gauvins

I've received the in-steerer version of the forumslader a couple of day ago.

Description

The attached picture should give a good idea. Basically, there is a steerer spacer fitted with a USB connector on one side and an indicator LED on the other. Cables lead to the electronic apparatus, which is attached to 3x0.7mAh lithium-ion batteries. At the bottom are a cable (black and white striped black) to connect to the dynamo, and 12V wires (red and black) (the picture could be misleading -- the red-black cable that seems to protrude from the electronics is in fact the termination of the cable labeled 4. 12V out, that I had disconnected)

Installation

Simple:

1. remove the star nut from the steerer. Drill with a 5/16 bit. The nut loses integrity and can easily be removed,
2. drop the charger inside the steerer. Pull on the black cable until the unit is almost completely inside the steerer.
3. insert the expander nut (not included with the forumslader. I've used the supernova expander)
4. route the wiring in the expander slot and tighten the expander.
5. pull gently from below until the connector sits nicely on top of the expander. Drop your old steerer cap on top of the connector assembly and tighten.
6. connect to your dynamo. No need to worry about polarity

Performance

The short version is that I've seen 6W+ at around 20 Kms. Quite impressive.

Measuring the exact amount of energy extracted by the charger is not easy, because the observed output comes from the cache battery. I believe that the maximum is 8W out.

Now, the LED indicator gives some information as to how much energy is produced and/or available. First, when it flashes green it means that there is more energy produced than consumed (i.e. the cache battery is charging). When it flashes red, the cache is discharging. Second, when the LED sends four bursts in a row, it means that the battery is at 70%+, 3 flashes at 30%+, 2 flashes mean under 30% and 1 means that it is close to empty.

I've connected a USB power meter to measure the output when connected to a Garmin Edge Touring and to a Samsung Galaxy S5. When connected to the Garmin, the observed power was close to 1W and the LED almost always flashed green, unless the bike was stationary (at a streetlight) or going quite fast (when the cache is full, the charger disengages, until it can safely resume charging). When connected to the S5, the observed power has climbed to as much as 7W. Once the phone is fully charged, it appears to consume under 2W.

It looks like powering a smartphone will not be a problem at all. Based on what I've read, there are two commercially available in-steerer solutions : (a) Supernova's the Plug III and (b) Sinewave's reactor. The reactor has no cache battery such that it is not the best to connect a peripheral requiring near constant input. The Plug does have a cache battery, by its power curve is less aggressive

Tourist in MSN

Thanks, I have been wondering how it would work out. Impressive power output. With the cache battery, you would probably have to disconnect the hub to prevent the battery from charging to assess for drag, can you feel any drag at all?

Assuming your wires are multi-strand wires, make sure your wires at the USB port and LED are well sealed, otherwise water could travel from capillary action between the strands to the electronics if any water gets past the cap when it rains.

My AXA Luxx 70 Plus goes no higher than about 3 watts, it delivers a bit over 500 milliamps regardless of how fast I go. But, I am not a power user so that is sufficient power for my needs.

gauvins

I didn't feel any drag. Now, it is cold and windy here, so that doesn't mean much (there is no magic involved -- power generation takes away 8W+ from the drive train. The fact that I don't feel a thing means that I am clueless..)

Yup, multi-strand. Hopefully well sealed (I asked Jens-the-forumslader-guy about corrosion and he mentioned stainless-steel/gold plated plug. It is bedded in epoxy so I hope it is relatively weatherproof.

3W isn't bad. Sustained over long hours, you could almost justify bringing a micro-wave oven

Scummer

Nice review. Good to know it works so well.
But, what I cannot grasp, is the power output. One the forumslader website it states, that the USB 5V output is limited to 1A, which means 5W of max. power. Unless you got the 3A version, which means, the limit is 15W and should easily power even the most power hungry cell phones.

Which version did you order? Also did you get the bluetooth option to monitor the charge and other interesting data?

Cheers

gauvins

Yes this is the 3A version. I blindly followed Jens suggestions I told him that our main usage would be to top off battery banks.

And no Bluetooth interface.

What kind of interesting data am I missing?

---

One more thing - the 3A version still requires input matched to the output. As of now I can only guess that it is reasonable to budget 6W. This appears to be the sustained extraction at 20 kms. But commuting today from the office, stopped by streetlights and dodging traffic, my phone did get through close to half of the cache, pulling 7W+ while I probably produced under 3W.

So in practical terms... One could ride "unplugged" to recharge the cache, and then recharge a battery bsnk fairly quickly. Then again, the bank has to be able to handle those amps.

Will update.

