Lurkin
100 kW
Interesting. Is that an app on your phone allowing you to do that heat imagery?
Another No Solder/Weld 18650 Build (Updated 03/09/2014)
- Thread starter snath
- Start date
Poron, as seen on the Snath battery pack thread, info from LFP
https://endless-sphere.com/forums/viewtopic.php?f=14&t=57810#p862290
Ecyclist
1 kW
Here is my final product. It is 10S6P with twin charging capability. I can charge it bulk with 42V charger, or I can balance charge it with SKYRC iMAX B6AC hobby charger. I can control amps. with VESC and I monitor cells with small volt meter and two battery testers / loggers.
I use XT-90 Anti-Spark Connector for bulk charging and power delivery and two XT-60 connectors for balance charging. The pack contains a fuse that doubles as a kill switch.
I use XT-90 Anti-Spark Connector for bulk charging and power delivery and two XT-60 connectors for balance charging. The pack contains a fuse that doubles as a kill switch.
MJSfoto1956
10 kW
Ecyclist said:
That is a stunning piece of design and superb execution. A+
(you should sell this kit!)
Quick question: why two XT-60 connectors for balance? Are you using two hobby chargers in parallel? (i.e. charging either 5s6p or 10s3p each?)
M
Ecyclist
1 kW
Thanks dude.MJSfoto1956 said:
I use two XT-60 for balance charging 5s6p. One half at the time. Keep in mind that my pack is 10s6p and with this setup I can go up to 12s. Parallel charging with SKYRC iMAX B6AC is no go IMHO.
I only discovered this forum after finishing my own No Weld build. I used my cnc machine to cut out the parts. I'd like to share my concept:
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Ecyclist
1 kW
Nice work. Thank you for sharing. :thumb:
Very nice work, Patrick. What is the thickness of the copper bus-plates?
bzhwindtalker said:
I like this design and would like to do something similar. Could you tell me more about the springs? Where exactly did you source them? Also, what's the thickness of the acrylic (I assume) and how deep are the cell holes? What exact diameter did you make the cell holes? I'm guessing something like 18.1mm?
Also what are the bus strips made out of, and where did you source those? Pure nickel, or plated copper? How thick?
liveforphysics
100 TW
patrickb said:
Looks so clean, nice job. If you could find a way to eliminate the nickel and make a single stage of copper, or nickel plate the copper (it's actually really easy to do it home with low cost plating solutions, a sponge and a power supply.) Nickel is great for keeping a low surface oxide finish, but pretty sad for electrical conductivity.
Samd
10 MW
Awesome.
I was thinking of a similar linear setup using carbon conductive spray on sanded copper, instead of nickel plating the copper. Thoughts?
I was thinking of a similar linear setup using carbon conductive spray on sanded copper, instead of nickel plating the copper. Thoughts?
If the spring element is separate from the conductor (which I recommend), then the conductor can be copper or 6063 aluminum.
I have seen nickel, zinc, lead, and tin as the most often used plating material. As long as it's thin, the resistivity "hit" is not too bad. However, if the plating material is thin, why not silver?
If the pressure contact is silver-plated, why not use aluminum as the conductor (double the thickness compared to the equivalent copper contact, of course). The genuine Anderson contacts are silver-plated copper. The silver on those is thin enough that it isn't too expensive. In fact, it only needs to be silver-plated on the part that actually touches the cell.
I'm thinking that...if you use a bonded fuse-wire on the positive end, you only need silver-plated aluminum contacts on the negative. Thanks, Luke!...
I have seen nickel, zinc, lead, and tin as the most often used plating material. As long as it's thin, the resistivity "hit" is not too bad. However, if the plating material is thin, why not silver?
If the pressure contact is silver-plated, why not use aluminum as the conductor (double the thickness compared to the equivalent copper contact, of course). The genuine Anderson contacts are silver-plated copper. The silver on those is thin enough that it isn't too expensive. In fact, it only needs to be silver-plated on the part that actually touches the cell.
I'm thinking that...if you use a bonded fuse-wire on the positive end, you only need silver-plated aluminum contacts on the negative. Thanks, Luke!...
markz
100 TW
Why not
1) a mound of solder for the contacts and compress each end plate?
or 2) a dimple and something behind it to keep it from crushing?
1) a mound of solder for the contacts and compress each end plate?
or 2) a dimple and something behind it to keep it from crushing?
