Higher charge voltage = better balancing? Here is my battery shelf result!
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- เผยแพร่เมื่อ 10 พ.ย. 2023
- This is part three of the test series where I changed the settings for my battery shelf to a higher charge voltage. Apparently, this enables better balancing. As we all know, the higher the voltage, the easier and more effective the balancer works.
Well, in part two he have seen, that even charging to 3.55V did not make any difference in balancing and there was literally no improvement in balancing.
We then fully top balanced the battery and left the same settings for another 4 weeks. Can the balancer at least maintain the top balance?
Here are the results and what I found.
Part 1: Something wrong in the battery shelf! Or just 'bad' settings?
• Something wrong in the...
Part 2: Does the passive BMS balancer work better when charging LiFePO4 to a higher voltage? My 6 weeks test
• Does the passive BMS b...
Charging LiFePo4 (LFP) to 3.4V and 3.5V with and without Absorption. What a difference!
• Charging LiFePo4 (LFP)...
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Hello Andy. I have been watching your videos for 6 months now (think I have seen nearly every video, some of them many times). I was totally new to off grid systems and have learnt heaps from you. I have now built a 16S 304ah Eve battery bank (approx 15Kwh) with a JK 2A active balancer BMS. I have used all Victron equipment, a MPPT 450/200 charge controller, a Multiplus II 48/5000/780-48 inverter, a 500A smart shunt and a Cerbo GX. The system was first turned on 5 days ago and is working fantastically. I am still grid connected but have only used 0.3Kwh's of paid power since turn on. I am still fine tuning the system and your video's are invaluable in helping me do that. I will be buying another 16 EVE cells very shortly and expanding my system. (I built it all with the aim of being able to easily expand, the battery cabinet can take another 16 cells and my power wall is prewired ready for a second inverter.) I paid for a SPAT for you a while back, but I think you deserve a few more. Will do that today for you. Thanks for all your help. Ooops, fat fingers, the Multiplus is a 48/5000/70-50
Thanks so much for sharing your journey! And watching so many of my videos of course.
That is a fantastic outcome and I'm really happy to hear and read about such success stories. This is exactly the intension of this channel to motivate and educate others so they start their own journey!
Thanks a lot for your support as well!🍺🍺🍺
Not sure how you manage to make boring technical stuff exciting, but you do an amazing job!!!!
Oh, hahaha, thank a lot for your kind feedback.
Hi Andy, you're simply the best! As a beginner I learned so much about Batteries, BMS and Balancers from you.
Thanks a lot, Gerd!
Danke Andy, immer wunderbar
Thank for all your test.
Love your work Andy!
Thank you for your contribution and support!🍺
Thanks man...much appreciated
good job Andy ! looking forward to the new BMS system for the battery shelf.😊
Thank you. Not long... not long...
Living in the UK where so many times the sun doesn't shine. I have to charge to a higher voltage to get the batteries pumped to a higher percentage. Amazon are now selling a big selection of lifepo4 batteries at near alibaba prices (when including bms and postage) soon so much storage and surplus electricity in the summer.😊
Andy your the test king! Funny I just re-watched two vids from 2 years ago and now this new vid haha Great show!
Thank you very much!😊
What a fantastic channel you have Andy, After me fighting for reliable information I found your information both enjoyable and very useful for my very basic 12v cabin system, now have set at 13.8 13.4, 1 hour absorption , working perfectly here in not hot, not sunny Cheshire UK. Didn't get full charge today but the sun was short and sweet today!!! Thanks Andy.
Awesome, thank you!
Yeah, 13.8V will definitely gently charge to 99.6% and give the balancer time to sort out the cells.
Thanks so much, Andy! Love your testing!
Thank you. Me too. Got heaps more to come...
@@OffGridGarageAustralia I've commented about my testing before. I have been testing cells for year with different techniques, and charging above 3.5v has proven to be detrimental to my cells. I'm already doing damage control. I will not charge above 3.5v per cell going forward. The degradation in just 1 year has been much higher than I had expected. I had several packs that I balanced, and 2 packs that I did not balance (lazy because they are in a case, and I thought they could handle 3.55-3.6v max without damage). I set my BMS to trip at 3.6v and it never hit 3.6, but daily, it hit >3.5 for 1 year. That 1 cell was always higher than the rest, so I just let it stay high instead of balancing it, and it is FAR weaker now after 1 year. It slipped to hitting 3.6v more often, and I backed off charging to only 55.2v or 55.3v just to keep it from closing in on 3.6v again. I finally did balance it and it's amazing how much less total capacity that 1 cell now has. Even top balanced, it is now the first cell to hit the bottom each day... so badly that I have had to set it to trip at the bottom at 50.8v just to keep it from hitting 2.5v. Measuring the total in the pack, that cell is hindering the entire pack so much that I am only getting 75% capacity from the 16 cells. I've pulled the entire pack and I'm rebuilding with new cells at this time. The other pack is similar, so I'm going to just replace the bad cell in that one, and do more testing (my own Frankenstein battery).
@@dustins4194 Oh, wow, there is something seriously wrong with this one cell. Charging to 3.5V should not degrade this cell that fast. It is well within the specs and you should not feel any capacity loss at all. Can you capacity check it?
@@OffGridGarageAustralia The degredation was done when it would go above 3.6v. I am taking apart all of the packs now and I will capacity check the bad cell, but I know it is weak, and I know that anything above 3.6v has caused it to degrade. I will not go above 3.55v ever again.
@@OffGridGarageAustralia I love your testing, and you can do whatever you want, obviously. I suspect someday you will do some long-term testing and find out that 3.6v degrades the cells a bit more. When I'm charging big power in the middle of the day, and my voltage starts to ramp up (high part of the curve as you say), it's hard to stop the inertia on a dime. It seems to always pop up over 3.6v (I've even seen it actually hit over 3.7 before the voltage rise actually completely stops. It's my strong feeling that closer to 3.6v is just a tad too high for these cells and they start to get a tad hotter than they are comfortable. I will not charge to 3.6v.
Andy, I have the same results on my 48volt system using the overkill bms. Since I installed the 5amp active balancer this has resolved my issues. Thank you once again for helping me through this issue. You are a blessing to all of us!!
