Over the last several years SONDORS has evolved the electrical systems of their bikes from open/generic Bafang to several different proprietary set-ups. The purpose of this document is to briefly explain each generation of bike and explore the issue of parts compatibility for upgrades and repairs.
The original "Original" (Generation 1)
In 2015 the SONDORS e-bike was born after backers on crowd-funding site Indiegogo waited for up to half a year for the first $499 e-bike. There was only one bike, and it came in a few different color combinations. The bike was single speed and there was no LCD available until months later, and shipping was $174 extra. It used an 8.7Ah bottle battery and there were no extended batteries available except from third party vendors months later. All of the bikes used the standard 3-LED, 6 pin throttle still in use today on single speed bikes.
These bikes are easily identified from a few visual clues:
The words “e-bike” printed on the battery box under the original SONDORS logo (see pic)
The etched controller serial number does NOT have the letter “U” at the end
They came in only a few colors that were never produced again – Yellow with orange anodized aluminum wheels, Black with red wheels and printing, and Black with yellow wheels and printing
These bikes used a generic controller, which makes them the only SONDORS bike where you can add an aftermarket generic LCD (like the KT-LCD3)
without replacing the controller. It also easy takes a 20A or 25A controller upgrade, which again will work with the stock throttle and any aftermarket or SONDORS LCD (available later in the year) that works with the SONDORS controller.
When SONDORS started shipping an LCD, it said SONDORS on it even though it used generic protocol. This is why you can’t tell what bike you have based on whether or not it says SONDORS on it.
The Kickstarter Generation (Generation 2)
Following a successful and disruptive IGG campaign, SONDORS did a follow-up campaign through Kickstarter. These bikes were mostly sold and distributed in 2016 and into early 2017, and came in a wide range of unique colors (Caribbean blue, gray, pink, and others), and new options. They still used the bottle battery, but you could now get an aluminum frame bike, an extended range battery, 4.0in tires, and even first-generation front shocks. They were still single speed, but they abandoned the generic controller for a proprietary one, which started the complicated path of compatibility.
A lot of bikes fall into this generation, and again there are some visual clues
No more “e-bike” printed on the battery box
The etched controller serial number now contains the letter “U” at the end, signifying a new, proprietary controller.
The bike will also have a bottle battery and not a newer triangle battery
The bike on the right is a 2nd generation SONDORS fat bike with optional shocks, 4.0 inch tires, and an aftermarket black trim kit and Ibera RA5 rear rack.
This is the beginning of SONDORS using a proprietary protocol for their controllers. If you have one of these bikes and want to keep the stock 15A controller, the only place you can get an LCD is from SONDORS. Your bike will run using an aftermarket LCD like the KT-LCD3, but the display will be wonky. It may not show speed, the PAS controls might not work, and the battery level display won’t be right.
Most owners with these bikes wanting an LCD (it wasn’t included) choose to swap out their controllers for an aftermarket 20A or 25A version (around $55-$65) and add a generic LCD for around the same price. The 3-LED throttle works fine with these aftermarket controllers. Because these bikes have a 350W motor with the smaller plug, going above 25A will usually require a motor swap and usually an upgraded battery at no small cost. Many people do 48v or 52v upgrades using huge, aftermarket triangle batteries for higher top end speed and more range than the average butt can handle.
The first SONDORS direct generation (Generation 3)
This could actually be 2 or 3 generations with all of the changes happening, but from a compatibility standpoint I’ll lump them all together. Following the IGG and KS crowdfunding campaigns, SONDORS took ordering in-house. They started with a bike that looked just like the KS bikes but with some new colors (including red and royal blue) and also included a bottle battery. For ease, I’m going to include those bottle battery bikes sold direct into the Generation 2 bucket because technically they’re similar. However, as 2016 turned into 2017 SONDORS started introducing triangle batteries, gears, the Thin, Fold, and even the X bikes. This generation used the proprietary KT-LCD3 LCD with SONDORS printed on it, and maintained the proprietary 15A controller with the “U” in the serial number. However, this new controller now had different plugs for the new triangle and fold batteries which added some complexity.
This is also when SONDORS introduced 7 speed bikes, which also introduced a proprietary 3 pin throttle. These 3 pin throttles look similar to the Bafang BBSHD throttle, BUT the pins are male instead of female. This is to keep owners from plugging the throttle into the PAS plug on the controller. These throttles are only available from SONDORS, although you can sometimes find them for sale by owners that have swapped theirs out.
There are so many bikes that fall into this generation you are better off using process of elimination. If your bike has a bottle battery, it’s either Generation 1 or Generation 2. If your bike has a triangle battery AND a rectangular LCD based on the KT-LCD3, you fall into this generation.
The picture on the right is a SONDORS-KT LCD3 LCD.
This is where compatibility gets “fun”. Like with previous SONDORS bikes that are not “Generation 1”, aftermarket LCDs will not work with the stock 15A controller. The bike will run, but the display will be messed up. Here are some key points:
If you want to keep the stock controller, you will need to get the replacement LCD from SONDORS
If you want to upgrade your controller to 20A or 25A, you will need a new, aftermarket LCD. You can get the tried and true KT-LCD3, but one of the known vendors is now selling a compatible color LCD for around $20 more.
If you upgrade the controller, you will need to get one with the correct battery connector, OR transplant the connector from your old controller to your new one. Most generic controllers are just 2 wire
If you have a 7 speed bike, you will also need to replace the throttle if you upgrade the controller. This is because the aftermarket controllers use the 6 pin throttle and not the SONDORS 3 pin version
If you need a new throttle for a single speed bike, you can get a generic 6 pin throttle from known vendors. If you need a new throttle for a 7 speed bike, you have only a couple of choices – buy one from SONDORS, or swap out the controller, LCD and throttle to something generic and not proprietary
Another option is a brand new upgrade kit available form SONDORS. This includes an upgraded controller and color LCD for around $200. If you get the right kit the LCD will be set correctly and it will be compatible with the throttle
Current mid-2018 Generation (Generation 4)
In mid-2018 SONDORS switched out the controller and LCD for a new square version called the KD51C-KDS (aka KD51). This new display is completely different under the hood, and it’s gotten mixed reviews. People like that you can adjust PAS power levels, but many dislike that you can no longer see voltage on the display. All bikes during this generation were changed. They all still have triangle batteries, but the controllers and LCD for the “Original” (yes, the name is confusing), Thin, Fold, X, Sport and Mini are all changed.
This one is easy. If you have a KD51 LCD, you have what we’re calling a Generation 4 bike. The picture on the right is the KD51.
All of the compatibility notes from Generation 3 still apply, but it’s also important to note that none of the previous generation controllers are compatible with this LCD, and none of the previous generation LCDs (or generics) are compatible with the Generation 4 controller.
You still need to be aware of the single speed versus 7 speed throttle compatibility with this new controller
While Generation 2 and 3 LCDs and controllers are interchangeable with each other, neither are interchangeable with Generation 4
This is why many with LCD, controller or throttle issues choose to go towards generic again unless covered under warranty by SONDORS.
Like with previous generations, SONDORS now sells an upgrade kit for around $200 that contains a new color LCD and either a 20A or 25A controller depending on the bike. These kits will also not be compatible with aftermarket parts, but it will maintain compatibility with your throttle if you get the right kit.
1.0.0 - Mike Ritchie