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There's a new wall in Germany!
(01-27-2018, 03:31 PM)Herbie Wrote: Hello Owitte
Im Herbert from Uganda new to DIY powerwall and planning on a powerwall so far  I've harvested 706 18650 cells 3 volts and above haven't yet gone through the testing, from the many designs I've looked at on the forum your design has inspired me to build one similar to the first you made of 24v could you please provide me with wiring diagrams for such a system with those displays(cell logger, that other display and battery monitor) inclusive thanks in advance

Hi Herbert,

here's a schematic representation of my powerwall with wiring:



The only thing that's missing is the battery SOC gauge, but this is simply connected to plus and minus of the powerwall. Hope this helps,

have sun!
Oliver
Korishan, Drokz, Herbie like this post

Cells tested: 5176 (overall: 10058 Ah, average: 1943 mAh)
Cells in production: 2940 (overall: 6174 Ah, average: 2100 mAh)
Wall bank: 7s320p, 672 Ah, 16 kWh
Box bank: 7s100p, 210 Ah, 5 kWh
Project page
Live solar/powerwall values
Daily graph
Reply
What would be really kewl is have RPi setup so you can scan all the voltages of all your packs. You'd have to use a few mux's to do the job, but that'd be easy to setup. Then display the output on 1 screen next to the wall(s). Since you'd be using 1 device to do the measuring instead of a whole bunch (the led voltage meters on ebay), you'd not use as much power overall.

Altho, for the length of the runs, you would probably need an arduino nano to act as a collector/repeater, maybe.
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, ...)
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(02-08-2018, 01:03 PM)owitte Wrote: The only thing that's missing is the battery SOC gauge, but this is simply connected to plus and minus of the powerwall. Hope this helps,

For a "real" Soc gauge, you need beside the voltage also the charge/discharge currents... a shunt can do the job, and ofcourse something to calculate the Soc.
To do it accurate, the energy going into and out of the battery, has to be compaired with the (remaining) capacity of the battery...
In short, not as easy as it sounds Wink
___________________________________
18x 300Wp solar off grid and 10x 180Wp solar tracker grid-tie
10KW 3phase hybrid inverter. 40Kwh 18650 storage (for now)
My setup: https://secondlifestorage.com/t-Instant-powerwall
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(02-08-2018, 07:11 PM)wim Wrote:
(02-08-2018, 01:03 PM)owitte Wrote: The only thing that's missing is the battery SOC gauge, but this is simply connected to plus and minus of the powerwall. Hope this helps,

For a "real" Soc gauge, you need beside the voltage also the charge/discharge currents... a shunt can do the job, and ofcourse something to calculate the Soc.
To do it accurate, the energy going into and out of the battery, has to be compaired with the (remaining) capacity of the battery...
In short, not as easy as it sounds Wink

yeah, I know... it's more of an estimate what these cheap chinese displays do. But I also have a Victron battery monitor which is much more accurate because it does all what you mentioned.

(02-08-2018, 01:29 PM)Korishan Wrote: What would be really kewl is have RPi setup so you can scan all the voltages of all your packs. You'd have to use a few mux's to do the job, but that'd be easy to setup. Then display the output on 1 screen next to the wall(s). Since you'd be using 1 device to do the measuring instead of a whole bunch (the led voltage meters on ebay), you'd not use as much power overall.

Altho, for the length of the runs, you would probably need an arduino nano to act as a collector/repeater, maybe.

nice idea, I also thought in that direction, first. But then I found a nice chip called DS2438. You may check the specs here, I already ordered a few of them. Another option would be the LTC6802 (see here), but I'll try the cheaper and easier-to-use DS2438 first, especially because it's on the OneWire bus just like the temperature sensors I'm already using (DS18B20).

Cells tested: 5176 (overall: 10058 Ah, average: 1943 mAh)
Cells in production: 2940 (overall: 6174 Ah, average: 2100 mAh)
Wall bank: 7s320p, 672 Ah, 16 kWh
Box bank: 7s100p, 210 Ah, 5 kWh
Project page
Live solar/powerwall values
Daily graph
Reply
Could you tell us about the rest of the system. Solar panels, MPP's /charger and inverter for feeding the house/grid? Impressive powerwall by the way Smile
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Hi DK100,

no problem, here're the specs:

(1) Solar setup: 16 x 55W monocrystalline moduls (70 Voc) and 18 x polycrystalline modules (around 37 Voc) from various manufacturers with 220-260W, 2 modules paired in series, then paralleled. I have connected them by orientation in 3 strings, which gives around 3kWp overall.

(2) Charge controlers: 2 x EPSolar Tracer 4210RN (MPPT, 12/24V, max 40A) and 1 x EPSolar Tracer 3215RN (MPPT, 12/24V, max 30A).

(3) Inverter: WesTech WT-Combi Eco, 24V, 3000W pure sine wave with uninterrupted (<10ms) auto-switching between battery and grid (or vice versa), can be used with grid priority as UPS or with battery priority (as I do). Also has a built-in charger, which I never used so far.

(4) Batteries: 6 x Winner SLA solar battery (12V, 280Ah, 2s3p, ~20kWh) plus 'the wall', 2240 x 18650 in 7s320p with approx. 16kWh.

Have sun :-)
Oliver

Cells tested: 5176 (overall: 10058 Ah, average: 1943 mAh)
Cells in production: 2940 (overall: 6174 Ah, average: 2100 mAh)
Wall bank: 7s320p, 672 Ah, 16 kWh
Box bank: 7s100p, 210 Ah, 5 kWh
Project page
Live solar/powerwall values
Daily graph
Reply
first german DIY powerwall on TV: MINE  Smile . Seems like I'm soon as famous as Pete - without the hassle of making youtube videos Big Grin
jdeadman, Stefaan De Ridder, Korishan And 3 others like this post

Cells tested: 5176 (overall: 10058 Ah, average: 1943 mAh)
Cells in production: 2940 (overall: 6174 Ah, average: 2100 mAh)
Wall bank: 7s320p, 672 Ah, 16 kWh
Box bank: 7s100p, 210 Ah, 5 kWh
Project page
Live solar/powerwall values
Daily graph
Reply
NICE! Big Grin And now we know what you look like Tongue

Oddly, I could follow along with what was being "said" even though I don't speak german Tongue
owitte likes this post
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)
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(03-01-2018, 12:09 AM)Korishan Wrote: NICE!  Big Grin   And now we know what you look like  Tongue

Oddly, I could follow along with what was being "said" even though I don't speak german  Tongue

thanks Smile  and hope it wasn't too much of a shock seeing me in real Big Grin .

Cells tested: 5176 (overall: 10058 Ah, average: 1943 mAh)
Cells in production: 2940 (overall: 6174 Ah, average: 2100 mAh)
Wall bank: 7s320p, 672 Ah, 16 kWh
Box bank: 7s100p, 210 Ah, 5 kWh
Project page
Live solar/powerwall values
Daily graph
Reply
I about fell outta the chair laughing Tongue
owitte likes this post
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


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