EVE 280Ah Lifepo4
- Thread starter boboxx
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boboxx
New Member
Yes that is correct
I received my 280ah cells back in January; these are pictures of the final end product. Two 280ah batteries for our 5th wheel.
For each one they use a group 31 battery box, a daly 200a BMS and a ISDT cell monitor. Bus bars are 1" copper. they also have a 14w reptile heater fixed to the underside which I will experiment during low temperatures. 8 Cells was $950. Total cost was about $1300. or about $650 per battery. they will replace my current 300 pound FLA battery bank.
For each one they use a group 31 battery box, a daly 200a BMS and a ISDT cell monitor. Bus bars are 1" copper. they also have a 14w reptile heater fixed to the underside which I will experiment during low temperatures. 8 Cells was $950. Total cost was about $1300. or about $650 per battery. they will replace my current 300 pound FLA battery bank.
That's impressive! When you wire the cell monitor (does it do any active balancing?) Are there leads from each cell's positive to each of the BMS AND the cell monitor or can the BMS and cell monitor share the balance leads somehow? Looks amazing for group 31 footprint -- may need a bit more height to accommodate the terminals.
good morning; the cell monitor does have a passive balance function which you can activate manually. the BMS and cell monitor share the same ring terminals which I soldered together and then crimped. I did buy some active balancer's initially but didn't install them because the cells are grade A and don't need them and for the reasons Will posted that active balancing is ineffective for the most part unless you are on the knee of the voltage curve. the battery boxes have plenty of room with the top on for the terminals. not really a problem.
CerealKiller
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I think there has been a wide number of people very happy with these cells. I sure am. they are of high quality. was kind of thinking of building another one but am holding off. I think having two for the 5th wheel is plenty for now. (6kw) My two batteries I just charged up via the solar panel a week ago and they are still within 10 or 15mv of each other. the daly BMS also has a balance function built in. but I also used the balancing function in the monitor jus for grins. (something to do while the sun was shining).
CerealKiller
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That was super helpful. Glad to see you are enjoying your setup.
LukeVader
Sun Farmer
That's really amazing information. How can you read those QR codes? I have 8 of the same and trying to figure out if the serial # portion has any info like date of manufacture, grade, etc.
Are the heat pads AC or DC? And do they have a built in thermostat?
Hi all,
can anyone tell me if I can mount the cells in other positions than upright? Due to space constraints I need to mount my cells on the sides with the terminals on top of each other. Would that be problematic due to the position of the pressure valve or for other reasons?
Cheers,
Marc
can anyone tell me if I can mount the cells in other positions than upright? Due to space constraints I need to mount my cells on the sides with the terminals on top of each other. Would that be problematic due to the position of the pressure valve or for other reasons?
Cheers,
Marc
good morning; there are two heat pads on each side of each battery. (8"x12" perfect size for the 280ah cells) they are AC, 7watts each. there isn't a thermostat but their spec sheet says they top out at a nominal temp of about 70-75degrees F. (the right temperature for a reptile). my plan is to just connect them to the output of the inverter either thru the night or in the morning to heat things up.
I guess theres really no need for a thermostat if they max out around that temp. Good failsafe having two pads per battery in case one were to crap out on you.
I’m planning to get some DC pads and run them directly off the charge controller load output on a timer setting. Also, thinking I may put my battery in one of those cheapo styrofoam coolers to make it easier to maintain temp for late fall/winter.
I felt that most of the DC heat pads were way too hot (around 80deg C). I put two heat pads with each battery as those 280ah cells are beefy. lots of mass to get warm. I also will look at insulating them but haven't dwelled on it as yet too much (looking forward to summer). I have victron charge controllers integrated with a BMV-712. they will not charge the batteries until the battery temp is detected at around 40deg. (I verified that this spring with some early morning temps) so a connection between the charge controllers and DC heating pads wouldn't work to heat up the batteries. But that's just my configuration in this instance.
sremick
Mostly competent. Knows enough to be dangerous
Did you ever get an answer to this or figure it out?
PScott
New Member
Can someone explain what "fixture" is referring to in the LF280 specification?
Refer to this thread:
diysolarforum.com
EVE-280 cells should these be clamped tight or spaced for expansion?