Thanks for sharing. Active balancer cure everything these days, it seems 😄
@@OffGridGarageAustralia except for RFI? I ordered the 2A JK BMS. Dreading to find out what it will do to AM/SW radio. Did you test this?
Nice job Andy !
Thank you.
I like your video,I have change my setting to 27.6volts
Now my battery is working very fine
Very interesting, thanks Andy
Thank you.
Danke Andy! Great work you are doing for the community! I have learned a lot from watching your videos over the last months and it saved me a lot of time that I would have spent exploring the one or the other rabbit hole while setting up my ESS 🎉
Thanks a lot for your donation and support. It is much appreciated 🍺
Good work 😊
Thank you.
Happy to see you chose the 'OLD' settings. I had set my 24v system at comparable voltage and my system seems 'happy' more often. Charging to higher causes faults.
Yeah, back to the conservative settings and system runs perfectly fine...
Hi Andy! and thank you again for your quality videos👍.
It's clear that with all these tests that you have already done from the start on your cabinet of 3 groups of cells! it's OK😀.
The important thing is that you were able to find the perfect parameters for your battery. (why change when it works perfectly? sometimes because of the weather? that's all.🤔.)
But as I have told you several times, your parameters are not always compatible with all battery packs, and different charging and balancing equipment.
Example for me is the charging limits (pack voltage) 54.15-54.45V.
with perfect cell balancing at 95-100% SOC.
Above 54.45V the cells have too much difficulty for balancing!. (with an Active balancer I can correct but not all the packs)
So for me my Max pack voltage settings 54.15- 54.45V are perfect! and when we look closer at 55.2 and 54.45V it's only 0.75 volts difference.😊
Yes, absolutely, hence I said this in the video!
Maybe if you charge to 54.4V only, you don't need to balance at all?
Thank you for your conclusion, i'll leave them as they are @55,2
Thanks Dirk, Also thanks for your donation on my other channel!
Thank you for another superb and helpful video, Andy! I have measured so many "same" cells now with different capacity results. How should I mix them? Which should go together in a 16s box? Do you have some tips from your experience for this?
Thanks Andy
Thank you Wayne!
I am already using the "new" settings you mentioned as winter-time settings. Need to squeeze every drop. The setting was made 6 weeks ago and it works fine, but then I have not reached full charge yet as there are many continuous days without sun. In spring+ time I intent to switch back to the standard setting, or even lower, since the battery is charged 100% until mid-day.
Hi Andy , yes I think you decided this correct because of the long time stability and long time performance will be better with this 3,45 V settings . Mach bitte weiter so !Greetings from good old germany , Torsten
Thanks, Torsten. More testing coming 😉
I have one of the aliexpress voltage relays controlling the active balancer for my small off grid system(600ah 12 volt bank) thanks to Andy for featuring this actually this channel is probably largely responsible for me building my own battery and solar charging setup.
I have settled on charging to 3.52 volts per cell, and it's been ticking along nicely for 6 months. I rarely see more than 30mv difference , and charge or discharging it's usually 10mv in the mid range. These are 8 300ah cells parreled for a 600ah single bank.
Nice, John. Thanks for sharing.
Heya, well pretty new subscriber but after a few vlog's watched I understood I have to watch all you vlogs so selected 464 vlogs went to the 1st uploaded vlog ( that was about 3 years a go or so ) and started watching back to the future. now almost havee way (297/464) I learned al ready a lot thanks for this and hope to learn even more from you. ordered 16 lifepo4 cell's and testers ect ect to start bilding by batterie bank (end of this month gone be dwlliverd) gone film this and upload it to my youtube channel. greatings from Holland
Oh, wow, that is a lot to watch. You may know more than I do afterwards.
Thanks for taking the time, my friend from Holland.
Thank god. I liked the old you that did solar panel reviews and cells. I've not checked my batteries in weeks. LOL
Love the channel. Goofy. Quirky. And a ton of information. Keep up the great work.
My setup, tons of sun, Grid sharing and a grid zero configuration setting utilizing outback radian inverter.
Essentially, stores during the day, supports all my loads & discharges to XX minimum battery settings overnight with a net result goal of ZERO grid usage.
Bulk 3.45vpc Absorb 3.45vpc and a float of only 3.33vpc. A slightly lower float holds my cells at +/- 80-90% while exporting excess power until the sun goes down.
Overkill BMS with Enerkey capacitive balancers - voltage triggered on @ 3.45vpc off@3.4VPC.
It has worked flawlessly for 3 years, but we're never really done "playing" with things, are we??
Cheers
Hi Andy.
At what value did you set the min SOC for these batteries?
THX for all videos...
The overkill with the 5a active balancer seems like a winner. Since my system is similar I'm happy.
Or just using the JK....
But, yeah, if you already have a BMS, you can upgrade with an active balancer.
Thank you very much again and sorry for the new JK bms but i i hope to find what i am looking for and that it’s Batrium bms now,that’s my first choice
Awesome Andy, great job, and absolutely exactly as I suspected. Milliamp balancing is never going to work with such large cells unless they are incredibly well matched.
ie: In the real world, you need an active balancer…. Period!
I use very similar voltages to you, and my JK BMSs handle it perfectly. 👍👍
Passive balancing would work, when they had enough power.
Problem is having to balance 15 cells with 2 Amp each, would be about 100 watts of heat, so you need alot of cooling.
Passive balancing in this dimensions would be a real problem in terms of heat but also waste of energy. I'm glad we are stepping away from that und use better technology these days.
@@OffGridGarageAustralia😢
I built a LifePO4 pack two years ago, started of with a Daly bms, dumped that later and changed it to the JK. 2amps of active balancing. 3,45v/cell, absorbtion of 1 hour, float of 3,35v. Works wirklich perfect.
Yes, that works very well!
@@OffGridGarageAustraliaHi Andy
What is the re-Bulk setting do you use?
@@eliasfigueroa1159 I have set 2.5V as re-bulk. I think fully charging the battery once a day is fine.
