These ETA3000 I.C. balancer have a good switcher that can pump from upper to lower or lower to upper cells. They are leap frog overlapped to transfer current up or down the stack of cells. The problem is with the voltage sensing which is just a comparitor to determine which of two cells per I.C. has the greater voltage. A single I.C. only measures voltage comparison when its balancing pump is idle. Problem is all the chips run asynchronously. This causes interference with adjacent I.C. causing the comparitor to sporatically report the wrong cell with higher voltage and results in balance pumping current is wrong direction. The more wiring resistance to cells the worse it gets.
I have a feeling you could end up with a cell balancer oscillator if you parallel these gadgets where they bounce between celles, one balancer pulling current from an outer cell to 'balance' the cell that's being discharged by the other balancer. would be interesting to watch the voltage across the super caps too
Bravo........I seen wire digram......4 parallel and 4 series .....they feed power from top ... 4 switchs ..4 cap..parallel .....4more switch ...4 more caps ......they would switch between on and off .....back and forth .......active balance.......cheers
Nice video Julian. So much more professional than my musings on camera. The pseudo MPPT boards can be paralleled on the output, but not on the input if charging a common battery pack. They are however very inefficient as the charging current is modest at best. I now use the BMS to terminate the charge, the charge current being supplied directly by the solar panels without any charge controller. I tried to parallel up the active balancers but unfortunately one let the magic smoke out, so I use just the one on my 3S pack, which seems to be ok, even with my 35Ah battery pack. Having reasonably balanced cells to start with really helps keep them in balance, with the balancers being used just in case one cell voltage slumps faster than the others in the pack.
Please just put a meter over the whole pack instead of guessing for half the video. 8-) You use to have some of those small panel meters and those would work well here by using an alternate battery for their own power enabling them to read down to zero. You could use them on each individual super cap. The balancers won't need "rebooting". Think about their intended use... rebooting wouldn't be an option. Good to see you getting back into this stuff!
when i was testing i did a discharge test on my pack noted capapcity and what bank went low first added an active balancer and tested again i found with each balancer i added i got a little more capapcity due to more current flow keeping the banks in balnce with each other i hit a point where all banks would deplete ate the same point cant remeber exactly but i think i gain about 5ah on capaity i also found the active balancer did nothing for alot of the time they mainly kicked in at low end of discharge when the banks went out of balance more
I would be very interested in any future MPPT videos showing in particular those cheap low current boards..if they can be paralleled and also how they work....it seems to me there is a lack of higher current boards for DIY use on eBay.
how exciting sir! how bout an experiment using 4s and 5s instead of 8s, 4s and 5s connects on the 4th battery, lets see if two active balancers can communicate with each other, please do an experiment on this, thank you so much and morepower
They operate by shuffling small currents as required. In time they balance the cells. No need to migrate amps at a time. Given time one of those could balance a 100Ah battery no issues. Unless you have some seriously messed up cells. I use those for my Head Way packs . They work.
I have 3 of the 5a ones and one or two of the small ones I can send mate, had them on my old lifepo4 and watching the lights wasn't exactly reassuring. Now I have new cells I don't plan to use them.
Since these balancers activate at ~100mV difference they're not really useful for anything. 100mV is a lot for a li-ion battery (ie you could have once cell overcharged at 4.3v when the others are at 4.2v). These also have relatively low balance current if i remember correctly, they only go to their rated balance current when way out of balance (>250mV).
How did you set the balancer to work on 2.5 Volts? I mean, are they not designed for 4.2 Volt? Or do they balance at any voltage? (Up to a certain minimum and maximum I guess)
australian andy showed some active balancers and realized that not every cell is chosen for balancing others .. this made me think in a too big system 300 amp cells i could make independent balancers on relays to maximize the capacity drain!!! ..
then they are connected in parallel how do you know that they are sharing the balance current? I would expect the one with the lowest voltage will start to balance before the other one even starts to think about starting to balance so it will just sit there waiting for the voltage across the cells to be to where it wants to start balancing. A bit like transistors in parallel you need emitter resistors to try to get them to share the current or one just takes it all and over heats.
next time, read the datasheet of the balancer. it start transfering current as soon as voltage is 0.1V different between 2 adjacent cells. before that nothing happens. it stop when voltages are as close as 30mV. check the cells voltages instead of the whole pack.
