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ajw22

Member
Joined
Nov 16, 2018
Messages
641
In our very hot July/August months I need as much as 109kwh/day to maintain 72F/22C

I think that's the problem right there. Set the A/C to a more reasonable 78F/26C and it'll probably only need 50% the energy. Wear shorts and place ventilators at strategic locations (eg. under desk) for extra cooling for just 10~20W. It's totally comfortable once you get used to it.
As a bonus, you get much less of a heat-shock whenever you step outside.
 

Cheap 4-life

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Joined
Aug 3, 2020
Messages
375
I think that's the problem right there. Set the A/C to a more reasonable 78F/26C and it'll probably only need 50% the energy. Wear shorts and place ventilators at strategic locations (eg. under desk) for extra cooling for just 10~20W. It's totally comfortable once you get used to it.
As a bonus, you get much less of a heat-shock whenever you step outside.
A/C is the toughest thing for all of us to power. I set my A/C at 77F. I used to set it at 72F before I got into solar. Honestly I don’t notice the difference in comfort other than there was times we were freezing when I had it at 72F. Setting the thermostat higher at 77F keeps the A/C from continuously running all the time. I read somewhere that a central A/C shouldn’t be set over 20F above the outside temp.
At night before bed it is usually under 72F outside so we turn off the A/C and use window fans in the rooms we will be in. Keeps the house cool all night.
 

OffGridInTheCity

Active member
Joined
Dec 15, 2018
Messages
1,738
I think that's the problem right there. Set the A/C to a more reasonable 78F/26C and it'll probably only need 50% the energy. Wear shorts and place ventilators at strategic locations (eg. under desk) for extra cooling for just 10~20W. It's totally comfortable once you get used to it.
As a bonus, you get much less of a heat-shock whenever you step outside.
In an emergency sure! and maybe higher and we have fans as final backup (way less power than AC). But reasonable is a slippery term when negotiating with your spouse and there's no emergency :) She also likes it (what I consider cold) in the winter.... so maybe it evens out.
 

Wolf

Active member
Joined
Sep 25, 2018
Messages
1,578
Little Update:
So we have been pretty warm in the NE, nothing compared to the west coast poor folks.
Nevertheless it is defiantly taxing my system with the AC being on 24/7.
With good sun I am able to recover pretty much throughout the day but if it is somewhat overcast my 4500 Watts on the roof just cant quite charge the batteries and run the house. There is another 750 Watts in the works on the shed in a couple of weeks but till then..........
I have found out one thing though, which I have discussed a lot on how cells behave in parallel.
Initial experiments with cell discharging has shown that deviations start to occur around 3.65V.
It appears to hold true no matter if you got 1cell or a pack of 80p cells x 42.
Looking at the graph of 42 packs it is incredibly clear that around 3.65V the differences in pack voltages starts to climb little by little.
Total affect to the battery is negligible as as soon charging starts and voltage rises the packs start to congeal and come together again.
On another note observing this phenomenon and getting a baseline on it will certainly give you a heads up if a pack is falling behind or has a problem.
Wolf

1624979417997.png

 

OffGridInTheCity

Active member
Joined
Dec 15, 2018
Messages
1,738
Yes sir - we hit a heat wave. Look this average kw/hour from 'normal (earlier in June) to last week or so. Sigh - I need another 50 panels.....
1624980489402.png
 

Wolf

Active member
Joined
Sep 25, 2018
Messages
1,578
Not build related but ................
So I have been on vacation/holiday for the last couple of weeks in my home town where I grew up and not much has changed in 50 years.
Will be sad to leave my mom but I must go to work and tend to my batteries and solar.
BTW a lot of solar installations in this part of Austria.
Wolf
20210701_150949.jpg
 

Wolf

Active member
Joined
Sep 25, 2018
Messages
1,578
Update:
Battery #4 is now in the final stages of construction. 1278 cells all tested and running through the final IR and SD check. After filtering out 1120 of the best cells the spot welding and pack construction will begin.
Wolf
1626092101512.png
 

Wolf

Active member
Joined
Sep 25, 2018
Messages
1,578
one gray castaway
He he yep I put that one in there just to see if you all are paying attention. Well out of 1278 purple cells all of which (except for a couple) were quite acceptable I drilled them down to 1121.
1627347624692.png
Popped them into Nemos RePackr and the results look good.
1627349732277.png
Now comes the sorting and spot welding.
Later
Wolf
 
