many 1s 120p packs in series to 48v

Cancri

Cancri

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Nov 2, 2019
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your thoughts on this? I am considering the idea of building many 1s 120p or more packs and hooking them in series to get to 48 volts, then have them in parallel with another set just as large.this will eventually be what will become a whole house powerwall being mounted in a very nice industrial MCC cabinet that I am getting through work. its fairly large so building a fairly large wall is the goal. what are the downsides to using this config and the advantages if there are any. I also have access to whatever sized cable I could ever need.
Thanks for your time and knowledge in advance.
 
there are many 14s 100p powerwalls on this forum look arround and use the search function and you find a lot of stuff about your setup that you are building :D
 
Thats basically what everyone does.
 
Only people who make a single pack that is 7s, 14s, etc and many in parallel (ex. 14s80p) are those who are using it in some sort of portable application like a gocart, large power bank (some have used a suitcase or large container), and the like.

Recommendation on building large parallel packs and then series connect them, make your connections so you can have individual strings so if you need to take one out of service you can without needing to bring the whole system down.
 
thanks for the confirmation on my plan guys. its great to have this resource.
 
Cancri said:
thanks for the confirmation on my plan guys. its great to have this resource.
Click to expand...

My powerwall is loosely 14s120p (as you have talked about).

I start with a base pack of 130ah (1s60p) and couple 2 together to make a base 260ah (1s120p) as you see here.

image_xvgzat.jpg


Each row of 14s120p yields 260ah@48v ~12.5kwh. I went with this 14s120p for shelf size and weight and Batrium longmon considerations. Turns outBatrium longmon easily balances 1s120p pack so1s240p or 1s300p 'balance wise' with Batrium is no problem. However, the physical weight etc is more convenient at 1s120p for me.

image_ywklel.jpg



The *key thing* that I did (accidentally) is I have a 'base pack' that can accommodate 76physical cells - using the cell holder structure to protect the +/- lugs. Typically I only need 46 to 60 cells to reach my standard 130ah per base pack - depends on the cell type. Putting to base packs together give me 260ah/pack and severalempty spaces for each pack. Once I put the packs online, I found that 5 (of 42 packs) so far have needed some tweaking - and I've added a few cells to them to bring them up with the other packs so that I have really goodbalance.

This is of course completely arbitrary to your situation, battery mounting, physical strength, area of work etc... I think every single person has done something a little different.Just sharing my experience in case it helps you :)
 
I have a large mcc cabinet from work that will house my power wall cabinet its a little over 6ft tall and 4ft wide. Will be anchored to the concrete floor of my garage. With four locking doors two on each side, one door has a thick acrylic window that runs most of the doors length. The other side has a 15 in flat screen monitor. Can i output the batrium screen to that monitor you think?
 
Cancri said:
I have a large mcc cabinet from work that will house my power wall cabinet its a little over 6ft tall and 4ft wide. Will be anchored to the concrete floor of my garage. With four locking doors two on each side, one door has a thick acrylic window that runs most of the doors length. The other side has a 15 in flat screen monitor. Can i output the batrium screen to that monitor you think?
Click to expand...
The shelves in my picture are exactly 48" and have 14s worth of packs per row - so you should be able to fit a14s 'battery' per shelf in your cabinet.

>15 in flat screen monitor.
The standard batrium 'piano-key'screen is a windows application - so sure as long as the monitor is hooked to a windows machine. Otherwise, you'll need to go deeper with your own app that reads Batrium info.
Here's the standard Batrium screen from my own system:

image_vbtpww.jpg
 
Depending on your battery supply chain have you considered using any other sort of large format battery?

If you are opting to do it for as little money as possible processing reclaimed cells is great, and the process is well documented, but many have also went the route of buying other types of batteries (EV modules, LiFePO4 prismatic, or similar)

Just something to consider before committing to a direction. While I enjoy using 18650 cells for portables and smaller projects, its a significant undertaking to source, process, QC, and fabricate batteries using 18650 cells. I would weight this against the cost of cells and the cost to make them into packs. You might be surprised at the cost per kWh comparison.
 
CrimpDaddy said:
Depending on your battery supply chain have you considered using any other sort of large format battery?

If you are opting to do it for as little money as possible processing reclaimed cells is great, and the process is well documented, but many have also went the route of buying other types of batteries (EV modules, LiFePO4 prismatic, or similar)

Just something to consider before committing to a direction. While I enjoy using 18650 cells for portables and smaller projects, its a significant undertaking to source, process, QC, and fabricate batteries using 18650 cells. I would weight this against the cost of cells and the cost to make them into packs. You might be surprised at the cost per kWh comparison.
Click to expand...

