Building an EV more efficient than walking

[Saladin]

I mentioned earlier you can fast charge an e-bike battery.

I also mentioned you might want to take the precaution of diode protecting the chargers from eachother. In hindsight I don't think that's necessary. They must already be protected because they don't let the magic smoke out when you leave them plugged into the battery and turn off the mains.

Any time I've done this "fast charging" method I was relying on the battery to voltage clamp both chargers and I pulled them before "float".
Which means I don't know if the diode is in the charger or the BMS or both...so if the discharge port blows your charger don't blame me.
Law of opposing voltages unplug the battery first and mains second she'll be grand!

A few (more) Caveats:

• DC barrel connectors are 3Amp rated. They will melt if you exceed this and sometimes even when you don't.

• The BMS is on the Charge Port if you are using the discharge port to charge then you have no balance circuit on that "input". To mitigate risk I reduce the charger Absorption voltage and use the charge port with inline BMS most of the time, meaning the cells can't ever be too far from balanced.

• I'm demonstrating this with 2 chargers. You could use an MPPT charge controller on the discharge port which can handle up to 40A I believe.

• Most batteries come with a charger that will take 8 hours to charge. eg. 24Ah battery comes with a 3Amp charger.
  The benefits are;
  The battery does get warm when you deplete it (at 1C), it'd be a bad idea to heat it further with an aggressive charger before it can cool.
  Slower charging facilitates better cell balancing and cell longevity.
  DC barrel connectors are junk and can only barely handle 3Amps anyway.

• It drastircally reduces risk of catarophic failure from charging at High C rates in low temperatures

• We all know it's actually because it was the cheapest solution...

Here's a dualy I strapped together and wired into the same mains plug.




Complete with custom adapters.




Visual proof of concept using the adapters. I haven't got an XLR female to XT60 direct. Outside of this thread I've never needed one but I would make one if I was doing this in the real world just to remove the DC barrel from the 4A circuit.



Same kinda thing with a 29Ah Triangle Battery

[Saladin]

What Tools do you need to convert a bike to Mid-Drive electric?
Not much!



I included the Chain Whip, Torque Wrench & Casette Removal Tool because I upgrade the groupset as a matter of course. Feel free to run the one ya brung. Either way you're going to destroy your first one. ...a bit like lead acid batteries..tehehe..remember those? I'm still using them for certain applications. I've a few healthy ones over a decade old. The battery was never the problem; always the charger...and a decent BMS for lead was always lacking.

Bottom Bracket Tool will vary depending on your bike, there's oodles. I avoid press fits.

Don't use the Crank Puller that comes with the kit. It could ruin you day. The Park Tool one shown won't strip it's own threads if you meet a sticky crank...those things can be extremely resistant to budging.

The Chain Breaking Tool and the Quick Link Pliers are too small to grant good purchase. They do the job but I'll replace them for better later.

The Flush Cutter is mostly for deweaponising cable tie ends. After you buy one you'll wonder how you survived without one all your life.

Not Shown:
Soldering Iron for XT60 conectors
15mm Spanner or pedal wrench to remove pedals.
Cone Wrenches because axles become consumable when you put big mileage on them especially in Winter with road salt..and wet. ...then again modern bikes use sealed bearings.

[Saladin]

Onbike Toolkit.

This is what I carry and I've never been stranded. The omission of a phone is accidentally on porpoise.



For that matter. I've never needed roadside assistance in my life because I buy reliable vehicles you can fix with a hammer and two spanners.
A 2003 vintage is the youngest I have. Funny how complexity inverted progress...

[Saladin]

It seems you can sell counterfeit and defective chains on that Rainforest Website with impunity.



I left a 1 star review with their own customer service agent conversation as the photo upload.



Hey wait..1 outtov 5 stars...isn't that 20% ¿
How do I give 0%?
...you can't!

[Moxi]

Hand it over to trading standards maybe ?

Moxi

[Saladin]

Hrmmm...I think I stopped caring Moxie. Moreova warning to the readers.
I'd say 80% of the chains I've bought on that site have been ridicously sub-par. I think I'll buy a 50m reel of KMC 11-spd e-bike rated. No joking. It's the equivalent cost to 3750kms in petrol for my car but it'll do 20 000km onna bike. In the mean time I'll just get them over the counter. I was actually thinking that was my last online batch as I placed the order. I was already so fed up of the shyte.
Most people don't measure brand new chains for wear.

