This kind of balancer most likely connects to each cell in a round robin fashion in order to be able to work. So, it will not pull from the highest to the lowest. And the missing amps, the clamp meter will not be able to visualize the flow because of switching frequency.

Okay Andy I have the same balancer that little solder joint next to the connector on the balancer next to the b- if you desolder that you have the two pads there you can connect a relay and turn that on and off with a switch or a relay I have mine programmed to the victron inverter to turn on at any voltage I want it to I said it to 13.8 for my 12 volt battery so it comes on just as the batteries are starting to come up in the curve and then I have it set to turn off when I start discharging the battery Yeah that is it you found it in the video

I think those balancers can only charge and discharge between adjacent cells. In other words, it is not able to take a charge from cell #1 and give it to cell #4 directly. It has to work through all the cells in between. So in your case, It looked like cell #3 was charging #4 heavily, #3 was getting rebalanced from #2, then #2 getting rebalanced from #1 the highest charge.

I use only a balancer on my 12 volts lithium setup. My solar charger and Inverter between the both have the low power , temperature and max volt cutoff and no bms is needed . This setup would have the most power you’ll get out of your solar panels

Missing Amps? Black Cable! After watching this video my neighbors asked why I screamed "MEASURE THE F***ING BLACK CABLE" several times 😂. Sum has to be the 0. Otherwise old Kirchhoff would rotate in his grave!

Remember current is flowing both in and out through some of the cables. It will ‘suck’ from one for a bit then ‘Blow’ into the other. The clamp meter will average this out. You may find for instance a difference between the current in the main negative lead on the lowest cell and the positive lead. You might think the current should be the same but the positive lead is common to the cell above as well. An oscilloscope between the two ends of one of the interconnecting balance leads, using it as a shunt, might be interesting.

I was just watching your old videos and you reminded me to remind you to be more careful.

THANK YOU for checking that!!! Put a Voltage Relais to turn on the BMS at high Voltage =). Kost 5 Dollars or so on Aliexpress. Dont balance it on discharge.

I use two of these balancers on a 260ah 4s pack, barely ever go out of balance, really good for cells that dont match that well 👍🏻👍🏻

Entertaining, if for nothing else than your Personality ! Great energy Andy ! ☺️

19:55 been searching for a long time to confirm which youtuber gave me the idea to add switch on this active balancer, and it was you all along. hehe

These active balancers likely operate on a principle similar to charge pump where capacitor banks are switched in parallel with their respective cell for one part of the cycle to equalize voltage between capacitor and cell, then put all capacitors in parallel with each other for the other part to equalize charge. Rinse and repeat until all cells are equal. The heat comes from I2R losses in the capacitors and FETs. As someone else mentioned, measurements not adding up is likely because the clamp-meter cannot capture high frequency components from capacitor switching.

Good episode, I like the mystery of the missing amps 😁 It makes it all more interesting!

Don't forget the balancer is a power converter, not a current converter. Consider the voltage of each cell also. If the balancer were not extremely efficient, it would be extremely hot, which you confirmed it is not. Impressive little device!

Always a pleasure learning from your videos and others comments.

the key to them is the fact that they work 24/7 and you don't have to worry about it anymore. the one thing you will notice is that when you stop charging the volts will drop a little bit over time till all the cells equal out that is were low current float really works great in concert with the balancer. i have 4 big batteries 13 balancers per battery. i have found that bring it up fast then hold it there (wherever you want it) then hold it there for works the best. at least for me. good for you.

Hi Andy, thank you so much for your videos. Just a note on the cellmeter 8, I've found that you can't trust the voltage as shown for each of the cells. Mine had an error of 60mV on 2 adjacent cells (1 +ve, 1 -ve, so 120mV difference) and around 30mV on 2 others. It didn't matter what configuration that the cells were in, it was always the same reading (6 and 7) which was in error.

Andy! You listened! You really, really listened to me! Lol 😝. But dang, what a torture test (or a torch test?), wow! I would be curious to see what the delta it would have ended at and whole battery voltage before and after balancing to see how much energy was expended for the process.