Agree 100%. I'm 18650 because my battery bank is 2/3 complete.. so its too late for me at this point as 18650 is cheaper in the short run and I have time (to build them up) and I have trusted sources to buy 18650s from hard experience.

If you could go tesla modules or Nissan leaf cells (bigger per unit)or LifePo4 (bigger and longer life) from the get-go, it might be easier in the long run. The problem here (for me) is establishing a trusted source to buy these things at a price near enough 18650 to take the plunge - I was just not able to do this.

18650 cells are 'many small units' and I've spent nearly 2 years part-time (I'm retired so its OK for me) processing 7,000 cells with 2,000 more on the way. Its been a *large* amount of personal time/commitment to process so many 'small' units.
 
OffGridInTheCity said:
Cancri said:
I have a large mcc cabinet from work that will house my power wall cabinet its a little over 6ft tall and 4ft wide. Will be anchored to the concrete floor of my garage. With four locking doors two on each side, one door has a thick acrylic window that runs most of the doors length. The other side has a 15 in flat screen monitor. Can i output the batrium screen to that monitor you think?
Click to expand...
The shelves in my picture are exactly 48" and have 14s worth of packs per row - so you should be able to fit a14s 'battery' per shelf in your cabinet.

>15 in flat screen monitor.
The standard batrium 'piano-key'screen is a windows application - so sure as long as the monitor is hooked to a windows machine. Otherwise, you'll need to go deeper with your own app that reads Batrium info.
Here's the standard Batrium screen from my own system:

image_vbtpww.jpg

many thanks. the bank in your avatar picture. is that a 40kwh bank? btw. thanks for the info on the batrium screen. sounds like a little itx board with some integrated graphics might be in order as well.
Click to expand...

CrimpDaddy said:
Depending on your battery supply chain have you considered using any other sort of large format battery?

If you are opting to do it for as little money as possible processing reclaimed cells is great, and the process is well documented, but many have also went the route of buying other types of batteries (EV modules, LiFePO4 prismatic, or similar)

Just something to consider before committing to a direction. While I enjoy using 18650 cells for portables and smaller projects, its a significant undertaking to source, process, QC, and fabricate batteries using 18650 cells. I would weight this against the cost of cells and the cost to make them into packs. You might be surprised at the cost per kWh comparison.
Click to expand...
when it comes down to time put into the project I am more than happy to spend that instead of money. If I am busy creating something then Im not getting into trouble or going stir crazy. I am one of those folks that if I have nothing to do I will find entertainment pretty quickly and thats not always a good thing.
 
>@Cancri said "...the bank in your avatar picture. is that a 40kwh bank? btw."
Yes, I use 260ah * 52v = 13.5kwh per row of 14s120p. 3 * 13.5 ~ 40kwh. I'm currently adding 2 more rows for another 26kwh to take me to 66kwh battery bank. This is because I'm adding 21 more panels + 2nd inverter to power my home AC.


>@Cancri said "...thanks for the info on the batrium screen. sounds like a little itx board with some integrated graphics might be in order as well."
For direct access to Batrium info - start with this recent thread https://secondlifestorage.com/showthread.php?tid=8198&highlight=Batrium for some ideas.
@Daromer has a GitHub with working WatchmonUDPlistener to access Batrium info - complete with UDP specs etc. (my hat is off to his sw development skills)
@Daromer is also youtube "DIY Tech & Repairs" channel and has some older youtubes PLUS it looks like he's starting a new series, see
on Rasberry PI, hopefully following up with latest access to Batrium.

I just bought my Pi and I may try to follow along / get it working :)
 
wait....you have a 40kwh bank and you cannot run your home AC on it? are there days where you are topping 60kwhs?
what is the SEAR rating on your unit? how many "tons" is it

Humble beginning.
image_awpxrh.jpg
 
Cancri said:

CrimpDaddy said:
Depending on your battery supply chain have you considered using any other sort of large format battery?

If you are opting to do it for as little money as possible processing reclaimed cells is great, and the process is well documented, but many have also went the route of buying other types of batteries (EV modules, LiFePO4 prismatic, or similar)

Just something to consider before committing to a direction. While I enjoy using 18650 cells for portables and smaller projects, its a significant undertaking to source, process, QC, and fabricate batteries using 18650 cells. I would weight this against the cost of cells and the cost to make them into packs. You might be surprised at the cost per kWh comparison.
Click to expand...
when it comes down to time put into the project I am more than happy to spend that instead of money. If I am busy creating something then Im not getting into trouble or going stir crazy. I am one of those folks that if I have nothing to do I will find entertainment pretty quickly and thats not always a good thing.
Click to expand...


