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Vinnie & Shaun Design
#11
Holders cost. Imagine doing 29000 cells like i have... Or just doing a 10ke system with 1400 cells. Spotwelding is faster and cheaper even with learning it all.


PCB in all its glory but they need to be mounted together too
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#12
(03-04-2020, 05:57 AM)daromer Wrote: Holders cost. Imagine doing 29000 cells like i have... Or just doing a 10ke system with 1400 cells. Spotwelding is faster and cheaper even with learning it all.


PCB in all its glory but they need to be mounted together too


You make a good point, I guess we could do some rough math regarding the battery holders.



10kW - 1400 Cells - Based on the Vinnie Marco Designed PCB's.

Each board holds 60 cells, so that's 24 boards rounded up (24 x 60 = 1440).

Each board would require 12 x 4-Cell Holders and 4 x 3-Cell Holders.
The 4-Cell Holders are 0.34p in GBP (around $0.26 in USD), the 3-Cell Holders are 0.32p ($0.24).

24 Boards would require 288 x 4-Cell Holders and 96 x 3-Cell Holders in total.

Per Board, that's £4.08 for the 4-Cell holders and £1.28 for the 3-Cell Holders. Total Cell Holder Cost per Board = £5.36 ($4.15).
24 Boards x £5.36 = £128.64 ($99.64) in Cell Holders.

Shipping as always hurts, I guess the more you buy in one go the better but I would like to think you could get 384 Cell Holders shipped for £50 ($38.73). 

So with a shipping fee of £50 (I don't know how realistic that is), the estimated Cell Holder Cost would be £178.64 ($138.37).

Additional Notes:
I costed this up using the plastic Cell Holders.
In the PCB design example, they used the metal clips which are dirt cheap, pennies.
https://github.com/WannaBAcoder/PCB-Powe.../README.md
Personally, I don't like the clips even though the plastic holders cost around 10 times the price of the clips.

I used my local currency GBP in the UK and a rate of 1.291 Dollars to the Pound for the US Dollar conversions which was correct at the time of writing.

So in conclusion, it will cost quite a bit more than adopting something like a DIY pack build using Nickel Fuse Roll. 
I don't think any of us was under any illusion that wouldn't be the case. I mean this was just a Cell Holder costing.
Going the PCB route also has Fuse costs and the PCB's themselves to factor in!

Its been a useful exercise, I costed up 32 feet of Nickel Fuse Roll to do 1400 Cells too and the cost was $84.18, $54.19 cheaper than Cell Holders but again going the Nickel route includes fusing so not a true comparison.

I may do a complete costing if I get bored of making Vinne's PCBs just for the hell of it.
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#13
I built a test system using pcb all is well but long term a nightmare. The small fuse tracks burnt out maybe a pulse or something Not sure so settled on traditional build. My moto build big and draw small. I have 15kw system and draw max 43amp running for 14 months now no problems at all. I have a cheap Chinese bms rated 100amp tracks voltage high and low also a active balancer (it took 19 days to get into balance) now I run pack within 20ma at high end without balancer. Takes about 3 months to drift to 90ma then reapply balancer.
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#14
Thanks, useful info, I decided to build my main power-wall as a 14S300P via the cell holder route.

I have a load of 7S Battery PCB's that I was going to sell on but have decided to keep them for future smaller projects where I can just quickly assemble as many PCB's as I need for whatever purpose.
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#15
I built a small pack with these a while back. The concept is neat but it's very expensive. Additionally, there is so much exposed metal, once you have a few boards stacked up, there is just no good way to grab it. I ended up having to use gloves and didn't even like doing that.

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#16
Hi,

I'm a newbie and this is my first post in the technical part, so please be patience with me and my ignorance, I saw the same Mike's cell holders in a youtube video from a Puerto-Rican dude (Hugo Tirado) but he is using wood for the structure and copper wire to pos/neg and fuses, not so pretty but practical. IMHO this is the best way to replace a fail cell, because it is not necessary to disassemble the whole pack and I will use it in the future. But just a question, remember I'm an ignorant newbie, I'm wondering if it would be possible to add one or a combination of leds to the system in order to identify more quickly the fail cell when the fuse is broken.

Thank you very much in advance
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#17
(05-14-2020, 04:27 PM)elnaib Wrote: I'm wondering if it would be possible to add one or a combination of leds to the system in order to identify more quickly the fail cell when the fuse is broken.
Not sure why the fuse wire would break unless overload or some bad event occurred.  Even so, a visual check or volt meter check of each cell's connection to the bus would find these in short order.     

My focus is at the pack level - e.g. to be able to find packs that can't maintain their balance within the battery.    Once you identify a bad pack, then fix/rebuild (at cell level) comes into play... which means you want to design the battery so you can easily remove/replace 'a pack'.

Once you have the bad pack isolated, then you want to be able to do things like
- Look for heaters while the pack is discharging or charging - e.g. some kind of charge/discharge rig for an individual pack.
- Be able to isolate cells from the buss (or the physical pack) to check for self discharge / 0v. In my case, I simply un-solder the fuse wire form the cell and lift it up and then I can push it down and re solder the good ones.
- Use a holder to allow replacement of individual cells without treating the whole pack apart. I use 4 x 5 plastic holders, break the tab and push bad ones 'thru' and replace them.

Its also a matter of scale. Since I'm nearing 10,000 cells, anything like LED(s) on each cell would just be a non-starter for many reasons and I'm coming at you from that perspective Smile
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#18
Hi,

Thank you for your prompt reply

(05-14-2020, 07:16 PM)OffGridInTheCity Wrote: Not sure why the fuse wire would break unless overload or some bad event occurred.  Even so, a visual check or volt meter check of each cell's connection to the bus would find these in short order.

This is my point, you conect the led to the fuse and when it is broken the led will be off


(05-14-2020, 07:16 PM)OffGridInTheCity Wrote: My focus is at the pack level - e.g. to be able to find packs that can't maintain their balance within the battery.    Once you identify a bad pack, then fix/rebuild (at cell level) comes into play...  which means you want to design the battery so you can easily remove/replace 'a pack'.
Once you have the bad pack isolated, then you want to be able to do things like
- Look for heaters while the pack is discharging or charging - e.g. some kind of charge/discharge rig for an individual pack.

In the Hugo's system is very easy to replace a cell and also a pack and implemented with a good BMS and IMHO I think is ok.

(05-14-2020, 07:16 PM)OffGridInTheCity Wrote: - Be able to isolate cells from the buss (or the physical pack) to check for self discharge / 0v.  In my case, I simply un-solder the fuse wire form the cell and lift it up and then I can push it down and re solder the good ones.
- Use a holder to allow replacement of individual cells without treating the whole pack apart.  I use 4 x 5 plastic holders, break the tab and push bad ones 'thru' and replace them.

Same than in Hugo's system

(05-14-2020, 07:16 PM)OffGridInTheCity Wrote: Its also a matter of scale.  Since I'm nearing 10,000 cells, anything like LED(s) on each cell would just be a non-starter for many reasons and I'm coming at you from that perspective Smile

This rationale can be applied to the fuses  Big Grin

Un saludo!
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#19
But you're overlooking the cost which is significant at 1,000(s) of cells.   10,000 cells * LED = significant, unnecessary $  compared to 10,000 * 0.5" of small gauge wire Smile
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#20
Hi,

10000 x 3mm white led are around 123€ shipping cost included, so I think is not too much. Remember that fuses are still needed. Furthermore, in the cost equation you should introduce the saved time to guess which is the failled cell, overall if you have a huge amount of cells to check

Un saludo!
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