Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Is this okay - or should I go the long route?
#1
My first pack, my first power wall.

Spot welded the positive side with fuses from BatteryHookup. The other side, these Double nickel strips from China. Now for the crossing direction, do I need to weld that strip on for every row, or as I’ve done it so far - for each 5 rows?

The AC load will be around 7kwh - powerwall will be 14s188P when all 14 cells are done.

See image -

https://ibb.co/rFbMCCw
Reply
#2
Is the load 7kW ?

Or 7kWh over what amount of time?

7kW inverter sound like a strange size inverter. Please clarify what you are going to hook up to the battery pack. If you have done your math before building the battery you should know what you need in terms of hooking the battery up to the system itself
NOTE! My links supplied in this message may be affiliated with Ebay and by clicking on them you agree on the terms.
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
Reply
#3
should go another route, like posting in the correct section Wink
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
Certified 18650 Cell Reclamation Technician

Please come join in general chit-chat and randomness at Discord Chat (channels: general, 3d-printing, linux&coding, 18650, humor, ...)
(this chat is not directly affiliated with SecondLifeStorage; VALID email req'd)
Reply
#4
(09-02-2020, 06:44 PM)Korishan Wrote: should go another route, like posting in the correct section Wink

Hah. I was looking for another section, which one was right?

(09-02-2020, 06:34 PM)daromer Wrote: Is the load 7kW ?

Or 7kWh over what amount of time?

7kW inverter sound like a strange size inverter. Please clarify what you are going to hook up to the battery pack. If you have done your math before building the battery you should know what you need in terms of hooking the battery up to the system itself

I have not decided inverter size yet. The house will maximum pull 7kwh at the same time.

We have calculated on busbars many times, but I’m unsure how to calculate how many nickel strips in the other direction.
Reply
#5
If its max at a time then its kW not kWh.. Kwh is power over time...

7kW is HUGE load!

7Kw with losses would at the battery side be around: 8.4kw in worst case.

8.4kW at 46 volt (minimum voltage of a 14s) is 182A.

Thats 1 A per cell in best scenario. In the worst thats up to 1.5A per cell. I hope you have tested your cells properly?!

Doing 180A towards pack then you need some heavy dury wire and contacts and the busbar need to be able to carry this current with as low resistance as possible.

You should run a HEAVY duty copper wire all the way from one end to the other to support this current. I would say around 30mm2 or heavier even. That nickelstrip is not enough to carry that current alone at all if you connect the pack at one end. You need to distribute it in a good way

As example on my packs that are made to do MAX 80A i have 15mm2 wire in total.
Korishan likes this post
NOTE! My links supplied in this message may be affiliated with Ebay and by clicking on them you agree on the terms.
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
Reply
#6
(09-02-2020, 07:37 PM)M1kkel Wrote:
(09-02-2020, 06:44 PM)Korishan Wrote: should go another route, like posting in the correct section Wink

Hah. I was looking for another section, which one was right?

The one it's in now Wink It's about battery pack design/build.
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
Certified 18650 Cell Reclamation Technician

Please come join in general chit-chat and randomness at Discord Chat (channels: general, 3d-printing, linux&coding, 18650, humor, ...)
(this chat is not directly affiliated with SecondLifeStorage; VALID email req'd)
Reply
#7
+1 OP you need some copper for those currents.
You could add a "harness" with eg say 6 or 8 smaller 6mm2 cables to join at points distributed over the busbars.
Running off solar, DIY & electronics fan :-)
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)