You may have missed the point I am trying to make

I paid LESS money for my EV cells, than I would have for salvaged 18650 batteries and the materials required to build them into packs.
You are also more likely to have problems or spend additional money in fix long term using very close to end of life cells.

I understand keeping busy if good, but not at the cost of the end result. You live in the US, getting a EV pack is pretty easy. All I am saying is to REALLY consider your battery options before really jumping into the deep end.

Just as an example
I got 33 kWh of capacity in one trip.
All the cells are testing at or near full capacity.
They are all consistent and healthy from my charge/discharge test.
The overall quality, consistency, and performance far exceeds anything I could have did with laptop cells and for less money.
I was so impressed with the end result that I could not imagine doing a large scale powerwall any other way.

Note: I still source and process laptop packs and 18650 cells for fun, so I know what goes into both. At the bare minimum, just try not to overpay for laptop packs because I see people spending way too much. Medical packs on the other hand are generallyin much better condition. Just be picky about your cells.
 
CrimpDaddy said:
Cancri said:

CrimpDaddy said:
Depending on your battery supply chain have you considered using any other sort of large format battery?

If you are opting to do it for as little money as possible processing reclaimed cells is great, and the process is well documented, but many have also went the route of buying other types of batteries (EV modules, LiFePO4 prismatic, or similar)

Just something to consider before committing to a direction. While I enjoy using 18650 cells for portables and smaller projects, its a significant undertaking to source, process, QC, and fabricate batteries using 18650 cells. I would weight this against the cost of cells and the cost to make them into packs. You might be surprised at the cost per kWh comparison.
Click to expand...
when it comes down to time put into the project I am more than happy to spend that instead of money. If I am busy creating something then Im not getting into trouble or going stir crazy. I am one of those folks that if I have nothing to do I will find entertainment pretty quickly and thats not always a good thing.
Click to expand...


You may have missed the point I am trying to make

I paid LESS money for my EV cells, than I would have for salvaged 18650 batteries and the materials required to build them into packs.
You are also more likely to have problems or spend additional money in fix long term using very close to end of life cells.

I understand keeping busy if good, but not at the cost of the end result. You live in the US, getting a EV pack is pretty easy. All I am saying is to REALLY consider your battery options before really jumping into the deep end.

Just as an example
I got 33 kWh of capacity in one trip.
All the cells are testing at or near full capacity.
They are all consistent and healthy from my charge/discharge test.
The overall quality, consistency, and performance far exceeds anything I could have did with laptop cells and for less money.
I was so impressed with the end result that I could not imagine doing a large scale powerwall any other way.

Note: I still source and process laptop packs and 18650 cells for fun, so I know what goes into both. At the bare minimum, just try not to overpay for laptop packs because I see people spending way too much. Medical packs on the other hand are generallyin much better condition. Just be picky about your cells.





I completely misunderstood your post, I thought you were telling me time vs money. as in ev packs would be more expensive but easier and faster. my bad. off to search the web for ev packs and such. research time. i had not considered this option as I thought pre built packs would be exorbitant in price.
Click to expand...
 
Cancri said:
wait....you have a 40kwh bank and you cannot run your home AC on it? are there days where you are topping 60kwhs?
what is the SEAR rating on your unit? how many "tons" is it

Humble beginning.
image_awpxrh.jpg

Click to expand...


My current system of 24panels (7kw PV array) tops out at 45kwh/day in summerfrom which I get 1150kwhin Jul and Aug (after inverter losses) and this powers the main house (lights, kitchen/cooktop, refrigerators, hot water heater, computers, workshop/tools, etc)

The 22yr oldACcompressor burns a1000kwh / month in Jul and Aug -so I need additional power to accommodate. It draws up to 23a@240v. I have room for 21 more panels (6kw) and will need anotherinverter to handle this additional load.The plan is to replace it with a whole house heat pump soonand be able to cool the house from solar but alsoheat the house (at least a few hrs a day) as well. Its 2,700sq ft so 6-7 Ton range.

The primary reason for such a large battery besides supporting 2,000kwh/month is to attempt longevity thru very low DOD. I'm hoping to get DOD below 30% on average and that the battery bank will actually last 1,000(s) of daily cycles at such a low DOD. We'll see over time....
 
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