13:38 i like the pegboard on the wall using hard drive magnets to hold-up the tools :)

Cool stuff! What I really like about my Heltek (JK) active balancer is what I use it for most.... It not only balances if needed, but also shows the specs of all 16 of my batteries. This is very handy! It shows the delta as well and you can set the parameters for the deviation to start balancing. Mine is only the 2a version but works well. Thanks

Good balance for the batteries found out how it worked, it works by a capacitor being charged from each battery next all the capacitors are connected in pairs so they are equalized next they are charged / discharged again over the cells and so on the lowest cell will get charge and some cells will not get charge. Nice to be able to turn it off now and then.

Another great video... I just finished to watch all of you videos... Keep up making this great videos, i am just as excited as you are when i watch them tests 😅

Electrical Safety Check gave me a good laugh, thanks.

By the way Andy, thanks for the previous video about top vs bottom balancing . You really got me thinking. Wunderbar video, vielen dank professor Andy. :-)

I really like the switch idea. You see, I think it would be great to use an active balancer when you have 15 cells high and one low. And use the BMS resistors when you have 1 high and 15 lower. Of course I set the BMS balance to .01V higher than my expected average pack voltage so only the ones which rise above the average get pulled back down. Now to figure out a way to automate turning on the balancer... hmmm.... I have had to watch in frustration as 15 cells were at 3.5v and one was at 3.4.... either wait 3-1/2 years (lol) for the BMS to pull down the other 15 cells or hook up a bench power supply to the low cell and boost it up.... this balancer will be nice.

Hab hier auch einen 17S aktive Balancer verbaut und gute Erfahrung damit gemacht! Danke für das tolle Video!

As Always, another “mind stretcher” … YOU doing what we only think about doing !🤣! 👍🏻👍🏻👍🏻

Hello, many thanks your effort for testing, enlightening and teaching in these videos. By the way, only the light at the rear of the active balance will light up? Thanks again

The balancer currents are at different voltages and therefore don't need to cancel out. Replace the bus bars with wires so that you can get the clamp-meter around them and you'll see that current also flows between the cells. Kirchhoff's law still applies.

Just installed one of these! It works awesome!

Yes. I got a bad batch of batteries from china... Very mismatched...But I put one of those active cell balances on them and have been using the 24 volt pack with 4 good and 4 bad cells and the active balancer has been working great at keeping the voltages perfectly matched...

Regarding the strange reading of current values or missing current between input and output in the batteries it is because two reasons: 1. This DC clampmeter it reads with a relatively large error rate. 2. I think the balancing done in time division scanning therefore if you can use oscilloscope you can see the pulsing scanning. Therefore the reading by clampmeter will give wrong values.

4s one burns about 12mA working and in-balance, but only about 1mA with that solder bridge open circuit. If you have very small capacity cells like me it's worth doing or fully isolating with a 4pst switch (what I do for a static non-solar long term storage situation).

When switching capacitors between high and low cells there are spikes of current flowing into and out of the caps and the fets have to carry that surge current through their slight resistance wasting some energy ... more for larger voltage differences.

Andy you blow me away. Keep up to your good work

Très belle expérience ! merci

Andy, why are you looking for “missing amps”? Your assuming that charging and discharging through a capacitor is a linear affair! Which is not. Remember the “missing amps” are maintaining the charge of the capacitor. If you disconnected the discharging cell, the charging cell would keep charging for a shot time until the capacitor has discharged as as well. I know you can graph this relationship (transient) on your whiteboard!

I believe the difference between discharge and charge current (misisng 2A as you called it) is due to the capacitor charge & discharge cycles not being 100% synchronized with the current flow to each cell. In other words, It is for example to have 6A of total discharge but only 2A going into a battery cell while 4A may be charging some of the Caps on the PCB at that moment.

Hi Andy good info in that video well done I liked that you found the run section of the balancer . So I thought I will get one for my 8s system that I am currently building, just as a backup for balancing. I used your link and tried to use the code but it did not work. Just thought you should know. Cheers keep up the good work. Update to this comment the code you have is only good for orders above $100

Andy I love your electrical safety test! We need more data from the balancer. I think you should install amp hour/watt hour meters on each lead going to the cells so we can see exactly how much energy is moved from each cell over time in the balancing sequence 😜

Hey Andy, if your looking for a better cell voltage monitor / balancer, I cant recommend the IDST BattGo BG-8S enough. Great little cell monitor up to 8s, and it shows all of the cell voltages at the same time with a fast update speed.

You are so lucky , i ordered some stuff from aliexpress going from china to belge airport in 5 days , coming in europe in 75 days ( estimated ) !!!

