e-bike: batteries!

My shipment of LiFePO4 batteries has arrived from China.

16 batteries, metal bars for connecting them up, plastic framework for supporting them, Battery Management System, wires and a charging unit.  The charger came with a European style plug, but I have a bunch of spare monitor power cables that will do the job.

They are BIG batteries!

But all together they should weight less than the four dead SLA batteries that the bike came with.

e-bike: handlebar controls

First mod on my e-bike has been to change the colour of the control switches on the handlebars.  Look at those original colours...

Eugh!  Like the controls off of some kiddie's toy electric truck or something.  Far too jolly and candy-like for my tastes.  If it had just been red or just blue I could've lived with it, but not both.

After disassembly (quite the mess of bits inside these things!) and a light sanding I tried soaking the buttons in liquid Rit dye.  Other people have reported good success in dying plastics this way, but it didn't do more than lightly stain the white button in the center of the turn signal switch.

So I bought some Rust-oleum Universal Advance Formula spray paint.  A coat, some light sanding, and another coat did the trick.

It was a pain in the butt putting everything back together again.  Made me wish I'd paid closer attention when taking it apart.  Here they are now...

Ahhh.. much better.  Much more sombre. ^_^

"But Andrew, how will you see the controls?"  If I needed to look down in order to use one of the controls, it just means that I should spend more time memorizing their layout.  Fortunately the layout of the controls roughly matches what I have on my CBR 125.

e-bike

I've added a new project to the pile of things I'm mucking around with:  Building a hybrid e-bike.

A while back I saw a "Zhejiang Nicom Electric Vehicle" or e-bike parked on the street out front of the Princess of Whales Theatre in Toronto.  I liked the look of it and though I don't need an e-bike, I thought it would cool to have one.

These bikes are sold under a wide variety of brand names; Switch 100, Top Prince, E-Road, Sprinter, Motorino VTS, Celtic Beetle, ezcruzr, etc.  The result of various e-bike retailers importing it, and other e-bikes, from China and slapping their own brand onto them.

After joining the Toronto Electric Riders Association forum to brush up on my e-bike knowledge I checked out the prices for new Nicom bikes - decided that over $1000+ was too much - and started snooping around on Kijiji and Craig's List for anyone selling a used one.  I found a 2010 "Switch 100" going for $400 so I drove out to have a look.

Fortunately the SLA (Sealed Lead Acid) battery pack was so worn out that the bike could only move under pedal power, so the seller readily agreed to $300 for it as-is.  Perfect for a bike that I was planning to strip and rebuild anyway.. fixing a little rust and having to rejuvenate or replace the battery pack would be part of the fun. ^_^

I'd brought along my tool box and was able to quickly partially disassemble the beast and cram it into my smart car.  (Only breaking one of the bike's mirrors in the process.)

The one thing that really impressed me about this bike is how HEAVY it is. >.<  The battery pack, frame and motor wheel are just massively heavy.  I am going to put it on a diet.

After driving home and drafting my husband into helping me haul the heaviest bits into the basement, I finished stripping it down to the frame.

And investigated the battery pack, which turned out to contain four batteries crammed inside of the plastic case.  Unfortunately for my "rejuvenate" plans they turned out to be gel based SLA batteries, which do not respond well to desulphination circuits and they were also too far gone for desulphination to make much of a difference.  C'est la vie.  Off to recycling the went.

Which leaves me having to buy a new pack.. perhaps the most expensive part of an e-bike.  Ouch.  But I kind of expected this to happen.. if you're picking up a 2nd hand e-bike you can be pretty sure that the original owner is getting rid of it 'cause the batteries are kaput and they're put off by the cost of getting new batteries for it.  I imagine we'll see much the same trend in the future with electric cars.

Would you want to spend $$$ on a new engine for your 5 year old car, or invest that into a new vehicle instead?

I decided against going for the cheap option of just buying a fresh set of SLA (apx. $200+) and decided to get lithium iron phosphate (LiFePO4) instead.  Just about any e-bike dealership also sells battery packs, that being the first part of an e-bike that needs replacing, so I thought it wouldn't be difficult to find someone selling a ready-made pack for my bike.. and I'd also need a new charger since the one for lead acid batteries wouldn't work with the different chemistry.

