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diy solar

Ordered/Received 52 280Ah EVE cells from Amy - Wonderful experience!

Cabbagefield

New Member
Joined
Mar 25, 2021
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1
Location
Colorado Mountains
This was an excellent experience working with Amy. She always provided timely updates and answered many questions for me along the process. She sent me the link to the cell report which I downloaded and saved locally. She sent me the FedEx tracking label information. She got answers from EVE for me about the QR code decoding. All cells were manufactured in either February or March of 2021 so all were brand new as promised. They arrived boxed very well except for one box had been dropped by the shipper. One corner of one cell had slight damage so I am currently load testing it to make sure it does not have internal damage. I took pictures and posted them to Amy on the Alibaba messenger app, which works very well for communicating with her. There was a short delay in shipping because there were not enough cells in stock for my order.

Summarized Timeline
  • March 26, 2021 - Requested quote from Amy and received the quote back the same day
  • March 30 - Payment sent
  • April 20 - Order shipped
  • June 23 - Delivered by FedEx to my house
I am building three 48v batteries with 16 cells in series using an Overkill Solar BMS for each battery (16s). I purchased an additional four cells to have as spares and quite frankly because I wanted to play with them for different projects so, of course, I needed a 12v 4s BMS for these as well. After pre-charging and top-balancing the cells I made my compression cases out of 1/2 inch plywood glued, pin-nailed then counter sunk each corner with two square-head wood screws. I received some unused plexiglass sheets that I cut to size for the top. So far, I have two of the 48v batteries in service with an ANL fuse and quick-disconnect switch on each battery case. I included a couple of pictures for reference. Still have some tasks, like tape down the balance wires and replace my original 2/0 battery cables with more flexible cable from WindyNation (Amazon) to make everything more pretty but they are working well.

Many thanks to Will and so many others with good information and videos and links to pieces and parts needed to make this project a success!

More later.

completed 48v battery.jpgbattery box.jpg
 
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I used 10mm Optix Polycarbonate for my pack tops, much easier to be able to view inside and looks better IMO.
Come to think of it, Will has never mentioned Amy or Luyuan.
 
I just got 16 of these from Amy also at about the same time. I wish I had got some spares like you as one of my boxes was also dropped resulting in a dinged corner. I'm balancing them now, and notice that the dinged cell is topping out first, hopefully just coincidence....
I did contact Amy a couple weeks ago and send her pics of the damage and asked if it was still ok to use but so far she has not responded. did she get back to you? other than that I was super impressed with her service and product and would hapily buy more from her again, but make sure she uses corner protectors on boxes next time.
 

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I did contact Amy a couple weeks ago and send her pics of the damage and asked if it was still ok to use but so far she has not responded. did she get back to you?
She was travelling a little while ago and got into dead zones for a little bit and then got flooded with stuff, just ping her again to remind her, she's really good with communicating but occasionally one falls off the pile, LOL.
 
I am building three 48v batteries with 16 cells in series using an Overkill Solar BMS for each battery (16s)
any reason for choosing the overkill bms? i am still not sure what bms to get, may go with chargery.
also, just thought id say, i would not be relying in the 1/2 in ply and nails/glue for compression, needs something heftier surely?
 
The Overkill Solar BMS has been tested to run continuous at its rated amps. Not may BMS manufacturers can match that. The challenge now is getting one of the Overkill Solar BMS. They have been wildly popular and their inventory is gone in a flash.

I agree that 1/2" plywood with just nails and glue may not be a long term compression solution. I used 3/4" plywood with threaded rod.
 
Do remember the time difference, that buggers me up occasionally when I don't think of it.

I built my battery boxes with 3/4" PureBond Plywood, Pocket Screws and PL adhesive, "snug fit" as the cells themselves are bound and also have "nylon pull strings" for every 4 cell bundle to help if removal is needed. Mine are for 8 cells (24V) Block packs and also have a space for the active balancer & for the wires from cells to batt lugs on the boxes. 280AH cells at 5kg/11lbs ea get's heavy fast. I've even taken one of these boxes and dropped it, banged it about (weighted equally without actual cells) and other than being scuffed took it all quite well. Albeit these are on a shelf in the powerhouse so they won't suffer much, so all good anyways.

box-assembled-a-jpg.30608

280ah-battery_box-jpg.30611
 
I'm balancing them now, and notice that the dinged cell is topping out first, hopefully just coincidence....
How are you balancing them? Did you get the test data with the cells? Were they capacity matched or did you order commodity cells? If they were capacity matched I don't think that ding would throw things off.
 
How are you balancing them? Did you get the test data with the cells? Were they capacity matched or did you order commodity cells? If they were capacity matched I don't think that ding would throw things off.
I got the test data link, they are matched grade A according to Amy. But when I went to the sent link, I got their cell data page but the fields were all empty(?)

