Great tutorial. Whilst passive balancing is of little value this is not a reason to omit the cables to the cells. Remember these cables are still important to enable the BMS to know the individual cell voltages so that it can shut down the battery should high or low limits be reached on any one cell.
Can't a passive balancer not be used to only balance at the top, when the bank is fully charged? And the passive balancer gets deactivated under 90% soc.
A passive balancer could theoretically be used to top or bottom balance. Most BMS passive balancing only kicks in at a higher soc though, as you mentioned. But the actual soc will depend on the manufacturer. After market passive balancers will also have their own disconnect soc, and that can be quite low.
Gosh!!! great points. So if my novice brain is to understand: First, start out with a top balance. Second, Rely on a good grade BMS to maintain the top balance. Question: I have watched some videos and did some reading where the claim was made that a battery bank eventually falls out of balance inspite of the BMS. Hence, a periodic top balance, perhaps once a year, is needed. Would it be beneficial and/or possible to switch to an active balancer from the regular BMS. once or twice a year. starting from the discharged state; letting the active balancer take the bank to a fully charged state; and then switching back to the regular BMS thus never changing the situation at the bottom? I am thinking that the active balancer could take place of periodic top balancing in leu of disassembling the pack and doing a top balance and then putting the pack back into serial connection and commencing regular use. This providing that the active balancer only be used in charging and not discharging. Of course this may mean using the BMS and active balancer alternately a few times in a row if the pack is totally out of balance. What do you think?
Great question. You can actually use both a BMS and active balancer at the same time (which is what I do). If the active balancer works then you will be in great shape. Just make sure to check in once in a while to make sure everything is working perfectly. If you don't want to use the active balancer all the time, you can of course disconnect the BMS and then install the active balancer to achieve a top balance without dissembling the battery. Just make sure you cells are charged (maybe 80%) because balancers work faster at higher voltages. Also, active balancers tend to move only a few amps an hour, so if you do have large cells, it could still take a day or so to balance them with an active charger. My suggestion: just put a BMS on there and an active balancer - but only after you do an initial top balance to start things off.
Hey Will thanx for all the help on building my system but it looks like I need more solar panels. I have six 100 watt panels now and are connected three on three for 60 volts and 10 amps I would like to know if I buy six more what would be the best way to connect them. I have a Victron 100/30 I know I will have to buy the Victron 150/50 also to charge my 8 200AH lipo4 12v I also have a Daly 120 4s BMS will i need to change this also?? Thanx Nap
Hi Napoleon, your question is a little too complicated for me to answer here. How many volts and amps does each panel produce? I think you should still be able to use your original batteries and BMS no matter what you do with your solar panels.
@@TheWilltoBuild Sorry for that. I think I have it figured out. I will connect the 12 solar panels in sets of 4 series of 3 to give me 30V per set and 5Amp per set to give me a total of =120V and 20Amp. My charge controller will be 150/35 So I just want to know is this a good way or do you have a better idea. So all together I will have 12 Rich solar panel and a Victron 150/35 8 eve 200Ah set to give 12V and a Daly 120 4s. Thanx
have you ever measured what happens in real life with different capacity cells? Because you are using your mistaken graphic analogy, you are assuming the voltage on the higher capacity cell falls at the same synchronised rate...this not what happens in real life. You are misleading your viewers.
I think you are misunderstanding the analogy. The amount of power used is the same, but larger capacity cells will have higher voltages, because they still have more relative power remaining. The entire point is that if you don't have cells matched on capacity, the voltages change at different rates.
@@TheWilltoBuild in your video you show and mention that the voltage is dropping evenly....I am not misunderstanding your analogy ....I am pointing out how your analogy is leading you and your viewers to the wrong understanding.....as said on a previous video comment ...larger capacity cells should be illustrated as wider but with the same height...for multiple reasons...one being that the BMS and battery chemistry determine when a cell is fully charged or depleted. If the ultimate goal is to obtain the best performance from a bank of cells in series ...the voltages of all cells is what balancing does..even if the internal resistance differences of cells slowly unbalances otherwise matched cells. In my observations and experience even the best cell manufacturers do not match AH capacity and internal resistance over many charge discharge cycles....at best they might test or charge once and supply them at the same voltage.. Any guarantees that are provided are on the proviso that they are used with a BMS.
@@mekuranda I think you are still mistaken but I do appreciate you making the effort to protect people. I do totally agree a BMS is ALWAYS necessary and I think I have been clear about that in my videos.
Great tutorials!! Best on TH-cam. I'd love to hear more of the inside story about how a BMS works.
Great idea, I am adding it to the videos list.
A make sense….. also a lot of people are scared of charging to 3.65v to make the cells last longer but the bms need a 3.65v to balance the cells.
