Log Project šŸ¦RoadRunner (Battery Powered Portable PC, in S4M-C #524)

Josh | NFC

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NFC Systems
Jun 12, 2015
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So... I'm in a bit of a predicament



Kinda expected it, just not this close. So close... *sigh*

A bit more close up look...



Horizontally..



I really just need the plastic bit to fit, now the question is, which one do I shave?

Easier route would be to widen the skyslot - but even if done ever so slightly, my guess it'll be jarringly noticeable.

The right way probably to shave the reader, but I'm afraid I'll ruin it - plastic doesn't sand well...

I think plastic hand sands extremely well. Just go slow and don't burn it!
 
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Choidebu

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Time to revive this build again...

Some updates after a while, haven't really got time for the good part of the year!

First, I finally got around to drill proper mounting holes for my drive brackets...



My stepdrill bit does not play nice with my dremel so unfortunately the 6 holes are not countersunk. The side panel still sit flush though, not one screw even scratch it, so I think I'll leave it at that.

Second, the Skyslot card reader I teased about...

It was a roller coaster ride... bought usb3 front panel, unsoldered the cable from it and tried to use angled USB adapter: failed, too tall.

Butchered one port (one usb 3 header goes to 2 type A port) to make the cable come out the sides instead of the bottom: failed, some plastic snapped inside and shorted some pins whenever I insert any device, making the system not even boot at all.

Bought usb 3 type-a connector, soldered the cable by hand, ruining one and failed even stripping these itty bitty wires multiple times....



Then I managed to solder a proper one (after a trip to buy additional connector plus a spare one), but tried plugging it in then nothing works... I mistakenly solder some pins backwards...

Unfortunately in the midst of soldering and testing, I must have fried my card reader since now it won't work even on the back i/o usb ports...

I did make it to work in the end, after painstakingly tested every iteration with flash drives...



So behold my very low profile vertical internal usb 3 port:



The header has 2 ports in it but I snipped one off - don't ask why. (Anyone know where can one buy 20 pin header with 2mm pitch?)

After making sure it works I filled the soldering with hot glue. Then I glued and cut up some plastic panels to get some sort of mounting point or fastener of sorts to enable me to affix it inside the case. Filled it up with hot glue too...

So here's how it looked from the side:



Yes it is angled the same as skyslots, as I wanted it to hold the reader while staying parallel to everything else inside.

And a pic with the (now broken) card reader inserted...



And after some wriggling and pushing and plier action the side panel went in...



The thing is rock solid - perfect height from side panel to side panel, just wedged between the motherboard and the excess cabling. Won't budge whatsoever.

So my next step is to buy another reader, cause, you know, this one is just for looks now.


I DO have another ridiculous plan for this build.

Batteries. Yeah. Inside. Uh-huh.

But as with this update, don't expect me to post again anytime soon hahaha. Family needs to eat, yo.
 

brt02

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I was looking at getting a usb-c port to come out through a sky slot as well, got a 3D printer now so i'm trying to mock up some brackets for it. Love the idea of a card reader integrated into the case. Looking forward to what you do with the battery.

I need to start spending some time in the build logs section of this forum, so many cool builds here. I've only just seen yours, better late than never i guess.
 
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Choidebu

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If I had a 3d printer it would've been cleaner indeed. But, knowing myself, it'd probably be stuck perpetually in design stage! There's a positive side to physical hacking like I do - you can't turn back and revise, you'll have to improvise as you go along otherwise it'll be unusable, so you kinda force yourself to actually finish stuff.

The hardest part is how to fasten such things in the skyslot, i.e. two part clipping system? Panel to panel full height bracket?

A usb type C will require the whole 19 pin of internal usb 3 header, so how about designing a bracket that goes vertically from the mobo header right to a skyslot in the panel?
 

brt02

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It's a 3.1 gen 2 socket on the motherboard that I'm going from, so was thinking of a vertical bracket from panel to panel on one of side vents behind the front panel and using a front panel usb-c cable such as this https://www.amazon.co.uk/CHENYANG-H...7973853&sr=8-4&keywords=usb+c+3.1+front+panel.

Hopefully i won't be modifying the cable. It will just plug into the motherboard header and screw into that bracket that i have yet to make.
 

Choidebu

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Yeah a 3.1 gen 2 works better for type c devices, afaik a type c from a 3.0 header doesn't have power negotiation so it won't fast charge.