These work by boosting the voltage of a high cell to charge the lower. The highest cell must discharge through all other cells between it and the lowest cell. Think waterfall cascade system

Andy, you need an osciloscope to measure the energy transfer between cells. Can't be done with a dc clamp because it can not measure correctly the pulses of the charge-discharge cycles

This was the live invention of the rotary switch ;-)

Andy I was thinking about how there was missing amps in this test. Do you think that its changing the voltage in order to shove the current back into the cells. So the higher voltage going in than coming out would account for missing amps... I'm not sure if I'm right but it seems the balancer would up voltage to put power back into cells and by raising the voltage the amps would lower. So that's why it appears to have missing power. The power isn't actually missing only changed. It probably does loose a small amount but not much since there is no real sign of heat build up

Thanks Andy, I might get one for my 12V pack I'm building. Just a thought on the lost amps, could the balancer be doing voltage amplification to transfer the energy between cells? If so this might account for the perceived consumption because 500mA for the amount of electronics on the board even with heat loss certainly seems high.

HOORAY!!!! :-D he has seen the light. Will he go back? I doubt it.

He finally bought a balancer. 🍻 Most of the balancing current flows immediately during charging and discharging to compensate the drift. When the battery is at rest, the balancing is marginal. If the battery pack is always balanced, little or no equalising current flows. Then you will not miss the 6 watts. The heat has to come from somewhere. At least not everything is adjusted to the lowest cell and burned up.

Andy, as you can see; the active balancer is not expensive and is quite effective. Yes it will use some power as all circuits do. The benefit is reliability of automatic operation. No BMS cut-off due to only one cell being too high or too low in voltage. Some argue that the continual transfer of current degrades the cells faster but the current is so low that I think differences in voltage would be worse for the cells and the reliability of unsupervised operation is worth the financial, power and cell degradation cost of unsupervised reliability.

I cant wait for the BIG BOX!!!!

I use heltec balancers on my 120p x 7s power wall, my tesla modules, and my 48p x 4s 12v. They do a great job in my opinion.

The capacitor transfer active balancers have to charge then discharge the caps so the charging or discharging current is not continuous. Your clip on ampmeter will not read these pulsing currents correctly. There is also a no current time gap where cell voltage is compared without any tranfer current voltage drop on wiring that would screw up the cell voltage comparison. Each connecting wire is a shared path between two adjacent cells so current on any given wire could be switching direction between adjacent cells. It likely does not fully read the cell voltage as in a BMS full ADC circuit. It only needs a comparitor to determine if one cell is greater or less then another cell. It only rates the cells from highest voltage to lowest voltage (without knowing precise value) via a two cells at a time comparison. Capacitors cannot instantly change voltage so there is some series resistance purposely put in the circuit which hurts transfer efficiency. The square plastic surface mount devices are power MOSFET's that do the switching between cells and capacitors. I am always concerned about the long term reliability of the electrolytic transfer caps especially with high ripple current during charging and discharging. I prefer the inductor switching active balancers. Just don't waste your money on the small ones using the ETA3000 I.C.'s. These small active balancers have a problem with their voltage comparison due to wiring current induced voltage drop screwing up the voltage sense comparisons. They often balance push current in the wrong direction. The other active balancer I have heard good things about is the one with a inductor based switcher that has its input and output moved around the cells to do charge transfer. This unit has good transfer power efficiency. It does up to 10 amps transfer but the average is usually much lower because it can only transfer between two cells at any point in time. It selects the highest voltage cell to draw from and lowest voltage cell to deliver to. It periodically stops transfer and reevaluates the cell voltage differences then works between revised highest and lowest cells for next cycle. This balancer is more expensive and physically bigger. It has BT monitoring.

Hi Andy, with regards to comparing the incoming vs outgoing currents and observing the “missing” current; Have you tried calculating the incoming vs outgoing power? The missing power should be the power consumed by the active balancer + any heat losses (inefficiency)

How do you know which one to order on the AliExpress link for the active balancer? I don't know what the difference between them are. I have a 16s bank.

Hello Andi, Iam currently trying to find where you could solder a switch on to the circuit board on the active balancers. I am not sure if it was for these active balancers or not. Please comment

Andi do you use the balancer along with the bms both at the same time.

