Schaef's Powerwall

Schaef

New member
Joined
Oct 26, 2020
Messages
14
So I've been watching a lot of Youtube and following threads here lately, and figured it's about time that I threw up everything I've done so far.

I'd been thinking about building a project like this one, but wasn't quite sure about how to go about building such a system, until I found the HBPowerwall Youtube channel, so i'm kinda following in his footsteps and building the 14s80p powerwall.. I am wondering, however, if I should make it an even 100p pack, just for a little bit more capacity.

Anyways, onto the still-ongoing build.

To start off the project, I bought ten tp4056 chargers for charging and an Opus Bt-3100 capacity tester. I purchased 60 modem batteries online to see what it would take to make a full scale powerwall without buying all the batteries needed and then spending tons of time taking the packs apart.
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Took these pictures cause it looked cool lol..

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After tearing apart the pack, and sorting the batteries, the BMS circuit board, and the nickel metal, I sorted batteries per brand and type... or color lol.. Eventually, I'll recycle the nickel metal and the BMS circuit board unless somebody wants them for a project or something.. I have no need for them..
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Anyways, after sorting them, I charged and then capacity tested each cell, and sorted them per mWh, and only keep cells above 1950 mWh. These batteries have almost all been above that magic number, however, and I'm fine with that.. and since I started the project, I've purchased almost enough to finish the system.. The slowest part of this build has either been only having purchased one Opus... orrr shrink-wrapping the cells white..and the Opusdied part way through the capacity test process, but still in warranty sooo I got it replaced.


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Now you're updated to the present day, waiting on capacity tests to finish...

Eventually, I plan on purchasing either the Sigineer 3000w orthe Sigineer 6000w inverter, I haven't really decided for sure, and it all depends on how large scale this project ends up being, and how much of the house I end up running.
Ill pick up a Batrium BMS for balancing and all of the exciting management of batteries that happens haha..
I'd like to build this to be scalable, to add capacity once(if!) I find room for it.
Once I've got the system up and running, Ill add solar to make it a true off-grid system.

In total, this project will end up costing a little over $3000, and to build each additional 14s80p pack, if I keep spending ~$0.50/cell(yikes), it'll cost around $600-$650, not including more Batrium cell moniters. If I'm getting free batteries, that cost drops significantly, closer to $200/14s80p pack, again, without Batrium cell monitors. Once the project is nearing completion, I can share my cost breakdown Excel sheet, if people are interested

Also, I'd like to contest for youngest Powerwall builder, if thats allowed.. I'm currently a high school seinor, and building this as a project for a self-policed class. I'm an electrician by day, and from everything I've learned there, as well as other projects, I figured I was up to the task! So far, it's been a great learning experience and I don't regret anything so far.
 

Schaef

New member
Joined
Oct 26, 2020
Messages
14
Short little update - I’ve got almost all the batteries I need to build the wall.. around 920..
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I got a bunch of scrap #6 for the pack wiring, stripped it all out, and bent it all into a shape to build the pack. I’ve purchased everything needed to actually build each pack, and I did so before HB posted the vid where he talked about how fusing both sides seems to be useless.. so I’ll be fusing the positive with 2A glass fuses, and the negative with 5a fuse wire.

i do get curious about the accuracy of the opus when this happens, however..
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Capacity does take a lot of time.. especially because I’ve only got one opus.. but I’m finally getting close!
 

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Dr. Dickie

Member
Joined
Sep 23, 2020
Messages
122
Fantastic, look forward to following your progress.
As far as Opus, yeah, in my experience (I have two Opus I used), one gave about 50mAmp capacity more than the other Opus. I also notice a statistical improbability of two cells next to each other having the exact same capacity--but considering the noise level, I figured it was going to be a wash.
Capacity takes time, then you have to have them sit for a month to check for self-discharge.
What I did was have to Miboxer chargers, so I measured IR, charged the cells in one changer, then put them into the Opuses (Opi?) for capacity, then, after capacity back to the charger to get them back up to full charge. Since each step took about 5- hours, I could get 24 a day done that way (since there were 24 cells in play at any given time).
 

chuckp

Active member
Joined
Jul 29, 2018
Messages
384
Looking forward to seeing your progress.
I to like Dr D. Use a separated charger for charging cells and then I have three Opuses (or Opi 😂 like it) for capacity testing. Separate 4 wire IR tester. Capacity on the Opuses can easily be different by upto 100mAh between chargers. Since we put so many cells in parallel and the way we build our packs that’s not really a huge difference to be concerned about. I use the pack builder but some of us use random selection from 100 mAh bins. Obliviously the closer the better. I do however capacity check each completed module before putting them into service to confirm that they are matched. I have a separate 150W capacity tester that I use for checking the completed modules.
 

