Snap-on headlight v1.0

So, autumn is here and with that the total darkness in the evenings.

To be able to ride we need a light source that’s easy to mount and remove on the bikes.. so this is the first trial version.

I bought a couple of small LED-lights on amazon and designed a mount that snaps on to the front shocks on my bike..

Printed and test fitted it looks something like this.

The holder for the light is adjustable both height- and side-wise. It snaps on perfectly and sits pretty snug on the shock..

If testing shows that it self-adjusts I’ll redesign the mount with some TPU inserts to make the mount harder to twist.

The battery case fits perfectly on the other side..

Welded a battery pack from three 3,5Ah LG MJ1 cells to get a 12V source. I had bought a stepdown that’d work with the main battery but I found no good solution to connect it to the pack so this’ll have to work. For the next bike I’ll be able to connect the stepdown to the charging port so that’ll be what my son will use. My charge port is a bit special so connecting to that can’t be done in any good way that’ll not interfere with my legs when riding..

This is the finished kit..

.. mounted on the bike. I had to turn the battery pack outwards a bit to not limit the turning of the handlebars. Next time I’ll put it forward instead which works just as good.

So, the result then?


The headlight is pretty powerful but it is a bit too narrow. Since it has a – shaped profile of the light it’s also limiting the height of the light which isn’t perfect for riding..

Took a spin on the road and a trip around the local ski track and here the height of the light beam is really hindering. Going 40km/h in the darkness is very tricky with this limited light.. Since I know the track pretty well it’s possible but going around corners means turning into total darkness.

So – conclusion: It works but a wider beam would be better. Will look into modifying this light to cast a wider beam.. The mount however works flawlessly with the light sitting firmly in place and not moving when going over rocky and bumpy sections. So, with a modified or other lamp I think this will be perfect!

Combining this with a helmet light would be perfect so that’s probably what I’ll do. I’ll just have to figure out some good way to mount a battery pack on my neck.. or somewhere close to the helmet. 😉


Trollface box

So, after having posted on social media about the boxes I built a finnish friend reached out to me asking for help in printing a box. He already had a design and proper 21700 batteries so I just threw something together in CAD and printed it out for him.

When I asked him for a logo to use he sent me a picture. I don’t know if he was serious or not but this is how it turned out:

He was happy with the result and the fit in the frame was more or less perfect.

Didn’t get many more pics of this project unfortunately, so this was just a quick update.. there’s still much more to come so stay tuned!

Mondraker battery build

So, a buddy from Italy reached out to me. He had seen what I’d built for myself and my family and had a super nice Mondraker frame for which he could not get a suitable battery case. Since it’s almost impossible to ship batteries abroad I offered to make him a case for him to weld his own pack in.

Same method as before but he wanted to fill the entire frame “triangle” on the bike with the pack, so we made quite the large compartment for the BMS and wiring. This was also done to minimize the total width of the pack and centering it on the frame.

Here you see all the components. The cell frame, the joiner, the sides of the box and the TPU gaskets to make it waterproof(er).

Since my buddy didn’t want visible zipties to mount the pack to the frame we devised a mounting system using CNC milled aluminium brackets to mount to the bottle holder holes and two additional holes he would make.

The brackets are made to make the plastic case survive the forces from the M5 screws holding it to the frame.

Perfect fit. The bit wierd method of having theese brackets under the box is so we could use the cellframe/joiner method to make it. The brackets are mounted on the frame and the box slid over them before putting the final side on the box. That way the box can be removed without tearing up the cell welds. 😉

To be able to make the logo more visible I printed white infills.

This box is now in place in Italy enjoying the sun and I got a picture of it all mounted.

Beautiful bike and the battery fits perfect in the frame!
This was quite an interesting build. The design my pal had already done and he had quite specific requirements for the mounting system and how he wanted it all to look. Turns out he knew what would look awesome in that frame!

Battery for my sons bike, 2 generations

So, of course when I ride an awesome ebike the kids want one too. First of all I had to build one for my wife but that’s just a standard bike with a hailong pack. This is what I was riding at the moment:

Generation 1, 2020

But since my son was a wee bit short (10 years old) the bike we got for him could not fit any standard battery, so this was actually the very first totally custom battery I built.

