32 280Ah Eve "grade a" from Shenzhen Luyuan (Amy Wan)

hipringles

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Figured its time to document my process of buying/receiving/testing these cells

First off: Working with Amy is nice. She responds super quick and gives honest (and true) information


I ordered 32 (8x4) "EVE 3.2V 280AH NEW GRADE A". Here is the timeline of events. Once my capacity tests finish I will put my overall recommendation (yes or no), on the top post...

  1. 1/31/21 I reached out to for a Quote
  2. 1/31/21 She replied asking for detailed shipping information
  3. 2/2/21 I changed my request from 16 to 32 cells
  4. 2/3/21 I got a new total quote: ($529) shipping to west WA, total cost of ~4300
  5. Some general back and forwards over a few days as I lingerd on if I wanted to pull the trigger.
  6. 2/6/21 I payed Alibaba
  7. 2/6/21 Amy Confirmed
  8. <Chinese newyear!!>
  9. 2/22/21 Amy replied said they just got the next batch from Eve, welding studs now
  10. 2/28/21 Amy said they went into shipping
  11. 3/2/21 I recieved pics of the cells being packaged, voltage checked, etc (but could not get a test report)
  12. 3/8/21 *domestic* tracking info provided (doesn't help when the cells are on the boat
  13. <LOTS of waiting>
  14. 4/1/21 I asked if she had any info on the boat, she replied with ETA in Cali on 4/4/21
  15. 4/9/21 I followed up for status
  16. 4/10/21 Amy replied saying they have been unloaded and cleared customs, waiting on Fedex in cali now
  17. 4/12/21 Fedex tracking came alive
  18. 4/19/21 all 16 boxes arrived on my door

Status of cells on arrival:

  • Packaging was great. I honeslty think you could have yeeted these off a 50 foot building and they'd likely be un-damaged. Very very nice packaging, double boxed, etc.
  • Every cell was 3.295
  • No visual imperfections (except one positive terminal is not centered by a mm or two)
  • Got 32 busbars and ~70 bolts (32 isn't enough for most uses, I mentioned this to her)
  • The bus bars, imho, do not look near thick enough to handle 300A of current. They are ~1/16th, maybe 1/10th of an inch thick, made out of <Some shinny metal?>, and 3/4 inch wide. But Will used these on his 280ah video and seemed OK with them /shrug.

Between then and now:
  • I screwed around with the cells quite a bit (hooked up 4 to series to test a few 12v things, hooked up a 48v string to test my Renogy inverter/charger, etc)
  • Had to figure out how TF im going to get more busbars. These aren't apparently things in the USA. I contated Amy and she was willing to send more over rush Air shipping for 1.2 per + 33$ shipping
  • I bought 18 feet of 1/8''x1'' copper, and made my own busbars

<To be continued>
 

hipringles

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I set my Victron smartshunt to 0 current before hooking up the inverter, along with setting it to full SOC once it was fully connected to the battery.

There seems to be a ~0.4a difference (@48v) between the shunt and a clamp meter. The shunt agrees with the current from the overkill solar (jbd) smart BMS ammeter

@27kWh of draw from the 2p16 per the shunt @ 3.173 per/cell
 
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D

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Everything has offset and gain error, including the shunt and your clamp meter. The only way to calibrate anything is to use a “more accurate” reference or to average several different types of measurements and presume the collection of them resides around the true mean (aka the “law of large numbers” in statistics)
 

hipringles

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Finish capacity test. Tl;dr 283ah. Top balance was done to 3.62, cells idled for ~3 hours, then test ran until 46.2 v on the pack.

Other general information:
  • Test was completed @ 48V/25A(ish) mostly, which is going to be my most common use-case for these cells.
  • Top balancing 32 280ah cells on a 10a bench charger literally took over a day to get from 3.58 to 3.62, and i figured ~15 hours in parallel on new cells @ 3.6 was good enough
  • AH was ~566 (283/cell) per the shunt, and ~589 per the clamp meter.
  • 29.5kwh on the shunt. I stopped discharging @ 46.2ish volts, figuring it was close enough to being drained and we exceeded 280ah

For anyone curious, I did all the charging (minus end of top balance, which took literal days), discharging, and re-charging with a Renogy 48/3500 all in on (the one Will hates). 0 issues charging 560ah @ 25A continous. Same with the discharge on a ~1200w load
 
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mzoid

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Finish capacity test. Was @ 48V/25A(ish) mostly (Powering some constant loads in the house). AH was ~566 (283/cell) per the shunt, and ~589 per the clamp meter.