All settings of my devices are here on my website for reference: off-grid-garage.com/my-settings/
Hi, good jobs in your videos, it helps me a lot. You dont think that maybe switching the "rebulk" too low we can lose hours of sun and charge? for example of I get the discharge level at 19:00 maybe I have no time to recharge battery. 0.1v is good I think@@OffGridGarageAustralia
The victron setting options are really great. My problem with the seplos is, that's not possible to set a float voltage. I charge to 55.6V and it stayes there until the sun gets down. I'm a little bit afraid of the first sunny day after winter here in Germany 😅🙈 because the battery works since weeks between 20 and 45 percent and there are almost the same number of weeks coming before sun gets higher! I pray, the neeeeey will be able to handle this!😅
Greetings to you, Andy!
can you explain when and or how to use a smart shunt in your video? thanks
Thanks!
Thanks a lot my friend. Much appreciated 🍺🍺🍺
It's fascinating how a capacitor-type active cell balancer works and the logic is relatively simple - Each cell is connected to an individual capacitor bank then they are decoupled and the capacitors are connected in parallel to even out and then recoupled to the cells - the process repeats over and over on a kind of PWM slowly shuffling differences about till they all even out- simples : )
I wonder if two similar batteries connected as a parallel bank would also somewhat self balance each other if top balancing was switched on and off? Would a peaking high cell, when charger is switched off (or imposed by BMS) then discharge in a second lower parallel battery in turn charging and equalising this second battery?
Stuart Pittaway made a fantastic video on how these balancers work: th-cam.com/video/VR-G-3D82e0/w-d-xo.htmlsi=o6azG0Dn673jW521
When batterie banks are in parallel, they will self balance out while charging and also discharging.
th-cam.com/video/bhCSccNsQOw/w-d-xo.html
@@OffGridGarageAustralia I saw that video - there are a few nuances like little inrush resisters - I imagine that they use a bank of smaller caps so run at higher frequencies - I've had one on my self-build 304ah 4s RV battery in tandem with the BMS 60ma passive balancer set to 3mV - what I found is the passive balancer trims the cells so fine the active balancer only takes effect when the difference gets larger under high loads like using the microwave through the inverter
Hi Andy. I purchased two 150AH LifePo4 batteries from Ali 8 months ago and had big problems with my Voltronic Axpert 5.6kw Inverter.
The BMS incorporates a Passive balancer and the deviation was around 70 MV when charging.
When set as a LifePo4 battery, they got to 85% SOC then OV'd and jumped to 100% SOC.
So after watching your video's I started to alter the settings.
Finally I settled on 54.8v charge with a Float of 53.8. The BMS is basic and doesn't allow you to set an absorption time, though I use Solar Assistant software from South Africa in an Orange Pi and they are looking to incorporate variable charging.
I found that at 54.8v and a Float of 54.0v the batteries charged at a faster rate than at 53.8v but were going up to 95% SOC (54.0v) rather than the target 90% SOC I was after.
53.8v I found to be ideal and at 90%-92% SOC 53.8v Float my deviation was a mere 6mv I n Battery 2 and 14mv on Battery 1. I have the Passive balancer kick in at 3.365v per cell - yes, crazy I know but it works with no Active Balancing required!!
So cheaper Chinese Ali batteries can work but do your research and don't believe the settings they tell you.
Thanks for sharing, Peter.
If you can charge to 54.8V without OVP, that is perfectly fine and will be 99%+SOC. I would not be too concerned what SOC the BMS or inverter shows. They can be different and not accurate I found. Once you hit 54.8V, you know, this thing is full!
At 53.8V, the deviation will be low as this is in the flat part of the curve. You can have a huge 10% difference at this point and it won't show! So, don't look at voltage difference at this voltage, it basically does not say much.
SOC sucks!! 😂
I have found that what the Battery SOC states can be way out at times.
These Chinese Batteries come steel boxed with an On/Off switch and turning the battery Off then back On can change the Battery plus or minus 2.0AH.
So the battery states 125AH, turn off and on and the number can change to 127AH or 123AH or anywhere in between 😮
Possibly programming issues?? or voltage deviation issues??
Great videos as always - keep on charging!!
@@peterwithers9276 with a lower charge voltage the tail end takes longer , and with shedding cutting short you may find that you don't hit 100soc and thus the bms/shunt does not calibrate itself back to reality
So if you don't hit the triggering points ie cell 3.65 or pack full voltage the soc could be out of touch with reality according to battery bms
Aiming for soc less than full on a lifepo4 , ie the 20-80 notion is folly imo
Since you can hit anything from 70soc to 95soc in the flat portion , depending on how long the tail end of the charge is
Some axperts tend to have charge time as part of the charging algo
Hence with a lower voltage i found that this would land me with a 70soc battery because it would hit the 2.5hrs it had as its max time to do the CC/CV phases
I think some refer to it as the axpert float bug
If you don't have solar and a high enough charge rate you don't know the bug exists
Slowing down the charge rate it reveals itself
Which can be the case with solar, as the voltage can hang around float voltage for a long time , lifting the float alleviates this
It is simply impossible to hit 80-90soc consistently judging by voltage , and even by shunt , as the shunt does not account for losses and thus over time 90=89 ,90=88 ,90=87 round and round you go until one day you hit a low voltage shutdown
If you never hit 100soc for the shunt to get back in sync with reality
@@leondavibe @leondavibe Thank you for the thorough reply which is much appreciated.
When I bought the batteries, I originally set the Battery type on the Voltronic Axpert as LifePo4 and every time one cell would go past 3.75v (whilst the others were around 3.45v) and with the SOC only at 85%. The Battery would immediately jump from 85% SOC to 100% SOC and OV.
I've top balanced several times and with my lower Bulk and Float charges the batteries works well and the deviation is minimal.
With patience and a Coulomb Counter, I've done a full battery discharge running a load of 1.5kw and was within 10 minutes of the expected discharge time.
The separate Coulomb Counter is generally within 1% to 2% all the time.
I shall try to fully charge the batteries now that I have my settings working well to "re-calibrate" the top end.
Many thanks again for your reply.
Dear Andy. To balance at 3.45v LifePo4 (flat curvr)is ussles and you know it😊. 10mv devotion could be 20-50ah difference.Might be better balance at the bottom and turn off the balanser for a while?😉😉😉
Thank you Andy!
