diy solar

diy solar

At this point... if you are buying From Alibaba/Aliexpress you deserve what you get.

I'm glad I mentioned the story about my computer teacher! I was in elementary school at the time, so my details seem to have been off.

I appreciate all of the cool information about the "old" tech world!
Yeah, we lived through an amazing era of human innovation.
 
We look forward to your results. If you are in Phoenix, I have equipment that I could loan you.
I am in Wisconsin but thanks!

I've got a load tester and chargers and stuff. Might go pick up the CBA analyzer if this local place actually has one in stock as their website says.
 
Gosh, this is so tough. I tell everyone to avoid the cheap listings, but I still love buying them :LOL:. It is so cheap, and sometimes I get really lucky. Even my "grade b" puff pastry packs will still work fine. Even the low quality packs from months ago had some nice cells inside that I used in other projects.

The problem is when 95%+ of people get good cells from a listing. Then someone comes on the forum saying that their cells from that listing are garbage. I don't know what to say. I know there is some risk, but you really have no clue where these cells come from.

I think people's expectations are a bit high when they purchase from the cheapest lifepo4 listings on the internet. Sometimes it bothers me that people get disappointed, but then again, I still purchase from them. Most of the time, I am pretty happy with what I receive. If I find something wrong, I usually get my money back, or a majority of it.


Here's maybe some good cheap cells $150 for 4 cells of 320ah

US $56.40 25%OFF | 100% New Lifepo4 320Ah 4-16PCS 3.2V Grade A 48V 310AH Battery Pack DIY RV Cell And Solar Energy Storage System EU US Tax Free
 
Here's maybe some good cheap cells $150 for 4 cells of 320ah

US $56.40 25%OFF | 100% New Lifepo4 320Ah 4-16PCS 3.2V Grade A 48V 310AH Battery Pack DIY RV Cell And Solar Energy Storage System EU US Tax Free

that store is a scam store that will never deliver your order, below is just a small list of stores that will never send any package and you might not get your money too easy from dispute so you might loose the money :

https://www.aliexpress.com/store/912331261 258 sales volume Store
https://www.aliexpress.com/store/912152020 1000Orders Store
https://www.aliexpress.com/store/912344599 10000orders Store
https://www.aliexpress.com/store/912342547 1369orders Store
https://www.aliexpress.com/store/912259801 1994orders Store
https://www.aliexpress.com/store/912159100 1999orders Store
https://www.aliexpress.com/store/912300063 2228orders Store
https://www.aliexpress.com/store/912157084 2999orders Store
https://www.aliexpress.com/store/912452025 3286 orders Store
https://www.aliexpress.com/store/912262802 3838 orders Store
https://www.aliexpress.com/store/912167090 3999orders Store
https://www.aliexpress.com/store/912332249 5888 sales volume Store
https://www.aliexpress.com/store/912316039 6668orders Store
https://www.aliexpress.com/store/912330273 6854 sales volume Store
https://www.aliexpress.com/store/912368333 68825orders Store
https://www.aliexpress.com/store/912270815 6899 orders Store
https://www.aliexpress.com/store/912168094 6999orders Store
https://www.aliexpress.com/store/912325252 7887sales volume Store
https://www.aliexpress.com/store/912308062 7899orders Store
https://www.aliexpress.com/store/912272790 8899 orders Store
https://www.aliexpress.com/store/912338622 8989orders Store
https://www.aliexpress.com/store/912261832 8999orders Store
https://www.aliexpress.com/store/912157082 9990orders Store
https://www.aliexpress.com/store/912307045 9999orders Store
https://www.aliexpress.com/store/912174633 Battery 18650 shop Store
https://www.aliexpress.com/store/912194128 Battery pack 18650 Store


collect in time.jpg
 
Wow just saw Will Prowse Latest video, even he got PUFF PASTRY 300Ah probably form a wrecked bus. I'm guessing the refurb CATL 300s.

SAD.

So yeah, if you are buying from Aliababa / Express you deserve what you get.