Started out by making a dummy frame just to see how many cells we could fit in his frame and to get an idea of the shape of it:

Made cell frames and fit K-power 2500mAh 12,5A cells in there.

Installed the second frame and welded it all together.

As you can see this is a 13s5p pack yielding a whopping 48V with 12,5Ah and a total power output of 62,5A. This is by far enough for a small 10yo child. Only once did he ever run out of juice with this battery and that was after a 40km+ ride starting out with a half full pack.

Kapton tape to insulate the pack and then it was just a matter of mounting the BMS and putting it all on the bike.

Printed the case on glass, that’s why the sides of the box is so reflective. That didn’t last for long with the abuse the kid put this bike through though. 😉

Generation 2, 2021

Skip forward one year. A couple of crashes later he has grown quite a bit taller and now enjoys following me on the harder offroad and downhill trails. Never complaining I can see how he suffers from the stiff rear end of the green Merida bike and having bent both the rear rim and the front fork quite badly I thought it was time for an upgrade.

I found a used Giant Glory 8 in small size for cheap, just some 350km away, so I made a roadtrip and picked it up. This frame looked like a perfect fit for an electrical conversion!

After some careful measuring (and a lot of not so careful grinding on the frame to fit the BBS02 motor) the normal process started.

Cell frame with cells. This was actually the first time I tried the frame-joiner-frame pack type due to a total lack of space in the frame. This time we wanted more speed so we decided to go with a 14s4p pack to get a 52v battery. The problem using only 4 cells is the low capacity of the pack so this time we built it on LG MJ1 cells with a 3500mAh capacity and 10A continuous power output yielding a 52v pack with 14Ah capacity capable of 40A output. This is more than enough for the BBS02 and even after upgrading to the BBSHD (after messing up a controller) the battery doesn’t even sweat power wise.

The joiner is installed over the frame with cells. Take note on the cell configuration. I’m trying, even though it’s sometimes hard, to get as good a serial connection as possible throughout the entire pack. For a 40A pack like this I want to get at least 4 or 5 serial connections with my 0.2 x 8mm nickel strips which means I often have to put several layers of nickel on top of eachother.

Other side cell frame put in place. It’s such a tight fit that I sometimes have to put the pack on the floor and use my weight to evenly push the frame onto the cells.
Welding and adding insulating kapton tape on the side of the battery before turining it around to weld the other side. I take real good care not to accidentally short the pack out. Shorting it out is REAL unpleasant and bad for the cells too..

After insulating the pack more with tape which I like to put between the cells and any leads running over it, I add the BMS to the side of the pack and then close it all up.

He did not want any logo on the side of the battery so this is how it turned out. Works flawlessly but 14Ah is a bit on the low side with the type of riding we do now so for next summer we’ll revisit this bike and somehow fit an even larger pack on there.

Specialized and mongoose battery builds

So, a couple of friends wanted to build ebikes of their own and of course they needed custom batteries to fit their frames.

Specialized – something

The first one was easy, some sort of Specialized bike without rear suspension. The problem with theese bikes is to build a battery that looks good in the frame.. I had built a battery earlier that he liked but wanted to increase it from 13s5p to 14s5p, so I printed an extension..

Here the pack is welded, the BMS is soldered and mounted on top – only the power leads left to fix.

The battery cover is mounted. Here I used 6mm aluminium rods that I drilled and threaded to hold the box together. Later on I found M5 thread inserts that – when mounted correctly – bonds great to the plastic print. Much less work and a better result.

Mounted in the frame the battery sits like this. Looks more or less like a standard battery, nothing special but it works. 52V 12,5Ah and a cont current output of 62.5A is enough to power most anything for quite some time.


Now this frame is an odd bird..

Unfortunately I didn’t get any pictures of the frame while it was here, so this’ll have to do. The suspension on this frame works in a really wierd way and there’s virtually no space inside the frame to build a battery, so we had to place it underneath the frame.

