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There's a new wall in Germany!
(02-23-2019, 11:32 PM)at21 Wrote: Wow, thx owitte!
Im totally impressed. I live in Salzgitter and want you to ask, if it’s possible to have a look to your masterpiece.
Greetz auke

Sorry for the late reply, if you want to come over, just pm me Smile 

Have sun!
Oliver

(03-07-2019, 10:29 PM)Chimaera Wrote: Hello. I really liked Your work, You are good. I would like to ask you to reset the full description and used details and how to do it. I just have a crisis in Ukraine and it's getting more expensive, and saving electricity would have helped me a lot. if you can go to the email:********. Thank you in advance.

As Korishan stated, just send me a private message. Hope you understand that I don't have the time to fully document my work here, but if you have specific questions, I will do my best to help you (like most others here).

Have sun!
Oliver

Cells tested: 6.234 (overall: 12.414 Ah, average: 1.991 mAh)
Cells in production: 3.360 (overall: 7.056 Ah, average: 2.100 mAh)
Powerwall setup: 7s480p, 1.008 Ah, 26 kWh
Project page
Live solar/powerwall values
Daily graph
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How do you add new packs in parallel to your already installed packs. They need to be in the same state of charge or voltage that's clear. But how do you make it?
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If owitte does not mind, I may be able to give You a few hints.

If Your new cell bank is within 100 mV it should be safe to just connect up.

If Your newbuilt 7s bank is fully charged, and Your existing bank is not, You may do this:

Find Yourself a standard 12V 40/45 W car headlight bulb. Connect the negative ends together and connect the bulb between the 2 positive connectors.

When the bulb does not glow any more, Your banks are equalised enough to be safely connected.

ChrisD
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Often it is so easy. Thank you. I always asked myself how a resistor could help equalizing 2 Packs. Now I know. And you take a resistor with optical control, cool.
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Again great wall.
I am going to do (not) exactly the same i think.
I will ?tilted? with 90 degrees, and use 100 cell a pack flat on the wall, 14 packs in one row for 48 volts.
So basically your wall is horizontal, i will use it vertical.

Really nice job neighbor!excellent.
So you invented this term: the "cartridge" type wall?
Or is this not a "cartridge" wall?

Thanks for your time and effort to post things around here, very much appreciated.
Selling everything at marketplace.
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(05-20-2019, 03:00 PM)Maniac_Powerwall Wrote: Often it is so easy. Thank you. I always asked myself how a resistor could help equalizing 2 Packs. Now I know. And you take a resistor with optical control, cool.

Hi,

ChrisD5710 is right, your new packs need to have approx. the same SOC/Voltage in order to connect them together. Otherwise you'll have a huge balancing current flowing from your new pack to the bank or vice versa, depending on which voltage is higher. I usually use a 20W halogen light spot to discharge a pack to the proper SOC. But it's not absolutely necessary to be within 100mV... you just have to make sure that the balancing current doesn't blow your fuses and you cells are capable of that higher charge/discharge current.

Have sun!
Oliver

(06-21-2019, 06:09 PM)100kwh-hunter Wrote: Again great wall.
I am going to do (not) exactly the same i think.
I will ?tilted? with 90 degrees, and use 100 cell a pack flat on the wall, 14 packs in one row for 48 volts.
So basically your wall is horizontal, i will use it vertical.

Really nice job neighbor!excellent.
So you invented this term: the "cartridge" type wall?
Or is this not a "cartridge" wall?

Thanks for your time and effort to post things around here, very much appreciated.

Hi and thanks for the compliment Smile . I know, if you have 48V in 14s, you wall needs double the height of mine Big Grin , so tilting it is a good idea.

I didn't know about the term "cartridge" wall, but that describes pretty much exactly what I have built. I only know of two things that I invented and everyone seems to use now: Resistor legs as fuse wires and copper tubes as bus bars...

Have sun!
Oliver

Cells tested: 6.234 (overall: 12.414 Ah, average: 1.991 mAh)
Cells in production: 3.360 (overall: 7.056 Ah, average: 2.100 mAh)
Powerwall setup: 7s480p, 1.008 Ah, 26 kWh
Project page
Live solar/powerwall values
Daily graph
Reply
Hi Guys, here's an update from my powerwall:

After biulding a box as a seperate battery bank with 700 cells (see here somewhere in the middle of the page) and a broken balancer, I decided to go back to the roots and just add more capacity to my existing powerwall. But since there's no more space at the wall, I extended it with flexible tubes (aka cables) into a shelf. Now there's space for another 7000 cells / 350 packs / 50kWh.

I took the box apart again and added the 7 packs (100p) from it to the wall and also already added another 21 packs. Overall, I now have 3360 cells in a 7s480p config (26kWh) in production. Already started to build the next 14 packs for another 2kWh...

As you can see from the pics, I now connect the packs with stainless steel clips. Found them accidentially on Amazon, they're sold as clothespin Big Grin . The spring is quite strong and it gives good contact with the copper terminals of my packs. No need for nuts and bolts anymore, makes maintenance even easier.

Have sun! Cool 
Oliver
 

Cells tested: 6.234 (overall: 12.414 Ah, average: 1.991 mAh)
Cells in production: 3.360 (overall: 7.056 Ah, average: 2.100 mAh)
Powerwall setup: 7s480p, 1.008 Ah, 26 kWh
Project page
Live solar/powerwall values
Daily graph
Reply
Don't expect to transfer high currents using those stainless steel clips. SS has a much higher resistance than copper and will be the limiting factor. Constant high loads will cause them to start to get hot.
You are also limiting your connection to only the ends of the clips, so the contact pad is very small.

Good idea for testing, but I wouldn't rely on them for production application.

IMHO, nuts/bolts are the best way to go as it provides a large contact area and a solid connection.
owitte likes this post
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(09-11-2019, 12:14 PM)Korishan Wrote: Don't expect to transfer high currents using those stainless steel clips. SS has a much higher resistance than copper and will be the limiting factor. Constant high loads will cause them to start to get hot.
You are also limiting your connection to only the ends of the clips, so the contact pad is very small.

Good idea for testing, but I wouldn't rely on them for production application.

IMHO, nuts/bolts are the best way to go as it provides a large contact area and a solid connection.
You're right, I'm just testing these clips. But until now, it looks quite good. Even on higher loads, nothing gets warm. But I stll need to measure the current flow from packs connected with the clips under higher load... we'll see.

If they don't work properly, I already planned to replace them with copper bars and nuts and bolts...

Cells tested: 6.234 (overall: 12.414 Ah, average: 1.991 mAh)
Cells in production: 3.360 (overall: 7.056 Ah, average: 2.100 mAh)
Powerwall setup: 7s480p, 1.008 Ah, 26 kWh
Project page
Live solar/powerwall values
Daily graph
Reply


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