Come to think of it, has anyone opened up a CHINS battery? What type of cells were in it? Where the refurb CATL the ones with FAKE QR code to the side?
Out of 112 kWh of battery bank from Aliblabla, I’ve had 20 cells that were under spec from LiitoKala and Sanben. I’m very happy with my $20K bank that can power my all electric home for 2-3 days. Now, tell me again how much a US Company would resell the same sourced cells for 112 kWh. Try about $60K+. No thanks.
 
Out of 112 kWh of battery bank from Aliblabla, I’ve had 20 cells that were under spec from LiitoKala and Sanben. I’m very happy with my $20K bank that can power my all electric home for 2-3 days. Now, tell me again how much a US Company would resell the same sourced cells for 112 kWh. Try about $60K+. No thanks.

what was the refund percentage you got for the 20 cells that were under the spec. and how much was under the pec ? did you test with 1C discharge current as in the spec ?
 
what was the refund percentage you got for the 20 cells that were under the spec. and how much was under the pec ? did you test with 1C discharge current as in the spec ?
Have you tried getting anything out of these two sellers. Don’t waste your time. I’m missing about 5-10 aH per cell on those 20 cells. So, not really worried about it, since 108 cells from Hayley and Amy meet or exceed specs.
 
Have you tried getting anything out of these two sellers. Don’t waste your time. I’m missing about 5-10 aH per cell on those 20 cells. So, not really worried about it, since 108 cells from Hayley and Amy meet or exceed specs.
Do you have pictures with your test device ? It is important to know that a cell capacity test result of 280ah discharged at 1C will have 310ah capacity discharged at 0.1C for 10 hours as presented in their graph (they even discharge for 17 hours I saw) but specs are 1C discharge rate ...
 
Do you have pictures with your test device ? It is important to know that a cell capacity test result of 280ah discharged at 1C will have 310ah capacity discharged at 0.1C for 10 hours as presented in their graph (they even discharge for 17 hours I saw) but specs are 1C discharge rate ...
The same three test devices (ECB-40L and two 20A load testers from Amazon- pics of these all online), at the same discharge rate that I used to measure the cells from Dongguan (Hayley) and Shenzhen Luyuan (Amy) cells. What DIY has a 280 amp load tester? When comparing different sellers products, 10-40A works just fine to figure out who’s selling Grade B or G.
 
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Do you have pictures with your test device ? It is important to know that a cell capacity test result of 280ah discharged at 1C will have 310ah capacity discharged at 0.1C for 10 hours as presented in their graph (they even discharge for 17 hours I saw) but specs are 1C discharge rate ...
The spec sheet for the version of EVE cells I purchased specifies 0.5C.
Newer versions have different rates, but mine are from 2019.
Testing at 40 and 80 amps respectively, identical results (within a tenth of an amp hour).
 
The spec sheet for the version of EVE cells I purchased specifies 0.5C.
Newer versions have different rates, but mine are from 2019.
Testing at 40 and 80 amps respectively, identical results (within a tenth of an amp hour).
I didn’t get the same results when I experimented with 40A vs 10A. But as long as we are consistent from cell to cell, seller to seller, these $50-$300 load testers work just fine, with some double checking of actual cell voltages during the 2.5 LVCO. View attachment 66114
 
I didn’t get the same results when I experimented with 40A vs 10A. But as long as we are consistent from cell to cell, seller to seller, these $50-$300 load testers work just fine, with some double checking of actual cell voltages during the 2.5 LVCO. View attachment 66114
On some cells you will see a difference of 5% - 10% capacity when discharging with 1C as in specifications = 310amps discharge vs 0.1C at 40amps discharge . Comparing 40A with 80A will not get you a noticeable difference but when testing at 1C rated discharge rate from specifications you will really find what bad quality battery you received.

Right ?
 
The same three test devices (ECB-40L and two 20A load testers from Amazon- pics of these all online), at the same discharge rate that I used to measure the cells from Dongguan (Hayley) and Shenzhen Luyuan (Amy) cells. What DIY has a 280 amp load tester? When comparing different sellers products, 10-40A works just fine to figure out who’s selling Grade B or G.

If you can find a way to discharge at 280A and measure capacity discharged than I can bet that cutoff voltage is triggered much faster at 1C because of voltage drop at 280A ... right ? so capacity will be a lot lower ....

but i think you can discharge with CC + CV at the end, not sure if all devices can do these 2 on a discharge cycle ...
 
