know how whenever there's a new build thread, there are seasoned members telling n00bs that they need to use torque arms?

Now you know why.

If you inspect the dropouts of your frame, I think you'll find that they're damaged.

I did not use torque arms.
HOWEVER
The dropouts don't have a scratch.

 

[heavymetalthunder]

As a starter goes 1000w is about as high as you want to go. Also stay with a 48v system. Like dogman dan stated 30 mph is pretty fast given it is still a bicycle. Because you will be traveling at a higher speed I recommend a helmet and daytime/nighttime lights. Depending on the laws in your area a moped might suit you better, electric bikes do have a limited range and one of the biggest cost in the batteries. If you do use a Li-ion battery you will probably have to go to at least a 30AH size battery. to Range is dependent on many factors, how far, how much pedaling you do, type of tires on the bike, and condition of the road, etc. Mopeds do have a advantage as you can always stop by and get some gas.

 

[markz]

30mph is 50kph
When I am on the street, I hardly ever go above 40kph = 25mph on my cruiser ebike. Its all residential roads, downtown there are too many red lights and stop and goes to do that speed.

 

[Chalo]

I did not use torque arms.
HOWEVER
The dropouts don't have a scratch.

Check to see that the slot edges are still parallel and closely fitted to a 10mm axle. The thing need not be scratched to have been pried open and bent.