But that's OOT.

Yeah panel to panel definitely should work. But consider a clipping system where you have one 3d printed part outside the case, shaped like skyslots only with an outer rim... then you have one part inside the case in which the outer part clips into. Now your port is sandwiched between the panel and this inner part. So outer - panel - port - inner.

I can envision this works cleaner if,
  1. Your port is significantly smaller than skyslot
  2. You don't mind a 'rim' on one of your skyslot
 

Biowarejak

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Or, have an overhang on the 3D Printed part that allows it to sit flush against the interior of the side panel, port flush against the external face. Then use super glue to adhere on the interior side. :)
 
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Choidebu

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Got my new card reader a while back and it's in working order.

Also received 100pcs 18650 battery holders, and last night I tried fitting them in to see how many I can actually cram in the case.



Between the brick and power plug, 'under' the gpu, I can only fit 4...

Thinking I could fit another 4 above the M2 slot affixed to the side panel...

But that's it. There's still some space beside the mobo where the cables and my reader is, but at most only 2 can fit and it'd be a hell to maintain.

Guess 8 cells it is.. Say I use 3500mAh cells. That equates to 28A@3.7V so a 103Whr battery (yes, not really, I know.. ) and I guess that makes it flight safe so there's that...

Bums me out a bit since that means not one hour of single game is possible with the battery.

And I also need 2 not-so-thick flat spaces to put a bms and a dc-ups board in. Oh and a step up board... Thinking somewhere above the gpu for the ups board, and the little bms just on top of either one of the battery packs.

Although I may not need a step up board if I switch to a 12V pico...

For the uninitiated, this may not make sense. I plan to update the second post of this thread to reflect the details on this 2nd part. Some early discussion was had here (On DIY Battery Powered DC UPS, for Portable SFF and Off Grid).

Edit: for those wondering the red cells above are18650 cells, they were from my old 2010ish netbook. And they probably have one fifth of life left (last time I used the netbook it lasted for 15 mins). I also gutted its screen - a measly 11.6" - and plan to make it into an external monitor. This would be done first since the battery project would cost more and need more dedication, tools etc. The monitor would get its 12V power from my dynamo's unused pcie power.
 
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Choidebu

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Fast forward 1 year!
What happened since then?

1> My hdplex ac/dc was fried. Just sheer bad luck maybe, it wasn't even on - was plugging in the pc after working on some cabling, plop it went. Pic in this thread.. Long story short, Larry gave me a new 200W unit albeit in old 160W casing for the price of shipping. Awesome guy!

2> I changed job and we moved back to my home country. We'll be coming back to Australia whenever my visa is sorted out. On the process of moving...



I had separated the monitor and the pc, and the monitor was in this laptop bag with a laptop. It was fine until we got home (I think), but since we didn't pack down straight away, sometime during the night or the following day the bag must've fallen from the table it was on, hit the timber floor on one of its corner, breaking my monitor and our laptop's power button assembly.

The monitor is scrap now. I'm ordering replacement part for the laptop from china, it's only 2 weeks ago - long way to go!



This too. I noticed that one of my motherboard's antenna socket was loose, but I was ignorant and just keep twisting it until it holds. Hold it did, but one day it just snapped.

This thing threw me on a rollercoaster. Turns out these itty bitty connector comes in 3 flavors (at least for now - who knows if they want to go even smaller): ipex, mhf3 and mhf4. You can find ipx or ipex on older mpcie cards, and the current mhf4 on m.2 cards. And my now-broken display's built in wifi antenna? Ipex. Funny thing is, ipex costs peanuts in my country. Like 2-3$ for an ipx to rp-sma pigtail cable. Mhf4 to rp-sma? 40$. Whyyy??

Long story short, china again it is. It supposed to come 10 days ago, or, not until next month. I'm content for now with a dongle.

Ok, update over.

-----===Ć·===----- New Development -----===Ć·===-----

I've mentioned above and perhaps several times, in different threads, that I wanted to pursue battery powered PC.

I decided it is time to slowly begin, while a crucial part is not here yet (a certain reasonably powerful but small, low profile, and power efficient card) I figure I'll be slowly ordering and testing other components as financials allow (and it doesn't allow much these days) anyway, so might as well..

