Robert Baumer
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Korishan said:
Do you have a recommendation on a good thermal gun? I am still working on my first pack... not sure which is worse... colonoscopy or 18650 battery screening!
Darmok's Power Wall build
- Thread starter Darmok
- Start date
Do you have a recommendation on a good thermal gun? I am still working on my first pack... not sure which is worse... colonoscopy or 18650 battery screening!
Korishan
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I just bought a cheapo from Harbor Freight. They aren't really that expensive, about $15. Now, the HF versions are probably in there because the laser pointer isn't properly centered. That's why it's at a discount in HF. I haven't taken mine apart to see if I can adjust it and make it more accurate.
The laser doesn't do the measuring. It's just there to know where you are pointing at. If you take the gun and place it "on" the packs/cells/etc, then you will get a really accurate reading. The thermal sensor is just giving an average of the center point. As you move away from the object, the area the sensor is picking up is larger. This is important when you are charging 4 cells in a holder that's only 1/4" apart. If you measure the 2nd or 3rd cell, you're going to pick up the heat from the adjacent cells and get an average. Placing the gun right on the cells gets rid of all that.
Btw, the 'brand' on the gun I have is Cen-Tek. But, I think that's just a rebranding of one of the ones you can get from the auto-parts stores as they are similar in shape, design, function, and display; as well as the sensor type.
I believe that's the same with the inverters that are branded as Cen-Tek. Though, they are still expensive.
The laser doesn't do the measuring. It's just there to know where you are pointing at. If you take the gun and place it "on" the packs/cells/etc, then you will get a really accurate reading. The thermal sensor is just giving an average of the center point. As you move away from the object, the area the sensor is picking up is larger. This is important when you are charging 4 cells in a holder that's only 1/4" apart. If you measure the 2nd or 3rd cell, you're going to pick up the heat from the adjacent cells and get an average. Placing the gun right on the cells gets rid of all that.
Btw, the 'brand' on the gun I have is Cen-Tek. But, I think that's just a rebranding of one of the ones you can get from the auto-parts stores as they are similar in shape, design, function, and display; as well as the sensor type.
I believe that's the same with the inverters that are branded as Cen-Tek. Though, they are still expensive.
hbpowerwall
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Great thank you, you get a star 
hbpowerwall said:Great thank you, you get a star
Cool,
Small update I have arranged all my cells intotheir140 cell countpacks and am doing a final voltage test looking for suspect cells. So far ive tested 410 cells and have found one cell totaly dead and 2 that were suspect (voltage dropped too far more than .30v). That's 5 months since they were tested and binned into thebucket for pack construction.
Testing 2200 cells with a multimeter is a pain in the ass. Does anyone have a quick method? My current method is using a cell holder wired to meter leads.
Better to go through another round of teststhan having ordinary cells pull packs down or cause more drama. Finding suspect and a dead cell vindicate it.
Robert Baumer
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Darmok said: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 sameconstruction. When you learn how to get into a pack and extract the cellsits 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 4months of processing.
Im very lucky that i have gotten volume batterypacksto 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;
<1800
1800-1900
1900-2000
2000-2100
2100-2200
2200-2300
>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 bluering 2600)
Sony Green G72550
Newer Sony Orange 2500
Panasonic purple 2500
Samsung blue 2400
Cells with rated capacity less than 2300 go into a binssorted by manufacturerand 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 ;
BMS
Batrium
Inverter
PIP 4048
Battery pack mounts yet to be decided.
Pictures to follow.
I am so freaking jealous..... I prey for grays before opening a pack, but they are typically green or red.
I was bloody lucky to get the Greys. I had enough to do the perimeter on the 120 size packs x 14, but when i went to 140 cell packs i had to cheat and skimp on the back.
Regarding greens and Reds I did have some that were right up there with the Greys they were Green G7 cells from memory.
Best Reds were the ones with light blue rings.
While doing my final voltage checks on the last 2100 cells. I am starting to finalise mount ideas. Packs now being 140 cells long i need a custom mount rather than Peters. I am thinking vertical sections of parallel electrical cable tray with the packs mounted so they can be removed reasonably easy. Although I don't envisage pulling packs every week. Cable tray provides good heat sink, plenty of fixings for cable (oddly enough) tray walls can be used to mount any separators (cement boarding) to protect parallel packs from each other in a failure. Plus it will look the part. I will see if i can find some images of what i am talking about. Something like this.