From still hot central Florida 😂
Always warm up there, isn't it?!
Just bought you Spat for the first time Andy engoy (emekenpen) and thanks for all your wonder video footage!!
Thanks a lot for your feedback and support. Really appreciate it!
I have two 16s 48 volt 272 amp hour batteries, each has an Overkill BMS. One battery stays perfectly balanced between delta .005 and .009 it seems no matter what voltage I charge at. However, the other battery does not work as well, even though I top balanced the cells three times. When I exceeded 55 volts charge there were always a couple of cells that exceed 3.65 and the battery would shut down. My settings right now are 55 volts absorb and 54.5 float. Initially at these settings the BMS would have to shut down charging many times during a charging cycle because a couple of the cells exceeded 3.65. But...over the last couple weeks the frequency of overcharge has diminished until now it shuts down only two or three times for a very short time during a charging cycle. It seems the battery pack is overall coming into better balance, even with the Overkill BMS. We'll see what happens now staying at these charging settings. THANKS for your videos.
Well Andy. You had me sold on jk bms. But your now saying there might be something better. And it was made here in Australia 😮. O I'm looking forward to seeing that 😁👍
Yes, it is mindblowing. I'll get it this week and very much looking forward to it!
Hi Andy. Please. Could you assist us in cas ewe do not have absorption time with a recommended voltage ? Thanks again for this incredible helpful you do worldwide !
I’m think it was 1 hour
You mean, if the inverter does not allow for any absorption voltage?
You can try and charge to 3.4V per cell only. The inverter will keep the voltage there until sunset.
@@OffGridGarageAustralia i will try. But I think the inverter will stop charging once reach the voltage target.
Is it Batrium? They are in Australië.
Yes, they are in Australia.
Hi Andy, received my JK BMS today and was able to install all correct. Activated with a old 12v Battery, and made basic settings all under 2 hours. All the good tips I learned from your channel made it possible.
One question: communication only over Bluetooth or can I reach the BMS also over WIFI?
Bluetooth only to the app on you phone. None of these BMS have Wifi.
What software version have you got on yours? Just keen to see what they deliver at the moment.
Deine Videos sind einfach der Hammer. Wenn das JK BMS was taugt für meinen SMA Batterie charger wäre das Traumhaft.
I have a System with 48 Cells (230ah)in 3p 16 s mit einem einzigen BMS. Alleine im jahr 2023 schon 5200 kwh rein und 4360 kwh raus geschoben.
Just wait for my 'new' system, I have announced. This is exactly what you need for your SMA inverter.
Nice test results. Didn't you swap BMS1 and BMS3? It seems Hellteck is not good with balancing. Good job! Thanksfor sharing
Yea, I swapped them a while back. The Heltec seems to have some software issues and bug. I never really got a reply from them. So the Heltec will go and be replaced with something new.
i wonder if the bigger voltage delta on the JKbms isn't exactly because it is active balancer, if cell resistances are varied , then the voltage lift on some cells are more than others while charging, and then start balancing on those cells sooner than maybe would be needed,
ie i have seen my JKbms start discharging a certain cell and moving that energy to another cell, only to move energy back to that cell it initially discharged when it gets closer to full, maybe just me badly matched cells 2nd life and 3 different batches
The battery in the middle shelf where the JK is connected to, uses aluminium bus bars. That could explain it. Further testing coming...
Good to see that everything works out just fine at 3.45v as long as you use an active balancer. This should make these cells last a long time.
There is some news about batteries not being recycled because just making new ones is much cheaper.
On the other hand some car manufacturers are saying that reusing NMC car batteries for stationary storage is a great option if they are too worn or the car is a writeoff after a crash.
Would you recommend doing this and which charge voltage would you set for these cells?
Yeah, these LFP cells will last a very long time.
That all depends what cells you have from used car batteries. NMC of LFP make a huge difference. They usually come in modules and have specific settings and voltage they need to charge.
@@OffGridGarageAustralia Okay, that kind of makes reusing car batteries a bit too complex for most people.
I guess it's better to professionaly dismantle and recycle the batteries to black mass and make new cells out of it that will come with warranty.
With enough big used EV batteries at low prices and limited mining capacity with future high demand this can become something profitable.
@@SolAce-nw2hfYes, some of the modules even have some sort of sub-BMS connected and need to communicate via CAN before they even let power in and out.
Others are in a weird configuration of 19s connection which makes it hard to find suitable equipment.
Hi Andy Good morning .
How do you think about NEEY 4 th generation ..its a good option to work with seplos BMS to balance my batteries
Yes, absolutely. I have installed one in the Jaki battery which has the Pace BMS with similar bad balancing as the Seplos BMS. Works a treat!
th-cam.com/video/__2Dgnas5mc/w-d-xo.html
@@OffGridGarageAustralia thanks Andy for your reply...We enjoy you to your videos.Keep going
@@OffGridGarageAustralia Andy happy new year.
I install NEEY a week ago with my seplos BMS..
0,2-0,4 mv difference. From 0.40
Nice machine
Great THANKS
Panos from Greece
If one cell voltage is low a passive balancer has the draw the remaining cells down to its voltage to balance the pack. A big job for a passive balancer.
the problem is the bmses with the passive balancers are turning off when the bms "thinks" it is not charging any more and has reached float level. Meanwhile the JK bms is still balancing the cells even when at float voltage. Its an unfair test and the bmses should all be in "static" balance mode.
What is over charge voltage recovery ? The same as charging voltage ? Because if you set recovery voltage lower, bms will be waiting for drop cells too long and cells will not gonna be balanced
Would we see a Batrium BMS in your garage?
😊The Batrium is made in Down Under, so...
I run the WatchMon-CORE with 3 K9 boards. Running smoothly.
Think, that we could se this setup soon here
hi Andy! now that you have those data, would you consider changing the two bms's? tripple jk maybe? or other brands? i also have 3 battery banks, 24v volts, but the behave differently than yours. i hope to see more vids of experimenting on the big battery. and i hope too see andy 2.0 again.
Well, charging to 3.45V, I never had an issue with the two BMS and balancing. Even after 1.5 years, they were still working fine and after such a time period (maybe ever 2 years), I can just connect an active balancer over night and top balance them again if I feel that way. But from a normal usage perspective, I don't even have to do that and can keep using them as they are.