What I'm doing is using a bms for safety, w and using a balance charger ever so often, or as needed, keeping an eye on the cell voltages, my battery bank is over 25kwh, and 7 series cells, and I stay between 3.2v and 4.1volts,
This was so interesting. It would be great if you showed the different circuits in a BMS board. I would like to play with the sensing of current and voltage. I still don't understand why you placed two balancing board on the capacitors. Then again I don't understand a lot of things:) It would be interesting to translate what a BMS board does electronically into English while reviewing a schematic. How much to teach me this subject matter? I want to build my own but have basic training in electronics.
Hi can you tell me if I can connect 2 lithium batteries in parallel and the two batteries in parallel and two more in series will I still double the amperage of the battery pack
@@JulianIlett sorry I just read my question doesn't make sense I'm trying to use for lithium batteries to make 12 volts wanted to increase the capacity by paralleling two out of the four
I have 4 battery packs that are 6s. They each have a set of balance leads. I use the 4 packs in parallel to power my 24v lawnmower. Each pack can handle 10amps. So the 4 in parallel gives me 40amps available. But doing this will cause each pack to go out of balance differently. So I built a balance lead with 4 connectors. Making cell 1 of pack 1 is connected to cell 1 of pack 2,3,and 4. Same thing for all the other cells. I plug 1 balancer into that and it balances the pack great.
Give me your address and let me know how many batteries you have that have "fire" in their name and I'll send you better ones. No joke, DON'T USE THOSE BATTERIES!
Finally an electronic video experiment again.
More LEDs! You have a whole new shed to make look like a spaceship!
Experiment "I guess it works".
These ETA3000 I.C. balancer have a good switcher that can pump from upper to lower or lower to upper cells. They are leap frog overlapped to transfer current up or down the stack of cells.
The problem is with the voltage sensing which is just a comparitor to determine which of two cells per I.C. has the greater voltage. A single I.C. only measures voltage comparison when its balancing pump is idle. Problem is all the chips run asynchronously. This causes interference with adjacent I.C. causing the comparitor to sporatically report the wrong cell with higher voltage and results in balance pumping current is wrong direction. The more wiring resistance to cells the worse it gets.
I have a feeling you could end up with a cell balancer oscillator if you parallel these gadgets where they bounce between celles, one balancer pulling current from an outer cell to 'balance' the cell that's being discharged by the other balancer.
would be interesting to watch the voltage across the super caps too
Bravo........I seen wire digram......4 parallel and 4 series .....they feed power from top ... 4 switchs ..4 cap..parallel .....4more switch ...4 more caps ......they would switch between on and off .....back and forth .......active balance.......cheers
Nice video Julian. So much more professional than my musings on camera.
The pseudo MPPT boards can be paralleled on the output, but not on the input if charging a common battery pack.
They are however very inefficient as the charging current is modest at best.
I now use the BMS to terminate the charge, the charge current being supplied directly by the solar panels without any charge controller.
I tried to parallel up the active balancers but unfortunately one let the magic smoke out, so I use just the one on my 3S pack, which seems to be ok, even with my 35Ah battery pack.
Having reasonably balanced cells to start with really helps keep them in balance, with the balancers being used just in case one cell voltage slumps faster than the others in the pack.
Please just put a meter over the whole pack instead of guessing for half the video. 8-)
You use to have some of those small panel meters and those would work well here by using an alternate battery for their own power enabling them to read down to zero. You could use them on each individual super cap.
The balancers won't need "rebooting". Think about their intended use... rebooting wouldn't be an option.
Good to see you getting back into this stuff!
Very good demo/test Julian. Thanks for the empirical evidence for your proposal that multiple cell balancers can work in parallel.
If you have good cells and ballanced packs, they should not really need balancing regularly, unless they are cycled hard,
when i was testing i did a discharge test on my pack noted capapcity and what bank went low first added an active balancer and tested again i found with each balancer i added i got a little more capapcity due to more current flow keeping the banks in balnce with each other i hit a point where all banks would deplete ate the same point cant remeber exactly but i think i gain about 5ah on capaity i also found the active balancer did nothing for alot of the time they mainly kicked in at low end of discharge when the banks went out of balance more
I would be very interested in any future MPPT videos showing in particular those cheap low current boards..if they can be paralleled and also how they work....it seems to me there is a lack of higher current boards for DIY use on eBay.
So if you buy a 21S board, could you connect it so it would work the same as parallel 7pcs of 3S boards?
Love to see you build a power wall
how exciting sir! how bout an experiment using 4s and 5s instead of 8s, 4s and 5s connects on the 4th battery, lets see if two active balancers can communicate with each other, please do an experiment on this, thank you so much and morepower
You'll be pleased to know that it's good enough for me too.