I first tried parallel charge with a Hyperion charger, at 17 amps it was slow going. particularly as the charger is only speced for 100ah so kept timing out.

after I got them to 3.2v or so, (week) I'v now hooked them up to an Adaptto max-e ebike controller, which has bms and adjustable charge control for all parameters with cell voltage display, nice but as its little balancing resistors are tiny it cant pull the massive high cells down fast enough to keep pumping in the juice. I'v been discharging the high ones individually with the Hyperion charger. I'v got them to between 3.32 and 3.37volts resting, im thinking of going back to parallel charge again.
 

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I got the test data link, they are matched grade A according to Amy. But when I went to the sent link, I got their cell data page but the fields were all empty(?)

I first tried parallel charge with a Hyperion charger, at 17 amps it was slow going. particularly as the charger is only speced for 100ah so kept timing out.

after I got them to 3.2v or so, (week) I'v now hooked them up to an Adaptto max-e ebike controller, which has bms and adjustable charge control for all parameters with cell voltage display, nice but as its little balancing resistors are tiny it cant pull the massive high cells down fast enough to keep pumping in the juice. I'v been discharging the high ones individually with the Hyperion charger. I'v got them to between 3.32 and 3.37volts resting, im thinking of going back to parallel charge again.
Just ping Amy and tell her the link she gave you was empty, she'll get you the right link, she is very good about that sort of thing.

I'm 24V & only 8 cells per pack. When I top Balance, I do it in sets of 4 cells and when each set has been Top Charged to 3.65 and settled, I put them all together as 8 cells in parallel and Top Balance the lot (much quicker even after the cells settled). I like to Top Balance the whole pack cells, allow to settle 24 hours and redo it again to <1.5A taken and they're good to go. I use a TekPower TP1540e Bench PS set to max 3.65V (DMM Verified) and start at 40A CC (Constant Current) allowing it to go into CV (Constant Voltage) allowing it to drop to 1.5A being taken (which is fully staturated).
 
any reason for choosing the overkill bms? i am still not sure what bms to get, may go with chargery.
also, just thought id say, i would not be relying in the 1/2 in ply and nails/glue for compression, needs something heftier surely?
48v at 100a is 4800 watts. Times 3 batteries is I think enough power.

At 120v (4800w times 3= 14Kw) that is 120 amps.
 
Thanks for that. That sounds like a plan. It might be easier in banks of 4 with the chargers I have currently. I still have faith in Amy but just been too busy to chase it up yet.
 
48v at 100a is 4800 watts. Times 3 batteries is I think enough power.

At 120v (4800w times 3= 14Kw) that is 120 amps.
That makes sense. Iv been looking for 250a bms as im only running a single 48v pack and want to run everything...
much more sensible to have multiple lower rated ones, i might end up getting another pack:)
 
Roh Oh... Trouble on the horizon, something not considered and no one pointed it out ? not even me till now.
Understand that a Paralleled bank will split charge/discharge between the pack in the bank. Take a bank of 4 packs in parallel, each pack with 100A BMS. Max load out support is 400A. Max input allowable is 200A all to be split between packs. But now you get 3 packs disconnect, 1 pack remains "hot" it cannot by any possible means take that charge/discharge rate by any means. A Force failure will occur is anything is exceeded.

We suggest not to exceed 250A draw capacity and for good reasons an I won't get into a well-beaten topic. (excluding surge capacity)
You have 280AH - 280A output capable batteries that can fill that requirement. Every single pack should be able to act as "The Last Man Standing" so that none will ever get over driven even if all other packs in the bank cutoff for any reason. IT HAPPENS !

Now with 4 packs and 250A capable BMS, that can deliver a MAX of 1000A which is more than enough for any surge...
48V@250A=12,000W and with a LOW Frequency Inverter that can goto 36,000W (750A), High Frequency can hit 24,000W or 375A.

No to be mean or nasty or anything BUT this is a decision that could cost you serious coin if having to upgrade and worse if cells get damaged due to poor config and NOT preplanning for "Worst Case Scenarios" which sadly DO HAPPEN ! Be Smart and consider this and weigh the choices carefully. These are "System Foundation Essentials" to be aware of. Like a house, the Foundation has to support everything that is loaded on top of it which includes all the crap that people stuff into buildings (which often weigh more all tallied up than the actual building) pending on construction type.
 
Roh Oh... Trouble on the horizon, something not considered and no one pointed it out ? not even me till now.
Understand that a Paralleled bank will split charge/discharge between the pack in the bank. Take a bank of 4 packs in parallel, each pack with 100A BMS. Max load out support is 400A. Max input allowable is 200A all to be split between packs. But now you get 3 packs disconnect, 1 pack remains "hot" it cannot by any possible means take that charge/discharge rate by any means. A Force failure will occur is anything is exceeded.

OK, I'll bite for a discussion on system design.

So, 4 banks of 48V and somehow we get 3 of the banks go down all at once. Can you see the problem?

