LiFePO4 charging and discharging curve explained. How far to go? (Qishou EVE LF304 capacity test)

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So, here we go with the first (actually second) full capacity test of the new EVE LF304 batteries with welded studs! And I did not want to just present the results to you but also explain how charging and discharging works with these cells. I'm getting a lot of questions from beginners on how to charge and discharge these batteries.
The first two tests with the EVE LF304 cells from Qishou turned out to be amazing, unbelievable, outstanding. The measured capacity was over 3% higher than rated. What a great outcome from Qishou again, delivering these fantastic cells. Super happy with the delivery!
EVE LF280K/304 LiFePO4 cells 3.2V/280+304Ah from Qishou Technology: off-grid-garage.com/batteries/
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How far to charge and discharge a LiFePO4 cell. Testing the full Charge and Discharge Curves. • How far to charge and ...
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8 апр 2022

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Комментарии : 170

@jws3925 2 года назад

OUTSTANDING summary, Andy. I just sent this to a fellow who I talked to on the phone the other night and had these questions. I think you answered all of them in this video. I know this is basically information from experiments performed several months ago but you put this together in a nice comprehensive package. Well done!

@OffGridGarageAustralia 2 года назад

Thanks a lot John. Appreciate all your comments and support here on the channel!

@upnorthandpersonal 2 года назад

With these large cells, patience is key. We see many people on the forum charging with a lab power supply. You can't expect a cell at 50% to be charged in a few hours with a 10A lab supply - in fact, it would take 15 hours for just once cell at these 10A. Now multiple this by 8, 16 or more cells... it'll take a while. Also: if you don't see the full current of the supply when it's set at 3.5V or so, your cables are not good enough: use thicker wire, and ring terminals - not those crocodile clamps that come with a supply. Most importantly: set the voltage on the supply before connecting, and once connected, do not touch the voltage knob. It's normal that the voltage will drop, while your supply is pumping its max current into the cells.

@jws3925 2 года назад

Always enjoy your comments, Up North

@dc1544 2 года назад

You are 100% correct. Is gonna take me forever to get my cells topped up unless I use my Inverter and bms.

@upnorthandpersonal 2 года назад

@@jws3925 Thanks John!

@evil17 2 года назад

I have an All in one 48v Mppt system for around $700 and a few 100A 5120W server rack type batteries I’m testing out at the moment with an already installed 9.6kw of solar already installed this was an easy install to power my house at night from daily solar excess. The all in one systems seem great for this and can charge to 80A as I just plug it into a wall socket (for now) on timer from 9am-4pm to charge the batteries, + it can handle up o 5000w & 450v of extra PV panels if wanted, it makes a cheap inverter / charger. Solar in, battery in, ac mains &/or generator input, ac output, and that’s basically it 4 connections, plus communications if you want, with heaps of settings for battery charging, load sharing etc. you have got to have more patience than me to try and charge one of these battery banks with a lab power supply, also, you could try a $70 20Amp 48v-60v power supply which could take 5-7hrs for every 100A battery you have. Great vids Andy, cheers

@keithcress1335 2 года назад

Not only the alligator er (crocodile AU) clips but also the other end of the leads, typical banana plugs frequently start heating up at about 5 measly amps. Always keep a close temperature monitoring of the banana plugs until you get the feel for what your supply's plugs can handle. You shouldn't allow them to get more than about 10C or 20F warmer than the ambient.

@johnwatts3339 2 года назад

Andy, you provide, indeed, a wealth of information in your videos. Well documented and explained. Kudos!

@keithcress1335 2 года назад

Thanks Andy! My brain loves graphs, especially clearly explained ones by yourself.

@MicroplaysMC Год назад

I thought I knew a lot about batteries, but there's a bunch of stuff in here I didn't know that will prevent me headaches in the future. Thanks Andy!

@kc79ta Год назад

Thank you for once again explaining things in a way us non professionals can understand. Slowly making my way through your videos and you clearing up a lot of the fog.

@user-li4nf8co8p Год назад

I am from india Thank you for video it clears all confusions of lifepo4 cell charge, Discharge, Volts

@OffGridGarageAustralia Год назад

You are most welcome

@showmequick2245 2 года назад

This is cool. Probably more stat on these batteries than the actual manufacturer videos. Good work bud -Abshir

@SoutheastOhioSolarHaven 2 года назад

Great information to see ! Glad to see the range of charging on these types of batteries.

