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Chuck's 18650 14S120P+1 UK Powerwall.
#61
Packs mounted and operational for 24hrs +.

28 X 40P packs configured as 14S80P at a little over 170 Ah, so not quite the 14S120P I wanted but still looking for cells. I have enough space on my main busbars for another 28 packs and room below to fit another set of busbars for 56 more packs if needed.



Now i wish I'd wrapped the first 11 packs when I made them, it's playing havoc with my OCD all these different colours but there's no way I'm stripping packs to wrap them.

24 hrs in since battery went online. This morning the battery capacity was down to 32%, sun up and solar supplied the house and charged battery up to 92%, battery started to supply house at around 1700hrs at about 3hrs in i had 78% capacity left, another 1 1/2hrs and I'm now down to 61%. So won't see me through the night without a little top off from the off peak supply,



Pack voltages are staying fairly balanced could be a little better though, swings back and forth between 0.041V and 0.076V. Pack 9 seams to be the culprit, I'm guessing that maybe a high resistance cell may have slipped through testing.

I have limited the charge and discharge current for the moment to see how it runs. Charge current limited to 30A/375mA per cell and discharge limited to 20A/250mA per cell.

Peak loads are only supplement by the battery at the moment, but since my typical demand is between 0.450Kw and 0.980Kw battery is meeting our requirements without any grid supply.
Korishan and ajw22 like this post
UK Southwest.

7 kWp Solar Panels (28 x 250Wp Shinetime Mono).
14 X APS YC500i Micro Inverters.
42 X 40P 18650 cell packs/modules configured as 14S 120P.
Sofar Mass Energy ME3000SP AC coupled charger/inverter.
Still sourcing and processing cells for powerwall.
About halfway into my next batch of cells for another 14 40P packs
13 kWh processed and operational so far.
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#62
Wall has been up and running for a week now.

Packs have now settled down and staying balanced to between 0.034V and 0.038V

UK Southwest.

7 kWp Solar Panels (28 x 250Wp Shinetime Mono).
14 X APS YC500i Micro Inverters.
42 X 40P 18650 cell packs/modules configured as 14S 120P.
Sofar Mass Energy ME3000SP AC coupled charger/inverter.
Still sourcing and processing cells for powerwall.
About halfway into my next batch of cells for another 14 40P packs
13 kWh processed and operational so far.
Reply
#63
I've set my BMS to start balancing at 3.8+V and 15mV delta. With only 50mA bypass, having it start as early as possible helps a lot.
chuckp likes this post
Modular PowerShelf using 3D printed packs.  60kWh and growing.
https://secondlifestorage.com/showthread.php?tid=6458
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#64
(10-05-2019, 06:27 PM)ajw22 Wrote: I've set my BMS to start balancing at 3.8+V and 15mV delta.  With only 50mA bypass, having it start as early as possible helps a lot.

Do you have yours set to Balance only when charging or do you leave it on all the time?
UK Southwest.

7 kWp Solar Panels (28 x 250Wp Shinetime Mono).
14 X APS YC500i Micro Inverters.
42 X 40P 18650 cell packs/modules configured as 14S 120P.
Sofar Mass Energy ME3000SP AC coupled charger/inverter.
Still sourcing and processing cells for powerwall.
About halfway into my next batch of cells for another 14 40P packs
13 kWh processed and operational so far.
Reply
#65
The BMS balances only when it's being charged. So on the android app, my settings are :
"Open balance: open" (not sure that it does... Chinglish for "enabled"?)
"Balance Mode: [when] charging"
"Balanced turn on: 3.8V"
"Balancing precision: 0.015V"

So as soon as the voltage of one cell increases to above 3.8V, and there is at least one other cell at 3.785V or lower, the high cell starts to be drained at 50mA... or rather charged 50mA less than the other cells.
Modular PowerShelf using 3D printed packs.  60kWh and growing.
https://secondlifestorage.com/showthread.php?tid=6458
Reply
#66
I'm using the version on iphone.

Very similar I just prefer the home screen with the bars showing the cell voltages.

I have a "Balancer Enabled" button and a "Bal. Only When Charging" button.
If I disable the Only When Charging but leave the Balancer Enabled, I would have expected the balance function to be on all the time a cell is above my start voltage and there's a difference greater than my delta to balance setting.

This is not the case it's only when charging with the Balance Only When Charging is enabled that it operates. I'm unsure if it's supposed to work like that of not
UK Southwest.