So, at this stage, I will only replace the Heltec BMS as it has some wort of software issue with balancing cell 1-10 all the time. The new BMS will be very interesting!
@@OffGridGarageAustraliaI am using two jk bms and a daly bms, I had to keep a active balanced handy since the daly cannot keep up balancing the cells. I have 3 banks with the same capacity. But the bank with the daly takes and gives more current the the two with jk's. And it has bothering me. Any chance that you could do an experiment on this? Thanks Andy, its been two years, I hope to learn from you in the next decade..
@@Jeffrey_Rodriguez can you swap the Daly and one JK BMS. I would be interested if the faster charging or discharging sticks with the Daly.
It could be, that the overall resistance of the Daly battery incl. the Daly BMS is lower and hence it takes more current.
Great video. Note: your cell wire resistance seems a bit high. On my JKBMS I can read between 0.054 to 0.071 ohm. A bit a pitty that the JK only balance at 2A, I saw a balancer running at 5A, wondering If I should move to that to fix faster the too high cell voltage above 3.65V(5A Active Equalizer Balancer from Daly)
Good job as usual Andy. I just want to say 2 things. 1. I bet it’s not Batrium. 2. Glad I have JK’s.
Thanks a lot. We will see what I will get 😉
Hello Andy. can you help me fix my seplos battery problem 😅
Off topic, but how do you make the one charger the master? What determines a master?
Also ... great video .. nice to have some actual visible facts on what charge voltage actually works ... thanks. 👍
That is the Victron feature. I made this video about how it works: th-cam.com/video/fr_P3DPZT88/w-d-xo.html
Shoot ... I guess I missed the Bluetooth requirement. My second charger is a
Blue Solar controller. It's networked, but not through Bluetooth. I'll be fixing that ASAP!! So many videos to watch 👍@@OffGridGarageAustralia
@@GregOnSummit I think you can upgrade with a BT adapter or so...
Klasse Video 👍🍺
Thanks
Higher the voltage, more species at SEI layer and higher AC impedance of the cell. So 6000 - 8000 cycles does not mean 20 years service live if voltage is high and current is high and temps are high. If you charge batteries with smaller current till evening, it is better, because nor BMS nor cell produce heat, and if cell is thick, temperature gradient is not the same, as if the cell is thin and is in free air instead of not ventilated battery box.
Yes, correct.
How do you get to lower the charge current for all the different batteries when they reach near full SOC? I mean, doesn't the Cerbo take only 1 BMS as the input for that?
Hey Andy, Just wanted to say AGAIN!!!!!! Thanks for all your time and effort! I was about to say if someone's battery is working fine at X voltage but another's works at a higher/lower voltage. There is no need to change.....but then you mentioned it! MIND READER😄
Yes, absolutely. There is no right or wrong and one setting may not suit another setup and design.
Thank you, my friend!
Hi good day Andy I have a question, can I pair two Victron MPPT charge controllers of different sizes eg. 100/50 and 150/45 using the Bluetooth feature on the app? I have 1 battery bank and I don't want either charge controller fighting each other to charge it.
As long as every MPPT has its own solar panel array, it is all good and you can pair as many controllers as you like.
I made a video about the Bluetooth function and what exactly it does: th-cam.com/video/fr_P3DPZT88/w-d-xo.html
@@OffGridGarageAustralia Thank you so much Andy. Is its possible for a victron blue solar mppt charge controller using a bluetooth dongle have synchronous charging with a victron smart solar charge controller.
Eg. Victron Blue solar 100/50 + victron smart bluetooth dongle
And
Victron smart 150/45 mppt charge controller.
What happened was, I bought a victron smart 100/50 mppt from Amazon but received the blue solar 100/50 mppt charge controller. And since I live in Trinidad and Tobago in the Caribbean it would have been impossible to return it. But as it had sale on victron components on Amazon I ordered a smart 150/45mppt and was wondering if both could still be paired on the same VE. Bluetooth network along with my smart shunt to allow for synchronous charging?
Thank you so much in advance Andy.
@@skullpoly1967 Have a look in this document from Victron. I don't see a problem...
www.victronenergy.com/upload/documents/VE.Smart_Networking/20723-VE_Smart_Networking-pdf-en.pdf
Hey can you help me out I been watching a lot of your videos for a long time and you are very experienced.
I have 2 Hybrid 24v Inverters 3000w each inverter 80amp change controller built in and AC out can I tie both inverters to my 600ah Lipo4 24v battery bank and I have 3200w solar panels tied to one inverter at the moment will this work to charge the batteries for both inverters I'm off grid
Thanks for your question.
You can have as many inverters connected to your battery as you like, there is no problem with that. Each inverter needs its own solar panel array to work (solar cannot be shared!). It will also work to have only one inverter connected to solar if the solar installation stay within the specs of the inverter. The second inverter will be only for supplying power to the load in this case.
@@OffGridGarageAustralia Thank you for responding back I see that you have a lot going on in your garage you have a lot of batteries wish I had a lot of batteries they are so expensive tho right now I just have 24v system if I knew what I know now I would have went 48v
@@rontech34 You can always upgrading to 48V later down the track. 24V is not too bad either and can get all your energy needs sorted. So maybe stick with it as you already have all the gear.
Jikong master race 👍
Yep, it feels a bit like that!
Looks like next year you will have some Catl na+ battery cells to test out Andy!
I have some sodium cells here for 2 months now... just not enough time to test them.
Personally, I don't think we will see them soon in the DIY market. It may take another 5+ years at least.
New battery tech just makes me excited :) Yeah would be cool if prices of the cells would go down , i see now that price for the lifepo4 280ah with ddp shipping to me here in sweden is around 100 euro per cell , suppose not to bad hence tax free and shipping included. @@OffGridGarageAustralia
I also keep my bulk charging at 54.6 and floating voltage of 53.3 only it has been two and a half years.🎉
Thanks for sharing. Charging to 54.6V will charge to almost 100% if you allow some absorption, so thill definitely will work.
How do you balance at these voltages?