Scummer

Here is the list that comes with the bluetooth option:

Ausgewertet, gespeichert und (bei Verbindung zum Smartphone) angezeigt werden unter anderem:

aktuelles Fahrtempo - actual speed
aktuelle Steigung/Gefälle - incline/decline in %
aktuelle Höhe - altitude
gefahrene Kilometer - trip distance
Fahrzeit - trip time
Uhrzeit - Time
Akkustrom - Battery charging/discharging current
Akkufüllstand - Battery charge level
Verbraucherstrom - USB current
Dynamoleistung - Power from the dynamo
aktuelle Schaltstufe - current charging stage
max./min. Werte von Steigung, Tempo (jeweils tages- und torbezogen) max/min for incline and speed (day/tour)
gefahrene Höhenmeter - climbing
letzte ermittelte Akkukapazität - last measured battery capacity
Spannung der einzelnen Akkuzellen mit der Genauigkeit von 5mV - Voltage of each cell measured with a tolerance of 5mV


For a data geek like me, some interesting data how well the whole package works.

gauvins

And how much was that?

Scummer

Bluetooth option is 27Euros, according to Jens' pricing pdf.

camp123

Is your forumslader still working? Did it hold up well over time?

gauvins

funny you should ask. I've retired it after having a couple of issues with cabling. We (prior to COVID...) used to fly with the bikes to our destination. Removing the wheel (2" tires) would squeeze the connector. Have had to do surgery in airport lobbies twice. Then crushed the USB connector when reinstalling the handlebars.

Other than that, absolutely fantastic piece of equipment. AFAIK no contest in terms of watts you'll get out of your dynohub. May not be robust enough to tolerate frequent disassemblies. I've "pivoted" to the battery bank strategy and minimal energy consumption. But may well reinstall the Forumslader this summer-where-we-can't-ride-far-anyway.

rifraf

Hi Gauvins,
did yours come assembled or........? I seem to remember early adopters self assembling.

And how much did your version cost excluding shipping?

I've been very happy with my E-werk since about 2011, if memory serves, but I'd consider a Forumslader should the E-werk suffer a terminal failure.

gauvins

As you may know, Forumslader is foremost a resource for DIY enthusiasts. But the author (Jen if I remember) offers to assemble kits for you, in exchange for a nominal fee. I believe that prices are listed on his site. The end product is impeccable, even though the design is/was tentative (ex. overtightening the top cap will crush the USB plug)

I can probably find the price I paid in my archives, but no guarantee that it is still the same. But certainly an excellent device.

rifraf

Thanks for the review and prompt response

Trevtassie

I reckon the way to go is to upgrade the batteries to much bigger ones and have it portable so you can use it as a battery bank with the USB charger. I installed mine with some 18650 batteries into a piece of PVC pipe about the side of a bike pump and mount it on the down tube using SKS pump clips. I got some screw connectors from ebay for the input connection. So I can run it on the bike, then take it into the tent at night, plus charge it from an AC outlet as well as a replacement for a battery bank. At some stage I might upgrade to 26650 batteries for more capacity since I sometime run a phone and a wireless hotspot on tour.

KC8QVO

Have you measured how much power you are consuming vs how much power you are able to put back in to the batteries (via the dynamo - as in on the go)? That is an energy consumption perspective - watt-hours, not usage or current draw at any given point in time (simple watts or amps).

I assume the 6-8w mentioned earlier was "peak", but that is only an instant value of power - not energy over time. If that, lets call it, 8 watts is at 6 volts and you are stepping that up to a 12 volt system voltage, of say, 13.6v at a 70% energy conversion rate then at 13.6 volts you would only have 5.6 watts going in to the bank at 13.6v. Over the course of a 4 hour ride, lets say, that is 22.4 watt-hours of energy - at peak production.

What I'd like to see (in numbers - if anyone has studied this) is if anyone can actually maintain charge sustainability off one of these systems. If so - for what kind of device(s)? If not - what are you doing to supplement what you can't get from the dynamo?

What are the numbers on your "bank" in terms of voltage and capacity? How well does it hold up for your uses and same as above - are you able to sustain on the system you have or do you have to supplement the charging somehow, aside from a dynamo?

gauvins

Most recent is Anker 26800 which accepts 30W from a PD charger. (I believe that more recent models will accept up to 60W. Charging capacity makes a HUGE difference -- you don't have to worry that your charger/battery bank will be stolen from where you left them it at night; you can acquire enough energy to last for a long time if you can use a wall outlet at a restaurant where you've stopped for a meal, etc). This is more than enough to sustain me. More importantly, perhaps, I've ditched my phone for most navigation. A smartwatch works on as little as 1Wh/day, meaning that my Anker will allow me to navigate for more months on end (one hour of recharge will power my watch for an entire month). That would be if I were traveling is remote areas. Usually, we'll use a couple of phones for a couple of hours to keep up with work/news/etc. So plugging once a week for a couple of hours will do.