@jerseyjeeper1575 2 года назад

Just the info I was searching for! Thank you…..!🍻

@KeithKropf Год назад

Great explanation! Thank you so much for the excellent info and a very good presentation. Aloha!

@lloydconner3034 2 года назад

This is the best that you have explained the batteries. Thanks

@OffGridGarageAustralia 2 года назад

Thanks a lot Lloyd!

@bartowl 2 года назад

GREAT summary! love it!

@tstrafaci Год назад

Excellent - I was seeing a similar curve for my battery, and I thought something was wrong. Thank you

@harrymuurling2742 2 года назад

From the first test you made long time ago i follow you advice for charging, i used lifepo4 eve cels from ups systems, when i did follow your advice about charging all my without a bms because all packets come from a 48 volt system 4 cels busbar laserd. I keep the total voltage to 54,4 volt and suddenly all sets have nk runaways any more all stable. I bought after your advise 8 sets of 4 cels more and i run now all my house already for 4 month without any problems, i monitor everyday the status but there are no problems any more. What you did with the testing off the cels makes it very clear, even after very cloudy days the cells perform excellent. Thanks Andy, i started to read more of the documents and charge and discharges curves and after your explenations and testing its all correct, don't compare with lead acid because before i used them and was very confused. Much thanks for all

@timha4102 2 года назад

I learned so much from your video. This was priceless. Thank you!

@OffGridGarageAustralia 2 года назад

Thanks for your feedback. Have a look at some older videos where I explained this in even more details and we analysed the curves in every way to understand the way LFP works

@jagos9376 3 месяца назад

Thank you! Great Video! I didn't know how the setting for the 16S (48V) Lifepo4 LF304Ah system but know I have all the data :)

@hendersonsobers396 2 года назад

Thanks for sharing Andy....this is great information. I'm going to try your suppliers out.

@LancashireProClean 2 года назад

Brilliant video Andy it will help a lot of people with there bms settings but I went on your website to download the data for the LF304 welded studs (as I have the same) and its coming up with the data for the palo cells

@danfitzpatrick4112 2 года назад

Awesome Test! I have said before.. I play between 50v and 54v or (3.125-3.375 per cell) These cells will naturally rest at 53.1 or (3.31 per cell, this is without using float charging under no load situations). Thanks Andy!

@Sunspirit8 2 года назад

I was just watching your previous video capacity test and i just saw your new video

@bishwagit 2 года назад

Old beer, new packaging..... Good to hear again.. Keep it up Andy...👍👍👍

@porter5976 2 года назад

It sounds like Dana Carvey from Hans und Franz at 8: 46. "I think my battery is faulty. It does not charge." I expected him to say, "My battery is a girly man." Hahahahaha! Another great video Andy. This is my favorite RU-vid channel. I asked my buddy the other day if he wanted to go into the business of installing this onto houses that already have solar panels. When I told him the cost, he said they may as well get a generator. My thinking is that, during a power outage, the house loses power while the the generator is spinning up but, with ac coupling of the batteries, you'll not lose power but may see a flicker. People with money may be willing to pay for that luxury. The startup cost of a business is probably more than I'd like to spend and it'd be hard work for someone nearing retirement age. Champagne wishes and caviar dreams.

@tomleonard6177 Год назад

Great video!

@guntherdrehsen 2 года назад

Nice to see that Qishou aka QSO sent you another batch of good quality / capacity EVE cells. 😊 I have seen that their Alibaba shop has been verified by TÜV Rheinland. 😁

@excillisbank2611 2 года назад

Vraiment très intéressant tes conclusions ANDY. Merci

@joshrg22 2 года назад

Thanks for this! I've been charging my bank just like this.

@TrevorFraserAU 2 года назад

I think the word you are looking for is resting voltage. Thanks again for your great work.

@jimmyjackson9090HVAC 2 года назад

Thanks!

@user-lq6ms5eq6j 2 года назад

Thank you very much for this good information

@OffGridGarageAustralia 2 года назад

My pleasure!

@solargarage 2 года назад

Awesome video

@martehoudesheldt5885 2 года назад

thanks for showing the volt drop from charge to static. that was the info i could not find. using A123 truck batts i could not find out what was normal for lifepo4 batts. i just figured out that my 6000 amp hr @24volt are at 99% cap not 80 thank you

@andreiapostolache3487 2 года назад

We thank u Andy is very nice to hawe nice info from first line

@chuxxsss 2 года назад

Morning Andy, out look for gold again today. ;)

@BobBohner4851 2 года назад

Great info

@gudrn 4 месяца назад

Hi the. Always a pleasure to watch your vids. So. Top voltage should be 3.45v and bottom voltage should not be lower than 3,15v. CHEERS from Brazil

@gumpster6 2 года назад

Another great detailed video. I know it's time consuming (it would take a month), but will you run a charge/discharge cycle on all the brand new cells just so you know they are all good (for peace of mind) or do you just trust the manufacturer and create a big battery without individual testing?