@OffGridGarageAustralia the 105 AH cells suprisingly doesn't need that balance. But the 280 AH after I manually balanced them every few months I take the voltage to 55.2 or a little higher the 105 cells didn't have activated balancer at first idid had current divergence between the two 105 packs I enabled the balance after more than one year 120ma was so sufficient to balance them and fix the issue but I couldn't access the settings of ANT BMS until I downloaded and purchased Vbms app. I activated balance on your advice past 3.45 even my testing I found that even balancing at 3.35 will mess the balance.
Moin Andy, thanks for this interesting test. Please send some ah to me here ind dark grey Nothern Germany😀. What´s up next??? I think Batrium BMS😁!?!
Thanks Sascha. Can I email you some as an attachment? 😄
Batrium... good guess...
Does 100s of volts out at the top even matter??? Because soon as a load comes they all balance out once voltage has dropped down to the flat part of the curve or even settled voltage?? Does it really affect lifepo4 that much after 54v 🤷🏻♂️
They don't balance when the voltage drops. They hide the imbalance, that's all.
I have had a passive balancer connected and active and in the year I've had my lifepo4 cells. I dont think ive seen any improvements from start to finish.
Batrium WatchMonCORE & CellMate-K9 BMS incoming ? 😜
Yes, this is made in Australia!
So the JK is the only one working as it should out of these 3 balancing (even with added balancers)...with a correct voltage of 3.55V (Absorb) and 3.45V (float).
it was an unfair test. The 2 other bmses are not balancing when they reach the absorption voltage or when in float voltage. I believe the app should have the "charge only balance" should be turned off so the bms will balance continuously while in float mode.
I tried with charge balance on and off. There was no difference.
Float on 3.45V is way to high, it was only for the test to give the balancers more time. It should be at around 3.35V
Hello Andy, nice video . But I think you should have been more critical about a 56.8 V charge voltage . If fore some reason the shutoff function of the bms fails it will be a big problem . You have cases of these batteries causing explosions in Germany where this could have been the case , just speculating here . Having a charge voltage of 55.2V is a much safer way of operating these batteries .
No, no, no... these batteries don't explode. Read the comments under this fake article.
If the BMS fails, there is something fundamentally wrong! This is not how you design solar and battery systems. We don't know anything about the setup, only that there were LFP batteries in the house.
It's like the press reporting on a Tesla fire because it was parked in the garage. The fire however initiated somewhere else.
FUD
Have you given thought to a larger BMS to manage the entire battery bank (single BMS)?
No. I would advise against that. I like the separate BMS which provide good redundancy in case I have to take one battery bank offline.
It's like one 3p16s battery instead of three separate 1p16s batteries.
i have a 12v timeusb battery can i hookup my loose cell 36 v with a jk-bms 8-20s in series for 48v?
Probably not, unless the cells are all the same voltage, capacity and chemistry.
yes! lifepo4 3.2v 12 cells series thanks . the 4-8s jk-bms support series also?2 jk-bms 4-8s for 48v will it work also😅
Why is the new JK BMS called an “inverter bms”?
Was really hoping by now JK would've fixed their BMS. Looking forward to your new BMS technology. Wondering if this is Batrium Andy...anyways, we'll see :)
I just got the new FW from them last night. Haven't had the chance to look into it yet 🤞
Nice....hoping it works well this time as well as with the inverters they advertised.
@@hendersonsobers396 Let's say my hope-meter does not show very high.
Andy if you are too hot down there and you want to cool down, take a look at my video of my Frosty old Panels with hot spots from snail trail track marks defrosting😱.(It's only 2mins long)
Make Daly great again! A wee 1amp Balancer is all shelfs 1&3 need.
As always
Love from 🏴 Gaz
I'll have a look at your video, Gaz. I saw the other one with beautiful blue sky over Scotland. Amazing!
Stay safe!
@@OffGridGarageAustralia Thanks mate, Can you remember what Frost feels like???
Thats Frost on the ground not a Frosted Beer!
The beutifull blue sky has gone, back to being battered by wind and rain. Storm Debi thos one.
You stay safe too!
Cheers Gaz
@@garys-half-baked-offgrid-dream you should get a wind generator!
@@OffGridGarageAustralia I have got them. Nearly ready to go, I had alot of repairs to do from manufacturing defects and damage and slowly saving up $$$ to buying cable components has been hard.
In Wind like I have now I will be turning them off 🤣🤣🤣
Very fascinating, im kind of disappointed my 4s x2 Lithium batteries are perfectly balanced. BTW i like your light system you made to drain the individual cells. Id like to make a similar device. Do you have a video showing how you made it what lights you use etc. etc. BTW i consider myself a noob compared to the set up you have plus all the tests you run.
I don't have a video about the light bulbs, no.
I used some 12V halogen lights and connected them all in parallel. I can just connect/disconnect them in pairs to reduce the power I'm pulling from my batteries.
I only have all this equipment because I'm interesting in all this testing and want to find out what happens if I change settings and parameters. If not for that, it would be an absolute overkill.
@@OffGridGarageAustralia Ok thanks. Ive seen other youtube videos where they used those lights or something similar. Ill do some searching around see if i can find a diagram so i can make one.Cheers!
@@OffGridGarageAustraliaActually it would be interesting to see a video that goes into more detail on the light board along with modifications you think might be helpful if you were to do it all over again.
@@inmyimage1081 I did a video on the LED lights actually.
Yeah, will do a video on improvements for the next battery shelf, great idea.
It is very intresting 158 charch cycle in 2.5 years. Your Batterie will Last for 47 Years until your shelf will rached 80% of livespan 😊
Yes, they will last a very long time. Calendar aging will degrade before that though.
Great testing as usual, I think that is fairly definitive for active balancing.
I disagree on the passive balancing though, your float might have simply been too high at 55.2 (3.45V/cell). I don't really understand why you set the float that high for the new test settings. Unless that was a type-o? At 3:46 in the video. A float that high will unbalance the cells (note 1) and undo all the work the passive balancers put in, and it will show up once you push them higher. You might as well not be testing passive balancing at all with a float that high.
note 1: Remember that minor differences in cell chemistry show up below the exponential part of the charge curve. I still feel that 3.45V is not deep enough into the exponential part of the charge curve (particularly when charging at higher amps) to remove the differences due to chemistry. That means if you float there you are likely undoing any benefit from the passive balancers.