29.5kwh on the shunt. I stopped discharging @ 46.2ish volts, figuring it was close enough to being drained and we exceeded 280ah

For anyone curious, I did all the charging (minus end of top balance, which took literal days), discharging, and re-charging with a Renogy 48/3500 all in on (the one Will hates). 0 issues charging 560ah @ 25A continous. Same with the discharge on a ~1200w load

Forgive me if this is a stupid question, but the 29.5kWh on the shunt and the 283ah/cell (also as per the shunt) don't make sense to me?
Wouldn't 566ah @48v infer 27.1kWh? The 29.5kWh figure would make sense if the voltage were sustained at 52v throughout but of course with discharge from full charge to low cut off, we know that isn't the case?
 

hipringles

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Forgive me if this is a stupid question, but the 29.5kWh on the shunt and the 283ah/cell (also as per the shunt) don't make sense to me?
Wouldn't 566ah @48v infer 27.1kWh? The 29.5kWh figure would make sense if the voltage were sustained at 52v throughout but of course with discharge from full charge to low cut off, we know that isn't the case?
The voltage is more like ~52-53 than 48
 

mzoid

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The voltage is more like ~52-53 than 48
Thanks - I needed to pay closer attention to the discharge curve for these cells. Looks like they only pass through 3v very briefly on their nose dive to low cut off point, so me choosing 48v (3v * 16cells) as a median was nonsensical...
 

hipringles

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Thanks - I needed to pay closer attention to the discharge curve for these cells. Looks like they only pass through 3v very briefly on their nose dive to low cut off point, so me choosing 48v (3v * 16cells) as a median was nonsensical...
Yep. I actually stopped testing around ~2.85ish per cell because its more or less the bottom and I hit >280ah (Im guessing they really had <1-2% left)
 

hipringles

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1619925548118.png

Here is a picture right before I stopped the test from my timelapse recording (Probably shoulda taken one more, but close enough)
 

hipringles

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Top balancing

This kinda deserves a good post on its own:

When I received the cells, as mentioned in the OP, they all tested to 3.295/.296. But, I got antsy and wanted to start playing around. I hooked up 1 string of 16s to my inverter, charged some, discharged some, didn't have bus bars torqued down well, and un-balnced that string from the other 16. Would not advice, but end of the day not a big deal.

Here is how I top balanced these cells:

1.) I made custom busbars for the 2p16s setup. Doing this with a handdrill was a 1/10 experience, could not NOT recommend enough. I actually ordered a drill press so I can come back and finish rounding out some of these holes a little bit as the fit is somewhat tight on the terminals. <please don't make fun of my lopsided holes on a few. This took way too many hours to do and kinda sorta figure out>

1619926390956.png

2.) I hooked up the cells on a 2p16s config, slapped on the trusted Renogy 48/3500 (Seriously the product is not *that* bad Will ;), and it has a marked grounded spot for the AC out that you missed in the video)
3.) Charged them like this for @25A until 1 cell (set) hit ~3.3
3a.) Note: the 16s bms can't reach them in straight line, and I have yet to cut the bus bars to make this a proper rectangle, so I did the oblong ending so I didn't have to mill anything else until my press gets here.
3b.) I should have let them go all the way to 3.6 on 1 cell. I jumped the gun because "cell" was creeping out higher than the rest. This could have been due to non-copper busbar connecting them (see below), or maybe not. Idk i am not an EE.
4.) The 16th cell group (on the Red positive) hit high voltage

1619926586874.png
5.) I took the cells and split them (poorly) into 2 sets of 16 again, with "cells" 1-8 now being 1-16 on string 1, and 9-16 being 1-16 on string 2.
6.) I series charged string 1 more, while starting to parallel charge string 2 @ 3.65V
6a.) The 10A/30V charger would only sink like 4A of current (prob because voltage was close-ish). After literally 48 hours the cell voltage just hadn't changed a meaningful number.
7.) While String 2 was in the forever parallel balancing act on the slow charger, I manually tried to balance some of String 1 (the series string) by adding resistors to the high cells, led light sinks etc.
7a.) This actually worked quite well. I got this string to hit HV disconnect around with them all being pretty close.
7b.) Parallel'ing was still going slower than life
8.) Swapped the string series (1) into parallel, and parallel (2) into series
9.) Parallel charged string 1. This was making slow but noticable progress from ~3.4 to 3.63 over a few days
10.) Did Step 7 with string 2 to manaually balance while in series. I also used boost charged some cells as needed to help speed this along
11.) String 2 *back* to parallel. Step 9 with string 2 now. This only took ~12-18 hours to get to ~3.63
12.) Re-trickled string 1 to be very close to string 2 voltage
13.) parallel connected String 1 and 2 now into 1 giant 32P battery lol. I put on the 3.65 and let it charge for another day or so until the current sunk to ~0.2A, and the voltage across the entire battery was 3.621