@sjdtmv 2 года назад

Andy, as a warning I thing I found when I had a failed cell out of a pack of 8 all cells tested to the right capacity, but when I graphed the results the charge discharge curve on one cell was nothing like the rest, even though they came up to capacity, so when you only look at each graph separately you could miss this bad cell, so on loading the graphs of each cells into one graph only is a good thing before commissioning a complete pack

@FutureSystem738 2 года назад

LOL Andy. “Not charging because the voltage isn’t rising?” Where on earth do they think that energy is going! The battery would be red hot if it “was not charging”. Great descriptive video 👍

@OffGridGarageAustralia 2 года назад

They come from Li-ion batteries where the voltage is linear to the SOC. Measuring the voltage gives a good indication of SOC with these batteries. Like in our cars. Hence Tesla recommends to fully charge the LFP battery cars once a week, so the BMS knows what's going on. They had massive problems at the beginning with cars being stranded despite still showing 40% battery.

@maikeljegerings5870 9 месяцев назад

Hey Andy, I like to view your videos. It feels like visiting a friend and talk about a hobby. Greetingz from The Netherlands.

@OffGridGarageAustralia 9 месяцев назад

Thanks a lot for your kind feedback.

@marclandry4175 Год назад

Andy! Your videos gave me the knowhow to build a battery bank for my dad's off grid cabin. Thank you! I am now top balancing 9x 280AH cells from Shenzen Qishou. They have been on the CV charger for about 2 weeks and are still ingesting about 3.5A @ 3.65vdc from the supply. The cells read about 3.35vdc. This seems like a really long time even when considering the flat charge curve. Does this seem normal to you?

@52gulfpapa 2 года назад

Another very educational video. Any chance of a capacity test on a Nissan Leaf 66 ah module?

@JR-kk6ce 2 года назад

I have been thinking about your videos. They are a wealth of information. There should be a way to categorize them, index them, where subsequent videos that add to or change the original subject, are listed so that one can refer to updated info. Maybe make a short book which you could sell at Amazon?

@bbrown_sc 2 года назад

This is great! How long should you leave the battery in absorption mode before it goes into float? The defaults for my Victron MPPT RS 450/100 keep it in absorption @3.55v for about 2 hours.

@DanBurgaud 2 года назад

18:20 CAVEAT: Discharging LiFePo4 cells to lower than 20% SOC will greatly reduce battery life.

@benoittheminerandgamer 2 года назад

Very cool to look, At 3.45-3.5v the batterie is almost full and at 3v empty! With 0.5v diff this batterie give us 304amps!!!

@tonynobes1464 2 года назад

Hi Andy, Love the channel, I have built a 300ah 48v battery for my off-grid home and love it it's so good But I was bragging about my battery on a facebook forum and was told it's not possible to have 300ah in a battery that weighs 5ish kgs per cell, So maybe you could explain how this is possible. I see the Winston 300ah 3.2v is 9ish kgs. Keep up the great work. Cheers Tony

@OffGridGarageAustralia 2 года назад

Thanks for your comment Tony. Not sure, why the cells weigh 'only' that much. I never compared the weight across other brands and batteries. It's definitely working, that's for sure.

@captainobvious9188 2 года назад

I use a Deye 8k inverter now, but I started years ago with those little blue GTiL2 inverters (made by Deye - which is how I found the 8k hybrid inverter and imported one before I found out that they are the SolArk manufacturer). Anyways, you can set a minimum voltage to bring the battery down to on it and you can also set a max output. I feel good about keeping this $250 inverter around so that when I load test batteries I can dump it back into my home loads and not waste the relatively infinitesimal amount of electricity ;-P

@OffGridGarageAustralia 2 года назад

That's a good point. As much as I like the ZKE tester, they waste all this energy during testing. That's not very efficient. I have to do these battery tests in summer when I have an abundance of energy 😉 I like to test these 12V batteries as I can use the inverter to get most of the energy back.

