Dynamo Hub- Forumslader Kit

Trevtassie
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Dynamo Hub- Forumslader Kit

Postby Trevtassie » Sun Jul 03, 2016 7:13 pm

So I finally finished the second Forumslader kit I had, the one with the Bluetooth sender so I could see whats going on.

Looks to do exactly what it says. Extract maximum power from the dynamo hub. The most I saw on the short test ride I just did was about 9.5W. Interestingly that wasn't when I was going flat out. The device has voltage multipliers inside that increase the available power and those work in steps. It looks like there is a step just above what I would say is a good touring speed. So you can harvest about 8W while cruising along. Even climbing hills slowly I was getting 3W. So yeah, plenty of power available.

More details. I purchased the batteries locally, I got 2500mAH Sony LiMn ones. The bluetooth option includes an altitude sensor. Once you set the specifics of your hub and wheel size in the Android App it can act as speedometer and altimeter, including % grade. Collects statistics like tour distance, climbs and descents Also can incorporate a HR monitor and cadence sensor, so basically you have a full function computer.

In my case I decided to make the units fit inside some 25mm PVC pipe, with a waterproof USB outlet and waterproof switch so I can suspend it under the top tube.

It doesn't charge when the light is on however. If you want that then there is an auxillary 12V output that can be used to run a light. If you want to run a dynamo light you'll need to get a voltage reducer to get it down to 7.2V.

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find_bruce
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Re: Dynamo Hub- Forumslader Kit

Postby find_bruce » Sun Jul 03, 2016 8:16 pm

I am interested in the forusmlader - very comfortable with the DIY electronics, not so with the translation from German http://www.forumslader.de/

Is there an English language version ?

Trevtassie
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Re: Dynamo Hub- Forumslader Kit

Postby Trevtassie » Sun Jul 03, 2016 9:59 pm

I have a partly finished translation of the instructions I've done, enough to get enable me to finish the job, but the format is a bit messed up because I translated a PDF document that was double column. It's come out in word with a mix of columns, tables and all sorts, but it is mostly intelligible. I've asked Jens to send me an original German .doc of the instructions so I can get the format right... either way I could send you a copy.
Technically the DIY bit is dead easy. I'm not sure why he doesn't sell completed devices because the hard yards are done with all the SMDs and chips soldered, the rest of the soldering needed is basic, if a tad fiddly. As supplied the finished kit product is a bit primitive looking, that's why I mounted it in a pipe. You could mount it in a box too.
But the device itself has way more technology packed into than you'd expect for the size. It's basically all microprocessor controlled. I'd definitely recommend getting the bluetooth version if you have an android phone.

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rifraf
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Re: Dynamo Hub- Forumslader Kit

Postby rifraf » Wed Jul 06, 2016 2:21 pm

Come on Trevtassie, you've got what might just be the most exciting innovation in dynamo charging for a long time.

Where are the pics?

Get your camera out and slather the thread in photos and your thoughts on whats achievable with the unit :)
Surly Ogre, Carry Freedom Y-frame Trailer, Extrawheel trailer.

Trevtassie
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Re: Dynamo Hub- Forumslader Kit

Postby Trevtassie » Thu Jul 07, 2016 9:05 am

Ah, well, I didn't take any pictures while I was assembling it, but I now have some from the instructions I could post so you can see what is involved. I can post some pictures of the finished item, looks like a bike pump in my case, because both my partner and my bike have threaded 1 1/8th steerers and the Ahead style wouldn't fit. If you had threadless then that would be the way to go, stuffed up the steerer tube.
Turns out the EU has as many rules as Australia, so he needs to send out kits, not completed items.He does as much work as he's legally able to, but PM me for more details.
As for what it can do, I've been talking Jens and keep discovering new things. Him and Sven, his brother are mad geniuses I think.
Here's a rather incomplete list of what I've discovered so far:
The system is based on 12V.
There are 3 3.7V Lithium manganese batteries that can be either 700mAH or 2250/2500mAH.
The charging system uses a series of voltage mulitpliers to lift the output from the hub to a voltage that will charge the batteries. This is why it works so well even at low speed. Even if the hub is only putting out a few volts they are increased to a level enough to charge the battery.
It will also take input from Solar Panels in through the dynamo input. The software is set up to limit the input current to 1.5A at 12V, but there is a bypass option that would take 3 or 4A.
There are two 12V outputs, one is a 12V output for devices that use 12V. This will switch off when the batteries are flat. The other is a 12V lighting output that uses the batteries until they are flat, then the dynamo from then on, so you always have light.
The USB output can be either 1A or 3A, you select that when ordering the kit.
The bluetooth option is mounted on the board. Even if you don't have an Android phone I'd recommend getting it if you are going to tour with somebody who does, load the software on their phone! The unit records every parameter you could ever think of, plus a whole lot you wouldn't either. These are stored for life in the unit. Jens says the bike will die before the memory is full. It displays on multiple screens, two look like the display of a bike computer, the other one has a huge list the records.