Last edited:

Wolf

Active member
Joined
Sep 25, 2018
Messages
1,578
Update on battery #4
Alright all cell in their proper packs
20210802_194214.jpg
Now for the final IR and Voltage check and placing the cells in their assigned location in the pack.
Using the python code for the RC3563 and the VB script to automatically enter the IR and V into the sheet will make this actually fun.
Considering I did all this manually before. Of course I now have the system down to a science as I build the last packs and battery.
I did learn a lot though so that has to count for something.
Wolf
1627949842591.png
 

Wolf

Active member
Joined
Sep 25, 2018
Messages
1,578
Battery #4 Update.
Well the final testing is going just great. Since I have just about automated the process shy of barcodes as I really don't need them.
I just use number stickers and essentially that is what a barcode is and excel is my friend as I can look up any cell number and get the cell data I want if need be.
The Megacell Chargers which after the workflow is done gives me all the raw data I want in an easy copy and paste format so 32 cells at a time get dumped into excel. The end V and mAh get transferred to the sheet with a rule, where the cell number are, and initial V and IR are recorded.
1628041852375.png
To record the initial V and IR and subsequent measurements of the same (post C/D/C capacity test, and 30 day SD test) the python code (by @enki) with some modifications to write to excel, and a custom vb script, works great, all I do is put the cell in the holder, hit ctrl s or whatever shortcut combo I choose to write to whatever Excel cells I want and the IR and V readings are copied to the appropriate cells from the RC3563.
As all my cells are in numerical order and the Excel Repackr (by Nemo) sorts all cells by optimizing the mAh for each pack but also retaining the cell number the process is straightforward and easy.
20210803_195124.jpg
I have also gone a bit crazy with cell analysis and tracking.
Besides recording the exact position of each cell in the pack I decided for excel to give me the whole cell history from initial touch to last and final IR and V check. I am also calculating the V drop per day which gives the SD check a whole new meaning.
It seems that no matter how many days have passed the average V drop per day for these M26 cells is 0.000339 V.
Maybe sometime in the future these numbers may allow us to glean some more diagnostic data from them.
1628044497668.png

The automation makes this actually a fun exercise. Too bad it took me till the 4th 14s80p battery to figure out this easy peasy workflow.
Now that I have it down to literally a science I won't need it anymore.
Vive la 18650 I will never surrender to the easy cop-out of the LiFePO4.
Wolf
 
Last edited:

Caseface

New member
Joined
Aug 1, 2021
Messages
3
Battery #4 Update.
Well the final testing is going just great. Since I have just about automated the process shy of barcodes as I really don't need them.
I just use number stickers and essentially that is what a barcode is and excel is my friend as I can look up any cell number and get the cell data I want if need be.
The Megacell Chargers which after the workflow is done gives me all the raw data I want in an easy copy and paste format so 32 cells at a time get dumped into excel. The end V and mAh get transfer to the sheet with a rule, where the cell number are, and initial V and IR are recorded.
View attachment 25794
To record the initial V and IR and subsequent measurements of the same (post C/D/C capacity test, and 30 day SD test) the python code (by @enki) with some modifications to write to excel, and a custom vb script, works great, all I do is put the cell in the holder, hit ctrl s or whatever shortcut combo I choose to write to whatever Excel cells I want and the IR and V readings are copied to the appropriate cells from the RC3563.
As all my cells are in numerical order and the Excel Repackr (by Nemo) sorts all cells by optimizing the mAh for each pack but also retaining the cell number the process is straightforward and easy.
View attachment 25792
I have also gone a bit crazy with cell analysis and tracking.
Besides recording the exact position of each cell in the pack I decided for excel to give me the whole cell history from initial touch to last and final IR and V check. I am also calculating the V drop per day which gives the SD check a whole new meaning.
It seems that no matter how many days have passed the average V drop per day for these M26 cells is 0.000339 V.
Maybe sometime in the future these numbers may allow us to glean some more diagnostic data from them.
View attachment 25795

The automation makes this actually a fun exercise. Too bad it took me till the 4th 14s80p battery to figure out this easy peasy workflow.
Now that I have it down to literally a science I won't need it anymore.
Vive la 18650 I will never surrender to the easy cop-out of the LiFePO4.
Wolf
Hi Wolf ,
Do you think the megacharger is worth the new price of 260 us or in my case 325 Canadian? I have 10000 + cells

