My 110 kWh PowerBucket

MichelKuenemann

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Joined
Oct 10, 2016
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Hi all,

I have started to build a modular "PowerBucket" based on 18650 batteries in august. Once totally equipped it will have a capacity of 110 kWh. The first phase of 10 KWh is finished now.

The first charge / discharge cycle of this battery was made yesterday november 29th 2016. It worked really well and I think I will add the second string of 1000 elements pretty soon !

My project is hosted by Hackaday https://hackaday.io/project/12296-a-110-kwh-powerbucket

This curve shows what happened yesterday - Read the details here https://hackaday.io/project/12296-a-110-kwh-powerbucket/log/49695-first-charge-discharge-cycle


image_pobret.jpg


Watch the current state of the system here: http://km-services.hd.free.fr:443/jour.html

CU
Michel
 
110 !!!! Huge!! Flicitation!

I also connected my first packs a few days ago and just like you said : lithium hold the charge very well, great efficiency!

Looking forwrard to see the next updates.
 
Wow 110kwh!! :shock:
Nice to see a french man (i assume ) talking English.
keep us updated on your project
 
Hi all,

Thank you for your kind and encouraging feedbacks.

The 110 kWh capacity (10 strings) will be reached in a few years. I use only new cells - Considering a budget of about 2000 per string, the limiting growth factor of the PowerBucket is more financial than technical !
I hope (like everyone here) that the /kWh ratio of 18650's will drop dramatically soon.

For now, next step will be to finish the design and realization of the BMS dedicated to this project.

You can see a mockup of this new modular BMS here : <!-- m --><a class="postlink" href="https://hackaday.io/project/12296-a-110-kwh-powerbucket/log/44704-testing-the-bms-with-a-mockup">https://hackaday.io/project/12296-a-110 ... h-a-mockup</a><!-- m -->

Currently the Li string in managed by my "Old" home designed lead-acid BMS that I have adapted (hacked) to acomodate the Lithium battery. It provides a good degree of safety and precision, but the next generation will (should) be much better :)

I will keep you updated as soon as news are available.

BTW: I am french - I live near Strasbourg.

CU soon
Michel
 
Considering the planned size of your battery, did you consider using larger format cells ?

I'm wondering why you selected 18650s - more so as you are only using new ones.

Nice project.
 
ex EV cells

Have you seen what Jason Hughes has done ?
 
Here's something that Jason Hughes (the actor) didn't build .......

attachment.php
 
The entire process is documented on the Tesla users forum, including the BMS

It's a very good (long) read.
 
Hi all,

I am currently building a second 11 kWh string for my PowerBucket. It is made of 1050 X PANASONIC NCR18650PF (2900 mAh)cells.

Check the process out here.

You will notice that I have abandonned the "Tesla Style Fuses". I had fragility and reliability issues with them.

Michel
 
I love those pretty green cells ;)
Was it difficult to solder the copper busbar to the nikkel strips? it seems to be a hard job to make a propper solder joint, i did try, but had no luck with it.
 
wim said:
I love those pretty green cells ;)
Was it difficult to solder the copper busbar to the nikkel strips? it seems to be a hard job to make a propper solder joint, i did try, but had no luck with it.

Hi Wim,

It's also my prefferred cell color. Fresh, clean, and overall GREEN !

It is easy to get very good solder joints. There are two things to consider:

  • usea JumboWeller EZ1 200 Watts soldering iron with a 10 mm wide Tip (as broad as the busbar itself).
  • Put flux paste on both bus bar AND nickel strip

As you see on the photos, I first add some tin on the bus bars - This also heats them up
I put them some flux on the strip
I position the stip on the bus bar and I heat the strip with the iron pushing gently on top of.
The solder melts quickly and the flux insures a perfect and cleanjoint.
I use a flat metalictool to squeeze the tin out of the joint to make it as thin as possible.

CU
Michel
 
Damn that looks pretty.

Dont you have concern about the bottom part of the pack on one of your images? There is 2 rows of cells instead of 1 on the other end.

Ie not a big issue at all on small current but still its a tiny bit uneven :)
 
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