To summarize where I stand:

1. Dynohubs are great, but induce uncertainties when you travel. And since travel is not so frequent, not easy to anticipate what can go wrong -- I've had issues twice/three times so I have searched for a more robust approach: battery packs
2. Energy strategy starts with reducing energy consumption.
   1. A smartwatch consumes next to nothing (will last close to a week in ultratrack mode on a single charge).
   2. A Kindle paperwhite consumes next to nothing compared to a phone or tablet.
   3. A smartphone + keyboard is a workable alternative to a full fledged laptop.
3. Battery capacity is probably less important than its absorption capacity. If you can pull 60W from the wall and store it in a battery pack, 30 mins a week might well be enough. Circumstances are such that I will not try to improve on our system in the short run, but will probably invest in a pair of smaller (10Amp range) banks with the highest absorption capacity available (60W+) next year or so.

Tourist in MSN

This is an article published in German, you will find a graph in the article that lists speed and output from several chargers including the forumslader.
https://fahrradzukunft.de/21/steckdose-unterwegs-4/

When I put that into google translate to put in this posting, the link gets mangled, so you will have to do the translate yourself.

I think you would have to buy your own USB current flow meter yourself to measure what you are getting out of it at the speeds you ride. I got a couple of these, it will measure your output and also measure the time power was going through it. But shipping from Asia these days is quite unreliable.
https://www.ebay.com/itm/USB-Charger...r/362518070646

Using one of those, I find that I average between 2 and 2.5 watts out of my Sinewave Revolution. It is virtually impossible to read in sunlight, but indoors works well.

Trevtassie

I'm almost the worst case scenario power use wise. I use my mobile all day for google translate, maps and strava and internets at night. I also have an Australian mobile that doesn't have the full range of mobile bands so it chews through the battery when overseas because it has to find towers with the right frequencies, and sometimes they are a long way away. Even with all that, if I'm doing that and riding around 5-6 hours a day it keeps up fine, ie coming to the end of the day with a charged phone and charged Forumslader. It struggles off road where you are going slow and stopping a lot and not covering a lot of ground, so off road I'd carry an extra battery bank to get to AC power every few days. In Japan where I use a pocket Wifi as well as the phone I have to supplement the hub by charging every second day from an AC outlet because it's effectively running two phones. I'll charge the Forumslader, phone and pocket Wifi.
When I first got it I had a go using the bluetooth and App and sitting on around 15km/h on the bike path I was seeing 8 -10W into the battery according to the App.
The upshot is if you are touring for weeks at a time, know that you won't be near AC power all the time and need to support high consumption then it is a goer. If you are setting it up for the first time I'd go for making it like a big battery bank. With high capacity 26650 batteries and easily separated from the bike. I wouldn't bother with the bluetooth option, once the novelty wears off you won't use it much. I would get the USB loader to charge it up from AC power, plus an AC charger that can put out at least 3A. Personally I use a tiny little 60W charger from Mi in China that can charge the FL, my phone and anything else at 2.4A each, all at once. If you thought you weren't going to be near AC power you can use a 12V solar panel on the input, but not while you are charging from the hub, unfortunately. Now that would be the ultimate, solar and hub at the same time.

KC8QVO

It's all a matter of perspective - what frame of reference you are speaking to/in. In my world you're still on the low end of power use.

Thanks for the detail.

I am working on a video series on sizing portable power systems. There really isn't a "target audience", other than anyone interested in alternative energy (on a small or large scale - except grid-tie) because the same principals of power use, storage capacity, storage ability, battery absorption rates, and charge capabilities apply to an enormous range of uses. When you look at a system as "self sustaining" - IE - not plugging in your Forumslader, and/or extra bank, to commercial power to charge on a trip - the same electrical principals are at play as an off-grid cabin powered by wind and solar power with a battery bank. My base voltage is a nominal 12v, not 5.5v for USB, because there are things I run that use 12v - ham radio namely (HF radio, HT charger, or HT battery-eliminator). There are lots of factors to consider for lots of different applications - but the root of all power systems comes down to the power requirement you are trying to meet. The converse can always be argued - by reducing the need you reduce the requirement to meet it. That is always up to anyone to figure out and to what level they want to skimp by, or if that is even skimping by in their perspective. When taking a 0 day without solar ability or mains to plug in to is there enough power to "stay connected" in what you have? Or can you do without until you can get power while moving the next day?

Trevtassie

Incidentally, the Forumslader is a 12V system. It takes 12-24V DC input and has a couple of 12V outputs. One with a regulated 5A maximum output and low voltage cut out and one to run 12V dynamo lights. With a reasonable sized solar panel it'd replace the need for a solar reg.

KC8QVO

Reasonable sized is the key.

The charge regulation has a current limit. That is even less than the limit of the transistors used because unless you can properly cool the transistors you can not get to their upper range of current spec. So it is easy to burn out controllers and parts.