I've lined up some general plan here, I'll just repaste the pics:




This is a sub 200W battery powered system, with automatic charging and power failover using 5S3P 160Whr battery. It should have reasonably fast desktop hardware at current time, 65W cpu and 75W gpu. Further goal would be to develop a custom firmware to monitor and report battery status to windows that it can be OS managed and presented just like a laptop battery would.

The steps toward this would be:
Procure hardwares:
  1. Zotac GT 1650 LP is the ultimate goal, but looking at stock status and inflated prices, no can do.. instead, for now:
  2. Buy used lp card, I settled on R7 240, 30$ in local market. Sell my RX550 while we're at it.
  3. RPS-200-24 to replace my hdplex.
  4. UPS-0528-11B dc-ups board.
  5. 5S 21V Li-ion BMS with balance, or this Tindie one.
  6. 18650 batteries or battery pack retailer. Local prices for authentic well known brands are at 9$/pc, I'm leaning towards cheaper ones at around 5$/pc, which are NCR18650PF and INR18650-29E. It seems that directly importing in from Ali is prohibited in my country....
  7. Connectors, wiring, nickel strips, and tools (do I need spot welder... >_<)
Build the minimum cells needed, test.

Order actual batteries/pack

Make brackets/ mounting hardware: that RPS unit gonna need aluminium plate backing with standoffs and mount screw holes to the case. Battery spacers, bms and fan mounting. 3d print maybe?

Case modifications: I'd need some new holes for the slided up skybracket.

Goals:
1. Automatic battery backup on AC fail.
2. Auto charging and stop charging on ac, auto shutdown on high temp and battery low (although at 16V the dynamo'll give up first I reckon), proper balancing.
3. Survive 1 hr gaming session on battery.
4. (Extended goal) battery status reporting through win10 builtin usb hid class driver.
 
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Choidebu

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In regards to integrated display to replace my broken one, I dug up my old, first laptop ever - a vaio FZ series from my parents' home.

It's got this gorgeous 15.4" display, CCFL backlit, 90% NTSC panel. Latency is bad@ 150 ms or more, but do I mention it is absolutely stunning.

It'd require a same model of display controller board, different firmware, cabling, and the addition of an inverter to run it. Should cost me 35$.

But I don't feel like making it an integrated display this time, probably more like a portable display, just a stand nothing complicated. Maybe because I treasure this panel more than the last one.

This was my beloved:


Any ideas?
 

Choidebu

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Follow up and updates on THE battery project....

This came in the mail today:

Repetitive viewing on a phone screen must've skewed up my size perception - these things are tiny!

Since I don't have the means to test them right away, I just did some connectors for now.


For the BMS, I soldered balance connector and modified the jumpers required for 5S (it came preconfigured for 4S)


For the dc ups board, I desoldered the battery screw terminal and soldered XT60 cable in its place. Not too pretty since the cable is too big for the board (14 awg) so it won't flush and I had to use hot glue to keep em from touching each other.


These are 18650 cells I pulled from dead laptops. The green ones are mine from my first laptop (up there) that I got 12 years ago, and the purple ones are from my friend's laptop (should be bought around 7-8 years ago) which he donated in exchange for shooting and uploading the testing assembly process to youtube. I did not promise him that it'll work ^^.

I'm 100% sure the purple cells work alright, but my green ones... I took great care of them since I used my laptop mostly without it, but judging by their weight and length of time in storage, they must be pretty depleted. Plus they are older cells with worse self discharge.

Next order of business would be to get a liion charger that has revive function. I'm hoping 4 out of 6 greens are still good. After that charge, match in pairs, and assembly to a 5S2P pack.

The cells would be soldered not spot-welded, figured for a run down, for-testing-purposes cells it won't matter much.

I'm also waiting on EPP-200-24 (like RPS, but with PFC). Should be here in 2 weeks.
 

Choidebu

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Epic progress so far, my friend!
Glad that one person actually saw my update!

My build log, as humble as it is, doesn't seem to attract people.

Well, who cares, right?

I've got some time rn to ramble, why not...

So, first... why? Why not a laptop? That must be the first thing most people ask when they see these sort of project.

Well if you ask me, my answer is clear: power.

A sub 1500$ laptop will never be a good enough computing experience compared to desktop PCs.