@edwardvanhazendonk 2 года назад

Thanks Andy, on their Alibaba site they are playing your videos, there is no better marketing they can do. It's time for me to contact Amy and see my options in the ever increasing price spiral. Thanks again for a clear video, one small question, getting around 95% of charge (between 3.45 and 3.1) does it stress the battery and will it garantee (within limits offcourse) the 6000 cycles, or are there more limits to this claim? Enjoy your SPAT, hope autumn is good with lots of sun and enough charge!

@peterdkay 2 года назад

Andy, Great concise explanation. Can you explain the glitches at about 1.5 hour and 6 hours into charge cycle?

@antoniodecrisci2369 2 года назад

By glitch you mean spikes, I have the same tester and that happens when the cables are moved or touched and they change their contact surface area on the terminal. It's likely someone bumped the cable or Andy had an earthquake.

@marcoarpago 2 года назад

Great summary Andy, today just arrived my cells from Qishou , (took months, but finally arrived. In Italy by TRAIN from China.. amazing) so happy ! Just one question, to store the cells for a later use (several months) what voltage wolud you raccomend .. 3.32 Volt ?

@OffGridGarageAustralia 2 года назад

EVE recommends to store them between 0-35°C and 30-50%SOC. So pretty much as hey came to you. I probably would top them up a little bit. Mine came with just 30% SOC...

@dc1544 2 года назад

I really want to see the 280ah eve with welded studs. So I can see what volts you think about to charge and discharge to. I think you should get about 288-292ah out of them. I see more Beers from me in your near future.

@reefr80 2 года назад

Cheers Andy. Question. With charging at higher C rates, it affects the voltage significantly. Is there a way you could overlay a 1C charge/discharge curve over your findings from this video. This will affect where people set balance start voltage, absorption voltage (is 3.45 too low at 1C?). Cheers.

@joemacdonald1181 Год назад

a bit off topic but this is one of my most trusted channels of information. i was just told by one of my suppliers that LFP prismatic batteries (and oter lithium batteries as well) have two connections, the negative terminal, as expected, and the positive terminal which is intentionally electrically connected to the case. is this common knowledge which escaped my attention of is it as suprising to everyone else? seems llike a metal case for an EV might br unhealthy.

@kswis 2 года назад

An Xtra 10 orso ah over the 16 cells is more than a extra 100 ah battery. Very nice cells

@BischesseHunting 2 года назад

Champions League quality , top, excellent value

@niccoc1603 Год назад

Great video, i just imstalled a small 240W solar panel system with two LiFePO 50Ah 12.8v batteries connected in parallel. Battery charging is managed by the vendor controller, but I habe an ATS\arduino switch sistem to commute from grid to battery. I was womderimg what would be the recommended cutoff and according to you recommendation 12.4V (3.1V) would be recommended. Also, at what voltage should I switch back to batteries?

@ShitkidOfJamrock 4 месяца назад

I've seen bad reviews on lifepo4 packs where people are like "it's been hooked up for 16 hours and it's only gone up by a tenth of a volt! It's faulty!" And it turns out they're using a 5 amp charger on a 200AH battery

@GarethJones-dk9yp 2 года назад

Great video Andy. I've just received my 280A cells and running some tests. One question I have is, if my charge cutoff is 3.45V per cell. What voltage would you recommend setting a active balancer to start balancing? 3.4V?

@alikayacan6768 2 года назад

When charging high balancing voltage (3.4V) may not be problem. But during Discharge balancing possibly will stop balancing below 3.4v. When one of the cells drops to low protection voltage BMS will stop current flow and in any case you will have unbalanced cells (while many cells still have power) untill you top up again. My personal choice : Set Balancing On, when cell voltage over 3.05V

@johnnyc4544 2 года назад

Andy, I'm using my A40L to charge my LF280K @ 40 amps to 3.65v @ 5a cutoff (They all take around 180ah), wait 1 hour, then discharge at 40A to 2.65v (to get capacity) and my cells are ranging between 277-280Ah. Thanks for the video showing how to set the A40L to do this automatically. Any thoughts on my test method?

@brendancronin7186 2 года назад

Hey Andy. Great video as always. When you've finished testing the top balancing capabilities of the JKBMS, how about testing the communications capabilities since we'd all love to know how to connect the BMS to our inverters (Growatt in my case, Victron in yours) using the RS485 port

@OffGridGarageAustralia 2 года назад

Thanks Brendan. This will come once I have installed the batteries in my shelf. There is such a long list of videos, enough for the next 20 years or so 😁

@brendancronin7186 2 года назад

@@OffGridGarageAustralia Hi again Andy. Firstly, thanks for the reply, didnt expect one. Secondly, you and others have inspired me to install a 5kw Growatt system and buy an EV so that we can set an example to our kids and future generations that fossil fuels are a thing of the past. Thanks for all your videos and encouragement.

