Help Building Basic Nice Looking eBike

[Pingmustard]

Hi all, I've been reading through the site, and have decided to jump on the ebike band wagon. I've seen some awesome work on this site, and hope to someday showcase some of my own. For now, I just have some newbie questions...

I have a 7 speed cruiser that is attached to a trailer to haul my 2 little ones around. We have some hills around the trail I ride, and I do enjoy the extra exercise, but when I'm tired, I'd like to be able to get some extra motored help. The kids are just toddlers -- 25lb / each is safe number. Myself I'm about 175lb.

The solution I'm looking for doesn't need to be fast (15-20mph is perfectly fine with me). However, I would like to minimize maintenance -- I usually only ride weekends, and sometimes as few as ~1 / month. I think I've settled on what seems reasonable, but I'd like to hear if anyone has suggestion to reduce potential stumbling blocks.


Parts thus far (from bmsbattery.com):

36V10Ah LiFePO4 Alloy 03-CASE EBike Battery With a Carrier Rack
AC Voltage : 90V~132V, Rack Color : Black
http://www.bmsbattery.com/36v/465-24v-lithium-ion-little-frog-abs-shell-ebike-battery-pack.html

2x HWBS - Hidden Wire Brake Sensor 1pcs
http://www.bmsbattery.com/459-hwbs-hidden-wire-brake-sensor.html

Q100 36V250W-350W Front E-Bike Kit with LED Meter
RPM : 201
http://www.bmsbattery.com/ebike-kits/420-250w350w-q-85100sx-motor-e-bike-kit.html

A Pair of EBike Torque Arm
Size : M12



My question is:

1. Do I need to get any connectors in order to hook the battery to the controller? If so, specifics/linkes?
2. Are the wire brake sensor worth it?
3. Do anyone know how this battery pack would compare against the Headway version here:

http://www.bmsbattery.com/packs/114-36v10ah-lifepo4-battery-38120-ebike-battery-pack-with-carrier.html

The headway doesn't mention anything about max "continuous" discharge current, nor do either talk about C rating. Neither does the LifePo4 linked above. However I would imagine the LifePo4 mentions a 15A continous discharge, so I'd assume it's 1.5C (considering it's 10Ah)?


Thanks for help!

 

[JimmieD]

Hey Pingmustard,

Welcome to the boards! For what my two cents is worth, I am not too familiar with the first battery that you listed with the alloy case in a rack, but as far as the Headway battery in a rack, that one has been known in the past to cause some headaches with the BMS/PCM that is used, not sure if this has improved much in the past 2 years, but I am sure it has, just not positive. The cells on the other hand are great, just that the PCM/BMS may need to be changed out sooner than expected! As far as the cells go, here is a test that I did last year (need to update to a more recent test!) for the Headway cells for a discharge graph to see current draw along with amount of voltage sag. Cells may be able to handle high discharge currents, but your limitations would be with the allowable current output of the PCM/BMS.

Best of luck to you in your search for a good first-timer ebike and again, welcome to the boards!

 

[Drunkskunk]

Welcome to the forum. You have described a good basic setup for hauling your self on flat ground and very light hills at sub-20mph speeds , however it's too light weight for hauling anything or taking on hills, and much too lightweight to do both at once. The Cute motor is a good motor, but its... well its just a cute little motor. You are going to need something in the 500 watt geared range to take on a trailer and a moderate hill.

What I would recomend is a MAC motor. http://www.emissions-free.com/catalog/i22.html That bigger motor would need a more capable battery. the headway pack you listed second would be the very bare minimum needed. and the BMS may need an upgrade.

In general, BMSbattery.com is to be avoided unless you like to gamble. they do sell some good motors and batteries. but they also sell some junk, and they have a history of not always sending what you order and poor customer service. If you can tinker and want to gamble, they're a good source for some good but tiny motors.

 

[Chalo]

You'll want to use a geared motor if you ever intend to ride unpowered. That one looks like a geared motor, and the comment says it's a little loud (which is another indication of gears), but you might want to make sure before you buy.

Almost all hub motors for bicycles use axles that are 10mm across flats. The 12mm axle version I have seen is for larger scooter-type motors. Whatever motor you get, make sure the slots in the torque arm or arms have a snug fit to the axle.

