diy solar

diy solar

EVE 280Ah Lifepo4

msdmaddog said:
so the cells just perform well Maast ? how many cycles ? how many months / years ? any problems ?
Click to expand...
I dunno yet, it's in the line to be tortured next. I've got a GFB277 on the tester now and at .5C I only get 6 cycles per day so it takes a looooOOOOOOOoong time (weeks and weeks) to do enough cycles to get enough data to extrapolate lifecycle. So far all I've done to the cell model the OP bought is initial capacity testing and charge voltage holding, which it passed.

For what was paid for them though I do have to wonder if its a B or a C cell. Or did I just get ripped off. The quickest test of a quality of a cell after capacity is how well it holds a charge after its been charged up to 3.65v per cell. It should drop quickly (hours) to roughly 3.5 but then hold that for at least a week before dropping below 3.5 or 3.45 at worst. Capacity and charge holding capability is the first test from the factory to differentiate an A from a B from a C cell.

I hope the OP tests the snot out of his and posts the results, I'm super curious and at that price point if they're decent cells I'll be upping the number of cells I'll be buying myself from them. I got mine from a completely different vendor.
 
Last edited:
April said:
Nah the aluminium is quite thick and would need to be pierced . Theres no pressure inside and LiFePo4 is not dangerous.Worst that will happen is electrolyte/coolant leaks out and stains stuff.
Click to expand...
For what it's worth, I got 4 cells without holes or terminals on them, on the first I gingerly drilled down 1mm at a time on my drill press and discovered the aluminum post is quite thick and very soft. The first hint of copper color was at 3/4 an inch. I then tapped it and then installed a 1.75" bolt, wrapped a strip of wet paper towel around the base of the bolt then cut the head of the bolt off with a grinder then tapered it.

The next three I bypassed the tapping and just drilled the hole, screwed in the bolt, unscrewed it and sanded off the ridge that formed around the hole, screwed it back in and cut the bolt head off. Saved a lot of time.

You can easily feel when it bottoms out and all you need then is just a couple of inch-pounds to secure it.
 
iam very excited about your results and thx you for that very helpful information Maast
 
Maast said:
For what it's worth, I got 4 cells without holes or terminals on them Never seen that on any advertised cells?
The first hint of copper color was at 3/4 an inch. Its the tabs squeezed together then a 1/8th rectangle of copper is spot welded to the bottom of the terminal with the tabs between . If you see copper you see the tabs
You can easily feel when it bottoms out and all you need then is just a couple of inch-pounds to secure it. If you do that you risk separating the spot weld allowing air into the cell and leaks out
Click to expand...
 
April said:
Nah the aluminium is quite thick and would need to be pierced . Theres no pressure inside and LiFePo4 is not dangerous.Worst that will happen is electrolyte/coolant leaks out and stains stuff.
Click to expand...
@TJ Tom, @April, @boboxx

Related to the visible aluminium damage (I have no idea whether the damage could be a problem), just as a reference I wanted to share:

NordkynDesign - lithium battery banks fundamentals,

in turn referring to (search for "edge", e.g. p32):

Lithium-Ion Batteries Hazard and Use Assessment, Exponent Failure Analysis Associates, Inc., published by the Fire Protection Research Foundation (2011)
 
I have been playing with my batteries for a bit now but I have a problem. I have on cell that has a dark blue wrap, it's different from the 3 other ones.

If I put my Virctron 10amp charger on the pack, 3 batteries will reach about 3.35v and the dark bleu will be way off. The fist time I had it charging it reached 4.02v before I noticed it! I installed one of these BMS (https://www.ebay.com/itm/322387253365) and it can keep the battery ballaced but cell will never pass 3.5v.

If I use one of the small active balancer at 1.2amp (https://www.ebay.ca/itm/312774496524) it dosen't look like it can keep up as the cells are out of balanced again (3.35, 3.35, 3.35, 3.86). I have a 5A Active Balancer on order to try out. (https://www.ebay.ca/itm/312799154132)

If all cell are equal at 3.35v and I use the inverter to drain they all go down at the same rate.

I figured I would ask in case someone knows what the issue might be and how I could resolve :)
 
I sounds like you got a cell with a much lower capacity than the others and there's no fixing that - at best you can mitigate it with a high amperage active balancer but thats a poor fix. I'd measure capacity of the 'good' cells and buy a replacement cell of the same capacity. The highest amperage active balancer that I know of is this one at 6A, but they're not cheap and you need one per cell.

Led Indicator 1S Battery Equalizer Balancer BMS Active 18650 Polymer DIY for sale | eBay

Find great deals on eBay for Led Indicator 1S Battery Equalizer Balancer BMS Active 18650 Polymer DIY. Shop with confidence.
www.ebay.ca
You can find these cheaper on Aliexpress but the best price is still $20 US a unit, they also make 8S ones that are already ganged together for a bit less per-cell cost.
 
Ya it's a bummer, how do I know that the 3 other cell are good?