@OffGridGarageAustralia 2 года назад

@@brendancronin7186 That is fantastic, Brendan. Exactly what I want to achieve with this channel! Thanks a lot for sharing!

@User1462uuw8w 5 месяцев назад

Thank You. Very informative. I understand, that better charge to 3,45 and go to float after absorbsion. How long to absorb? In my case, charging to 3,5 or 3,55 I never can get 3,364 after resting (28,8v) always have 3,32 (around 26,6v) Is it normal? Maybe this is because, my inverter doesn't have absorbsion function? So I have lower SOH? So at 3,45 without absorbsion I will get much lower SOC? Maybe smurt shunt culd help to understand the SOC...

@Christian76S 2 года назад

Thanks for your insights and charging specs Andy. I'd like to give a lower absorption voltage of 13.8V a try (currently at 14.2V). As you're charging with solar, what is your charged voltage in the BMV set to, 13.6V?

@FutureSystem738 2 года назад

I’ve had 400Ah of Winston LFP batteries (12v) in my caravan for over six years now. (Cells that I bought from China and assembled myself.) I use about 13.85v as top of charge with the 4 cells, which then drops to 13.5v float. I’ve seen no measurable degradation in that time.

@haydenwatson7987 2 года назад

Andy, I have always suspected that you might have a screw loose and at 1:19 it was confirmed! ;>) Sorry but I couldn't resist. Now that I have stopped the video, I need to vent on a pet peeve that was pounded into me by my EE200 Professor in collage. The single unit device which converts the chemical energy into electrical energy is called a CELL. A BATTERY is the collection of electrochemical cells which either connects in series or in parallel to create more capacity or potential. At 0.29 you "couldn't even see the CELL for all of the BATTERIES"

@OffGridGarageAustralia 2 года назад

Hahaha, glad I found it back then 😆

@dredre9484 2 года назад

G'day Andy can you please do a short video on battery Meters for the people without Bluetooth on their bms

@BrazzaB1 2 года назад

Also remember that when the voltage drops, if you've got say, an inverter with a set load, the current will increase, so stressing the battery even more.

@daveduncan2748 2 года назад

The problem with stopping charging at a certain voltage is that there is voltage sag while discharging at high amperage rates. The voltage sag in LiFePO4 is WAY better (less sag) than with lead acid batteries, but there is still some. It would be interesting to note the voltage at the same SOC (4%-ish) when discharging at 40A vs. when you are charging the Tesla with 160A.

@daveduncan2748 2 года назад

Or maybe compare the voltage after discharging to a certain voltage (like 2.5V) at a high discharge rate, and then seeing what it rebound up to after it settles for 10 or 20 minutes (the "at rest" voltage).

@ngocdangdinh9874 11 месяцев назад

Hi Sir, what would be the best Charge/discharge % for prolonging the LiFePo4 life?

@teinsdb 2 года назад

Hello Andy, i have a question, how do you normally use your batteries, you charge them full let them stay for a couple of time and than start to discharge ? I`m asking you this because in order for me to be able to use everithing that is produced from the solar pannels, during the day i have some automations which based on the production it starts my Boiler heater, and my air conditioner, fact is the boiler heater runs constantly on 1800 wh consumption, but the air conditioner is working for lets say 15-20 minutes with 1800wh than it stops for another 5-10 minutes than again it starts and so on, therfore i have the following scenario and i don`t know if it affects the batteries in a bad way. let`s say i`m produceing 2800wh, boiler and rest of the house has a consumption of 2000 wh, than airco starts so my consumption goes to 3800wh, which means for 15-20 minutes i`m dischargeing the battery with 800-1000wh, than airconditioner stops for 5-10 minutes meaning i`m charging the batteries with 1500wh. So practically during the day i`m charging and sicharging the battery every 15-20 minutes, will this damage my battery , or i can work with it like this ? Basically i`m reaching SOC of 90% during all the day but constantly charging and discharging the battery, and at the end of the day at 90% SOC when solar is not produceing anymore, boiler heater and air conditioner stops, and i start discharging the battery with about 500-1000wh constant more or less. Thank you for the answer, and really thank you for the great videos!! It helped a lot, i also realised that my Daly BMS is not doing a good job in balanceing the cells, and i have ordered the JK BMS, waiting for it to arrive and hope my celles will be much more ballanced with the JKBMS.

