Zwy
Emperor Of Solar
Heck, I have no idea exactly what he is doing other than possibly playing with fire. LOLHe fixed that and the charger is connected to the BMS. See the photo above on this same page...lol.
Heck, I have no idea exactly what he is doing other than possibly playing with fire. LOLHe fixed that and the charger is connected to the BMS. See the photo above on this same page...lol.
I really think you should try.I dont think thats the cause as it charged fine up till a certain point. The bms is turning the chg mos on and off
It could also be a bad connection, what does the BMS say? Is it turning off charging? Is it hitting high cell voltage disconnect?I dont think thats the cause as it charged fine up till a certain point. The bms is turning the chg mos on and off
As already stated, the bms is turning off charging. The chg mos light turns on and offIt could also be a bad connection, what does the BMS say? Is it turning off charging? Is it hitting high cell voltage disconnect?
Not sure what your comment is attempting to point out? The opening post clearly points out what I am trying to do which is charge the battery in series using my PSU. If you cant help someone in need, dont bother commenting.Heck, I have no idea exactly what he is doing other than possibly playing with fire. LOL
Then you might examine cell high voltage disconnect settings. The BMS is likely disabling charging due to the settings telling it to.As already stated, the bms is turning off charging. The chg mos light turns on and off
The reason Im doubtful that its the connections is that the clamp meter matches the amps of the PSU
further, the connections charge fine up to a certain point and then the chg mos does this turning on and off again
I looked at the settings of your BMS and they all look good to me. I may have missed it but have you checked the cell voltages with a DMM to verify they match the voltages displayed by the BMS? I am leaning towards a defective BMS based on the information you have provided so far. The BMS should cut off when the voltage of the highest cell reaches 3.650 volts. Apparently it's not working properly.As already stated, the bms is turning off charging. The chg mos light turns on and off
The reason Im doubtful that its the connections is that the clamp meter matches the amps of the PSU
further, the connections charge fine up to a certain point and then the chg mos does this turning on and off again
The thing is it's always a good idea to test the LVD and HVD of the BMS. He needs to check the voltages at the cell terminals to see if they match the voltages of the BMS. You are right, one cell could be hitting 3.65 volts causing the HVD. But the voltages of the BMS do not show any cells at 3.65 volts.Maybe I'm missing something, but it looks to me like he must have one cell that is hitting 3.65V and causing the BMS to do a HVD. When charging at a lower voltage it seems fine, but the BMS shuts off charging at the higher voltage.
I think several people in this thread have attempted to tell him he doesn't need to charge at that high of a voltage, but he doesn't seem to be reading those comments.
Hey @Gazoo - Bad on me if I missed it, but where did you see that no cells were at 3.65V? He posted a couple of screen shots from the app, but the only thing I could see was a "Cell Characteristics" page, which I took to be where you setup the app for what each cell is like. He didn't show us any page that showed the voltage of all the cells (specifically when the charging was cut off), did he?But the voltages of the BMS do not show any cells at 3.65 volts.
The 13.7v measures to 3.425v per cell. The difference between 3.425v per cell and 3.65v per cell is LESS than an amp hour. Your BMS is turning off charging to protect your cells. You might want to check cell voltages with your meter, if all cells are around 3.4v, you are 100% full, and might want to take the hint your BMS is giving you.I fixed this
i already fixed this as per the other posts after I realised it myself.
the problem is still persisting after changing the psu to 5 amps instead. It jumps between 13.7V and 4.95 amps TO 14.49 and 0 ampsUnsure what to do. Any other suggestions? Photos attached for values, changes every 5 seconds
Cell voltages are displayed at the bottom of this screenshot:Hey @Gazoo - Bad on me if I missed it, but where did you see that no cells were at 3.65V? He posted a couple of screen shots from the app, but the only thing I could see was a "Cell Characteristics" page, which I took to be where you setup the app for what each cell is like. He didn't show us any page that showed the voltage of all the cells (specifically when the charging was cut off), did he?
But the BMS HVD is set to 3.65 volts? Why is the HVD kicking in at a lower voltage. I never had this problem with my Overkill BMS.You might want to check cell voltages with your meter, if all cells are around 3.4v, you are 100% full, and might want to take the hint your BMS is giving you.
He said you are playing with fire because you are trying very hard to charge above 3.4v per cell. Take it or leave it, seems a helpful comment to me if you understand what it means.Not sure what your comment is attempting to point out? The opening post clearly points out what I am trying to do which is charge the battery in series using my PSU. If you cant help someone in need, dont bother commenting.
