pwd
10 kW
That's right; I'm planning on laying them out the first way. Basically like this (not my photo, I don't have the cells yet) - the green line represent compression faces:
PWD's Yamaha XV250 Virago build
- Thread starter pwd
- Start date
pwd
10 kW
The cells have finally arrived but I'm a bit disappointed upon inspecting the first couple of cells. I may have been sold new old stock where the internal resistance is higher that I was excepting.
The first cell I looked at has a manufacturing date of March 2019 based on this info decoder site:
The datasheet says that between version D and E of the cell (revisions made in 2021) the internal resistance was specified as ACR(1KHz) ≤ 0.6 mΩ and then improved/changed to ACR(1KHz) : 0.35±0.1 mΩ;
I've measured ~ ACR(1KHz) 0.6 mΩ on the first cell @25C / 3.6V
Looks like I have some checking to do and a task I dislike - trying to prove to the seller I was screwed to some degree
The first cell I looked at has a manufacturing date of March 2019 based on this info decoder site:
The datasheet says that between version D and E of the cell (revisions made in 2021) the internal resistance was specified as ACR(1KHz) ≤ 0.6 mΩ and then improved/changed to ACR(1KHz) : 0.35±0.1 mΩ;
I've measured ~ ACR(1KHz) 0.6 mΩ on the first cell @25C / 3.6V
Looks like I have some checking to do and a task I dislike - trying to prove to the seller I was screwed to some degree
Last edited:
pwd
10 kW
I may have just discovered that the cells I received are not even the same brand or capacity I had ordered. Still doing some digging but my cells look an awful lot like Sunwoda 3.7V 75Ah and not Svolt 90ah.
I can see their response now: "bbbuuuttt...we sent you cells? why complain?" :/
FWIW, the tiny bit of the as-received cell I can see in your pic
doesn't look anything like the cell picture you'd posted (from their site?) previously, of the ones you were ordering
other than that it has a vent, posts welded to the contact blocks, and it's prismatic. All the details of all those things are significantly different.
FWIW, the tiny bit of the as-received cell I can see in your pic
doesn't look anything like the cell picture you'd posted (from their site?) previously, of the ones you were ordering
other than that it has a vent, posts welded to the contact blocks, and it's prismatic. All the details of all those things are significantly different.
Also, if interested, this is a useful video on how the QR code came about, and how to make one (which also means how to manually read one):
pwd
10 kW
Yes exactly, they looks visibly different. The dimensions are nearly identical. I've sent the seller my findings and am waiting for a response.I can see their response now: "bbbuuuttt...we sent you cells? why complain?" :/
FWIW, the tiny bit of the as-received cell I can see in your pic
doesn't look anything like the cell picture you'd posted (from their site?) previously, of the ones you were ordering
other than that it has a vent, posts welded to the contact blocks, and it's prismatic. All the details of all those things are significantly different.
This lithium cell code decoder actually shows the manufacturer; and the same production date:
I found a fairly good explanation of how to manually decode the production date here:
QR decoder parsing differences
QR codes appear to be parsed differently in different QR decoders. In the Basen and Gobel online decoders, as well as the Android LiFePOQR decoder, the QR code eg 07HCBC1P22G06AC700002596 indicates a manufacturing date of 7 Jul 2022. However, on sites such as Docan Power, Energie Panda and...
diysolarforum.com
Here is the text from the key post in that thread:
"
Code decoding standard, informative but not super understandable:
GB/T 34014-2017 English Version, GB/T 34014-2017 Coding regulation for automotive traction battery (English Version) - Code of China
GB/T 34014-2017 English Version - GB/T 34014-2017 Coding regulation for automotive traction battery (English Version): GB/T 34014-2017, GB 34014-2017, GBT 34014-2017, GB/T34014-2017, GB/T 34014, GB/T34014, GB34014-2017, GB 34014, GB34014, GBT34014-2017, GBT 34014, GBT34014www.codeofchina.com
Code breakdown:
1-3 - unique manufacturer Id, 07H = Higee
4 - battery type, C = cell
5 - Chemistry, B = lithium iron phosphate
6-7 - manufacturer product code, not unique across manufacturers, C1 =that version of the Higee 120ah LFP cell
8-14, manufacturer custom info. Space left for manufacturers to put what they want, decoding only available properly for eve cells, p22go6a
15-17- Date of manufacturing. This is where at why things are confusing, they do not give in the English translation a format for the date just that 880 equals Aug 31st 2018. So people do not know if that is m/y/d or y/m/d. That is the difference you are seeing between the code readers above.
Days run from a-z (skipping a few) then 1-0
Month is 1-9 then a-c
Year is 8-9 then a-z
"
pwd
10 kW
Update so far is that the seller admitted the wrong cells were sent but only wants to pay the price difference on the cells. I sent a reply to that and am awaiting a response.
pwd
10 kW
I have come to an agreement with the seller and will be keeping these 75ah cells. I received a little compensation + $144 USD for the cell price difference and three replacement cells for ones that were dented. I am disappointed that I'll be using lesser cells but I really want to get this project rolling; I'd rather get it working than wait another 1-2 months + the cost.
In hindsight and for anyone new to ordering cells from China: do your research, ask the seller lots of questions and confirm the specs before ordering - at least then you'll have proof of what was supposed to be sent (I at least had that). Also, start the cell ordering months in advance if you have a planned date for build completion; then you have more time to deal with issues and can save money on shipping if you aren't in a hurry.
Here is the worst of the damaged ones:
Typical resistance of these cells @ ~20 degrees Celsius and ~ 50% State of Charge:
They won't be horrible, but I may lower my expected maximum current to 400A.
I started making the first tray for the battery pack - it will sit here but it still needs frame supports etc...
Here are the materials I'll be using to make each sub pack: aluminum end plates to keep the pack together/slight compression with coated stainless steel cable ties. I'll be using 2mm rubber between each cell and as padding in the tray:
In hindsight and for anyone new to ordering cells from China: do your research, ask the seller lots of questions and confirm the specs before ordering - at least then you'll have proof of what was supposed to be sent (I at least had that). Also, start the cell ordering months in advance if you have a planned date for build completion; then you have more time to deal with issues and can save money on shipping if you aren't in a hurry.
Here is the worst of the damaged ones:
Typical resistance of these cells @ ~20 degrees Celsius and ~ 50% State of Charge:
They won't be horrible, but I may lower my expected maximum current to 400A.
I started making the first tray for the battery pack - it will sit here but it still needs frame supports etc...
Here are the materials I'll be using to make each sub pack: aluminum end plates to keep the pack together/slight compression with coated stainless steel cable ties. I'll be using 2mm rubber between each cell and as padding in the tray:
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