Ok . While using DALY BMS should I use one of those active balancers?

Hi where did you get the wires that you connected to the digital balancer , as I bought one and my bms balancer wires don’t fit the digital balancer meter ?

Andy, what is the tested voltage across the 'Run' pads? Is it possible you could take a voltage and current measurement (when the circuit is complete)? Or anyone else who has one of these...

Have you tried using these active balancer with a BMS? Like the JBD? I'm not sure if it would conflict with the BMS. The BMSs do not keep up when charging at high rates. Love your videos! Solar is great!

The exposed (unused) leads from your cell meter, the blue one, should those be touching the 4S Balancer ? Everytime they ‘connected’ in camera view, I tensed …. 🤓

what would happen if you put 2 of those balancers in parallel? would it balance twice as fast?

Hi, have you considered trying the batrium BMS ?

Total wattage. Voltage * current = power There's loss but you need to calculate the power on the charge side and discharge site. Then you can figure out the efficiency.

I have a cellmeter-7 for my 32ah headway 38120hp bank but where can i get the wire harness?

Thevenin's current law says the summation of the incoming currents to a node has to equal to the summation of the outgoing currents. So, the only explanation is that the clamp meter is not reading currently. I have the same clamp meter and I noticed that you need to reset the calibration button every time you take a new reading.

I purchased an 8S balancer for the 24V battery. If there’s a 10mV difference between cells, what would be an estimated time to balance all cells? And will all cells have the ‘exact’ same voltage or be within 1-2 mV? Great video, Thanks!

I want to see how it does and works when drawing a big load off a battery bank or a lot of amps going into the bank charging. Could this be a way to get rid of the normal type of BMS and just use these balancers? When I first got lithium this is what I thought a BMS did to balance cells

Could I theoretically hook up 4 of those in series to my 16s bank?

You have so many toys!

Sorry dass ich störe! Danke für dein Videos, sehr interessant! Kannst du mir sagen wo ich das 9 Pin Kabel zum Cellmeter 8 bekommen kann? Habe keinen Lieferanten gefunden. Danke und Gruss aus der kalten Schweiz

the amps comming out is at a different voltage so power is conserved

Hi Andy, I m going try the 123 smart bms now, after blowing up de daly bms s4 100A😁 maybe something for you?

The active balancer works 24/7 not just at the end of charge . The 24 - 100 amp per day is usable . But if it's getting up to the 100 amp mark you have big problems !

Dear Friend pls I not understand if the balancer works if the lamp is on or off?

Andy, a tong tester only measures the net magnetic field around the wires and the amps are calculated from that. With intermittent current from the capacitors a tong tester will not give accurate readings. You would probably need a smart shunt on the black or common negative wire to get an accurate reading. With the switch capacity of the balancer it should be possible to have a relay automatically switch the balancer on late in the charge cycle and switch off again during discharge based on voltage. However I do not have the expertise to say how.

update as i had same problem using the smart bms... a year on your videos triggered me to sort it ... the cure for smart bms is not to use charge balance and use the static balance set at 3.5 v ... give it a week or so set like this and like me you ll find the solar regulator pre set at 14.6 trips before any cell set at 3.64v trips the voltages are that close between cells. at very full charge and delivering full capacity again. ps.. we need to know if this new balancer of yours cures the problem when in normal use on you re pack... i m guessing not from what i ve learned from my pack !!!

Electrical safety check. Lol. I did the same with my active balancer 😅

I am still not clear on which would be better, one 12v, 300AH LifePo4 battery with one BMS, or three, connected in parallel, 12 v 100AH LiP04 batteries each with their own BMS. Which would be better for balancing and longevity?

I would like to see what it does if you would leave it alone and see how close it gets the cells before it quits balancing and when it starts working again . And the idle consumption when it quits balancing . Cheers !

If I buy 10-14s, can under 10S also use this battery balancer? 🙏🙏

This is very interesting....if all cells were at the same voltage...3.2 V but one cell is at a higher stage of charge will this active battery balancer resolve the problem and drive all the cells to the same level of charge ??? If this active balancer work as expected...then I don't have to put my cells in parallel...and all cells should be driven to the same stage of charge... Any thought on that? Thanks.

Is this something you can leave on the battery array permanently ?

