Mountain bike conversion using "ebike-emsbattery.com" parts

[edblanch]

I have recently completed the conversion of a Schwimm front sprung 24 speed mountain bike to an electric powered bike.

The new mountain bike I bought was from a local store ready for the conversion it had only front suspension and rim brakes because I was unsure how I was going to complete the conversion. I paid A$350 for the bike.

Next I after looking at many posts on this forum I decided I would need a 1000W geared hub drive to give me enough torque to get up the steep hills, about 15 per cent slope, around the hilly part of Tasmania where I live.

Again searching across the net especially "Alibaba.com" I came across the Chinese seller "ebike-emsbattery.com".

On their website store they had a 1000W 48V Rear Hub Motor for US$179.00 plus US$9.80 for the 26 inch rim and US$7.80 for the spokes plus US$7.80 to mount the rim on the hub and US$5.00 for a free wheeling hub.

Having decided on the motor I then decided on their 48V 10AH LiFePO4 Aluminum Alloy Shell Battery Pack For E-Bike US$292.47 plus US$35.00 for the controller, US$5.00 for the twist grip throttle, US$24.68 for a 2A charger and plus US$20 for a rear rack for the battery.

The specs for the battery pack and controller are:-

1. Nominal voltage:51.2Volts.
2. Rated capacity @ C/3 20 ℃:10Ah
3. Lifecycle: 2000Cycles.
4. Dimension: 69mmX148mmX360mm(15Amp BMS),69mmX148mmX370mm(25Amps)
5. Operating temperature:- 20 ℃ to 60 ℃
6.Charge temperature: 0 ℃ to 45 ℃
7. Storage temperature: -20 ℃ to 45 ℃
8. Operating humidity:5% to 90%

BMS Specification:
1. Operating current: 15A(or 25A)
2. Peak current: 50A
3. Charge current:15A
4. Over-voltage protection:3.9 V
5. Under-voltage protection:2.0 V
6. Cell balancing function:Yes
7. Output port+ / P-
8. Charge port:C+ / C-

Charger Specification:
1. Input: 110 or 220V AC(your country's standard)
2. Output:58.4V DC 2A

To keep an eye on the power consumption I bought their "Watt-up" power analyser for US$25.50.

As I was eager to to complete the conversion ASAP I paid US$198.00 for express air freight.

I had placed my order through their sales person Jenny Hong via e-mail.
Jenny then e-mailed me an invoice offering two methods of payment either direct electronic funds transfer or Paypal with a surcharge.

I decided to use electronic funds transfer which worked fine but there was an additional US$25.00 fee I had not taken into account so the amount deposited into their bank account was US$25.00 short so I had to amend my order taking out the free wheeling hub and going for a 2A rather than 4A charger.

Once my order was squared up with deposited funds the goods were dispatched very quickly and arrived here in Tasmania Australia super speedily in four days!

The packaging was adequate with a little damage to bike rack which had the battery mounted in it.
The assembly instructions were brief but self explanatory as the plugs/sockets for the various connectors were unique.

The only bike part I had to source locally was a free wheeling hub for the new wheel with the hub motor. This cost me A$40.00 fitted!
I also fabricated a torque arm for the new rear wheel

Myself and a friend mounted up the new rear wheel and rack in half a day and did the wiring in about the same time.

I started with the battery mounted in the rack but found that the bike was very back heavy and unstable on the steep slopes I was riding up so I mounted the battery pack in the middle of the frame as you can see in the photo.

I have been using the bike most weekends for the last six months going for about 20km on hilly terrain using about 5AH worth of power out of the battery.

The bike has proved to be just what I wanted to keep me and the dog exercised!

 

[motomech]

I had browsed their website before, but as far as I know, you are the first to purchase from them. Glad it went off without a hitch.
Do you know if the motor is a Direct Drive type? It looks like an Atomea, a motor that is only available here in the States as a front mount.
If it is a genuine Atomea, that is a great price.

 

[dnmun]

the 48V controller has a 41V cutoff LVC for the SLA batteries. your 48V lifepo4 still has a lot of charge remaining at 41V so it is better to use the 36V controller so you can draw the battery down below the 41V level to get maximum charge from storage in the pack. maybe you can adjust the LVC down. there is another thread open now where someone has to lower their LVC for a 36V battery and a 48V controller.

nice bike build.

 

[edblanch]

Motomech,

My understanding is that the motor has a 5:1 reduction from the motor to the wheel hence it has a high torque output.

Dnmun,

I'm not sure quite where you are coming from in suggesting I use a 36V controller as the motor is a 48V unit. Please explain more to a novice.

 

[dnmun]

the controllers for the bike motors are made to be used with SLA batteries. that is why they go in 12V units from 24V-72V.

a 12V lead acid cell can not be discharged below 10V without being permanently damaged.

the Low Voltage Cutoff LVC is built into the controller electronics and will stop the operation of the controller when the total voltage in the 4 SLA packs drops to 41V.

a 48V lifepo4 is made up of 16 cells of lifepo4 in series, 16S.

these cells charge up to 3.65V each so the total 16S is 58.4V when fully charged.

they discharge down to 2.1V before they are totally discharged.

so 16S of discharged lifepo4 is around 34V, so if your controller shuts off at 41V then that charge remaining in the pack is not useable and you do not get the full capacity of the pack to use.

so it is better to use a 36V controller with a 31V LVC (for 3 SLA) so that the controller does not shut off before all the capacity of the 48V lifepo4 pack is consumed. this will add about 10%-15% capacity for use by the motor. this is worst case situation since you don't to actually discharge your pack that low, but it allows you to do so if you need to. the pack will get more unbalanced when discharged totally too.

the internal components are the same in a 36V controller as in a 48V controller, except the LVC is different. 31V vs 41V.

 

[appyarry]

I have recently completed the conversion of a Schwimm front sprung 24 speed mountain bike to an electric powered bike.

How's this going ed, I'm interested to see how it's settled down.

Thanks,

 

[wesnewell]

the 48V controller has a 41V cutoff LVC for the SLA batteries. your 48V lifepo4 still has a lot of charge remaining at 41V so it is better to use the 36V controller so you can draw the battery down below the 41V level to get maximum charge from storage in the pack. maybe you can adjust the LVC down. there is another thread open now where someone has to lower their LVC for a 36V battery and a 48V controller.

This sounds totally wrong to me. 36V controllers LVC is normally 30-31V. That would discharge a 48V lifepo4 pack (16s) down to 1.875V per cell. Recommended max discharge is 2.5V per cell with damage occurring below 2.0V per cell. So I'd want an lvc of 40-42V using a 16s lifepo4 pack to keep cell voltage around 2.5V.

 

[edblanch]

appyyarry,

I have not used the bike for a couple of months as I have had a total knee replacement done.

I am working hard on my exercise bike in the house so I can get back on my mountain bike.

I will let you know how I go.

Yours, Ed