@reneroman1421 2 года назад

Hello.....Nice video.... Hello..... I have a question about a bank of cylindrical lifepo4 batteries... Most of the time they charge up to 54.2V, they never reach 54.4V. Does it affect the batteries at all not taking them up to 100% charge? or is it healthier for the life of the battery that they do not reach that %? ... thanks

@thomasmoore4576 2 года назад

Testing batteries is great but can you by chance test the sun gold power inverter 4000 w I'm thinking about getting one but would like to know if it's worth the money they advertise it on your website

@noosestroke 2 года назад

Thanks for the detailed test. What BMS would you recommend for 16s configuration, with max. 150A loads.

@dc1544 2 года назад

he ahs a link on his website for JK BMS because they use 2 amps for top balancing. I ordered 4 200 amp versions. they have 150 amp also. My setup will never go over 60 amp per battery pack. I do not want to stress my batteries.

@lexicase8805 2 года назад

I bought the jk bms for exactly this purpose, hoping to install it in the next few days.

@camielkotte 2 года назад

I went for the jkbms too because of this channel and Mary her channel.

@mirorava3296 2 года назад

Thanks Andy for your tests, as always they are very useful and complete, it is good to know the charging and discharging curves so accurately, online every one uses different numbers and the curves are very poor quality images with wrong scale even... So thanks for your help in understanding all of this! Unfortunately even after all of this precautions and informations, my 8s battery pack that I bought for an off grid mountain house (A grade from litiokala) is pure rubbish, I think they are more like a D grade battery pack, I can barely pull out of them 160 ah each and they are completely unmatched (cell number 6 is also for me the worst, ahahahahah) do you think I should find an active balancer for my pack? I have a Daly bms, it's very good apart from the fact that has no active balancing... I hope the new 304 ah cells that I ordered from quishou are grade A, and after seeing your videos I'm confident they will be Thanks again for everything you do!

@alikayacan6768 2 года назад

I feel that Lito selling used batteries :(

@monsieurd.6890 2 года назад

In fact if you charge at 3.65. Then let the battery sleep some hours, then charge at 3.65 again, then sleep few hours, etc. at the end you will have about 3.65 that does not go down. The battery is fully charged (not usefull at all but fully charged with a constant 3.65). That is why the duration of the charge (so the amperage of the charge but the effective variable is duration) change completely the state of the charge at a same voltage. If I charge to 3.65v with a very high current (si quickly), the battery will be much less charged than if I charge to 3.65v with a low current (so a long time).

@OffGridGarageAustralia 2 года назад

This will massively overcharge the battery. Never do that! 😉 The difference between slow and fast charging at this voltage is maybe 0.005% difference in capacity. It is not worth charging higher than 3.45V.

@monsieurd.6890 2 года назад

@@OffGridGarageAustralia I do like I said only when I top balance. In normal circumstances I tell my Growatt 5000ES inverter to charge until 56.4 volts (in fact between 56 and 56.4 because I have 2 of them in parrallel and one of the report 0.4v less than the other : chinese quality !). And thats all (not real absorbtion possible with this inverter). I think it gives me about 95% full capacity but in fact it varies : when there is low sun, it charges with low current and the charge is more complete, with full sun I set 100A charge max for my 3 310ah batteries (33 each) and the charge is a little bit less.

@SuperBrainAK 2 года назад

You have to understand chemistry a little bit when dealing with batteries. LFP cells are very typical in how you normally think about or experiment with when learning about batteries or dissimilar metals. The voltage produced is going to be the sum of the different metals. So the LFP cells are going to like to stay around the nominal voltage of that particular chemistry, which is why it has such a flat charge and discharge curve then at the end it shoots high or low because the chemistry has depleted enough to change the output voltage. So yea as I saw someone said dont go under 20% SoC which is a good idea if you want the most longetivity of the battery. The same applies for charging dont go over 3.45v because you just stress the battery. The chemistry doesnt want to be at that voltage (why it immediately drops back to 3.35v). It is unneeded stress of the chemistry and will lead to degredation, you only need just enough voltage to get the chemistry to charge which is why absorbtion time is beneficial to LFP cells. So that is my 2 cents

@OffGridGarageAustralia 2 года назад

Great comment and thanks for sharing your knowledge. he 20% point is very hard to determine though as this is still in the flat part of the curve. When the voltage lowers, we're already at 5-7%SOC. So I guess voltage matters the most, don' go too high or too low. As soon as the voltage changes in either way, stop charging or discharging. Yeah absorption time matters a lot with these cells. I made several videos about this and did a lot of testing.