Battery life is king in the portable space, and that is all they pursue these days. It's like they assume all of us work in cafes all 4 hours a day. Yes you can get bulky slab#gamer#laptop, but there they made another assumption: that only gamers would pay for such monstrosity. What if we just want more cpu and less gpu?

(For 1500$ upwards yes you can find all sorts of customizable workstation laptops)

So my observation leads me to believe that current portable computing power can be classified in wattage:

#1 Sub 50W cloud dependent ARM/Atom devices
#2 Sub 100W pared-down-desktop-components "consumer" laptop
#3 Sub 200W "no expense spared" ultra customization workstation, also ultra expensive.
#4 Sub 300W gaming "slab" top

Now I see a gap there. That unreachable-unless-your-company-issued-you-one workstation laptop. That shiny thinkpad, fujitsu or dell slabs.

I know I can't live with #2 anymore after touching current desktop pc, my phone can do #1, I don't game in lan parties with #4, and I can't afford #3. Or..... can I?

I see a number of projects here in concepts that just pretty much trying to replicate a laptop. Trying to make a perfect (read: ugly slabs) enclosure for it, with displays, keyboards...

Well I see that as missing the point. If we want customization at that price point and power, why do we limit ourself at the first step?

I always tell people who asks me for suggestion in buying laptops; that they should look into two things first: the display, and the keyboard/touchpad.

Why? Cause that's two things you can't change after you buy it! If you don't like either, you're stuck with them, and you're more likely to hate them over time than learn to love them.

Hence I believe we need to start at the machine first. Interface comes later. Wouldn't it be great if one day someone comes up with a thin clam of just display and keyboard, connected with single usb-c cable to your portable pc? Or maybe to your VR headset and a laser aided keyboard? Or maybe a single cintiq tablet?

Think about it. See the possibilities.


*I based $ = AUD, sorry if it is confusing
 
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Choidebu

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Now let's talk technical. Details.

What do we need to power our sub 200W machine?
Say we settled on ITX form factor.

We'd then need a DC-ATX psu. This is non-negotiable, unless you want to shove an entire UPS into your case.

Okay, a DC-ATX capable of 200W. What input then? We've got 12V, 19V and wide-input: 16-24V, 6-30V.

Let's omit 19V - cause then you're aiming for a specific voltage without any benefit other than accepting common laptop adaptors.

Let's also omit 6-30V - too wide, designed for rough environment like boat or car which assumes it gets connected to a generator. Too expensive for our needs.

So the choice is 12V or wide-input 16-24V
Both have merits:

Wide-input means your battery can just plug right in without regulation, as long as its voltage is in range.

12V needs regulation at input, but also means you are not constrained by battery voltage and your brick voltage, so long as your final regulation module can handle it. This means more choice in choosing packs, charging circuit and input power supply.

For batteries, we have a lot: UPSes uses lead acid, laptops use LMO (actually LiMnCO[sup]2[/sup], multiple similar chemistries exist) cells, later on they move to lipo (Li-ion Polymer, or as I'd like to remember it, li-ion in POuch) cells. RCs, drones and e-bikes, hoverboards use LiFePO[sup]4[/sup] cells. There's also NiMh, NiCad...

We are omitting obvious offenders against sff - lead acid for weight and NiMh/NiCad for volume.

Maybe we can omit lipo as well? Unless in pack form, it's usually made to shape and capacity as ordered by the big players unreachable to us.

Now let's leave these choices first, promise we'll get back to it..

The heart of every battery backup system is what you call "power path management" IC or module. For lead acid batteries, supply, load and charge can all be the same, parallel to the battery terminals so this can be omitted.

But in the case of Lithium, prolonged trickle charging is not good for longevity and safety, so a proper lithium battery backup system should charge the battery when needed and stop when it should, while maintaining seamless switchover to battery when mains fail or vice versa when mains returns.

You can, choose not to implement this and just use swappable packs and charge them separately.

For power path management, I found some ready made solutions:

OpenUPS and friends by mini-box.com
> all-included-solution limited to 120W, expensive, and rightly so - it's even got battery status reporting to windows via usb.

UPS-0528-11
> limited to 15A input/output, no output regulation (direct battery output or mains straight), no undervoltage and low battery start protection. Can be added though via daughterboard.

UPS-1228-12
> pretty much everything above, plus output regulation. Output is limited to 8.3A (at 12V) though.

