New ebike build

[jebike]

Hi,

I'm new to the forum and to e-bikes. I was hoping to get some info on the build I'm putting together. I just purchased a battery off eBay from Vpower. The specs are listed below. I am thinking of pairing this with a 36v 500w or 800w front wheel kit from yescomusa.

I'm new to this type of battery tech and was curious how safe the lifepo4 batteries are? Im also trying to understand BMS, is that generally the charger that comes with the battery or purchased separately? Would anyone be able to give me a ballpark on what type of range and speed this setup would produce or if there is something better in the $250 price range? Thanks

Hi-Power Third generation Lithium-ion Battery Green power Renewable Energy 36V 20AH
Size： 290mm*210mm*100mm
Voltage: 36 Volts
Maximum discharge current: 40A
Capacity: 20 Amp Hours
Life Cycle: >500 times
Weight: 7.5KG
Rated Charging Current: 6 Amp
Rated Discharging Amperage: ≤12 Amps
Charging method: Using the configuration charger

 

[d8veh]

The BMS is a circuit board attached to the battery - normally inside the covering. Its like an automatic electronic switch. It'll switch off power when any cell goes below the minimum voltage, when the temperature goes too high or when you try and draw too much current. It'll also switch off charging when any cell reaches the maximum voltage. Lastly, it balances the cells by bleeding off some charge from the highest voltage cells.

Your battery has a BMS inside the covering.

 

[wesnewell]

Welcome to ES****Do this before your first post or now (it's retroactive)*****
Please go to the User Control Panel, select Profile, and then enter your city, state/province, and country into the Location field (country minimum) and save it. Once done, your location will appear in every post so you won't have people asking where you are ever again. This will help people help you. Example: Wylie, TX, USA. or just USA, but country as a minimum, and country is the most important. There are many cities with the same name all over the world. Without knowing what country you are in it's hard to make any recommendations. Thank you.

The answer to most of your questions will be in the wiki.
http://www.endless-sphere.com/w/index.php/Main_Page
You can check speed and range with the simulator.
http://www.ebikes.ca/tools/simulator.html

 

[dogman dan]

Speed should be in the 23-25 mph ballpark, and at wide open throttle you should go 20-22 miles.

Perhaps a tad less, since that brand of battery is a bit notorious for not putting out the rated AH. But you will have range, at a slower speed, 18mph, 30 miles for sure.

Lifepo4 is supposed to be the safest. The bms will balance the pack every charge. But it must be charged overnight to fully balance the pack.

Charge the pack overnight, then do some very short rides followed by recharge till the light turns green the first day. Charge overnight again, and now you are ready to go for a very long ride.

Your battery is a perfectly sized choice for the 36v kits from Yes.

 

[jebike]

Thanks for the info, much appreciated. After reading more I think I am going to go with a rear wheel set up. Apparently they are supposed to be safer and accelate/climb better.

I have a DMR single speed conversion kit that I would like to put on the hub. Will that work with the hubs that come on the yescom setup or do those not use normal cogs/cassettes?

I was also wondering how pedaling works w the rear drive motors. Can you pedal w the motor going and is there any drag when the motor is not on?

Thanks again for the help

 

[wesnewell]

Max speed on the yescomusa 500W motor I had was ~23-25mph on a 51.8V (14s lipo) battery pack even with a modded controller for ~45A. I ordered the 48V 1000W kit about a week later. It did a little over 30mph and had a lot more power. The extra cost is minimal for the additional speed and power you'll get.

 

[jebike]

The 36v battery would not work w the 48v kit correct? Is there a nicer rear wheel kit for 36v that would preform better? I just got an email on the batt and it is gonna take awhile to get here so I have some more time to save for the wheel kit.

 

[Drunkskunk]

You won't be able to use the DMR cassette kit on the motor. they take a freewheel, which is a different system.

You can pedal along with the motor just fine. it's no different than riding a tandem where two people are supplying power.
There is a little drag on a direct drive motor when the power is off. Some people notice it, some don't. For most it's about like riding with knobby tires when you're used to slicks, but if you twist the throttle just a little, supplying minimum power to the motor, it goes away.

A rear motor doesn't give any more torque or acceleration than a front motor. they are essentially the same motor with different axles. There are some conditions where having a rear motor will let you use more power because of better weight transfer, but you aren't building that kind of bike. At the power levels you are talking about, Front VS rear is mostly a matter of personal taste.

