Tandem 24" Electric Bicycle Conversion

I have now converted my tandem bicycle to an electric tandem bicycle using a new 8Fun 24V 250W motor installed to the front wheel. The new hub motor model # is SWXK24V250W205R and has no engraving on the drive/right side. My 5-year old SWXK24V250W190R has engraving that says 'ZL200320123400.9 The brushles motor for e-bike'.

24" 6-speed Adventurer folding tandem bike manufactured by Intersource Enterprises and sold by Camping World for 269 USD. Converted to an electric bicycle by replacing the front wheel hub and spokes with an SWXK 8Fun motor hub from LEED and 203mm 12g Sapim spokes from Holmes bike. The cable and 30K Samsung battery pack are from LEED. 

The original tandem looks like this

The original handlebar has been replaced with a 620mm 6 degree mountain bike handlebar. A pannier rack and rear mud guard have been added as well.

The original lacing of the front wheel is 3 cross using 36 Sapim 12g spokes and nipples as can be seen here

The original aluminum rim, interior tube, and tires were used and only the 12g Sapim spokes and hub were replaced. I initially used spokes supplied by Clean Republic (203mm 13g spokes of an unknown brand). The 8Fun motor is from LEED although the same can be purchased from Clean Republic for the same price. LEED provides free shipping though. (Update: I just got a word from LEED that they also sell spokes although you will not see this anywhere in their website e-bikerig.com, instead you have to order it by email.)

The 8Fun motor hub is bigger so the only way to re-lace the wheel is by using a 2 cross pattern.

I road tested the re-laced wheel for 6 kilometers to see if the truing will hold and to set the spoke tension to its permanent position. The trail consists of at least three 4% grade climbs and one long 6% grade climb. The total road testing weight of two riders is 250 lbs and the original bike (with the 12g spoked front wheel) has a maximum capacity of 400 lbs. I tested the new 13g spoked wheel in longer rougher rides more than 6 kilometers and steeper grade climbs. Update: the 13g spokes made rattling sounds because they are too small for the wheel and the weight. I had to replace them with higher gauged spokes.

12g Sapim spokes from Holmes Bikes 

I custom ordered a set of 12g Sapim spokes from Holmes Bikes which I used to replace the 13g spokes I initially installed. After doing so, the wheel spokes no longer make rattling sounds like before. They are all tight and strong and the wheel feels smooth to roll.

Lacing the front wheel using 2 cross pattern

Lacing the wheel is a bit different from the DIY instructions that can be found on the Internet. Most of the stuff available are 3 cross instructions. One has no choice but to use this or this. What is not clear in the instructions is where to place the key spoke relative to the air valve hole such that the result will give access to the hole. The usual instruction is to place the key spoke on the top hole to the left of the air valve hole. I did that blindly at first and ended up with the air valve hole without access. Then  I discovered that one has to start on the left/non-drive side with the key spoke placed to the top hole to the left of the air valve hole. Otherwise, if the key spoke is placed on the right/drive side then it has to be placed one rim hole to the right away from the air valve hole and follow the sequence described here since the rim has right hole on the bottom and you can only put the key spoke on the rim top hole.

NOTE: More posts on e-bike conversion projects are available here. 

Recycled bicycle repair stand

Orphan bike frame that has been thrown away can be recycled into a bicycle repair stand as shown below.

NOTE: More posts on e-bike conversion projects are available here. 

Electric Bike Conversion Kit Battery Pack: Overheating Issues

From my own experience with 24v 6.6 Ah lithium-ion battery packs from Clean Republic (the ones that come with their Hill Topper electric bicycle conversion kits) are prone to cutting out or automatically turning off in long climbs.

Users try to overcome the issue by turning the battery pack off then on again. The off-on solution works until the controller inside the battery pack get busted (perhaps the fuse or the protecting wire in the controller burns out upon reaching a maximum temperature). If the controller does not get busted the high temperature sometimes melt the soldering inside the chrome plug connector, cutting out the power supply to the motor. It is difficult to determine if the cutting out of the motor is due to melting of connections inside the chrome plug or burned out controller.