[Saladin]

Time to talk about hardtail-life's ups and downs..narf...

Boom! Hardtail suspension!



Ooh it's soo good I hadta take it onna 80km test ride across the hills on both sides of this valley.

I tried the suspension seatpost on it's own and it's very good, but when combined with the spring seat the progressiveness is sublime.
I can't believe it's a hardtail anymore. When you think about it the bike is 30kg with dual batts I'd say 25% of that is sprung on the front fork, I'm 85kg-ish, leaving 23kg unsprung...and whatever cargo I'm hauling...that's a significant improvement. The rear tyre is a 2.35" wide which helps lots too.

I think hardtails make much better everyday bikes. The service schedule and component cost on a full-sus will break the bank if you run it high mileage all year and do as much mud-boggin' as I tend to.
Fox shocks (pneumatic) are super plush but they need a €75 service every 30 hours in the dry or 6 in the wet.
Suntour (coil spring) on the other hand are rugged, reliable, you can service them or completely neglect them and they'll be fine they're just twice the weight and motor so who cares!
Then there's bearings...my full suspension is a very simple design. That has 14 bearings in the rear that need to be extracted, replaced and pressed in when they get contaminated.
Don't ask me why MTBers are too cool to invert the stanchions or put on some gators on to keep the mud out...the answer's gonna be corporate cynicism..

The suntour seatpost has an optional extra neoprene cover to keep the krust away from it's gubbins...it's also a lot further from the mud and spray than a full-suspension linkage would be. The internal spring can be swapped for a lighter one for kids or a heavier one for size plus riders. The stock one has preload adjustment variability for riders I think between 60kg to 100kg.
The parrallelogram design is specifically so it reacts in the direction of the bump (vector from rear wheel) and also to maintain the distance from hip to pedal. The uppy-downy cheapies are not as good responsively nor geometrically.



I hadta flip the aux battery around and extend the feeder cable to allow for the extra travel.



The suspension seatpost comes in various sizes because so do seatpost tubes.

I ordered the smallest diameter suspension post and extra adapter sleeves to fit everything in my fleet so I can swap the seatpost between bikes.





I think a lot of people don't realise that comfort is the secondary purpose of a suspension.
The primary is traction; when your wheel is bouncing off the ground you can't steer or keep the power down. If the wheel is sprung against the frame as the bike lifts the rider weight etc reacts against the spring pushing the wheel back down giving you significantly more control and traction.

[Saladin]

Motor arrived.


Stop everything! Build a boike time!



Factory grease in the reduction gear casing.



Molybdenum Disulfide I reckon



Whadya mean I shoulda cleaned it first ¿
P-sah...that'll quieten her right down. I've 6000km on the daily now and haven't opened her since.
I covered the Hall sensor with Butyl Tape.

Next up. Crack the motor off because otherwise it won't fit the boike.



Reassemble, then open the motor controller on thuther side and replug in the connector for the hall sensor that got disconnected from the motor side.

It's tight. 10mm clearance no frame modifications necessary.

[Saladin]

Triple batteries happened one rainy day back when..



Derated to 55Ah @ 52V.
Oh I reckon she'll do 110kms unladen at 100% duty continuous.



The rest is just nuts, bolts, mounting ancilliaries and cable management.

{Edit}: Thats a wheel speed sensor on the chainstay. It plugs into the motor and reads a signal from a spoke mounted magnet. Wheel diameter is programmed in the display and/or motor controller flash.

[Saladin]

Run the rear derrailleur cable through the gear shift sensor and it acts like a momentary motor cutout and ramp up every time it detects movement on the cable. It's a drivetrain preserver. I've never broken a chain.



If your gears are indexed correctly it works fantastic. I rarely use it as anything more than a failsafe. My gears are indexed but I still prefer to use a manual cutout so I can make absolutely sure I'm not shifting under load.

I did add a motor cutout on the front brake lever mostly for the functional brake light signal.



This is the hydraulic brake solution. Reed switch on the resevoir and magnet on the lever. I'm sure that sticky tape will never fail...
{if you lose the magnet unplug the reed switch or the motor will be disabled}...{and waterproof the shift sensor...Tesa Automotive Loom Tape is my prefered choice for this}