When making a battery like this the first thing I do is, like in the picture above, take a picture of the frame as straight from the side as possible with a reference measurement in the picture, like the caliper taped to the frame above. That way I can import the picture into Fusion360 to start design of the battery box.

I then figure out the cell placement and the overall shape of the box and design the battery cellframe. From this drawing I make a PDF that I print on regular paper to test fit in the frame and when the fit is good I continue with the CAD.

I make a 3D design of the cell frame making sure the cells will fit in the holes and that there is room for the BMS and all the cable routing. I also make sure there’s room for the bolts, or in this case we used zipties to hold the box together. When possible I try to make sure the layout of the cells is such that good power transfer between the cell clusters is achievable when welding the pack.

Next the Joiner is designed. Now the outer shape of the battery takes form. When possible I try to make brackets on the joiner that fits the frame for the most secure mounting possible. Channels for zipties are added to the design to make mounting easy and secure.

“Rubber” gaskets are designed and finally..

.. the outher shell, or sides, of the box is designed. Custom logo added on demand. 😉

After this it’s just a matter of letting the 3D-printer do its job which usually takes 40-60 hours for a box of this size.

After the printing is done the cells are added to the cell frame, the joiner installed over the bundle and the second cell frame mounted on the other side. The cells are then welded taking super cautious care not to short anything out and then after the BMS has been added, the sides are bolted on and the pack ready to go on the bike.

For this pack I tried using zipties instead of screws to hold the box together. It works fine but looks a bit wierd and after finding the threaded inserts that’s the way I’m building packs further on.

Unfortunately I do not have any pictures of this pack on the bike. Will try to get some the next time we ride together!

Well, more packs and builds to come. Please leave a comment if you appreciate the build posts, or send me a message on social media or discord.

Radon Swoop 200, custom battery build(s)

So, the first eBike I built for myself was a Canyon AM 8.0 which I first installed a BBS02 on and upgraded to the BBSHD after a month or so. Since my wife didn’t think I should make everything myself I bought a hailong battery with 13s5p LG-cells. It worked but the way I was riding the bike I could not find any method of getting the battery to stay on the frame. Eventually there was a combination of custom aluminium brackets, zipties and electrical tape which.. well, it wasn’t really my style.

Since I was 20kg heavier back then and the AM wasn’t really made for the kind of riding I did I eventually got an ok to upgrade to a used Radon Swoop 200 I found online.
Since the shape of the swoop frame doesn’t allow for a standard battery and since I wanted as much capacity I could possibly fit in the frame..

RunstenRacing battery version 1.0
Amazingly I fit 98 cells into the frame making this a 14s7p battery with a huge capacity of 24.5 Ah and almost 1.3kWh.

This frame however did not allow for mounting the BBSHD in any good way so it was pointing straight down. With 200mm of travel there’s not much room under the chainwheel when fully compressing the suspension on landing. After having been thrown a couple of times over the handlebars due to the motor hitting the ground I eventually “upgraded” to the CYC X1 pro. The style of mounting of this motor is much better suited to my style of frame.

Well, the CYC with the BAC855 can handle 72v..

RunstenRacing battery version 2.0

I really don’t know how, but I found room for 2 more cells rendering this a 20s5p battery. Since the 50A cont output of the MJ1 in a 5p configuration is not enough for the BAC855 I upgraded to SonyMurata cells capable of 35A each giving a total of 175A continuous power output – which is INSANE. The downside is that the Sony cells only had 2600mAh capacity, so this battery was a 72V battery with 13Ah capacity, or almost 0,95kWh. A lot less than the LG cells would have given but you can’t have a battery that’s not up to the job!

Well, since I wanted a lot of power output I bought a DALY BMS, 100A and 20s. That’s the red thing mounted under the frame. It was too big to fit inside the battery in any good way. This was a bit awkward but it worked, for a while..

One day the bike just wouldn’t turn on. Turned out the BMS was fried for some odd reason! Well, now I had no way of balancing the battery cells so..

RunstenRacing battery version 3.0

New design, new detachable mounting system with the same 20s5p layout using Molicel cells with the same 35A output and 2600mAh capacity as before. This time I bought a cheap BMS that fit inside the battery. Since the maximum output of that BMS is 30-ish amps I simply didn’t route the power cables through the BMS, so it’s just for carging and balancing the cells. Works flawlessly.