14.) Let them rest for a few hours, then re-set them up as in step 4 (but used copper bars on the main negative, main positive). Hooked them up to the inverter and let the capacity test begin. The cells were really locked in voltage (imo) all the way down. Never got more than ~.007 apart

Fun facts. I did make sparks only once, and thankfully that was when messing with the parallel pack @3.5V or so. And boy did it rain sparks for a few seconds (I tried to connect 2 sets of 4 backwards (P --> N and N-->P)


Overall this took probably 5-6 days to fully do. Could have been ~2-3 if I knew what I was doing, and had enough trust in what I was doing to let the charging happen overnight the first few nights (I was too worried about un-intentional overvoltage, so I disconnected when I couldnt monitor)


Thanks for coming to my tedtalks
 

Boondock Saint

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Wow what a detailed and informative documentation, much appreciated!

I think you could publish a concise How-To wiki on a 48v setup and really save folks (like myself) a lot of time and mental energies.

And you used only the Renogy unit and a BMS or two to do all of this?

I think I want to repro the fast version of this. I'll just sleep with a fire extinguisher next to me at night. :D
 

hipringles

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Wow what a detailed and informative documentation, much appreciated!

I think you could publish a concise How-To wiki on a 48v setup and really save folks (like myself) a lot of time and mental energies.

And you used only the Renogy unit and a BMS or two to do all of this?

I think I want to repro the fast version of this. I'll just sleep with a fire extinguisher next to me at night. :D
I will for sure. This is mostly me dumping information before I forget. #remind me in 7 days

48V is not bad. just don't be a dumbass. Use non-metical tools, don't go sliding batteries while busbars are held in your hand, wear glasses (gloves if you want, I did a lot), and pre-charge your caps with resistors like Will shows and the danger is managable.

I used the Renogy 48/3500 all in 1 to AC charge in series, and discharge. The BMS was a single JBD smart BMS from Overkill solar. Each cell was in 2p then 16s. so 1 bms lead per each set of 2p.

The BMS is fine, the app is meh, constantly frooze/crash when trying to tweak settings. The balance is (too?) weak for cells this big.


If I was to do it all again, i'd let it charge overnight. I now have a decent understanding of how long a charge will take, and some faith for the BMS to work :). The only thing I wouldn't do overnight is the final chunk of charging from ~3.61 to end, incase the bench charger voltage is wrong and overvolts the batteries (ie over 3.65). Though the risk for this is absurdly low.
 

Boondock Saint

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and pre-charge your caps with resistors like Will shows
err . . shows where please? Have a link?

0 issues charging 560ah @ 25A continous.
Ya well I live IN my RV and travel in it, it's my daily driver etc. I find shore power where I can, but I don't have unlimited access. So even if I source the Renogy and Victron parts, BMS etc etc I still dunno exactly how I'm going to do any of these balance testing methods.

Use non-metical tools,
Do you think THIS set will do or should I get the deluxe edition?
 

hipringles

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Things I would do differently

1.) Biggest and by far: Not made busbars by hand. Jesus this took like 6+ hours, and they still don't fit perfectly (a little tight on some), unless the cells are well compressed. I am going to expand these holes on the bus-bars in a few days with a press
2.) Maybe gone 16s2p rather than 2p16s. At first I was annoyed I didn't, but now that I am balanced and the capacity test went well, I am not too upset with skipping the second BMS.
3.) Not screwed around before just doing straight into a top balance
3.) Get a automatic screwdriver. Threading, unthreading, threading, unthreading 64 bolts over and over gets.... old
4.) Bigger (30 or 50a) power supply for the top balance
5.) Be sure all bolts are torqued down pretty well so I am not chasing erroneous high/low voltages on some cells :)
 

hipringles

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err . . shows where please? Have a link?


Ya well I live IN my RV and travel in it, it's my daily driver etc. I find shore power where I can, but I don't have unlimited access. So even if I source the Renogy and Victron parts, BMS etc etc I still dunno exactly how I'm going to do any of these balance testing methods.


Do you think THIS set will do or should I get the deluxe edition?
See this vid (
) @ 10:30 or so for the next 10 seconds. He does it on most his 48V newer videos.

also a thing I did, which worked well for me, I would plug in the inverter (to the wall), turn it on, let it get going etc, then unplug it from the wall --> then hook to battery. This made basically 0 sparks as the caps were charged from the AC power)
 

hipringles

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I hope my copper busses look half as good as yours :)
Excellent work
Thanks! if your doing a larger setup (more than 8 cells) i cannot stress how much I think the value of a $100-150 drill press will make. If you don't have one get one!
 
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