I really like your methodology of processing.

thanks 18650 for life
 

Wolf

Active member
Joined
Sep 25, 2018
Messages
1,578
Do you think the megacharger is worth the new price of 260
Short answer yes!
Now to qualify that yes.
Considering you are going to process 10,000+ cells let's look at a couple of things.
First off 260/16 is 16.25 per slot for a charger analyzer that will charge at 1A discharge at 1A and give you the results in a machine readable format.
There are only 2 other chargers commercially available that I am aware of that will C/D/C all (4) slots at 1A Opus and SKYRC.
Forget the LiitoKala, Zanflare, etc. if you are looking to do some serious cell testing. I have owned most all of them and still have the XTAR Dragon, Vapecell S4, Foxnovo, Opus and SKYRC MC3000.

OPUS $50/4 12.50 per slot. To get the OPUS to work reliably and properly at 1A it needs a fan modification unless you live in a refrigerator. Also you need to copy the mAh results manually to whatever method you use to track your cells.
SKYRC 110/4 27.5 per slot. The SKYRC MC3000 is a very cool C/D/C unit with cell specific programmable parameters. Has a bit of a learning curve is highly accurate does have a PC interface for programing each slot but the mAh results still need to be manually copied.
I have 2 Megacell chargers and believe me the first release was not pretty see https://secondlifestorage.com/index...ellcharger-has-shipped-yippee.9855/post-69397
Also if you have facebook check out this group https://www.facebook.com/groups/646858045823609 and do a search on Wolfgang for my post there regarding the first batch of the MCC and what I did to fix some of the issues.
Now with the new batch Alex is supposed to make a video with the reason for the price increase. If there are certain hardware enhancements made I may even buy another one.
I digress.
I do not use their database I find it extremely clunky and unreliable. I use excel. After the workflow finishes it is easy to copy and paste the finished data into excel and move on. Besides I record way more data and parameters of each cell than their database does.
Other than that I love it. I can process 32 cells at a time and if I am in a hurry 64 a day that's over 400 in a week.
So yea even though I am critical of some of the design flaws which some have been fixed with the second release, this third release may be really good. Alex and his video really needs to convince me though.
Wolf
 

Wolf

Active member
Joined
Sep 25, 2018
Messages
1,578
Battery #4 update.
4480 spot welds with the fabulous KWeld, 30 feet of 5p nickel fuse sheet, and battery # 4 is on its way for bus bars getting each pack ready for capacity testing. So if all goes well by the end of August my journey will have reached the milestone of an 800Ah battery constructed out of reclaimed/recovered 18650 cells. I started this project August 7th 2019 so it took 2 years.
Considering the operational restrictions of 4.07V to 3.5V per pack or 56.98V to 49V I estimate a usable 600Ah or ≈30kWh. :)
Wolf
1628771811254.png1628771894322.png




 

Dr. Dickie

Member
Joined
Sep 23, 2020
Messages
218
Battery #4 update.
4480 spot welds with the fabulous KWeld, 30 feet of 5p nickel fuse sheet, and battery # 4 is on its way for bus bars getting each pack ready for capacity testing. So if all goes well by the end of August my journey will have reached the milestone of an 800Ah battery constructed out of reclaimed/recovered 18650 cells. I started this project August 7th 2019 so it took 2 years.
Considering the operational restrictions of 4.07V to 3.5V per pack or 56.98V to 49V I estimate a usable 600Ah or ≈30kWh. :)
Wolf
View attachment 25823View attachment 25824




WOW!.
That is fantastic, makes my powerwall look like a flashlight battery.
Thanks for all your help. I would not have what I have with out yours and others help from here.
 

OffGridInTheCity

Active member
Joined
Dec 15, 2018
Messages
1,738
WOW!.
That is fantastic, makes my powerwall look like a flashlight battery.
Thanks for all your help. I would not have what I have with out yours and others help from here.
Mine has solder globs everywhere + duct-tape + random wire holding things together. it's only pretty if you do that old-fashion fuzzing of the picture :)

REALLY nice work!!
 

jdeadman

Member
Joined
Mar 28, 2017
Messages
948
Yea I gotta Step up my game Need to get a spot welder
 
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