 

[jebike]

Thanks, would a bafang 36v 500w mid drive produce better results? I'm struggling w all the options I'm finding on the forum!

My set up with me on it will probably way no more than 240. Hoping to be able to go just over 20mph and have a 20-30 mile range.

I was watching an install video of the bafang and it looks like you don't need a bottom bracket. Is that correct? I'm guess the answer you provided regarding pedaling is the same w the bafang, you can just pedal along w the motor right? Who would be a good retailer to buy that motor from?

Sorry for so many questions and thanks again.

 

[jebike]

Aright, need some tips on the yescom kit. The fit seems pretty, I'm gonna shave the drop outs and derailleur hang down a bit to get the Axel seated a bit better. I'm running into one other problem though. I have the 3 bolts/washers sitting on the outsit of the frame as directed. The problem is when tightening them down the freewheels smallest cog hits the frame. I was thinking of putting a washer on each side, but can't fit one over the drive side cabling. Any tips?

 

[jebike]

Pic

 

[jebike]

Don't know if this is okay, but w one of the washers the kit came w on the inside my prob is solved. Any reason this way would cause a problem?

 

[Ykick]

In order to change axle hardware you need to learn how to disassemble connectors.

 

[jebike]

I think I can figure that out if need be. Do u think having the one washer inside is a problem or will put to much pressure on the rear triangle?

 

[Ykick]

As long as nothing rubs an inside washer won't hurt anything.

 

[jebike]

Thanks Ykick, appreciate your help! The wheel seems centered well w a washer inside and outside the dropout and the wheel is spinning freely. That washer I put on the inside instead of outside has a little protruding part. Do you have any idea what its purpose is?

 

[Ykick]

My idea is that it's a safety when tab placed in the open portion of the dropout. It might help, might not?

 

[wesnewell]

Don't know if this is okay, but w one of the washers the kit came w on the inside my prob is solved. Any reason this way would cause a problem?

Washers were placed wrong on the axle. You need to remove them and get them right. The one with the lip should fit in the dropout. Either as the inside washer facing outward or an outside washer facing inward. You'll have to remove the hall connector, which is very easy to do with a small jewelers flat screwdriver. Once it's off, you can slide the washer off the cable and arrange how you want them. Here's how the lipped washer should fit.

How to remove pins from hall connector.
http://www.youtube.com/watch?v=LjF8g9H0Zo4

 

[jebike]

Thanks for the pic and video. I flipped it around. My bike has vertical dropouts so not sure if those will do to much. They sit pretty far away from the frame.

I decided to give it a go making my own torque arm. Looks a little ghetto, think this will be sufficient?

 

[Drunkskunk]

Sadly, No. I can see that the axle flats aren't lined up with the slot in that piece of metal. in order to work, the torque arm needs fit snug against them. It also looks to be a rather thin piece of mild steel. That axle is capable of applying many thousands of pounds pressure at the edge of the flat, and will eat through that like Cookie Monster on a bad of ChipsAhoy.

 

[jebike]

Alright, I think this will do the job. Thanks for helping.

 

[Ykick]

Last attempt seems plenty good enough. I look at torque arms like bullet proof vests - you only need one if you get shot. Keeping the axle nuts tight will do more to prevent spin-outs than anything. But, TA's are a last line of defense if/when axle nuts loosen up.

I don't know if you're gonna do regen braking but if you do keeping axle nuts tight is very difficult. Should you go down the strong regen road you need to work out the clamping style TA's and that introduces another layer of complications. Potentially twisting axles in half...

 

[jebike]

Almost got it together. Just need the battery to arrive now. Hoping to put a larger front wheel/disc brake on when money allows.

I was also wondering about the electric brakes. I bought some switches off GBK to use with my standard levers. Will I need to mess with any wiring on those or will they just plug into the controller where the normal brakes go?

 

[jebike]

Was wondering if someone could help w another question. I bought a brake sensor to use instead of the ones that came w the yescom kit. Wanted to be able to use my own brake levers. Anyhow the controller has a different connection for the brakes than what came w the after market sensor. If anyone can give me some tips on hooking the sensor up to the controller it would be much appreciated.

 

[jebike]

Here's another pic