Schaef

New member
Joined
Oct 26, 2020
Messages
14
Another smaller update.. just processing more cells, and getting big packages in the mail!.. I Think I now have all the batteries that I need.. that'll depend on if they all test good or not.. but they have so far. I received my WM4 a few days ago in the mail, and am waiting for my Inverter now. I ended up purchasing the Sigineer M5000H-48BP inverter, and should get that later this week. The master plan is to connect the batteries to the Inverter, which actually outputs 240v. I'm in the US, however, so that will go straight through to a transformer, which will convert my 240v to 120v.
I suppose the biggest questions I have now are just where to put everything.. cause it takes up some good room! Right now, the plan is to build a concrete 'box' under the stairs in the house, in which I'll keep just the batteries inside. This way, they're in a climate controlled area, but not much of a safety(burn the house down) issue. I'll bring wire outside the 'box', and connect to the inverter from there. I'm planning on separating each pack with Lexan or something, to (hopefully) protect them from each other in a vent/fire situation. Keep in mind, however, that this is very tenetive. I'm thinking this is the best route for me, however.
 

OffGridInTheCity

Well-known member
Joined
Dec 15, 2018
Messages
1,462
Another smaller update.. just processing more cells, and getting big packages in the mail!.. I Think I now have all the batteries that I need.. that'll depend on if they all test good or not.. but they have so far. I received my WM4 a few days ago in the mail, and am waiting for my Inverter now. I ended up purchasing the Sigineer M5000H-48BP inverter, and should get that later this week. The master plan is to connect the batteries to the Inverter, which actually outputs 240v. I'm in the US, however, so that will go straight through to a transformer, which will convert my 240v to 120v.
I suppose the biggest questions I have now are just where to put everything.. cause it takes up some good room! Right now, the plan is to build a concrete 'box' under the stairs in the house, in which I'll keep just the batteries inside. This way, they're in a climate controlled area, but not much of a safety(burn the house down) issue. I'll bring wire outside the 'box', and connect to the inverter from there. I'm planning on separating each pack with Lexan or something, to (hopefully) protect them from each other in a vent/fire situation. Keep in mind, however, that this is very tenetive. I'm thinking this is the best route for me, however.
You didn't mention your home's main panel / wiring. If you can, I'd put the inverter/distribution-box so you can reach the home's main panel - this will let you tie into home wiring for consumption and in the other direction use the grid to charge your battery (if your inverter has charging capabilities). It need not be physically close so much as just leaving a 'route' to run some wire. In my case its 150ft under/up/over/down (complicated) - can't do it myself - and I wish I could have.

BTW - Congratulations on your progress!
 

Schaef

New member
Joined
Oct 26, 2020
Messages
14
Well I'm halfway through the cells that I got last.. I bought 360 batteries from BatteryHookup and had been processing them... Its the modem batteries with 6 cells inside. Anyways, I'm about 200 batteries through capacity testing, and I have gotten about 15 good cells from this batch... so I haven't been too excited with this last batch. I ended up purchasing 200 cells from BatteryClearingHouse, and just got those in the mail today, so fingers crossed! I've currently got about 1900 cells, and about 1,000 of them are either too low in capacity (less than 1950mAh), self discharge, or were the Sony G5 cells, which I tested only a few of, and was so disappointed in the mAh, that I decided they weren't worth testing... I've got about 320 of those alone. All this being said, I'll plan on selling/recycling whatever I don't end up using, so if people want cells, I'll have plenty:rolleyes:😂..

Now, to respond to OffGridInTheCity - I am planning on putting the entire system underneath the stairs in the house, which is about 10 feet from my panels. The room itself will end up being fireproof, (concrete) and is my first option. My second option would be to build a little shed or something outside for the system, but would have to heat it in the winter somehow, since our temps get pretty cold in the winter.
 

floydR

Well-known member
Joined
Aug 23, 2017
Messages
1,002
I vote for outside in a shed. For ideas look at what wolf is doing to warm his shed.
Later floyd
 

Schaef

New member
Joined
Oct 26, 2020
Messages
14
Well... in the past month or so, I have been thinking about my entire setup, and I have decided that it wasn't good enough for me, hence why I'm now selling a whole bunch of cells, as well as an inverter on eBay. Basically, I decided I needed more power, and less points of inefficiency, so I have switched to using a different 18650, and am looking at purchasing a different inverter as well. I've also decided to put my batteries in the fireproof room I was talking about in a earlier post. This allows everything to stay inside; temperature is the same all year, panel is right next to the system, and accessibility. Anyways, I've got lots of cells on the way, as well as hopefully an inverter in the near future.
 
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