Yes, but he also showed later (without showing cell voltages) a pack voltage while it was charging above 3.4v per cell. I suspect he may have a bad busbar connection that makes it appear as if one cell shoots up causing disconnect, then immediately drops when current is stopped. Even with good connections, trying to charge when average cell voltage is 3.4675v (13.87 divided by 4) is going to trigger the BMS within minutes. Just sounds like a bad idea, to me anyway. Even with good top balancing, one of those cells is likely hitting high voltage disconnect.But the BMS HVD is set to 3.65 volts? Why is the HVD kicking in at a lower voltage. I never had this problem with my Overkill BMS.
Yeah, actually that makes sense. That why we have been asking him to measure the voltage at the cell terminals. Doing so would give everyone a much better idea of what's going on.I suspect he may have a bad busbar connection that makes it appear as if one cell shoots up causing disconnect, then immediately drops when current is stopped.
My BMS cuts off when the highest cell reaches 3.65 volts. And disconnects when the lowest cell is 2.50 volts.Even with good connections, trying to charge when average cell voltage is 3.4675v (13.87 divided by 4) is going to trigger the BMS within minutes. Just sounds like a bad idea, to me anyway.
I wasn't commenting to you, just making a side joke as you made a mistake that could have been costly. But I'll offer some help.Not sure what your comment is attempting to point out? The opening post clearly points out what I am trying to do which is charge the battery in series using my PSU. If you cant help someone in need, dont bother commenting.
Not sure how you came to the conclusion that my cell is at 3.650V? They are all roughly 3.4V with the multimeter, as reflected accurately in the BMS app.I looked at the settings of your BMS and they all look good to me. I may have missed it but have you checked the cell voltages with a DMM to verify they match the voltages displayed by the BMS? I am leaning towards a defective BMS based on the information you have provided so far. The BMS should cut off when the voltage of the highest cell reaches 3.650 volts. Apparently it's not working properly.
DMM reads 3.4V when I last checked and was charging. I think I outlined all of this information in the opening post but maybe I'm wrong.Maybe I'm missing something, but it looks to me like he must have one cell that is hitting 3.65V and causing the BMS to do a HVD. When charging at a lower voltage it seems fine, but the BMS shuts off charging at the higher voltage.
I think several people in this thread have attempted to tell him he doesn't need to charge at that high of a voltage, but he doesn't seem to be reading those comments.
OK! Excellent post John. So 3.4V is full? I did notice the comments where people where suggesting to charge to 3.4V, but was unsure as most threads Ive seen say to charge to 14.6V/3.65V.The 13.7v measures to 3.425v per cell. The difference between 3.425v per cell and 3.65v per cell is LESS than an amp hour. Your BMS is turning off charging to protect your cells. You might want to check cell voltages with your meter, if all cells are around 3.4v, you are 100% full, and might want to take the hint your BMS is giving you.
Unless you are using really bad cables to charge with, you can set the power supply to 13.6v and wait until current going in is less than an amp. That will give you 99% capacity.
People only use higher voltages to charge with because they are impatient, with good quality cables and connections the current will drop once you hit 13.4 or 13.5v.
Thank you. It appears people are skipping ahead to comment without actually reading the information I've provided.Cell voltages are displayed at the bottom of this screenshot:
Thanks John. Was completely unaware that charging above that voltage was not recommended as every video and post I have seen so far advice to charge to 3.6V at least.He said you are playing with fire because you are trying very hard to charge above 3.4v per cell. Take it or leave it, seems a helpful comment to me if you understand what it means.
Thanks Zwy.I wasn't commenting to you, just making a side joke as you made a mistake that could have been costly. But I'll offer some help.
First thing is did you ever top balance the cells in parallel?
Second, before installing busbars, were the terminals cleaned?
Third, did you capacity test the pack after top balancing?
Fourth, have you put the pack under load after the attempted charging and pull it down until one cell hits 2.5V?
Fifth, why do you need to charge until charging cell voltage cut out at 3.65V?
I never said any of your cells voltages were 3.65 volts. I said:Not sure how you came to the conclusion that my cell is at 3.650V? They are all roughly 3.4V with the multimeter, as reflected accurately in the BMS app.
You are welcome. The only thing I wasn't sure of was if the voltages at your cell terminals were matching the voltages displayed by the BMS's app. You have now confirmed they are the same.Thank you. It appears people are skipping ahead to comment without actually reading the information I've provided.
For longevity of the cells it's good to keep the cells between the knees. Charging to 3.65 and discharging to 2.50 will still give you at least 2000 cycles. Damage can happen if the cell is held at a high voltage.Thanks John. Was completely unaware that charging above that voltage was not recommended as every video and post I have seen so far advice to charge to 3.6V at least.