Hi Andy. Greetings from San Diego California. I keep wondering why you are concerned about mppt not charging your battery in daylight hours?? Isnt the idea of a battery to hold energy for use when it is needed?? My thought is a car battery. It only charges when it needs it. Otherwise the battery will be destroyed i must be missing something???? Thank you for sharing your experiences with off grid solar. In private life are you in the entertainment business?? Commercials for instance?? Me?? Auto repair. Great show you have. Drama and humor. A great combo for sure...

The weak link in the design of many low cost active balancers is what happens when variable inverter load current causes some cell voltage slump with inverter load current. If the active balancer cell voltage sensing does not take all cell voltage reading at same point in time there can have been a change in load, or charge current by inverter or charge controller which effects the cells' voltage sensing resulting in corruption of the relative cell voltage reading comparisons. This can cause active balancer to select the wrong charge transfer direction. Second issue is the common single sense wire between two cells. The extra voltage drop for the interconnecting bus bar between cells and its battery terminal connections can effect the individual cell reading, under higher load or charge current, which has the bus bar within the serial path of a given cell. Best that can be done to reduce this is ensure the sense wires are connected so every cell has one bus bar connection in series with a single cell so the bus bar voltage drop is equal from all cell readings. This wil not fix the issue that some bus connections might have a bit more or less resistance then others. It is very important the interconnect bus bar connections are clean and secure to get the best matching of their added series resistance. Also, if the higher balancing current is active when balancer makes voltage reading the balance current through the common, small gauge, sense wire will have additional voltage drop that effects cell reading. Any reasonable balancer design will temporarily shut down balancing currents before making the cells' voltage sensing to avoid the sense wire voltage drop.

How long does it take to charge a 48V, 360ah lifepo4 battery?...Thanks

The four leds should light when each channel is balancing. Do they need to be enabled?

Off-Grid Garage : I have a 16 S Li-Fe-PO4 105 AH battery bank and when this battery bank is charged, the BMS (DALY 100 AMPS 16 S) will cut of at 55.5 volts (factory setting..I don't have any control in how to set this BMS)...but the bad part is that there are differences in voltage to about 250 mvolts between cells. However, during the discharging process in few hrs all battery cells are at the same voltage with differences of no more than 1 mv. The issue is during charging!!! Maybe this active battery balancer will make a better work than the BMS.The BMS is a DALY J25AGD21. Will this issue have anything to do with the stage of charge ? Thanks

Thank you for researching and testing. FYI, Andy, the Hankzor code only gives me $2 discount on minimum of $130 order, oh well.

thank u so much!

Educate me please. What is the difference between a balancer and a BMS? Also, I did not see accommodations for high temp/low temp cut offs

The active balancers are effectively a bunch of buck and boost converters that are enabled/disabled by comparators. You could do the same thing manually... but the automatic approach from either hard wired logic or software in a microcontroller has definite appeal.

I have an 8s configuration I have the bms connected and put on the active balancer but it seems the the bms says battery 1 is the most positive but on the active balancer it seems backwards so bms + is battery 1 and + of active balancer is battery 8 is this right anyone ?

Hello, first of all : this is not a complaint !!! I bought that exact balancer after watching the video, looked very promising, soldered a switch to not have it running permanently. Today I had to remove my JBD BMS ( smoked when discharing and load port off :-( ) for pictures for support team and I found that the balancer circuit board was very warm close to hot - even if the balancer was not working ( LED off ) The heated area was on the same side as the connector next to the black cable. Have you experienced that as well or is your board cold when not switch on ? Viele Grüße aus Schleswig-Holstein, tolle Videos machst Du !

Active balancing looks nice since it is fast but when using it all the time you may overheat a bad cell with the added charging/discharging current. From my understanding I would be carefull with this and only use a normal bms instead.

Can anyone tell me if the polarity of a PV disconnect depends on the load/source side?

Voltages at which the amps go in/out are different so to keep same power also currents would be different me thinks :\

Damn! I wanted to show of my knowledge mentioning Kirchhoff, but someone was me before, how rude LOL!

Missing current: 2 things: 1. Power is being transferred, and thus the current will be different as the voltage is different. But that's not enough to account for the "gain", so: 2. Don't trust your uni-t meter and learn to use it properly. IE, it's probably asymmetric so reverse the clamp on the ones flowing the opposite way. Try both ways, chances are you get like 0.9 for all 4 and 1.4 for all four the other way around. ;-)