-Matt
the issue is the two bmses are turning off the balancing function when in float mode and the JK bms is still balancing when in float mode. The other bmses should have a function in the app to turn off "balance when charging" so then when the battery is floating or "not charging" the balancer will continue to work and match the voltage of all the cells.
@@uhjyuff2095 That's a good point. I don't know why the designers of these BMSs thought it was a good idea to do that. Balancers should pull energy out of any high cell above a certain (programmed) cell voltage regardless, simple as that.
To be honest, I'd be happy with a per-cell bleed resistor circuit. There is no real need to actually transfer energy into other cells since a healthy battery is, for all intents and purposes, going to be near 100% SOC anyway once the voltages get up there.
I set the float to 55.2V (3.45V) for the test to give the balancers maximum time to balance out these cells.
Of course, 3.45V would be far too high for a float setting. It should be at ~3,35V as this is the natural rest voltage of a fully charged cell anyway.
@@OffGridGarageAustralia Holding the voltage above the proper float threshold for too long will overcharge the cells by differing amounts based on minor differences in cell chemistry. In otherwords, it will start to unbalance the cells rather than balance them.
This is (another reason) why the balancing should only occur well into the exponential part of the curve (aka 3.50V+). Because when held at that voltage, ALL the cells are slowly being overcharged at roughly the same rate if we discount balancing activity. Which means that the balancing operation itself will have a positive effect.... it will bring the actual SOC of the individual cells more into line with each other.
When trying to balance at lower cell voltages, minor differences in chemistry will cause the "perfect balance, 0mv deviation" to slowly overcharge the cells at different rates (due to minor differences in cell chemistry), which is not what we want. Keeping in mind that any voltage above roughly 3.40V will, if left long enough, overcharge the cells. It will top out, but at different relative SOCs, so on the next cycle if you try to push any higher, some of the cells will shoot up past 3.65V.
--
Maybe that other posters comments points to a better research path... I always just assume that balancers work properly, but it has become very clear that for many of these BMSs, their balancers do not work properly. Are the balancers even operating the way we expect for the time interval we expect?
For example, some BMSs do indeed stop balancing when the charge current drops to zero, which makes passive balancing far less effective. Other balancers might start working on the cells starting at too low a voltage, which is also detrimental.
What we want, basically, is for the BMSs passive balancers to take energy from any cell whos voltage is greater than (current_pack_voltage / 16) for any current_pack_voltage that is above a certain configured value. It can optionally put that energy into a low cell, but it doesn't need to because as long as the charge controller is holding the pack voltage >= (configured pack_voltage), the charge controller will clean it up.
So for example, if this configured value is 3.50V/cell = 56.0V, and the battery is held in absorption at 3.55V/cell = 56.8V, then the balancer will take energy from any cell higher than (current_pack_voltage / 16), aka any cell higher than 3.55V.
But once the pack voltage drops below 3.50V, meaning that the charge controllers are no longer holding the pack in absorption, the BMS must stop trying to balance stuff (because doing so will unbalance the cells rather than balance them).
So for absolutely sure we do not want the BMS to try to balance anything below the configured pack voltage, because that will also unbalance the cells rather than balance them. And for reasons of cell chemistry, we really don't want that configuration parameter to be set too low either.
I personally think that 3.45V is too low for any balancing operations to be active (and because it may not work well in colder temperatures), but it is definitely arguable. Regardless of that, the pack can't be held above the float indefinitely (whether balancing or not), because we do that for long enough and we will undo all the good the balancers did.
That is what we want the passive balancer to do. But I guess most of these blasted BMSs still don't understand how to balance cells properly.
-Matt
@@junkerzn7312That makes sense, Matt. Thanks you.
I think passive balancer will disappear at some point. They really make no sense with LiFePO4 chemistry unless you go really high. Nowadays, we just have better technology and active balancers are so cheap and just get the job done, even at 3.45V.
When you go back to 55.2 will you still keep the bms balance start at 3.45 v and stop at 3.40v ?
Yes, that will be the start and stop voltage for these balancers. I can only set one voltage in these BMS, they start above and stop below that set voltage.
The problem is in your setting for absorption voltage and time it should be the same as your charge voltage also you should leave it running for as long as possible , you have something very estrange there with all those top of the line BMS and an difference like that, my low end batteries are always with a deviation less than 0.07 v by the time they get full at 28.4 v
Keeping cells at higher than float voltage for extended durations are one of the major drivers for premature cell failure - we've known this since lead acid first came to the market and LFP is no different. If you don't need rapid charging, higher voltages only have downsides - no upsides.
@@Stefanfj different chemist
@@cabanasolar9730 this happens to all chemistries above their float voltage - since float voltage is defined as the point where damage doesn't occur.
When LFP is fully charged to 3.65V and we let the cell rest for 24h or longer, the voltage will drop to ~3.35V. This is the natural rest voltage of LiFePO4 and also the float voltage for these cells. At this point, charging has stopped and we only 'float' here to keep the cells at 100%. And in fact this float voltage is only necessary because if we pull a higher current than our solar can deliver for that moment, it would discharge the battery. Float voltage will top it up again after the load has ben removed.
Hm, interesting - when your BMS reach the max. pack voltage they don't actively discharge it seems - at least not with a big current. My Seplos BMS hectically discharges with multiple amps down to some lower voltage, only to then charge again up to 55,2V. And this cycle continues for a long time... Would love to know if this is "normal" for the Seplos BMS or whether some of my settings are still wrong...
It doesn't discharge, the surface charge dissipates until the resting voltage is reached , the cells aren't full yet. Take a single cell, charge it and then disconnect it. you will see the same drop of the voltage, the charge wasn't absorbed yet. The surface charge behaves like a capacitor
The Seplos BMS does exactly that micro cycling. I hate it. You can turn this off with one of the function switches. It is called Intermittent Charging Function. Try that and it should hold the voltage at 55.2V.
@@OffGridGarageAustralia Thanks - I assume I should switch that off? Or does it have to be on?