The idea of multiple banks is to provide redundancy in case a fault occurs in 1 bank and still allow some operation, limited capacity and load but still the system is operational. Of course, some type of monitoring system should be in place. Second, the remaining banks have to carry the load and will each reach a cutoff point high discharge limit or a fuse/breaker blows in a properly designed system.This would require a very large load. 4800w times 3= 14Kw (120 amps). I don't know about you but my house doesn't even approach that on the grid with the AC on with the well pump running.


We suggest not to exceed 250A draw capacity and for good reasons an I won't get into a well-beaten topic. (excluding surge capacity)
You have 280AH - 280A output capable batteries that can fill that requirement. Every single pack should be able to act as "The Last Man Standing" so that none will ever get over driven even if all other packs in the bank cutoff for any reason. IT HAPPENS !

Who designs a system where you have 1C rate of discharge? Using your scenario, that would be 1 hour use for 1 bank, 4 hours for 4 banks. Are you intending to power a small village? :cool:

Just what are you doing with that much power? The idea of any off grid solar system is to minimize load first as it costs way more to install a system that handles an inefficient load than to upgrade loads to minimize usage. Maybe I'm old school but I've always said to minimize loads and maximize conservation first as it is much cheaper to practice conservation than add generating power.


Now with 4 packs and 250A capable BMS, that can deliver a MAX of 1000A which is more than enough for any surge...
48V@250A=12,000W and with a LOW Frequency Inverter that can goto 36,000W (750A), High Frequency can hit 24,000W or 375A.

No to be mean or nasty or anything BUT this is a decision that could cost you serious coin if having to upgrade and worse if cells get damaged due to poor config and NOT preplanning for "Worst Case Scenarios" which sadly DO HAPPEN ! Be Smart and consider this and weigh the choices carefully.

System design plays a huge part in safety, no one here will disagree.

Designing a system where you lose 75% of power reserve without some type of cutoff would be a huge safety concern, never mind the overloading of components such as the inverter.

I'm still old school where I design a system where the max sustained load on the inverter and other components never exceeds 50% of rated capacity. Running high amp loads at rated capacity will always lead to shortened component lifespan. The main killer is always heat and you will get heat generation running at rated capacity.


These are "System Foundation Essentials" to be aware of. Like a house, the Foundation has to support everything that is loaded on top of it which includes all the crap that people stuff into buildings (which often weigh more all tallied up than the actual building) pending on construction type.

I think your 75% system failure is just a little over the top myself. Think of it this way. 4 banks and system design is for 50% max load or rated capacity. If 2 banks were to go down, the system should still be able to operate safely at rated capacity.

Could your 75% failure scenario occur? Most definitely anything can happen. I also could get hit by lightning in bed some night while I'm asleep. Doesn't mean it could happen, but there is always that possibility. This is why system design comes into play with correct fusing, using less than full rated capacity (50% preferred for sustained load), and setting for inverters and BMS systems.
 
I didn't say anything about 4 banks. I used an example of 4 packs in one bank. Pack being an assembled battery.

1626625938888.png Part of my previous setup.

BTW, My system is built to handle the 250A IF REQUIRED and I have hit it (Mig Welder, Air Compressor) but after seeing that they only get Genpower.

Coffee maker 50A + Nuke 75A and Mrs hit Hairdryer and Surprise ! your getting there (I'm 24V)

Right now at this very moment I am using 7A, not on battery which are all in float now. If the fridge goes on, 11A.

Worst Case scenario's must be considered, most especially if you depend on it.

I use a Grundfos SQ softstart, 120V and at top draw it's 1100W. God only knows how many times I have told folks that Conservation is far cheaper than Generation & Storage...
 
I didn't say anything about 4 banks. I used an example of 4 packs in one bank. Pack being an assembled battery.

View attachment 56759 Part of my previous setup.

BTW, My system is built to handle the 250A IF REQUIRED and I have hit it (Mig Welder, Air Compressor) but after seeing that they only get Genpower.

I'll bet you saw the surge really go wild with welder and air compressor. :)
Coffee maker 50A + Nuke 75A and Mrs hit Hairdryer and Surprise ! your getting there (I'm 24V)

Yes, but we were talking 48V so that makes amps half already......


Right now at this very moment I am using 7A, not on battery which are all in float now. If the fridge goes on, 11A.

If you had 48V, it would be half........:)
Worst Case scenario's must be considered, most especially if you depend on it.

I use a Grundfos SQ softstart, 120V and at top draw it's 1100W.

23a on 48V. Remember, we were on 48V which means a 100a BMS is 4800w.

How deep is your well? I had a new pump put in under warranty last year and if it goes out again (might be a long time) then I might consider changing to softstart or DC powered.

For now, it will remain on grid power.

God only knows how many times I have told folks that Conservation is far cheaper than Generation & Storage...
Even in something like my truck camper switching from 12V DC powered incandescent bulbs to 24V LED's will save many watts. No need to run buck converter and it's idle draw when not needed plus bulbs will take much less watts when turned on. Add up those little wattage draws and it shows up as big watts consumed leading to needing more panels and storage.
 
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