Great tutorial. Whilst passive balancing is of little value this is not a reason to omit the cables to the cells. Remember these cables are still important to enable the BMS to know the individual cell voltages so that it can shut down the battery should high or low limits be reached on any one cell.
You absolutely need to wire the BMS correctly, including all the individual cell wires, for it to work properly.
Can't a passive balancer not be used to only balance at the top, when the bank is fully charged? And the passive balancer gets deactivated under 90% soc.
A passive balancer could theoretically be used to top or bottom balance. Most BMS passive balancing only kicks in at a higher soc though, as you mentioned. But the actual soc will depend on the manufacturer. After market passive balancers will also have their own disconnect soc, and that can be quite low.
Gosh!!! great points. So if my novice brain is to understand: First, start out with a top balance. Second, Rely on a good grade BMS to maintain the top balance.
Question: I have watched some videos and did some reading where the claim was made that a battery bank eventually falls out of balance inspite of the BMS. Hence, a periodic top balance, perhaps once a year, is needed. Would it be beneficial and/or possible to switch to an active balancer from the regular BMS. once or twice a year. starting from the discharged state; letting the active balancer take the bank to a fully charged state; and then switching back to the regular BMS thus never changing the situation at the bottom?
I am thinking that the active balancer could take place of periodic top balancing in leu of disassembling the pack and doing a top balance and then putting the pack back into serial connection and commencing regular use. This providing that the active balancer only be used in charging and not discharging. Of course this may mean using the BMS and active balancer alternately a few times in a row if the pack is totally out of balance.
What do you think?
Great question. You can actually use both a BMS and active balancer at the same time (which is what I do). If the active balancer works then you will be in great shape. Just make sure to check in once in a while to make sure everything is working perfectly.
If you don't want to use the active balancer all the time, you can of course disconnect the BMS and then install the active balancer to achieve a top balance without dissembling the battery. Just make sure you cells are charged (maybe 80%) because balancers work faster at higher voltages. Also, active balancers tend to move only a few amps an hour, so if you do have large cells, it could still take a day or so to balance them with an active charger. My suggestion: just put a BMS on there and an active balancer - but only after you do an initial top balance to start things off.
Hey Will thanx for all the help on building my system but it looks like I need more solar panels. I have six 100 watt panels now and are connected three on three for 60 volts and 10 amps I would like to know if I buy six more what would be the best way to connect them. I have a Victron 100/30 I know I will have to buy the Victron 150/50 also to charge my 8 200AH lipo4 12v I also have a Daly 120 4s BMS will i need to change this also?? Thanx Nap
Hi Napoleon, your question is a little too complicated for me to answer here. How many volts and amps does each panel produce? I think you should still be able to use your original batteries and BMS no matter what you do with your solar panels.
@@TheWilltoBuild Sorry for that. I think I have it figured out. I will connect the 12 solar panels in sets of 4 series of 3 to give me 30V per set and 5Amp per set to give me a total of =120V and 20Amp. My charge controller will be 150/35 So I just want to know is this a good way or do you have a better idea. So all together I will have 12 Rich solar panel and a Victron 150/35 8 eve 200Ah set to give 12V and a Daly 120 4s. Thanx
I am lost. BMSs are using the passive balancing method, so why do you say we may not need passive balancing. Do you mean active balancing? Thank you
But they work for my OCD.
That is an important point!
have you ever measured what happens in real life with different capacity cells? Because you are using your mistaken graphic analogy, you are assuming the voltage on the higher capacity cell falls at the same synchronised rate...this not what happens in real life. You are misleading your viewers.
yes, testing the graphic analogy would be interesting
I think you are misunderstanding the analogy. The amount of power used is the same, but larger capacity cells will have higher voltages, because they still have more relative power remaining. The entire point is that if you don't have cells matched on capacity, the voltages change at different rates.
@@TheWilltoBuild in your video you show and mention that the voltage is dropping evenly....I am not misunderstanding your analogy ....I am pointing out how your analogy is leading you and your viewers to the wrong understanding.....as said on a previous video comment ...larger capacity cells should be illustrated as wider but with the same height...for multiple reasons...one being that the BMS and battery chemistry determine when a cell is fully charged or depleted. If the ultimate goal is to obtain the best performance from a bank of cells in series ...the voltages of all cells is what balancing does..even if the internal resistance differences of cells slowly unbalances otherwise matched cells. In my observations and experience even the best cell manufacturers do not match AH capacity and internal resistance over many charge discharge cycles....at best they might test or charge once and supply them at the same voltage.. Any guarantees that are provided are on the proviso that they are used with a BMS.
@@mekuranda I think you are still mistaken but I do appreciate you making the effort to protect people. I do totally agree a BMS is ALWAYS necessary and I think I have been clear about that in my videos.
No. Use an active balancer. Much better.