Apparent overheating issues are reported by least 5 people who posted their experience on the net.
1. Angela Medina of Seattle (see Sept 27, 2013 CR Facebook post)
2. Noel Jarvis of Florida (see CR Facebook post)
3. Elrollo (on Clean Republic forum)
4. Rinataga (on Clean Republic forum)
5. cwestergard (on Clean Republic forum)

The cutting out issue is consistent with my own experience with my Clean Republic 10-mile Lithium-ion Sprinter.  I had two of my controllers busted which I had to return to Clean Republic two times. Thanks to them they replaced both but with some delay the first time and promptly the second time. Unfortunately, I spent 125 USD total to get the two replacements: 50 USD for sending back the first one to Clean Republic for inspection and replacement, another 50 USD for sending the second one, and 25 USD for Norway import duties for receiving the second replacement (which Clean Republic sent back as ' 90 USD merchandise' instead of the customary '1 USD gift' customs declaration). I was levied double import taxes because of Clean Republic's erroneous re-export declaration of the repaired Sprinter battery pack as a new merchandise. They should have correctly declared it as 'repaired item resent to customer'. When I alerted Clean Republic about the mis-declaration, I was advised to notify them on how to declare the repaired item next time before they could sent it back to me--which is weird considering that it is THEIR responsibility as shipper to accurately declare a shipment's content as repaired item sent back to customer and not as a new merchandise which will definitely incur the receiver new import duties!

Anyway, the main issue here is the problem of CR's and LEED's battery packs/controllers cutting out power on steep climbs due to overheating. I discovered that this issue is due to overheating of the battery pack controller on steep climbs which burns out a component inside. Replacing the controller with a new one solves the problem but this costs money to the user, especially if the user sends back the whole battery pack to Clean Republic/LEED. The most cost effective way to get the controller replaced is to simply report the problem to seller. Ask them to send back the repaired pack as a gift. Otherwise toll charges will be levied again.

Overheating is normal with Lithium-ion batteries especially when the output required is high (in long climbs this is true!). Turning the battery pack off and on will only reset the controller but will not solve the overheating problem and will either result to the controller burning out or the the chrome plug connections melting.

My old SLA battery pack melted the connecting wire in a 1 kilometer steep climb back in 2011. Last March 2014, my new LEED battery pack (purchased January 2014) had its soldering inside the chrome plug connector melted after several steep climbs on this route. First, I thought the controller was busted but upon inspecting the chrome plug it turned out that the controller is still OK and only the melted soldering in the chrome plug is the problem. After I re-soldered the wirings the LEED battery pack worked again. This reminded me of a similar problem I had with my SLA battery pack in 2011.

The moral of the story is this: there is a maximum temperature (perhaps, between 50 - 60 Celsius) that Clean Republic and LEED battery controller (especially the chrome plug soldering) could tolerate in long climbs even if users assist the motor by pedaling. In other words, there is a limit to how long the battery could assist a user's climb--the maximum temperature that the battery/controller could tolerate.

Some of the batteries from Clean Republic and LEED are packed in phase change material (PCM) that is supposed to protect the batteries from overheating (see here for LEED battery specs and  here on AllCell and Clean Republic's  joint venture).

Possible work around: avoid overheating the battery!

Mike Shoppe advises not exceeding 32 Celsius in his post on the Forum (see here). I am sure he meant the outside operating temperature but the battery connector/chrome plug itself gets too hot such that the immediate surrounding area near the chrome connector plug could get as hot as more than 47 Celsius in my experience (in this peripheral temperature the connector itself is too hot to touch).

My 30K Samsung battery pack from LEED also shuts down on long climbs but does not reset when I turn it off and on again. Instead it turns off and cannot be turned on again until I have recharged it. To avoid this problem I installed a thermometer to measure the temperature of the connecting chrome plug. There is a 30-second to 1 minute delay in detecting increase in temperature but as soon as it hits 31 Celsius, I turn the battery off. The temperature still increases up to 47 Celsius even with the battery off but cools down again. As soon as it cools down I turn the battery on again.  I haven't tested this with my Clean Republic Sprinter but this seems to be the way to avoid burning out the controller.