Anyway, gotta go to work. TBC

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Re: Dynamo Hub- Forumslader Kit

Postby find_bruce » Thu Jul 07, 2016 10:46 am

I suspect there is more to the forums ladder than they are letting on.

The thing about hub dynamos (they are actually magnetos) is that they produce what is effectively a constant current however the voltage they can produce increases with speed. In the dim days of halogen bulbs you needed a voltage limiter to prevent blowing bulbs.

So at low speed you are getting 0.5a, but at very low voltage. One LED needs around 2 to 3 v to light up - which you get at ~7 km/h, so at ~7 km/h you are generating say 3v @0.5A = 1.5w. If want 12v you dramatically reduce the current - 1.5w / 12v = 0.125A. The opposite applies at speed - if they are producing 1A at 12v they are voltage halving not doubling.

What I suspect they are doing is taking advantage of a very funky characteristic of dynamos, referred to as load matching. At a particular load for a given speed you can get a dynamo to produce way more than 0.5A - almost double. The particular load is speed dependent, so that if you are slower or faster than the speed for that load, the current drops back to 0.5A.

My DIY lights have 3 white LEDs and 1 red LED & they have a capacitor to take advantage of this characteristic. Most of my commute is at speeds of 15-25 km/h so I sized the capacitor to suit that speed. At 40 km/h the light output drops back to what it would be without the capacitor. Yes it is a bit freaky to have less light when I am going faster. I compensate for this with switching my helmet light to high.

What I would really like is to automatically switch the load, but my electronics skills are not up to that level of complexity.

What has attracted my attention with the forumsladder kit is the suspicion that they may have achieved this. My dynamo lights run at ~12v (11.12v (AT) 0.5A, 11.97v (AT) 1A) so if it works they way I think it does I should get a noticeable improvement in light output at speed.

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Re: Dynamo Hub- Forumslader Kit

Postby Trevtassie » Thu Jul 07, 2016 6:17 pm

Pretty well you're on the money there Bruce. It has 5 load matching steps I think, all controlled electronically. Plus the voltage boosting at lower RPMs to take advantage of the higher current. If you really want to know PM me and I'll give you Jen's email. I'm boggling at how much is squeezed onto a circuit board that can fit inside a 25mm ID tube. Most of the "large" componentry is the capacitors for load matching.
For running a big headlight it'd be ideal. You could easily run a 5-8W light off it without touching the battery capacity.

Trevtassie
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Re: Dynamo Hub- Forumslader Kit

Postby Trevtassie » Sat Aug 20, 2016 4:08 pm

After 5 weeks on the road all i can say is get yourself a Forumslader. They work, and work well. Get the 3A version. Bluetooth only if you are a gear nerd. Large batteries. Job done, you'll always have power.

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Re: Dynamo Hub- Forumslader Kit

Postby savvas » Sun Apr 22, 2018 5:57 pm

Old thread I know but maybe worth reviving - I've just been researching the forumslader V5 myself! It occurs to me that you could maybe run one (or two) of the Phillips Saferide ebike lights (6-36v) or the new Spanninga Axendo equivalent off the lighting output of the forumslader! I don't think these ebike lights have the same rectification circuitry as the regular Saferide/Axendo so they need to be fed with DC only. I have one or each already and have been eyeing off the forumslader for a 'desert' tourer based on a Surly Troll frame. Any thoughts...? Ta, Sam.

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Re: Dynamo Hub- Forumslader Kit

Postby Trevtassie » Mon Apr 23, 2018 8:47 pm

savvas wrote:Old thread I know but maybe worth reviving - I've just been researching the forumslader V5 myself! It occurs to me that you could maybe run one (or two) of the Phillips Saferide ebike lights (6-36v) or the new Spanninga Axendo equivalent off the lighting output of the forumslader! I don't think these ebike lights have the same rectification circuitry as the regular Saferide/Axendo so they need to be fed with DC only. I have one or each already and have been eyeing off the forumslader for a 'desert' tourer based on a Surly Troll frame. Any thoughts...? Ta, Sam.

Jens has made a new circuit board for the B&M IQ-X that can run off the 12V lighting output and still use a tail light (and also has a bunch more functions than the standard light. But since you already have the lights have a go. There are two 12V outputs on the forumslader, one that works off the battery ie outputs until the battery is flat, and one that is driven from the dynamo, so will go off when you stop...

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