7 kWp Solar Panels (28 x 250Wp Shinetime Mono).
14 X APS YC500i Micro Inverters.
42 X 40P 18650 cell packs/modules configured as 14S 120P.
Sofar Mass Energy ME3000SP AC coupled charger/inverter.
Still sourcing and processing cells for powerwall.
About halfway into my next batch of cells for another 14 40P packs
13 kWh processed and operational so far.
Reply
#67
Not 100% sure, but unless you have a battery that is both capacity and IR balanced, you may want to stick with just balancing when charging.
Say you have pack#1 that has a somewhat higher IR.  That pack will show a relatively high voltage when charging, and show a relatively low voltage when discharging, even though the SoC is perfectly in sync with all other packs.  Depending on the balancing tolerance, you could have the absurd situation of the balancer draining #1 when charging, and draining #2~#14 when discharging.  ...In theory...  a long working day, and quite drunk, so take it with a bucket of salt.

Also, wanted to commend the beautiful layout.  Though a little space inefficient, I believe it's the most maintenance friendly design I've seen so far.  You can easily see both sides of all cells, and you can just take out a pack without much consequence by just disconnecting 2 connectors.  


[see pic] Is there a reason why some are red and some black?  Are they just heat shrinks?  And I don't think I've seen those mid-section terminals.  Are they crimped?  Soldered?
chuckp likes this post
Modular PowerShelf using 3D printed packs.  60kWh and growing.
https://secondlifestorage.com/showthread.php?tid=6458
Reply
#68
Earth rod clamps, so screw thread compression.

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#69
(10-07-2019, 11:40 AM)Sean Wrote: Earth rod clamps, so screw thread compression.

OOOOOHHHHH  those are nice

And I do love the look and layout of your System Chuck
chuckp likes this post
******Hi My name is Jason and I have SOCD (Solar Obsessive Compulsive Disorder)*******
Current Powerwall - 1400 Cells 7s200p (modular 40p packs) ~ 12kWh of storage     4x 315W Canadian Solar Panels

Working on the next 7s40p packs     ~2.5kWh

Waiting on 2000 Cells of unused Sony vt4 (2000mah 30A) ~ 15kWh      hehehehehe  More Power
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#70
(10-07-2019, 11:26 AM)ajw22 Wrote: Not 100% sure, but unless you have a battery that is both capacity and IR balanced, you may want to stick with just balancing when charging.
Say you have pack#1 that has a somewhat higher IR.  That pack will show a relatively high voltage when charging, and show a relatively low voltage when discharging, even though the SoC is perfectly in sync with all other packs.  Depending on the balancing tolerance, you could have the absurd situation of the balancer draining #1 when charging, and draining #2~#14 when discharging.  ...In theory...  a long working day, and quite drunk, so take it with a bucket of salt.

Yes they stay in balance very well, since I've change it to start balance at 3800mV with a delta of 15mV they are sitting better at between 26mV and 30mV



(10-07-2019, 11:26 AM)ajw22 Wrote: Also, wanted to commend the beautiful layout.  Though a little space inefficient, I believe it's the most maintenance friendly design I've seen so far.  You can easily see both sides of all cells, and you can just take out a pack without much consequence by just disconnecting 2 connectors.  

Thank you for your comment.
Yes the idea was to make it as user/maintenance friendly as possible, I could have condensed it down a lot more but the pathway I've built along never gets used for access and space wasn't a constraint. i have space for another 6 rows that's another 84 packs at the moment. Also should the need ever arise I have enough wall expanse to repeat the same set up another two times, not that I think I'll ever need that amount of storage capacity.

(10-07-2019, 11:26 AM)ajw22 Wrote: [see pic] Is there a reason why some are red and some black?  Are they just heat shrinks?  And I don't think I've seen those mid-section terminals.  Are they crimped?  Soldered?

Just heat shrink, I only had around half of what I needed in red or black to do them all the same. Since the middle 13 bars are both pos and neg i thought that mixed on those bars, with all red for pos and all black for neg would look ok.

The bars are standard 3/8" or 9.5mm earth rods with extra terminal clamps spaced evenly at a little over pack and mount length.

The terminal connections are 10mm2 X 8mm hole terminal lugs crimped.



I may crimp and solder on the next rows though but it would be only for belts and braces, not really required to do both.

(10-07-2019, 11:40 AM)Sean Wrote: Earth rod clamps, so screw thread compression.


Yep that's exactly what I've used.

(10-07-2019, 12:35 PM)jdeadman Wrote: OOOOOHHHHH  those are nice

And I do love the look and layout of your System Chuck

Thank you jdeadman, yeah I'm pleased with the way it's shaping up. Thinking about doing something with a RasPi and a display screen now. But I'll have to beg borrow and steal the programming, its something I've never been involved with.
UK Southwest.

7 kWp Solar Panels (28 x 250Wp Shinetime Mono).
14 X APS YC500i Micro Inverters.
42 X 40P 18650 cell packs/modules configured as 14S 120P.
Sofar Mass Energy ME3000SP AC coupled charger/inverter.
Still sourcing and processing cells for powerwall.
About halfway into my next batch of cells for another 14 40P packs
13 kWh processed and operational so far.
Reply


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