Gosh, this is so tough. I tell everyone to avoid the cheap listings, but I still love buying them :LOL:. It is so cheap, and sometimes I get really lucky. Even my "grade b" puff pastry packs will still work fine. Even the low quality packs from months ago had some nice cells inside that I used in other projects.

The problem is when 95%+ of people get good cells from a listing. Then someone comes on the forum saying that their cells from that listing are garbage. I don't know what to say. I know there is some risk, but you really have no clue where these cells come from.

I think people's expectations are a bit high when they purchase from the cheapest lifepo4 listings on the internet. Sometimes it bothers me that people get disappointed, but then again, I still purchase from them. Most of the time, I am pretty happy with what I receive. If I find something wrong, I usually get my money back, or a majority of it.

What discharge rate and device did you use to test ?


If you can find a way to discharge at 280A and measure capacity discharged than I can bet that cutoff voltage is triggered much faster at 1C because of voltage drop at 280A ... right ? so capacity will be a lot lower .... but specs are specs and we must test on specs not lower ...

but i think you can discharge with CC + CV at the end, not sure if all devices can do these 2 on a discharge cycle ...

What do you suggest to use to test and have a valid proof at 1C if that is the rated discharge rate ?
 
What discharge rate and device did you use to test ?


If you can find a way to discharge at 280A and measure capacity discharged than I can bet that cutoff voltage is triggered much faster at 1C because of voltage drop at 280A ... right ? so capacity will be a lot lower .... but specs are specs and we must test on specs not lower ...

but i think you can discharge with CC + CV at the end, not sure if all devices can do these 2 on a discharge cycle ...

What do you suggest to use to test and have a valid proof at 1C if that is the rated discharge rate ?
Most of us can only check Capacity (at 1A-40A, affordably), IR and Self Discharge over time. You are the second forum member asking for proof of capacity testing with pics. We are hobbyists, enthusiasts, experimenters, tinkerers. We likely wouldn’t be on a DIY’er forum if we had professional grade, .001% accuracy testing equipment. When comparing cells to cells from various sellers on the same cheap inaccurate testers and for what we are using our cells for, it is sufficient.
 
Most of us can only check Capacity (at 1A-40A, affordably), IR and Self Discharge over time. You are the second forum member asking for proof of capacity testing with pics. We are hobbyists, enthusiasts, experimenters, tinkerers. We likely wouldn’t be on a DIY’er forum if we had professional grade, .001% accuracy testing equipment. When comparing cells to cells from various sellers on the same cheap inaccurate testers and for what we are using our cells for, it is sufficient.
Most have no idea what "measurement uncertainty" is, no clue of the distinction between accuracy and resolution or repeatability. There is no surprise that even a respectable vendor will get tired of customers with claims of purported under-capacity results with oh so questionable equipment and methods.......
 
Most have no idea what "measurement uncertainty" is, no clue of the distinction between accuracy and resolution or repeatability. There is no surprise that even a respectable vendor will get tired of customers with claims of purported under-capacity results with oh so questionable equipment and methods.......
Most vendors have no test equipment other than a 4 wire voltage and IR meter (that specifically states it is not accurate above 100AH capacity cells).
 
ebc-software.jpg

EBC-A40L High Current Lithium Power Battery Capacity Tester

The Youtube Channel off-grid garage has been using this fine piece of equipment and had my itchy online shopping finger ready to say:"buy it now".
It has a high capacity but is limited to 5V cell voltage.


For a nonprofessional setup, it requires some careful selection of procedures to measure capacity with common equipment (e.g a shunt and coulomb counter), but there are no guarantees of absolute accuracy other than 2% (+/-? 3 sigmas? 2 sigma, RMS who knows).
I'm only going to rely on capacity data (matched to the labels) right from EVE because I assume they can afford and use something at least as good as the off-grid garage.

People agonizing of voltage matching is pretty much irrelevant unless they can somehow ascertain that there was actually a change in voltage from a perfect match in transit. If you can't trust the vendors then you are already in an uphill battle trying to prove with hobby equipment that their "factory data" is in error.
 
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