@SuperBrainAK 2 года назад

@@OffGridGarageAustralia yea I wouldn't go off of capacity I would just set the charge and discharge limits to the appropriate voltage. Happy to share. Cheers!

@orbitsonneumeister5155 Год назад

Hi Andy, ich stehe vor der Entscheidung LF280K oder LF304. Preis pro KWH stehen die lf304 besser da dafür haben die lf280k mehr Zyklen… aber wenn man pauschal davon aus geht 3500 nach 10-15 Jahren haben die lf304 nur minimal weniger Kapazität als die 280er. Für welche würdest du dich mit deiner Erfahrung entscheiden? Schöne Grüße aus dem verschneiten Thüringen

@SkypowerwithKarl 2 года назад

Andy I’m kinda leaning to treating all the cells for a bank with exactly the same life experiences. By taking a few cells out to test may cause those cells to have different memory and different curve than the rest. Very subtle, but could be enough to see later. If you’re not going to do this to each cell, please note those cells when you put the bank together and see if it’s an issue. Curious as heck.

@sichambers9011 2 года назад

Have just put a 4s lifepo4 battery together in my solar rig. Have a Daly smart BMS. I've had flooded battery previously so was used to working with voltage to gage the capacity which is a struggle with these batteries. Can anyone recommend a BMS or battery monitor that will do the job? I've searched online to see if the Daly SOC monitor is based on coulomb counting but it seems like Daly have a new model every month with no supporting documentation so I have no idea if that is accurate. Ideas, anyone?

@joshg1244 2 года назад

Nice work. I hope to see you put the battery pack together with the cells unbalanced and use your BMS to have it balance.

@claytonodonnell4336 9 месяцев назад

Hi. I recently purchased 16 LF280 cells, supposedly "brand new B grade". The only measurements taken so far is voltage and internal resistance. All voltages were around 3.265V. internal resistance generally around 0.5 mOhms but a couple higher, one at 1.1mOhms. the specs for lf280 says should be

@OffGridGarageAustralia 9 месяцев назад

Forget about matching voltage and internal resistance. This is just a snapshot, nothing else. It's more a marketing trick than anything else. The cells will be fine, build the battery, top balance and enjoy.

@headdown1 4 месяца назад

Can anyone tell me how to zoom in on the graph as Andy does around 9:30?

@renewyers4699 2 года назад

Hi andy would it be ok to pump u for some info please?I purchased some 200 amp H CALB BATTERIES THE TERMINALS HAVE 8 MILL BOLTS WOULD U HAVE ANY IDEA HOW MANY NEWTON MTRS I SHOULD TENCHION THEM AT, I ASKED THE BATTERY SUPPLIER AND HE SAID FINGER TIGHT🤔 so I assume he doesn't have a clue ,cheers from sunny victoria🥰 love your effort on Uribe.cheers Rene.

@OffGridGarageAustralia 2 года назад

I found some information but don't know what cells you actually have. I would start with 4-6Nm and see if the terminals are getting warm. They recommend 20Nm in this datasheet but I think this is far too much as they use copper and AL terminals: shop.gwl.eu/docs/pdf/CALB-User-Manual-LFP-Cells.pdf

@bbrown_sc 2 года назад

The EVE LF304 Version: B (2020-06-15) product specification, says the recommended SOC window should be 10% - 90%. How would you do that with a curve that's so flat?

@larryumolo4532 2 года назад

Use a coulomb counter like the Victron bmv-712, but the JK BMS active balancer also counts coulomb so you can tell how many ah has gone in or out of your batteries.

@twingoman2000 2 года назад

If you ever would test winston lifeypo4 cells, it would be really helpful 😊

@OffGridGarageAustralia 2 года назад

Where can I get them from? Must be an American thing?

@mfgxl 2 года назад

@@OffGridGarageAustralia They come in packs of 20 and one needs a lighter to use them. Ha Ha. I don't recommend wasting time with them, as they are not very popular any longer. They use to be the standard. The ones in the plastic cases with "castle" shape on sides.

@twingoman2000 2 года назад

@@OffGridGarageAustralia Hi there, no its also from China. Those Cells are very reliable once with Ytrium. As Aron wrote, this things are kinda standard once but at least in Germany it is often used in camper vans. I do have 4 300Ah cells in mine.

@twingoman2000 2 года назад

@@OffGridGarageAustralia one more hint, I found, that this cells you use should be "pressed" together. This would improve the cycletime a lot. Is this something known?