Chalo

 

[Pingmustard]

Hey Pingmustard,

Welcome to the boards! For what my two cents is worth, I am not too familiar with the first battery that you listed with the alloy case in a rack, but as far as the Headway battery in a rack, that one has been known in the past to cause some headaches with the BMS/PCM that is used, not sure if this has improved much in the past 2 years, but I am sure it has, just not positive. The cells on the other hand are great, just that the PCM/BMS may need to be changed out sooner than expected! As far as the cells go, here is a test that I did last year (need to update to a more recent test!) for the Headway cells for a discharge graph to see current draw along with amount of voltage sag. Cells may be able to handle high discharge currents, but your limitations would be with the allowable current output of the PCM/BMS.

Best of luck to you in your search for a good first-timer ebike and again, welcome to the boards!

JimmieD, thanks for the response, but you lost me with all that information and fancy graph Do you have recommendation on a battery pack that is works "for dummies" (connectors, case,... instructions)? I don't need a battery that will run long (high Ah), but maybe one that could support a more powerful hub if I need to upgrade later.

Thanks!

 

[Pingmustard]

Welcome to the forum. You have described a good basic setup for hauling your self on flat ground and very light hills at sub-20mph speeds , however it's too light weight for hauling anything or taking on hills, and much too lightweight to do both at once. The Cute motor is a good motor, but its... well its just a cute little motor. You are going to need something in the 500 watt geared range to take on a trailer and a moderate hill.

What I would recomend is a MAC motor. http://www.emissions-free.com/catalog/i22.html That bigger motor would need a more capable battery. the headway pack you listed second would be the very bare minimum needed. and the BMS may need an upgrade.

In general, BMSbattery.com is to be avoided unless you like to gamble. they do sell some good motors and batteries. but they also sell some junk, and they have a history of not always sending what you order and poor customer service. If you can tinker and want to gamble, they're a good source for some good but tiny motors.

Could you recommend a complete kit with battery? I was browsing the site, and a key point I'm trying to figure out is enclosure/connector for the battery to the controller. I'm ok with the battery on the rear with a decent aluminum enclosures. Unfortunately, the emissions-free site doesn't have a whole lot of useful information/pictures of complete setups.

Thanks!

 

[wesnewell]

First thing you need to do is go to the User Control Panel, select Profile, and then enter your city, state/province, and country into the Location field. This will help people help you. If you don't care about getting help, then you may disregard this post. Example: Wylie, TX, USA.
Personally I think all your choices are too weak. Secondly, I'd never use a front hub motor, especially if I were going to be hauling children around. Too many case of front mounted failures. And when the front wheel comes off, you and your kids are screwed. And have you checked the cost of your selections with shipping charges? BMSbattery is known for really high shipping charges. If you can find a dealer in your country it should be cheaper.

 

[JimmieD]

JimmieD, thanks for the response, but you lost me with all that information and fancy graph Do you have recommendation on a battery pack that is works "for dummies" (connectors, case,... instructions)? I don't need a battery that will run long (high Ah), but maybe one that could support a more powerful hub if I need to upgrade later.

Thanks!

Hey Pingmustard,

I am so sorry about the insta-information and graphs, but when you mentioned 'C' rating, (and you were correct in your guess of the 'C' rating!) I thought you knew a bit more than you admittedly do, so thanks for letting me know and I'll try and explain a bit better.

A quick run down of a battery. The battery is an important part of your set-up, so getting a quality battery is important. Try not to save a buck by going super...er frugal (nicest way of putting it) because you do not want your first experience with an eBike to be full of headaches, especially while using it to tote the kids around! There are a couple of parts to a basic battery that you should be aware of, the cells (more than one cell together makes a battery), and the PCM or as they are more commonly referred to 'BMS' (Protection Circuit Module or Battery Management System) which typically have 5 major functions for battery and cell protection: over charge protection, over discharge protection, over current protection, short circuit protection and balancing of the individual cells making up the battery. When you had mentioned 15A continuous, this number may well be from the capabilities of the PCM/BMS. The cells/battery may be able to go higher than 15A, but the PCM/BMS limits the output to 15A.

You may not think that you need one that will run long (high Ah), but in addition to 'running long', higher Ah also allow for greater power (watt output) if an upgrade is later used. It also puts less stress on the individual cells since you are lowering the 'C' rate when you increase the Ah or capacity ('gas tank size') of the battery. So there is advantages to getting a battery with high Ah, but with the advantages, there is also more cost.

Hope I haven't lost you again!

As far as recommendations....I'll send you a PM :wink:

Also here is a link to another post you may be interested in http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=38457