I really like the new design too but the mounting system is just too much trouble to be worth it. I won’t make another battery using that.
The idea was to have a battery that was easy to remove so we could build extra batteries to charge while we were riding so we could simply swap batteries when empty and go on riding.. This is still an idea but this mounting solution isn’t good enough.

eBike battery builds

So, since there seems to be an international interest in the eBike batteries I’ve built for myself and friends I’ll post some pictures of batteries, cases and give a bit of insight as to how I’m designing the cases.

I’m thinking I’ll make one post for one or a couple of batteries. That way it’s easier for me to post something a little now and then, and it won’t be a massive boring post of all of the batteries and iterations I’ve built and taken apart. 😉

So, enjoy, or just skip to something else!

So – one of the first custom batteries I built was for my brother.

So, of course there has to be a logo on the case, but since we couldn’t figure out what to put there he got the standard.. 😉

This is a 52V 14s7p battery with LG MJ1 cells making it a whooping 24,5Ah and almost 1,3kWh – which is insane for an eBike!

As you can see there’s the cell frames into which the MJ1 cells are mounted and welded. On top of that there’s kapton tape to protect the connections from shorting out. Then there’s a frame – a Joiner I call it since it joins the two cell frames together. On top of that there’s a TPU gasket to make the battery a bit more waterproof, and then there’s the top piece.

After adding the balance leads I used proper electrical tape to further insulate and protect the cells – something I’m not doing anymore since it makes the size of the battery too hard to predict. Also adding more kapton gives a better protection and a neater size.

The battery mounted in the frame of his Radon bike, propelled by a BBSHD motor. At 70A continous power output this battery is pretty oversized for the application but it gives a good range.

Skrivhuvuduppgradering Stoorn v2.1

Nu har jag kört nya skrivaren ett tag och har märkt att den har lite oljud för sig ibland och så här om dagen gav fästet för remmen vika på skrivhuvudet och gjorde sallad av hela utskriften.. då fick jag nog av plasteländet till printhead och tog en kväll till att cadda upp ett nytt.

Denna gång avsett att fräsas i aluminium. Eftersom att aluminium är “tungt” så försökte jag minimera mängden material i huvudet samtidigt som det måste se bra ut och hålla allt som behöver finnas på plats.

Här är allt utom kanalerna för partscoolern på plats. Denna design blir mycket öppnare. Det gör att man ser alla kablar vilket inte är lika snyggt, men det gör den mycket enklare att serva och nu får funktion gå före form!

Så när allt var caddat och klart så är det ju bara att börja fräsa då.

Alla delar fräses ur 6mm eller 4mm alu och det blev rätt mycket spånor att skapa då mycket material skulle bort. Fick köra en del 3D-operationer vilket var nåt nytt jag fick lära mig, men det fungerade mycket bra.

Vissa delar krävde så mycket som 4 uppspänningar och jag börjar ha fått till metoderna för att mäta in och spänna upp delar med bra repeterbarhet. Det gick snabbt och enkelt och alla delar blev tillräckligt bra på första försöket så jag behövde inte göra om någonting.

Eftersom att alu är lättare än stål och eftersom att jag redan använt ett par gröneloxerade aluskruvar tidigare på printern så fick det bli såhär. Rätt snyggt blev det ändå tycker jag.

Det fina med att fräsa istället för att printa är att alla delar passar så sjukt bra ihop! Inga hål som behöver efterborras, inga passformar som skiljer någon tiondel.. Här snackar vi hundradelar och klockren passform! Riktigt roligt att montera “byggsatsen”.

Sen var det ju bara att montera den på skrivaren, plocka dit alla delar som ska fast, böja lite alurör till luftkanaler och testprinta..

Nu går det att spänna remmarna ordentligt. Inga missljud. Den klarar ordentligt med acceleration och fart och första lagret blir likadant hela tiden då skrivhuvudet inte flexar märkbart i någon riktning.