Solder is a horrible conductor and will cold flow over time.markz said:
I was very close to ordering a set of N.E.S.E. modules from http://18650.lt/ but they're pretty expensive and I'd still need to make some sort of enclosure for the BMS. So I decided to build something very similar to patrickb (thanks for your post!). Here's the model I have so far:
I have two Tiny BMS boards from EnergusPS sitting around waiting for this project (I intend to build 2 packs like this). The holder is symmetrical so I'll fabricate 2 copies for a pack. The slot on the right should fit the BMS board. The cell holes are 18.7mm in diameter and 5mm deep to fit LG MJ1 cells. The electrodes will be dimpled nickel plated steel strap, .15mm thick and 8mm wide. Underneath the electrode strips will be strips of compression foam.
Originally I was assuming I'd CNC the cell holders, but 3dhubs.com has the cheapest fabrication quotes I've found, and printing 2x of these is 107$ whereas machining is 200$ more. I'm planning on printing with PETG because I've heard that printed ABS can be pretty brittle. I'm not entirely settled on this because ABS is stiffer and that's obviously important. The two halves will be held together with 10-12 M4 bolts with nuts and washers. The material at the bottom is 3mm thick in the thinnest parts.
Does this look reasonable to people with experience building this kind of pack? One thing I'm thinking of changing is making the whole thing 1-2mm thicker for extra stiffness. Another change I'm thinking might be worth making is making all the edges thicker with a groove, for holding a gasket and sidewalls for a full water proof enclosure.
I have two Tiny BMS boards from EnergusPS sitting around waiting for this project (I intend to build 2 packs like this). The holder is symmetrical so I'll fabricate 2 copies for a pack. The slot on the right should fit the BMS board. The cell holes are 18.7mm in diameter and 5mm deep to fit LG MJ1 cells. The electrodes will be dimpled nickel plated steel strap, .15mm thick and 8mm wide. Underneath the electrode strips will be strips of compression foam.
Originally I was assuming I'd CNC the cell holders, but 3dhubs.com has the cheapest fabrication quotes I've found, and printing 2x of these is 107$ whereas machining is 200$ more. I'm planning on printing with PETG because I've heard that printed ABS can be pretty brittle. I'm not entirely settled on this because ABS is stiffer and that's obviously important. The two halves will be held together with 10-12 M4 bolts with nuts and washers. The material at the bottom is 3mm thick in the thinnest parts.
Does this look reasonable to people with experience building this kind of pack? One thing I'm thinking of changing is making the whole thing 1-2mm thicker for extra stiffness. Another change I'm thinking might be worth making is making all the edges thicker with a groove, for holding a gasket and sidewalls for a full water proof enclosure.
Did a tiny bit more reading, and PETG (with Glycol) is actually softer and stickier than PET, but worksalot better with FDM. This means I indeed want ABS. Also I have a much updated model, now made with parametric modeling so cell configuration can be changed nearly effortlessly:
https://gallery.autodesk.com/fusion360/projects/battery-pack-case-for-18650-cells-fully-enclosed
UPDATE: Some of the parameters could probably be specified more conveniently (It's my first attempt at using Fusion360 or any parametric modeling). The main issue is when I export to STL there's intersecting faces, which 3dhubs.com complains about. Any ideas on how to fix this?
UPDATE2: Pulled the trigger at 3DHubs for a total of 185$, they didn't seem to think the intersecting faces warnings were an issue. I did figure out which operation causes them: the 3 plane fillet. I updated the model more, some minor physical changes, but mostly better parameterization for changing things (I hope). This is my first venture into both physical modeling and 3D printing, so I expect there to be some issues. I already thought of one (forgot to leave some tolerance for the top case to fit around the base, so I'll have to sand it down probably). New model:
https://gallery.autodesk.com/fusion360/projects/134566/battery-pack-case
https://gallery.autodesk.com/fusion360/projects/battery-pack-case-for-18650-cells-fully-enclosed
UPDATE: Some of the parameters could probably be specified more conveniently (It's my first attempt at using Fusion360 or any parametric modeling). The main issue is when I export to STL there's intersecting faces, which 3dhubs.com complains about. Any ideas on how to fix this?
UPDATE2: Pulled the trigger at 3DHubs for a total of 185$, they didn't seem to think the intersecting faces warnings were an issue. I did figure out which operation causes them: the 3 plane fillet. I updated the model more, some minor physical changes, but mostly better parameterization for changing things (I hope). This is my first venture into both physical modeling and 3D printing, so I expect there to be some issues. I already thought of one (forgot to leave some tolerance for the top case to fit around the base, so I'll have to sand it down probably). New model:
https://gallery.autodesk.com/fusion360/projects/134566/battery-pack-case
Luke / LFP discusses the specifics of how heat on an 18650 cell affects the insides (the common method of spot-welding nickel buses onto the cell-ends)
https://endless-sphere.com/forums/viewtopic.php?f=14&t=99012#p1450141
https://endless-sphere.com/forums/viewtopic.php?f=14&t=99012#p1450141