DIY method with mini-box's Y-PWR, separate charging circuit, buck/boost circuits etc.

The choice is easy, I want as close to 200W as possible, so UPS-0528-11 it is.

The implication? Well with no regulation on output we either need a regulator or a wide-input dc-atx. Wide input 16 to 24V it is.

Now that we've decide on our output let's choose our battery chemistry and arrangement.

Battery cells can be arranged in series, parallel or both - pack. The resulting pack's voltage is the sum of the voltage of cells arranged in series, while its capacity is the sum of the capacity of cells arranged in parallel.

First we'll determine how many cells in series we need to be in the range of our dc-atx's input.

Say we go with LiFePO[sup]4[/sup], with nominal 3.2V, range 2.55V to 3.6V.

One configuration would be 6 cells in series, because then the entire pack's range would be 6*2.55 = 15.3V to 6*3.6 = 21.6V.
In fact the pack would never come below 16V, since our pico would shut down when it happened. So each cell will only reach 16Ć·6 = 2.67V.

7S (7 cells in series) would be 17.85 to 25.2V which means individual cells go from 2.55 to 3.43V (24Ć·7).

Both are good contender: 6S meaning we don't need to worry about undervoltage protection, 7S means we never charge them to 100%, which is beneficial for cell longevity.

Following the same math, for LMO cells, with nominal 3.7V, 3 - 4.2V:
5S: 16 - 21V, @3.2 - 4.2V
6S: 18 - 24V, @3 - 4V
For LFP summaried from above:
6S: 16 - 21.6V, @2.67 - 3.6V
7S: 17.85 - 24 , @2.55 - 3.43V

If we are after pack longevity, we'd choose configuration which limits our upper bound. But since (1) our chosen power path manager doesn't have UVP, and (2) its charging circuits requires our supply to be at least 1V higher than pack's maximum voltage, for simplicity's sake we are limited to 5S for LMO and 6S for LFP.

Now if you notice this means we never use the whole capacity of the cells. If the goal was to use every coulomb of charge in the cells, this is not the way to go.

But since lithium batteries are expensive to replace, this is a trade off that even Tesla is making. Idk how true they are, but online articles say Tesla only runs their cells at 70% capacity for its EVs.

And now, how do we decide how many to parallel?

We start at our needs. Maximum load is 200W but safe to say we won't design a pc without wiggle room for peaks and such, so let's settle on ~176W typical max load. That means 8A at 22V, all the way to 11A at 16V.

Yes I arbitrarily choose that number cause it gives nice, even results.

We can now talk about C-rating.

Batteries is rated by how many amperes they can provide in an hour. For bigger batteries it is simply Ah, smaller ones use mAh. 1C, for a certain cell, means a current flowing at a rate of this number for that cell. Different battery chemistry has different recommended rate of charge and discharge.

We'd actually need to consult the datasheet to find out this ratings, but generalization does exist for similar chemistry of batteries.

For most lithium batteries, 1C rate of charge is considered quick charge. Typical is 0.2 to 0.5C for cell longevity.

For LMO, discharge is typically 1C, max 2C.
LFP can go all the way to 25C. This is why they are used in RCs and stuff.

Looking at these, seems like LFP is the way to go isn't it? Well I do think so too, the fact that it's more stable is a bonus.
What's the catch then? Energy density. LFP still lags behind LMO for capacity per volume, a.k.a specific energy. More self-discharge and a little higher cost.

For example, LFP in 18650 form factor is currently limited to 1600mAh. Contrast this to current king of 18650 at 3400mAh.

Good, relatively cheap 18650 (a moniker for its size: 18 mm diameter and 650mm height) can be found in ~2600mAh variants.

This is important, because as I calculated above, we'd need the parallel cells to provide up to 11A. Say we run them at max 2C, this means we want 5.5Ah C rating. While LFP can prob handle that with one cell (flat in 10 mins maybe), LMO needs at least 3 cells in parallel. 3 parallel 2600mAh LMO can provide typical 2.6A*3 = 7.8A and max double that at 15.6A.

5 in Series, 3 in Parallel, 5S3P, 15 cells of 18650 LMO. So there we go. A quick rundown to how I came to this numbers.

While doing this, I realised why noone's doing it in bigger scale.

A properly designed battery backup system have to make a lot of trade offs. A reasonably small system needs to be carefully calculated for it can only serve an equally small range of hardware and uses.