Supernöjd med uppgraderingen, nu börjar nog den här skrivaren vara så färdig de någonsin kommer att bli. =)

RunstenRacing Radon Swoop v2.0

Så var det äntligen dags att montera nya batteriet på min cykel. Det har legat ihopsvetsat ett tag och väntat på tillfälle att få leverera lite kräm.

20s5p, 100 celler av SonyMurata som kan leverera 35A blir ett kraftpaket om 72 volt på 13Ah som toppar nätta 175A i kontinuerlig ström. Det här batteripacket ska alltså klara av att leverera lite drygt 12,5kW, GALET!

Men självklart passar inte min gamla låda, som var byggd för 91 celler, till det nya batteriet.. Det fick bli en ny design.

Eftersom att jag använt cykelnhela vintern har jag inte haft möjlighet att testmontera denna alls utan har fått bygga den bara efter bilder och gissningar. Med 100 celler och en ORDENTLIG BMS så rymdes inte BMS:en i lådan. Jag har testat lite olika lösningar för det men det jag till slut kom fram till är att en fristående BMS-hållare under ramen blir bäst.

Istället för att använda en färdig laddkontakt så plockade jag isär den för att få ett trevligare utseende och funktion och för att den skulle ta mindre plats. Det visade sig att det fungerade MYCKET bra med den lösningen.

Så när äntligen aprilsnöstormen kom passade jag på att rensa ramen och rengöra för att kunna testmontera lådan. Den passade inte.


Så vad gör man då? Jo, man designar om den lite, tar bort en del material och sen passar den. 🙂

Testade en ny lådmodell i sektioner istället för en stor bit bara. Detta för att det ska vara enklare att montera lådan samtidigt som den blir stabilare. Alla sektioner har genomgående hål som passar ett 6mm aluminiumrör som jag gängat M5 i ändarna.

Mellan varje sektion sitter en packning av TPU för att täta lådan och låta den flexa lite.

Först monteras centrumhalvorna i ramen (notera avståndet mellan låda och stötdämpare, gissningsvis 0,5mm).

Monterad efter smörgåsmodellen med en klämd gummipackning i mitten.

Efter det är det relativt enkelt att stoppa in batteriet och dra kablarna dit man vill ha dem. Eftersom att BMS inte kommer sitta i batteriet så ska alla kablar ut ur lådan nertill.

Baksidan skruvas på, enkelt och snabbt med 10st M5 skruvar (overkill DE-luxe).

Sedan är det bara att dra kablarna genom framsidan och skruva fast den på plats. Hela lådan monteras i ramen med buntband och BMS:en lika så undertill. Tyvärr glömde jag att dra buntband genom kanalerna jag gjort i BMS-hållaren innan jag skruvade ihop hela kalaset och jag orkade inte göra om allt, så..

Motorkontrollern sitter rätt utsatt vid bakdäcket på cykeln och har signalkablar som sticker ut rätt bakåt. För att den ska hålla lite bättre gjorde jag en skyddsplast till den innan jag återmonterade hela kalaset.

Nu kanske den håller _lite_ bättre. Dräneringshål finns lite här och där för att den inte ska fånga vatten/smuts i onödan.


I slutändan blev cykeln riktigt trevlig. Den går som ett skott men jag har inte fått till inställningarna riktigt som jag vill ha dem än. Den går snorsnabbt men klipper när man busar. Jag har beställt ett mindre framdrev för att göra den starkare och mindre snabb så får vi se och jag har lite planer om hur jag ska konfigurera om kontrollern för att få den bättre.. Men jag får väl erkänna att jag redan beställt en ny kontroller till cykeln som inte ska lida av samma problem som denna gör. 7 månaders leveranstid gör att jag nog inte får testa den i sommar dock. :/

Giant Glory 8 electrified

Så blev det dags att montera batteriet i ramen och färdigställa grabbens downhillprojekt.

Batteriet passar riktigt bra, nästan som att det var byggt för att sitta där. 😉

Lite kabeldragning senare var det bara att trycka på knappen och testköra. Tyvärr är det snöstorm utomhus så det fick bli en snabb testtur i garaget bara.

Sjukt nöjd kille! Denna kommer vi ha mycket roligt med i sommar!