@@OffGridGarageAustralia Hm, that was already off - but the cycling still happens. Any idea what could still be wrong?
Learning
Off topic, ive got the new JK BMS 2A 200A. No current sensor anomaly when solar input and inverter load are equal and the nett batt current hovers between +/-. Also nice setting of SOC 0% and 100%. But it cannot power up my 24V/3000W Latronics inverter or my 48V/8000W Mppsolar inverter it detects short circut even it has a precharge function. The MppSolar can be precharged (100 Ohms Resistor) but the Latronics not. For this one i have 200A circuit breaker betwenn B- and P- which i close. Then i set the JK into emergency mode. Then i power up the inverter, then i open the circuit breaker and finally i cancel emergency mode.
I started a conversation with the official JKBMS store but at some stage they just deleted all my messages instead of responding.
Edit: I measured all my cells (those stupid BYD 320Ah with one terminal on each side) using the blue 40A tester and after a period to try and error come to exactly the same conclusions with Voltages and balancing.
Gut gemacht, Audi.
With a pre-charge resistor you shouldn't experience this.
Try changing the SCP Delay to 300000ms
@@naijawindandsolarIn case of the 8kW inverter the pre-charge did the trick. But the Latronix cannot be precharged and it's ramping up requires the internal resistance of a lead acid battery. Lithium just merciless hammers the Amps in. I tried, it still shuts down with short detected.
@moestrei Then you should probably just gift out the inverter to someone with Lead Acid battery.
They deleted your conversation?! Wow
The JK software is still buggy. They basically start from scratch with almost everything. I'm not waiting for that to progress, I'll move on...
@@OffGridGarageAustralia Yes but not everybody can just move on. I have 5 JK systems running (House, cabin, shed, ride-on mower and motorcycle) and happy to use just one app and mastered all the quirks. You're still young and adventurous but in my age you like to settle on something which works.
So, Andy, I know you have gone back and forth with balancing on then balancing off during charging. What is the final conclusion? It appears the balancing is turned on during charging, at least on the Overkill (which is what I am running presently).
For some reason I thought in one of your videos you felt it was best to turn off balancing during charging in the settings??
Yeah, it's a tricky one. I have done both for a while and could not see a difference in the result of balancing. Neither is optimal!
@@OffGridGarageAustralia Thanks for the reply, Andy. Always a pleasure to hear from you and view your videos.
@@jws3925 I'm always here😉
👍👍👍
What about life impact running a battery up to high state of charge? I hear daily charging on EV of 70 to 80%. What do you do on your Tesla?
that’s for different lithium chemistry. There’s not such a difference with LFP, when going to 3.55v per cell. charging to 3.65v per cell on a daily basis might have an effect.
tesla vehicles with LFP batteries need to be charged up to 100% at least weekly otherwise their range estimate loses calibration. this is not a problem on the NMC type vehicles since the charging curve isn't so flat below 90%.
@@Stefanfj interesting point. I’m very familiar with LFP as an off-grid storage solution (I live off grid and rely on it). Because the voltage curve of LFP is so flat between approx 20% - 85%, it’s very difficult to accurately assess SOC from the voltage alone within that range. So yes a full charge to 100% helps to reset the SOC tracking. that’s only to aid the range readout though, and to help with cell balancing. It’s not required to prolong the lifespan of the cells (although it also won’t hurt).
The only reason Tesla recommends charging LFP to 100% once a week is to calibrate the BMS (and range estimation) as discussed above. All answers are correct 😊
I have NMC batteries in my Tesla and charge to 50-60% on a daily base only. Only for longer trips, I charge to 70-90% as needed. Charged to 100% only once for testing purposes (on my other TH-cam channel).
Degradation after 4 years and 62.000km is less than 3% (as per the BMS in the Vehicle).
Hello Andy.
Hmmmm....is Stuart an Australian ... ??
I thought he is in the UK.
Yes, he is in the UK.
@@OffGridGarageAustralia
OK, wrong guess, it is not his BMS....
I'm excited what new BMS you have found 🐸
6:37 it´s like shift registers. You will loose some unimportant things. 😜
😂😂😂
Obviously these numbers stick for some reason. Unlike some birthday dates of family members😄
So you are going to try out the Batrium ?
Well 😊
Andy, every time i watch your videos my calculator ends up on my desk.
Don't check on me, hahaha.
Let hope it's not Batrium 🧐
Why is that?
@@OffGridGarageAustralia I have been using a watch Mon and long mons for about 5 year and had lot of problems with it long mons failing and now the WiFi will not work and if I unplug the USB from my laptop the thing completely resets even with the power supply also plugged in and as it is not active balancer it has a hard time with the life04 system. Support is not that good well unless you have a large TH-cam channel.
Maybe the new stuff is better I will wait for your videos but I looking at the jk bms.
@@GarryL277 I have heard similar stories...
I think, I found something bullet-proof now...
And...... Cue the keyboard techs... Now 😂🤣😂🤣 Danke Andy.....
Thanks a lot, my friend!
14:45 So Andy is going to install a Batrium with three CellMate K9?
It is coming from Australia, right!?🦘
I'm betting on Batrium
Good guess 🤘
I guess the issue with higher voltage charging is the weedy passive balancers being unable to stop cells hitting 3.65V and switching all balancing off. Using an active balancer should remove that (and maybe you'll gain 2% capacity 😅)
No, it's about the cells, you push them over 3.65V (saturation) with safety cut off at 3.75V or more Safety margin depends on the cell manufacturer. When they are saturated they burn some energy in heat and settle the charge, they are like a keg overflowing, but it allows the connected other kegs to fill up until they overflow.
That is called top balancing. cell voltage and measured voltage differ, as you measure while current flows, hence you have a voltage drop / voltage increase due to impedance and wiring / connector resistances.
@@aaabbb1579 The BMS is programmed to cut off charging at 3.65V. The whole point is to protect the cells.
Also, BMSs stop charging very briefly when checking cell voltage.
An active balancer will definitely help...
@@OffGridGarageAustralia My main point was that the passive balancers are just too small. 2A passive balancing is far more effective (e.g. REC BMS) but I'd still rather use a good active balancer to avoid damaging the BMS.