SON Ladelux Review

My SON Ladelux Review

“If you keep carrying old bricks, you’ll keep building the same house.”

Germany and Regulations

The SON Ladelux review must start with some context. You have to understand that Germany has bazillion regulations for literally *everything* and that includes bicycle (dynamo) lighting. The infamous 6V/3W number/value a dynamo is actually still today in 2026 and it is based on halogen bulbs. I have a detailed video on the subject , though suffice to say with LEDs we have gone light years (pun intended) ahead of halogen bulbs, yet the German standard still requires StVZO lights (having K-mark) to respect that.

So while LEDs are 30x (yes thirty times) more efficient, LED bicycle lights and dynamos are still stuck in century old technology. This is the most important part for you to get out of this SON Ladelux Review.

While a lot of people when they think StVZO lights, they think cutoff beam, a light has to meet ***multiple*** standards (we are talking Germany after all…) so yes cutoff/light distribution is one, however ELECTRICAL specification is another.

Which means the Ladelux being German it means the Main beam/cutoff beam needs to produce 2.4W in order to meet specification. It says it right on the light itself.

Also having variable intensity that is USER selectable (as on all of my products) makes the most out of what is available (0.7W is plenty with modern LEDs…). The SON Ladelux (or no other dynamo light actually) does not have variable intensity (well it does with varying speed but this is unintentional…). Dynamos especially below 15kph barely go above 3W even with ALL the tricks in the book (more on that below) so if you want the lights on and have some lights to spare you are out of luck or you need a buffer.

Internal Buffer or Largely NOT for SON Ladelux

So (similar to my own products) I discovered very early in my electronics journey that for charging (and no flicker at low speeds) you need a buffer battery – dynamo power outputs way to variable to be useful. Several things you need to know about the SON Ladelux buffer battery.

Most importantly it has to do a LOT of jobs and as you can imagine multitasking means things get not done – just like people.

1. Capacity of the SON Ladelux is 1200mAh, as compared to 1600mAh for my products (and others on the market such as the Exposure Revo 5) and it not being used to full capacity (it works only in the 20-80% charge) you are dealing roughly with a 720mAh capacity or LESS THAN HALF of a 1600mAh cell, ***before any conversion losses to 5V, etc.***
2. Most (if not all) supplementary functions (besides the main/cutoff beam) – High beam as well as charging depends on the battery. So if you want lights and charge you better be riding faster than 25kph. Just charging, if you are riding below 15kph you will tap into the buffer quite a bit and eventually run out so you will lose charging (and high beam).
3. There is no real ‘pass through’ as in all my devices (starting from The Stalker) so even if you have enough power from the dynamo, if the battery is not within the 20-80% you are out of luck – no charging and no high beam. Why is that an issue? Li-ion battery recharging takes TIME. You can’t just pump in all the current you want, nothing beats ”pass through in efficiency and the SON Ladelux does NOT have that.
4. THE SON LADELUX BATTERY IS NOT USER REPLACEABLE AT ALL. EU REGULATIONS REQUIRE THAT (Garmin Varia Vue 820 is the perfect example of what is currently possible for a bike light).

Innovative?

It is good to have a marketing department, even better if they don’t know what they are talking about so they the sky is the limit who it comes to claims. YOU should care because they are basically treating you like an ignorant idiot, they just use fancy words so you don’t nortice it…

What you need to know is that dynamos are what they are because of GERMAN regulations (VIDEO). This is the ONLY regulation in the world and as I already mentioned they are severely handicapped as this is based on having a light and a halogen bulb.

Unfortunately. this has de facto become the international regulation Even though if you are not inGermany it doesn’t matter even 1 bit…. When that regulation came about, charging things while cycling wasn’t a thing. GPS, cellphones didn’t even exist, we used vacuum tubes to listen to the radio and watch TV!

You have to understand that with parts they had on the shelf, without any NEW development me and SON made a dynamo 300%, yes 3 times more powerful that what is currently out there, 50% more efficient with 3W at 5kph (walking pace!). The technology is there.

So rather than making a better dynamo ) to update things you have to resort to

ALL The Tricks in the Book.

First of all even with all I am going to describe below 15kph you are still in the 3W range which is largely not enough (most high power devices need at least 5W to be charge ok). This is largely a physical limitation of the coils, magnets etc which are all done to meet the ancient German regulation. You physically can’t get more out. So you have to resort to trickery – or know as Maximum Power Point Tracking (MPPT).

Another German product (Forumslader) has done, it though in a kit form with wires sticking out and Igaro made it in a light actually, though you need an app to get the most out of it…. Which means you squeeze EVERY possible milliwatt from the dynamo at every condition. The principle is not new (paper here) and has been done THEORETICALLY.

You can do it either actively over all speeds or passively (like I have done with my products over the speed were most people ride).You need a FAST microcontroller and LOTS of code. Again Stealth was a paper (on the mathematics of propagation of waves) by a soviet scientist until Lockheed Martin actually made a stealth plane. Making theory into practice takes a LOT of headaches, though while nice you are still trying to squeeze out something that was not really there. Kudos for SON if they actually managed to do it, though seeing that the SON Ladelux is forbidden to operate on e-bikes (12V DC) and is dynamo only, means for at least some part they rely on passive MPPT (this makes things AC/dynamo only). There are multiple ways to go at it so SON (and anybody) can get creative, though one thing that we don’t need to be creative is USB-C as the work has already been done, yet SON Ladelux chose to.