Pleased as politically incorrect Punch :)
the active balancers only work when they is an offset voltage of x amount they dont work like passive balancer that top balance
"Active Cell Balancers" Sounds like the latest Covid remedy. ;)
They prevent powerbanks getting viruses
They operate by shuffling small currents as required. In time they balance the cells. No need to migrate amps at a time. Given time one of those could balance a 100Ah battery no issues. Unless you have some seriously messed up cells. I use those for my Head Way packs . They work.
Where to find them?
I have 3 of the 5a ones and one or two of the small ones I can send mate, had them on my old lifepo4 and watching the lights wasn't exactly reassuring. Now I have new cells I don't plan to use them.
Since these balancers activate at ~100mV difference they're not really useful for anything. 100mV is a lot for a li-ion battery (ie you could have once cell overcharged at 4.3v when the others are at 4.2v). These also have relatively low balance current if i remember correctly, they only go to their rated balance current when way out of balance (>250mV).
How did you set the balancer to work on 2.5 Volts? I mean, are they not designed for 4.2 Volt? Or do they balance at any voltage? (Up to a certain minimum and maximum I guess)
They work on voltages between 2.2V and 4.5V
If you want to play with lithiums in a similar situation, use tiny lithium cells harvested out of e-cigs or dollar store drone toys.
australian andy showed some active balancers and realized that not every cell is chosen for balancing others .. this made me think in a too big system 300 amp cells i could make independent balancers on relays to maximize the capacity drain!!! ..
then they are connected in parallel how do you know that they are sharing the balance current? I would expect the one with the lowest voltage will start to balance before the other one even starts to think about starting to balance so it will just sit there waiting for the voltage across the cells to be to where it wants to start balancing.
A bit like transistors in parallel you need emitter resistors to try to get them to share the current or one just takes it all and over heats.
True. I had intended to build ammeters to test the transfer current of these balancers. Now I'll just have to build more ammeters :)
next time, read the datasheet of the balancer. it start transfering current as soon as voltage is 0.1V different between 2 adjacent cells. before that nothing happens. it stop when voltages are as close as 30mV. check the cells voltages instead of the whole pack.
What I'm doing is using a bms for safety, w and using a balance charger ever so often, or as needed, keeping an eye on the cell voltages, my battery bank is over 25kwh, and 7 series cells, and I stay between 3.2v and 4.1volts,
This was so interesting. It would be great if you showed the different circuits in a BMS board. I would like to play with the sensing of current and voltage. I still don't understand why you placed two balancing board on the capacitors. Then again I don't understand a lot of things:)
It would be interesting to translate what a BMS board does electronically into English while reviewing a schematic. How much to teach me this subject matter? I want to build my own but have basic training in electronics.
Do you have links to the balancing boards you used on this video? It would be nifty to get some for a battery based item I want to work on. :)
Here's one - can't guarantee it's the cheapest though: ebay.us/XMPEmD
@@JulianIlett , thank you. Well I have learned that some times the cheapest isn't always the best lol.
very informative, video thanks for sharing
Just to remind you, they work down to 2.2volts.
A timely reminder - thank you. I was just starting to forget again :)
Could you increase the inductors to get a higher balancing current ?
I think the current is defined by the ASIC on the balance board.
Ohh!! I was expecting some sort of Juggling skills :-)
Can you remind us where you got the power supply?
I think I found it.
Hi can you tell me if I can connect 2 lithium batteries in parallel and the two batteries in parallel and two more in series will I still double the amperage of the battery pack
Best to do your parallel-ing and series-ing at the cell level.
@@JulianIlett sorry I just read my question doesn't make sense I'm trying to use for lithium batteries to make 12 volts wanted to increase the capacity by paralleling two out of the four
I have 4 battery packs that are 6s. They each have a set of balance leads. I use the 4 packs in parallel to power my 24v lawnmower. Each pack can handle 10amps. So the 4 in parallel gives me 40amps available. But doing this will cause each pack to go out of balance differently. So I built a balance lead with 4 connectors. Making cell 1 of pack 1 is connected to cell 1 of pack 2,3,and 4. Same thing for all the other cells. I plug 1 balancer into that and it balances the pack great.
too much guessing, had you added 3 volt-meterr there might actually have been some value here
Give me your address and let me know how many batteries you have that have "fire" in their name and I'll send you better ones. No joke, DON'T USE THOSE BATTERIES!