A Forumslader tucked in the head tube isn't going to have airflow for cooling, and I am not sure how you would sink the transistors to the head tube.. but if you could that would be a nice heat sink, unless your stem and bars are black and you're in the sun when its 95degF out.

camp123

With respect to the optional solar panel modulo for the FL, if you were riding around trees such that the sun exposure on the solar panels would be frequently change from shade to sun back to shade, etc., would the Forumslader perform well at capturing solar energy in this situation?

KC8QVO

Someone else that has direct experience may be able to correct me if I am wrong, however it should not matter the source of the "power" - either the input from the dynamo or solar.

The power that you are harnessing (from what ever means) is converted to "amps" to charge the batteries (whether internal/associated with the device or an external "bank"). When you have a power source (such as a dynamo that is AC and rectified to DC) that isn't producing constant power (you start and stop riding, and move at different speeds) what you end up with is a "cut in" point, then all power above it is converted to amps. The "cut in" point is where the DC output voltage of the energy source meets the voltage of the batteries. Under this voltage no charge current flows. Above this voltage current will flow. As you get further away from the "cut in" point (higher, not lower) the voltage remains the same (in the theory example here), however the current (amps again here) is what increases.

That fluctuation in current has no bearing on whether or not it will "work" - it all "works". The question is how much.

If you take the faucet on the sink in your bathroom, for example - put the drain plug in so water stays in the sink. If you turn the faucet on a generous trickle (low stream) and let it sit the level of the sink will rise at a constant rate. Now, if you turn on the faucet full blast for 1/2 second out of every 5 seconds the sink will still rise - but the "power" of the water going in to the sink is much greater. The rate of the sink filling up over time could very well be the same as the trickle even though the "power" of the trickle is much less.

Whether you have 1 faucet or 2 faucets filling up the sink the sink is still filling up.

Whether you have a steady trickle from the faucet or a pulsed blast the sink is, also, still filling up.

If you have a steady trickle on one faucet and a heavy blast from another faucet the sink is, also, still filling up.

As to how the Forumslader does the power - my understanding is there is an option that allows you to simultaneously get power from the dynamo AND solar. I don't know exactly how that works, other than the power sources (dynamo and solar, respectively) would have to be prior to any control circuitry.

Back to the point above about "cut in" - if you take a low-grade solar panel that has a full-sun, unloaded/open circuit voltage of 14.5 volts and try to charge on a cloudy day you likely aren't going to get any power.

If you take a higher-grade solar panel that has a full-sun, unloaded/open circuit voltage of 21 volts and try to charge on a cloudy day you are going to get SOME power. Maybe not much, but some.

The unloaded/open circuit voltage is important to know because for any given base voltage system (6 or 12) you will need a higher voltage of production to charge. Any drops in efficiency (clouds and a solar system, for example) will drop the voltage of the system. The higher the voltage you are starting with the more head room to loose some efficiency, and still get SOME power, you have.

Going back to the above example of the higher-grade solar panel producing 21 volts - for 12v nominal system the "at rest" voltage may be 13.5 volts. So that means the solar panels can push charge current all the way up until 21 volts - another 7.5 volts from the "at rest" point of the battery (full charge would be around 13.9-14.4v, depending on battery chemistry, but they won't sit there once unplugged). For this reason, you need to have a control circuit that won't allow the batteries to "over-charge". What ever head room there is in the solar panel example here for voltage is converted to current. So the power (watts), for the same intensity of light, would be the "same", but the battery voltage is what dictates the voltage of the charging device(s). Ohms law states that P(watts) = V(volts) x I(current). Divide P/V to get current. If V is constant (battery voltage) - as the input power (solar, dynamo) surpasses the "cut in" voltage the current (amps) is what you are seeing change - either by going faster (dynamo) or brighter sun (clouds/no clouds or getting out of tree shadows).

At the end of the day, the sink rules. How the water gets to the sink doesn't matter. Or, if you are draining it and not replenishing it, or not replenishing it quick enough, you will run "dry".

As long as the Forumslader is set up to accept charging from a dynamo and solar simultaneously - turn your two faucets on and have at it. Just don't supply too much input wattage than what the device can handle. That gets back to my comment about the cooling of the transistors:

dwyane

hello. I have Son28 dynohub and E-Werk with 361A cache, but its only deliver 800 mA but its enough to powering Sony XZ3.
What to buy if I want to charge GoPro 8 which must have 1A charging? I found here sth abot Forumslader 3A,is it good for my 2 devices?

Trevtassie

On average while riding the Forumslader will put out around 1.5A, either into it's internal batteries or into whatever is plugged in. Depending on the option, it will put out 3A, but some of this will come from the internal batteries. So you need to ride for a while to recover the "missing" 1.5A and recharge the internal batteries. If you think you are going to be a high energy consumer I'd say get one with the large battery option and get a USB charger so you can charge it up from an AC outlet when you get the chance.