USB-C Standard NOT Respected

It is nice to have standards and yet the SON Ladelux does NOT follow them. The USB-C specification has 3 current levels Default (2.5/4.5W), Medium (7.5W) and High (15W).

From experience Medium is well a good medium ground for high power devices like smartphones (Garmin Edge x40 and Varia 820 charge at either Default or Medium depending on the charger), HOWEVER, ‘3W dynamos’ at most riding speeds are not that, so picking the lower (Default) value is practical, especially if you want to use lights and charge. Ladelux claims 5W (5V/1A) steady output. There is no 5W ANYWHERE in the USB-C specification. Strike 1.

The SON Ladelux use a proprietary connector/button which is VERY nice (yes I am jealous). However, it only has 2 pins (+ and – . 10-20 years ago 5V is all you needed to recharge via USB. Nowadays the USB-C cable has 4 **additional** pins that ALL they do is *talk* with the other USB-C (compliant) device to discuss how they will charge. The 5V is not turned on UNTIL AFTER CABLE PLUG-IN AND HANDSHAKE. The SON Ladelux USB-C cable is always on. So (I know from personal experience here) some USB-C devices will interpret this a non-compliance and refuse to charge. Strike 2.

Lastly (I am dong some educated guesswork as I tried to do what SON have most likely done) if you announce Medium current (1.5A/7.5W) and limit it to 5W, some devices will also interpret that as an error (crap/bad charger). For example iPhone 16 Pro Max. In addition some Garmin Edge devices lose touchscreen functionality when being charged from the SON Ladelux. Also some powerbanks (notably with USB-C bi-directional ports) will also not charge (as there the USB-C specification is paramount to be respected). Strike 3.

12W power??!?!

So why is it so limited in when they claim lots of power available – 12W it is right there in their website:

First of all this is quoted at 40-kph per hour or 25mph. Let me repeat this is at 40kph/25mph. To achieve this speed SUSTAINABLY, you need to look something like this.

You have to put out 350+W and in general experience quite a bit of pain. People who use dynamos almost NEVER (or actually never…) go those speeds unless on some descents, where you need to climb for hours at 10-12kph to get to them….

Second I have personally asked the SON engineers who designed the Ladelux about that number, so has the Igaro engineer and neither of us has received a comprehensive answer. The internet currently does not like facts so any kind of bold claim goes… I give SON the benefit of the doubt that English is not their first language and I do not speak German, though no answer.

Though Physics is physics and Igaro have measured the SON28 dynamo hub and can get about ~9.6W, this is a limit of the coils/magnets, etc. Give it some tolerance and call it 10W. Maybe this is why Ladelux has 10W on the housing…

Still Project X does this at 10kph/6mph. SON actually make dynamos and know ALL the specs of what they put inside the dynamos so this type of impossible claim is inexcusable. Makes you wonder what else they are lying about….

INefficiency

According to the SON engineer in a thread on Reddit, the SON Ladelux circuit in operation consumes 0.2W (200mW) or already 6% of the dynamo power. No charging, no lights, just being active. This is VERY inefficient in today’s terms, where typical operation currents are MICROwatts (1000x less)!!!

Second, on order to avoid over voltage (frying the electronics) in some conditions, the SON Ladelux short circuits the dynamo which causes MAXIMUM resistance. While 3W lights do slow you down about ~3min each hour you are riding with the lights on (I actually measured it) when you short circuit it you get MAXIMUM resistance (so couple of minutes more) so even when it is not doing anything (internal battery full) the SON Ladelux is SLOWING YOU DOWN WHILE DOING NOTHING!

Now that is REAL innovation…. /sarcasm

The SON Ladelux Review Conclusion

The SON Ladelux makes some bold claims for currently (JUL2026) the most expensive (by a 10-20% margin) dynamo light+USB-(C?) charger package. For those who understand Ohm’s Law and 12 Ohm resistors/halogen bulbs, pretty much all of those claims fall short, sometimes by a quite a bit.

Compromise is part of any product design, so this is ok, I know that, claiming/lying to customers is wrong PERIOD and I will not do that, it is just plain wrong. Exposure are guilty of it as well, though this is another story (LINK) These are my 2 cents. I am speaking of somebody who started way back in 2019 from 0 and had to learn it all the really HARD way, not knowing what is a resistor was, to actually making some of the innovative dynamo powered products on the market. The internet does not like facts or reason, and I do not ‘argue’ or even have the time to post on forums, so this article will most likely get buried under (paid) advertising, though I consider this as therapy, I need inner peace so I had to get this off my chest. As I don’t have a marketing department or social media ‘presence’ this is my platform.

Thanks for reading!

NB: Original text is in English. All other languages are automatically translated so I take no responsibility of correctness.

Source: Personal conversations with SON engineers, Reddit, SON Ladelux Manual and most importantly my own headaches and experience designing dynamo lights with a charger.