Regarding greens and Reds I did have some that were right up there with the Greys they were Green G7 cells from memory.
Best Reds were the ones with light blue rings.
While doing my final voltage checks on the last 2100 cells. I am starting to finalise mount ideas. Packs now being 140 cells long i need a custom mount rather than Peters. I am thinking vertical sections of parallel electrical cable tray with the packs mounted so they can be removed reasonably easy. Although I don't envisage pulling packs every week. Cable tray provides good heat sink, plenty of fixings for cable (oddly enough) tray walls can be used to mount any separators (cement boarding) to protect parallel packs from each other in a failure. Plus it will look the part. I will see if i can find some images of what i am talking about. Something like this.
Just scored a full size server rack with built in ventilation fans. Going to explore utilising this. Photos to follow.
In other news I've Soldered up one 140p pack. I'm still deciding on how the ends will be finished off. Didn't go too bad. The learning improvement as you go is noticeable. Anybody who needs to get they're head round soldering, watch Daromers soldering video. Important points worth noting:
get a 150 minimum wattage iron.
Practice
and get into a rhythm as Daromer advises counting in your head for contact time.
After much chasing and phone calls I have another batch of laptop batteries to process.
Does anyone have an idea for a fair and reasonable price for both seller and buyer for excess collected packs? Would $2 a pack be reasonable? Considering all the running round and time spent?
In other news I've Soldered up one 140p pack. I'm still deciding on how the ends will be finished off. Didn't go too bad. The learning improvement as you go is noticeable. Anybody who needs to get they're head round soldering, watch Daromers soldering video. Important points worth noting:
get a 150 minimum wattage iron.
Practice
and get into a rhythm as Daromer advises counting in your head for contact time.
After much chasing and phone calls I have another batch of laptop batteries to process.
Does anyone have an idea for a fair and reasonable price for both seller and buyer for excess collected packs? Would $2 a pack be reasonable? Considering all the running round and time spent?
Darmok said:
Why are you selling the packs? Low capacity?
I bought a couple low capacity batches on EBay. Need to find a more consistent better source.
My local battery store gives me packs for free, and they are very high quality, but not enough of them to keep up with my harvesting speed. So I fill in with purchased ones, but the better cells cost a lot more.
Early on, I got some great packs with dell 97 wh batteries. I just opened 30 or so of those and most all of the cells tested with above 3 volts.
I have not started capacity testing yet, but the nominal rating on the cells is3000 mah.
I just got 5 dell 60 wh 6 cell packs free from the battery store last night. good stuff.
Darmok said:
Hi Darmok,
here in Germany the average prise is around 3.00 euro per pack if you buy on ebay. You never know the quality of packs and you have lots of rounds to process this cells and so on and so on.
In meantime there are new original Sanoy cell with 2250mAh/5A for 1.60 if you buy 540 pcs.
I see that the prise for new cells is slowly falling and one day it is maybe easier to get new cells and use them for storage.
BR
BigBen
Thanks for the input. Im selling the excess packs I have. I have a fair idea which packs contain the cells i'm after from external spec label which from pulling apart hundreds of packs i've got an idea of cell manufacturer and original capacity. Plus I need funds to purchase a BMS and Inverter plus other hardware.
Bit of an update. I took a break for a while due to other commitments. Then got into it again and put a bit of work in. So 6 x packs soldered up and the remaining 8 packs constructed with soldering to be done. Purchased the Battrium 14s kit which is still sitting in its box.
Yet to be decided on;
Method of linking packs in series. I'm thinking making a loop point each end with the 10 sq mm bus bar cable and then link packs with lugged off flex cable of similar or slightly larger 25mm flex cable.
Method of fixing packs on server rack shelves. More than likely go very simple with very large nylon cable ties.
Number of packs per shelve. Looking at 4 as the full size rack has plenty of room. 4 per shelve gives lots of separation.
Yet to be decided on;
Method of linking packs in series. I'm thinking making a loop point each end with the 10 sq mm bus bar cable and then link packs with lugged off flex cable of similar or slightly larger 25mm flex cable.
Method of fixing packs on server rack shelves. More than likely go very simple with very large nylon cable ties.
Number of packs per shelve. Looking at 4 as the full size rack has plenty of room. 4 per shelve gives lots of separation.