I working on my 4s 280ah battery plans. I thinking of my battery box. should these cells have a air space between them or be bonded tight together with a hose clamp or something similar.
diysolarforum.com
Refer to this thread:
EVE-280 cells should these be clamped tight or spaced for expansion?
I working on my 4s 280ah battery plans. I thinking of my battery box. should these cells have a air space between them or be bonded tight together with a hose clamp or something similar.
Start a bit further up the page, and continue reading beyond Steve's comment. My recollection is that his opinion (Snug but no pressure/force applied) was the minority opinion on this question, and did not appear to be supported by the manufacturer's specifications.
Like @sremick and @LukeVader I'm also hoping for clarity on the maker of these cells, OP states EVE, April thinks they are Ganfeng (based on the QR code?).
So what's the difference if one compresses the cells or keeps them snug enough to prevent the cells from expanding....lol. The aluminum around the cell isn't going to know any difference of the amount of compression unless one compresses the cell so much the aluminum is crushed.
The whole thing of compressing the cells per Eve's specifications with that much force never made any sense to me. However applying enough force to keep the cells from expanding does make sense. And that amount of force would be tiny, or snug.
I was looking at threaded rods and 3/4 inch plywood on home depots website. In my mind cutting two pieces of plywood to match the size of each end of the pack, then putting the plywood on each end of the pack and using the threaded rods to apply a snug amount of compression should suffice. Others have used this method and I think it's great.
Good question, some clarity from EVE would be helpful. In my eyes firmly snug and tight, and light compression are two ways of saying the same thing. However the linked comment states in the first sentence: "Compress does not mean put under pressure ! In this context, it means snug & tight but not under pressure or force." This statement is the only point that was questioned/received pushback from people as it appears out of step with the manufacturers recommendation of 300kgf compression. Beyond that I think everyone was on the same page that cells should be somewhere between snug and moderately/lightly compressed.
Setting that aside, I think the open questions are (1) do other cell manufacturers make similar recommendations (2) how is the 300kgf measured/derived and how specific is it (3) how best to accomplish it in our DIY designs.
I won't pretend to fully understand EVE's logic. But unless you are confident you do fully understand or have more info, it seems like a prudent default is to follow or at least approximate the manufacturers specifications as best we can.
Fully agree, I think this is a good method, and probably what I will do. I think its the best low tech, cheap, DIY friendly method that approximates the manufacturers guidance.
I'm wondering if tightening the threaded rods to the point of snugness at low SOC would achieve roughly the right amount of compression at mid and high SOC. I'm also wondering if I'm overthinking this
hard to say with so little info to go off of. Worst case scenario if you do nothing to compress your cells is your cells last a really long time (2500 cycles) as opposed to a really really long time (3500 cycles) If you dont want to overthink it I think using the method you referenced reccomended by MarineHowTo, Nordkyn and others and tightening to the point of firmly snug is a solid plan.
It's just my own common sense although I am not the brightest bulb around here. I don't know where they are coming up with 300kgf from. I had thought it might be a misprint and/or maybe they are referring to the aluminum casing. As you know there is a pouch contained within the casing. Or maybe they mean 300kgf is the required force to keep the cells from bulging when charging at the maximum C rate.
I'm wondering if tightening the threaded rods to the point of snugness at low SOC would achieve roughly the right amount of compression at mid and high SOC. I'm also wondering if I'm overthinking this
I have over thought about this too. If the cell has no bulge, which it shouldn't when new, then it shouldn't matter what the SOC is when mounting them snug.
hard to say with so little info to go off of. Worst case scenario if you do nothing to compress your cells is your cells last a really long time (2500 cycles) as opposed to a really really long time (3500 cycles)
And that is probably true. BUT.....if you do nothing to compress the cells and they never bulge, then why wouldn't you still be able to get 3500 cycles?
If I had to do an educated guess it's because it prevents the layers from delaminating.
1) I don't know. 2) Imagine you put something weighting 300 kg on the cell (you can convert it to a pressure if you divide it by the surface of the side of the cell if you prefer). 3) Use threaded rods, a torque wrench and a torque to traction/compression force table. +/- 10 % would be pretty good and probably good enough (and still better than nothing...)
They do bulge a little at high SoC, a few % at most but it's here.
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