If I would want to charge the cell individually, with a bench top power supply, would it be ok to just set the voltage to 3.65v@3a?
 
boboxx said:
Ya it's a bummer, how do I know that the 3 other cell are good?
If I would want to charge the cell individually, with a bench top power supply, would it be ok to just set the voltage to 3.65v@3a?
Click to expand...
Exactly, then a hall effect amphour meter and dump it to a load of some kind. FYI a 15 inch length of .032 stainless wire will draw about 5 amps at 3.3V, parallel a few of those and drop it in a bucket of water and you've got yourself a cheap and easy loadbank.
 
Thanks Maast, have you noticed similar with the battery you got or are they all good cell?
 
So far they've been good, different capacities with different battery models but thats to be expected.
 
Good day everyone; I also just popped for 8 of these EVE 280ah cells for our 5th wheel. (planning on a 4s2p for 12v bank) they should be here in a few weeks and I'll keep everyone apprised of the progress and results. I know they'll be grade B cells. but at this price and the expected low consumption I don't anticipate too many problems with using them and putting together a nice 12v bank. Will most likely also go with a pair of 5A active balancers which I also just ordered to try out. Will be glad to be rid of my FLA bank. (which weighs in at about 250# in the cargo bay)
 
backwash said:
Good day everyone; I also just popped for 8 of these EVE 280ah cells for our 5th wheel. (planning on a 4s2p for 12v bank) they should be here in a few weeks and I'll keep everyone apprised of the progress and results. I know they'll be grade B cells. but at this price and the expected low consumption I don't anticipate too many problems with using them and putting together a nice 12v bank. Will most likely also go with a pair of 5A active balancers which I also just ordered to try out. Will be glad to be rid of my FLA bank. (which weighs in at about 250# in the cargo bay)
Click to expand...
Did you also order from Billion Electronic Technology on Alibaba? I am getting a quote for shipping - though I don't know what to make - they claim these are Grade A cells...
 
yes; they did say that they are Grade A, with zero cycles. but I would say my expectations are 'realistic'. they might be dinged up. but as long as the capacity is 'close' I'll be happy. With zero cycles even better. Might have a bit of difficulty balancing if not quite matched but expect with typical low drain/load it will be ok. which is why I kind of went overkill about getting so many ah. way more than I need. The price was too good to try this out and see how it goes. $75/each+350 shipping. $950 for 560ah. plus I'm going from 250# of battery to a nice compact 75#. My existing FLA bank is about 425ah. (~200ah usable). I would expect at least 450ah of usable capacity.
 
It is very tempting, even with $418USD shipping to Canada. I am leery of @Maast's post above regarding receiving cells without terminals or post holes. I definitely don't feel comfortable drilling into a battery!
 
Oh you can specify that they come with holes - I just went with the slightly less expensive models intended to be welded to a bussbar like for a EV, one of the vendors I was corresponding with did say that these are the largest cells you can buy directly that are A cells, anything larger you find will almost certianly be B cells rejected from the chinese EV market.
 
just a quick follow up; I ordered these EVE 280ah cells on tuesday. I just got a tracking number (the vendor so far has been great to work with) and they will be here Monday! I will follow up toward the end of next week with photos of the cells and their condition for anyone interested.
 
good morning; I ordered from the same place as the original poster. billion electronics on alibaba. I have 8 cells coming for $950. Dave...
 
and if anyone is interested here is the datasheet they gave me. big cells. 3" thick. so a 4S-12v pack will be 12"x 7" x 8" high. it will weigh about 35#.
 

Attachments

  • LF280(3 2V280Ah).pdf
    685.7 KB · Views: 170
boboxx said:
After a few individual cycle, each cell is charging and discharging at the same rate :)
Click to expand...
What charger or method are you using to test cycle? I've ordered the capacity tester discussed on this forum but haven't picked a charging set up. options are variable DC power supply? Using a ISDT active balancer would take too long. My bank will end up in my boat which has a shorepower charger but for my home lab I'm not certain what I should pick up.
 
I have a Victron IP65 and a bench top power supply. For draining I have a Kisae 2000W inverter and 1500w space heater. None of it is very fast but it's winter here and I still have a few months.
 
You must log in or register to reply here.

Similar threads

X
EVE 280ah problem with 1 battery only?
2
Replies
26
Views
914
GXMnow
GXMnow
Offgrid Aussi
My 48V LiFePO4 Battery thinks 53.33V is 100% charged. Is that all right?
Replies
18
Views
843
Offgrid Aussi
Offgrid Aussi
W
New Apexium 280Ah - Eve Cells - Problem?
2
Replies
33
Views
630
Welly
W
B
Battero Tech BT280 3.2V 280Ah LiFePO4 Cells - US$55.00 _ GobelPower.com
Replies
8
Views
1K
Skypower
S
Alkaline
Basen EVE 280 Dead as a Doornail in 3 years.
Replies
13
Views
904
Loadtoad
L

diy solar

diy solar
Back
Top