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Darmok's Power Wall build
Hi all,
Please see below details of my system and what I am doing. I am keen for any feedback and input, I appreciate the interest shown.
I have a SMA 5000TL-20 inverter and 6kW of panels on the house roof. I export 40% of what generate to the grid and get a small cheque from the retailer.
Where I am it is not in my favour to yet have the power wall connected to my house . I currently get a good feed in tariff (48 cents). The feed in scheme is a local state one and has been running for 8 years. It will run out in 2.
A requirement of that agreement i have with my electricity retailer is that i have no batteries connected to that system. Obvious reason you could milk the system; charge at night at 28c and export at day for 48c. Utility and retailers here in Western Australia are still yet to get their shit together and offer attractive peak and off peak incentives.

So instead of waiting I am building a standalone system in my workshop. which will hopefully run a 1600w pool pump, workshop socket outlets and LED lights.

My process;
When I get batteries they come as laptop batteries. I get 1-3 tubs of them. I then sort packs into manufacturer then model of the batt then do the high capacity ones first, ie above 50 Whr per laptop battery pack. Saves a hell load of time only processing batts with the higher capacity first and importantly of the same construction. When you learn how to get into a pack and extract the cells its good to stay in that mode till you've done all those pack types.
 I've just completed my assembly of 15 x 100 cell packs (14 and a spare to change any out for service) with all cells in each pack better than 2300 mAh.  I am going to progressively make these cells bigger when i process more cells. Anyone see any issues extending the packs longer than 25 cells long? 30 or 40?

To get to 15 x packs of 100 has taken 4 months of processing.
Im very lucky that i have gotten volume battery packs to be able to do this. Does depend what volume of packs you are able to source.

My testing methodology has changed over time. At first I was testing voltage of every cell and then binning based on voltage. I have since stopped this and bin based on manufacturer and rated capacity. I then test in 6 x Opus charger/testers. Then bin for capacity.

I have graded tested cells into bins as follows;
>2300 went into the packs. Best i had was 3200mAh cells.

What I've found (going from memory) is;
Panasonic Grey 3000
Samsung Light blue 2800
Samsung Pink 2600
Sony Red (light blue ring 2600)
Sony Green G7 2550
Newer Sony Orange 2500
Panasonic purple 2500
Samsung blue 2400

Cells with rated capacity less than 2300 go into a bins sorted by manufacturer and are not tested at this stage. These cells could be potentially sold to recoup costs or for other projects or expansion of system once I see how version 1.0 performs constructed with only cells greater than 2300 mAh cells.

I am yet to decide on the Inverter and other hardware. I am keen to hear thoughts from people.
Early options are ;


PIP 4048

Battery pack mounts yet to be decided.

Pictures to follow.

jamesk9 likes this post
"ie above 50000 " is wrong right or?

Batrium with PIP would work fine. Just beware of it may be recomended to have something in between that controll the pip based on the BMS. Im working on one way to do this alongside with the Batrium stuff.

ie if the Batrium BMS senses that the voltage is to high on 1 cell it will stop charging if needed so it can balance that cell.

On the other hand i think you are spot on. Though if you have plenty of 2Ah+ too you could build strings of that too. Smile

I like your n+1 approach. Always keep 1 or more in spares so you can switch out if needed.
Darmok and hbpowerwall like this post
The Ultimate DIY Solar and build place
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
Correct daromer i added in one to many 0's. Fixed now. Cheers.

So Peter has gone with a separate charger to the PIP my understanding is the PIp won't charge to full 2.20v and he doesn't like the software, Is that all?
Daromer thoughts on just running the Opec to do a charge to determine capacity. Could i get cells that don't hold voltage slipping through with this methodology?
Re 2Ah+ yeah that was the plan. Although running a more longmon gets expensive. Id rather have bigger packs than multiple packs.
Daromer how many cells are you running in each pack?
5000mAh? There is no 18650 that hold that much capacity from laptops Smile

Peter is using the PCM60x.
charge to full 2.2V?
Its kind of the same software on the PIP as the PCM60x. they just refurbished the software between their models Smile

If you run the charge/test cycle you will end upp with fully charged cells. Then you just check the voltage 1-4 weeks later and you will catch the ones not holding voltage.
I have 80 Cells in each packs for the laptop packs. But i also have packs with 300Cells in each that is 390Ah LiFePo4 packs / longmon.
The Ultimate DIY Solar and build place
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
Its battery pack spec not cell. 50Whr for a laptop battery pack which has 18650 cells in it. Avoid lesser Whr packs 40-48.

I heard Peter mention that the PIP 4048 doesn't charge to full voltage, might be 4.22v I unsure maybe he coould provide?
Max voltage my PIP4048 does is 58,4V
On 14s that is = 4.17V. With some losses that could be 4.1/Cell.
On the other hand you may not want to go that high to save some cycles. So thats the reason Smile
The Ultimate DIY Solar and build place
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
Interesting re the pip voltage, thanks for that.

Daromer how do you calculate KWhr for cell packs and strings?
Note - you can't balance cells at max voltage with pip, i tried Smile video to come soonish !
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I'm currently working my way through testing a bunch of Sanyo red light blue ring cells. I think they're 2600 cap from memory.
It always amazes me how many of these go what I call "runaway". They just keep taking full charge current and get from mild warm to too hot to touch. I pull them as soon as they show any signs of heat. What are others experiences?
Yes, some will go into furnace mode. Odd thing is, some of them, once they have cooled off over a few days and settled, you can drain them a little and put them back in the charger and they act normal from then on.

However, if you use those cell, I'd recommend you mark them and put them in an easy to get to place in case of failure. Those cells would probably be one of the main reasons for fusing each cell.

I actually had one where it was making an odd smell cuz it was so hot. That was the only reason I knew it was hot for I was in the living room when I smelled it. After that, I got a thermal gun so I could monitor them a little closer.
Proceed with caution. Knowledge is Power! Literally! Cool 
Knowledge is Power; Absolute Knowledge is Absolutely Shocking!
Certified 18650 Cell Reclamation Technician

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