If you are not constrained by weight and volume, UPS is still king. How do you beat a 12Ah 12V battery if you don't mind a 2L box weighing 4kg?

But everyone's got to start somewhere ^^
 
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ignsvn

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Glad that one person actually saw my update!

My build log, as humble as it is, doesn't seem to attract people.

I believe people who are interested in (portable) power delivery do think that your project is interesting.

A sub 1500$ laptop will never be a good enough computing experience compared to desktop PCs.

Yeap agree. The thing with laptop is.. Let's say it has a top mobile CPU, capable of matching any desktop CPU. And let's say they both can reach at 4Ghz top speed.

I can run my desktop CPU at 4Ghz pretty much all day long. But with laptop, we can probably reach that top speed for only X minutes perhaps, before heat becomes an issue & the CPU starts to throttle down.
 
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Choidebu

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I wonder if I should split off this build and the battery project into another thread.

But then again this log is only at 2 pages long anyway.

Also been thinking on a codename.

How does "RoadRunner" sounds? (Please don't say "Beep Beep" - I know that)

It's a lightweight ground bird - implying the build doesn't aim to 'fly', a.k.a pack as powerful hardware as possible, but just enough for most. But...

It just keeps running. On.... and on...
 

Windfall

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I wonder if I should split off this build and the battery project into another thread.

But then again this log is only at 2 pages long anyway.

Also been thinking on a codename.

How does "RoadRunner" sounds? (Please don't say "Beep Beep" - I know that)

It's a lightweight ground bird - implying the build doesn't aim to 'fly', a.k.a pack as powerful hardware as possible, but just enough for most. But...

It just keeps running. On.... and on...

Beep beep. ;)

This looks interesting, I'll be following it!
 
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Choidebu

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Update:

My EPP-200-24 arrives!

Got some hookup wires coming from @Thehack in a week or so, so a clean build would be after that, but in the mean time I plan to test the acdc and the ups to power my system with rudimentary cables/jumpers lol.

Also a good news, my friend gifted me yet another laptop battery to torn apart, so I have 18 batteries now! Enough to test out 5S3P config. At this rate I might forget buying a new set of 18650s entirely..
 
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Choidebu

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This will be my last update until next month. I'm going on a road trip to my wife's hometown and will stay there for the rest of the month.

It actually might be a perfect time to test stuff, but I'm still on the fence about bringing the project along.

Anyway,

I've bought 3 fractal design R3 silent 50x10mm fans...


One will go at one end of the battery pack, two will be at the other end, mounted on top of the EPP psu to provide the 10 cfm it needs to do 200W continuous.

I've also bought a nitecore UM4 (which should arrive tomorrow), to try and charge these cells, and maybe revive some of them if needed. Then I'll catalog them based on capacity and internal resistance. Oh and I bought a cheap multimeter. Again.

I also need to design battery compartment enclosure and psu fan bracket, which I'll most probably do using lasercut acrylic.

I've tried off the shelf battery spacers but 2mm between cells means 62mm thickness for 3, and that won't do.

Instead the cells will have to touch each other (54mm) and 1.5mm on each side. This comes up to 57mm, which is what the s4m-c inner dimension states.

In reality however, that 57mm is inclusive of the inner frame. And that inner frame on the bottom extends to about 15mm in. On paper this is 1.5mm steel, but in reality it should be around 1.2 something (couldn't find where josh stated this on the forum, this is where I understood the importance of caliper in our world).

Actual outer height of the case is 63mm, with 1.5mm aluminium side panels we have 60mm panel-to-panel height.

This means I have an extra 3mm to work with. So I plan to do 3 circles smushed and bevelled with 54mm + 1mm wiggle room, and 2mm on the sides. As a bonus I can enclose them on the sides with more 2mm acrylic (skyslotted for airflow), giving it structure without invading potential gpu space.

It'll be 2 side panels and 9 layer panels: 2 for fans, 2 for between cells' tops and bottoms, 4 for structure containing the cells.

Prolly hard to understand without some cad drawings, but mind you I am using this post to braindump. This is the only documentation I have, and refer back to, about this project so far. I haven't got the time to actually put time behind Illustrator and cad this for lasercut, but trust me when I do I'll be putting this post up for reference haha.

Actually, I might do that now...