@lenaanaji8672 2 года назад

Hi andi, are you interested in combining a super capacitor with a Lifepo4 battery and doing a test for us. Thank you

@OffGridGarageAustralia 2 года назад

Combining? What does that mean and for what purpose? Supercaps can release (or take) huge amounts of energy quickly, like to charge an electric vehicle.

@figueirp8854 Месяц назад

Hi Andy, I would like to get a copy of charge and discharge data so i can use excel to generate a plot of my own.

@ReadyNeck 2 года назад

Does the tester record the actual current being accepted by the battery over the charging cycle? I'm interested to understand what the 'charge accept' curve would look like in order to govern how much time it would take to go say from 70, 80 or 90% soc to 100%. If I don't have any other load other than charge load on my solar panels then as the battery gets closer to full will it accept less power from the solar panels leaving energy on the table so to speak that could be used elsewhere such as a diversion load to heat water or do these batteries charge accept 40 amps all the way to 3.65v and only then taper down to 15 amps?

@CollinBaillie 2 года назад

The red curve is the accepted current. So yes. Once it hits 3.65v the red curve drops off fast, showing the accepted charge reducing, because the charger keeps the supplied voltage at 3.65, and the cell won't accept higher current. If your SCC can put more into the "system", then other loads can use the excess. You have to have something smart monitoring the system to be able to decide when to turn those loads on.

@ReadyNeck 2 года назад

@@CollinBaillie Thanks Collin, after watching it again I see the charge current indicated on the graph in the popup bubbles at 40Amps as he points to various areas, and at about 11:30 where the voltage hits 3.65 we see the current begin to drop and Andy states as much and answers my question if I would have just listened closer the first time ;-).

@CollinBaillie 2 года назад

@@ReadyNeck if you sent max voltage to a lower value, say 3.4 or 3.5, you'd observe the charge current drop off to be less dramatic. It's able to absorb more at that lower voltage, so the accepted current drops off more gradually, although you would hardly call it a gradual decrease. 🤓

@igorkvachun3572 2 года назад

Yes👍🔋⚡ 💡 🇺🇦✌☀

@dobrzpe 2 года назад

FYI - the link on your website to the data for the "EVE LF304 LiFePO4 cell, 3.2V 304Ah with studs" goes to the info on the Palo cells instead. :(

@OffGridGarageAustralia 2 года назад

Argh... thank you. I'll fix it tonight...

@dobrzpe 2 года назад

@@OffGridGarageAustralia hey andy! just a reminder to fix the link, my friend! it's invaluable info for me... :)

@OffGridGarageAustralia 2 года назад

@@dobrzpe my good man, this is now all fixed. I did it right away after your second comment. Before breakfast😉

@dobrzpe 2 года назад

@@OffGridGarageAustralia HAHAhahahahaha! thank you so much! (i saw the note on your website too! LOL) you are a gentleman and a scholar, sir!

@rnishanthan1988 2 года назад

Can you reset Victron Mppt lifetime total kwh history

@durrinfaqihah 6 месяцев назад

Can i leave lifepo4 battery more than 4 years. Can make the battery dead?. Tq

@randypeterson4055 2 года назад

Please explain cell grade definitions, as in A,B,C grade etc. I think its a sales tool. No industrial standard for LiFePO4 grades.

@JR.M.S 2 года назад

Are they considered to be cells or batteries? Definitions are important to give everything sense. Is it that a cell with multiple cells in parallel is a cell or is it a battery? I mean that words means something. Is it that cells in parallel means a cell and only when they are in series they are called batteries?

@andrewradford3953 2 года назад

Collins dictionary: A battery is a device for turning chemical energy into electrical energy, consisting of a number of primary or secondary cells arranged in series or parallel. So Andy has cells that are connected to make a battery. The Nissan Leaf car has many batteries, as each module contains two lithium cells. I guess then we add 1.5v cells into a torch to make a battery.

@opless 2 года назад

54th!

@Dutch_off_grid_homesteading 7 месяцев назад

still waiting for my 16 cell shipment😗

@ronwest7930 2 года назад

Don't overcharge or over-discharge and help the batteries last longer.

@vickipps6821 Год назад

Hello Andy how can I get hold of you as I saw a message for me to get hold of you on Telegram

@loganv0410 8 месяцев назад

Am I wrong or at 22:50 did I hear a German say he "can't drink that much" beer That's like one of my neighbors in E TN USA saying the same thing Blasphemy!!