But after looking around I couldn't find anyone selling a battery pack that looked plug-n-play for my bike.  Which I suppose isn't that surprising since there are a lot of different e-bikes on the market and trying to keep a bespoke pack for each model on hand would be a bit of a logistical nightmare.

While browsing around various e-bike maintainance and tech sites I came across this page which shows a LiFePO4 battery pack being made inside of the plastic battery case from a Switch 100.

After some more hunting around I found a few different retailers of those big blue Headway batteries and kits for assembling different sizes of battery packs - such as Headway Headquarters - with prices that varied considerably.  I noticed that the US places tended to charge quite a bit more for the batteries, and though they would be less for shipping if I lived in the US, I'm Canadian, so it made more sense to buy from China.

That's what I've done; just over $675 for a 48v 15Ah battery pack kit from ev assemble via their eBay store.

It will have the batteries, BMS (Battery Management System), charger and various bits and pieces for assembling the batteries into a pack.  Should be fun to put together. ^_^

Yes.. this means I've nearly spent as much on a two year old rust bucket as I could've spent on a new bike.. which probably doesn't make any sense to some people.  It does to me for a few reasons:  That new bike price would be for one with a SLA battery pack, which only last a couple of years, whereas this LiFePO4 cell should have a much longer life and be a fair bit more powerful as well, extending the bike's range.  In addition I'll end up with a custom bike that is unique, and an expression of my creativity.  I'm also reducing waste by taking something that otherwise might have been discarded or recycled and making it useful again.  Finally it's just fun to do this.. mucking around with the guts of some old heap and bringing it back to life again.  It's a hobby.  It doesn't need to make money or sense.

While I wait for the batteries to arrive I've begun cleaning up the rest of the bike.

I hope no one minds bike parts in the shower...

Motorcycle Cameras - Part 2

After taking a long break from working on my camera power supply (rather like the long break I just took from blogging) I picked it back up again by giving the finished power supply a looong burn-in test to see how well it would perform.  Running both cameras for an hour, just sitting on the dining room table running off of a 12v power supply.

The hit sink became very hot to the touch.  Worrisome.  Especially with some of the extremely hot weather we get in Toronto during the summer months.  Converting so much of my bike's electricity into waste heat also seemed like.. a waste.

So I decided to see if there were any more efficient ways to convert 12vdc to 5vdc and I came across the LM2675 High Efficiency 1A Step-Down Voltage Regulator.  This seemed much more suitable so I ordered a bunch from an online parts source, since there were no local shops that carried it.  I had to buy 5 units, but I may want to build another some day, so that doesn't seem like a bad deal.

I assembled a new power supply using one of the reference circuit diagrams from the LM2675's documentation.

A couple of capacitors, a diode, an inductor and the LM2675 IC.

But I messed up and used an inductor that had far too low a voltage rating and though the above board did run, the inductor overheated like mad.  After doing a bit more research I determined what the correct inductor was and, again, had to order three of them from an online resource.

Quite the size difference, eh? >.<

But everything ran nice and cool once it was put together.  Even pulling enough watts to run both cameras from the one IC, rather than from three 7805 ICs the way my previous design did.

I assembled everything into a new project box, adding a power socket as well so I could easily take the power supply off of my bike for things like winter storage.  I don't want to leave those capacitors sitting out in zero degree weather for extended periods.  Might not bother them, but better safe than slurry.  I decided to leave out the heated grips switch this time.. didn't really ride much in cold weather last year. *shrug*

Another burn in test...

Which barely drew any current from the power supply that I used as a stand-in for the bike battery.  That red thing is a bodged in 10 amp fuse for just in case something shorts.

And I was all ready to install the power supply and USB cables in my bike.

I bought these great stick-on tie downs from Sayal, which made it a breeze to zip-tie the wiring into place in the bike.  They should be easy to remove if/when I want to remove the power supply.. always something I like to keep in mind when building a mod:  How easily can I un-do this and take it back to stock?

The power supply will ride, loose, inside the storage area under the passenger seat on my bike.  It's so cool now that I don't need to have it out in the open so keeping it somewhere that stays dry makes it much easier to build the project box.

Nose camera:  Check!

Tail camera:  Check!

Ready to go shoot some video.  (That's my old Ruckus in the background.  Sold it this spring.)

So here's a view from the tail of my bike, going for a short blast on the 401. ^_^

That's it for building a power supply for my Honda.  Please leave a comment to let me know what you think or to ask me questions if there's anything you want more detail on.