If your controller gets busted, just send it back to Clean Republic/LEED. But first check if your chrome plug connector soldering is intact

In case you have already busted your controller due to overheating in long climbs, just send it back to Clean Republic/LEED. They should replace it with a new one. Do not send the whole battery pack if you want to avoid the expensive shipping fees and possible re-importation duties (due to possible mis-declaration errors that could happen). Before sending the controller, check if your chrome plug connector soldering is intact using a multimeter tester. Otherwise, you might unnecessarily send back the controller that is still working when the real problem is actually just the melted soldering inside the chrome plug.

NOTE: More posts on e-bike conversion projects are available here. 

E-bike conversion kit controllers: LSW153-45-6

What is inside the controller?

I opened an old busted controller I got from Clean Republic back in 2011 to see what is inside and here is what I got.

If you visit the URL written on the circuit board, you can infer that the controller is manufactured in China by Nanjing Lishui Controller Research lnstitute. There are several IC chips, diodes and capacitors on the board which might be possible to replace if you know what you are doing. 

To open the controller, just remove the screws on the side where the wires come out. 

Then unscrew the sides.

 Lastly, slide out the circuit board.

Compared with Other Controllers Out There

Here is a table showing 3 different ratings of the same CE-G3M20211-1592-16 numbered controllers. Note that the unique product number determines the variation in ratings not the CE-G3M... numbers.

Clean Republic/ Leed 24V kit Rated Voltage: 24V Maximum current: 14A Rated current: 7A Low voltage protection: 21V Throttle adjust. voltage: 1.2v-4.4v Product number: LSW153-45-6

Another 24V kit Rated Voltage: 24V Maximum current: 14A Rated current: 7A Low voltage protection: 21V Throttle adjustment voltage: 1.2v-4.4v Product number: WS 0806021626

Alien 36v 10Ah kit Rated voltage: 36V Max current: 15A Rated current: 7A Low voltage protection: 31V Throttle adjustment voltage: 1.2.v - 4.4v Product No WS X0907-18830

Clean Republic and LEED use the same 24V controllers for their Li-ion batteries, although they use different chargers. You can see below that the ratings are the same.

Clean Republic Controller LSW153-45-6 / CE-G3M20211-1592-16 used for Clean Republic's Sprinter 10K Samsung Li-ion battery pack. The 10k battery pack's watt hours is 105.6 (24V x 4.4 Ah) which makes the pack very airline friendly. The watt hour limit for carrying batteries installed in your  electronic device is 160 watt hours.   

Leed Bicycle Solutions. Exactly the same controller used for LEED's 30K Samsung Li-ion battery pack. The watt hour rating for the pack is 249.6 (24V x 10.4 Ah).

Since both Clean Republic and LEED's lithium-ion battery packs use exactly the same kind of controller, it made me wonder if Clean Republic's SLA battery packs also use the same controller. So I re-opened my old SLA pack from Clean Republic which I had opened before and discovered that it uses exactly the same controller as the one used in lithium-ion packs that power the 24V 8Fun motors. It is the same CLSW153-45-6 / CE-G3M20211-1592-16 as you can see in the photo below.

Controller inside Clean Republic SLA Battery Pack (Product number: LSW153-45-6 X11030003974 Ex-factory date: 03-2011). I got this as a replacement of the original controller I had for my SLA kit. The watt hour rating for the SLA is 192 (24V x 8 Ah) but each battery (when separated) has a watt hour rating of 96 (12V x 8 Ah).

This is what the SLA battery pack contains: two 12V 8Ah (UB120) SLA batteries, one LSW153-45-6 / CE-G3M20211-1592-16 controller, one LED switch, and the Hengguang Power HG6S240160 24V=1.6A charger with chrome connector. SLA battery packs are charged with the switch on (LED light).  

You can see from the photo below that even the old original controller of my SLA kit has the same product number LSW153-45-6 / CE-G3M20211-1592-16.

Original controller for my Clean Republic SLA kit (Product number: LSW153-45-6 X10010004013 Ex-factory date: 01-2010): the same CE-G3M20211-1592-16 controller used in lithium-ion battery packs.

NOTE: More posts on e-bike conversion projects are available here.