Don't forget to check the individual cell voltages before you put them in parallel to further equalize them. I used my 4x10A lab supply and a 400W electronic load. Cycling 16 40Ah cells took ages. 280Ah will take eras 🙂
What difference would the invidual cell voltage make if I'm going to equalize them anyway? My idea is to put them in series, have them equalize between themselves a bit and the charge to like 85% to 90% of the way, lots more watts like that. The disconnect everything, put it in parallel and then top balance them all. At that point, everything should be in the same state. Once in series again with BMS and load, any outliers would pretty quickly become apparent I think. I am doing individual tests right now, but that's more for the videos, so we'll see more about it in the future!
@@IntermitTech Well, when charged in series (even with an balancer) the cell voltages may (still) differ, and when next connected in parallel a large equalization current may flow. Best to check that the difference between the lowest and highest cell voltage is no more than 20mV or so. Keep in mind these large 280Ah cells can easily provide several kA.
Ah like that, yes Thnx, that's a good reminder! That I do understand though and I don't except them to differ too much if I let them equalize a little bit after charging and use thick busbars to minimize any voltage drop. I have also planned a pre-charge resistor between the battery and inverters, maybe it could be useful here too if one of the cells is really out of balance.
How do you mean exactly? In theory if you connect 2 sells in parallel the higher voltage one will charge the lower voltage one and in the end balance out.
@@IntermitTech I think I worded my original comment poorly. What I mean is that you’re powering the charger/discharge from the wall then burning off 280ah to heat. Instead of losing the 280ah to heat on the discharge test, it would be cool if transfer that energy into discharged cells. Of course there would be losses.
What some people on the internet do, guys and girls, is use a complete batterypack for that. But that's the chicken and the egg:-) So, one 48v 16S pack, inverter and then the ZKE to charge each cell. Andries, as it looks like, you have enough cells for 6 batteries. (all for your self?;-) I suppose measure 16 cells, create one pack and use those + the inverter and ZKE to measure the next 16 cells. Build a pack with those -and because they are fully charged, charge the next 16 cells, etc. Afterwards you know all characteristics of each cell and can rearange the cells to create 6 optimal packs.
Nice setup, many things to do and I will follow up
Thanks
I am addicted to these.
HaHaHa...... damn you.... you got me!!! Loved the unboxing
Je kijkt (ook) teveel naar Andy van de offgrid garage 'from 🌞 hot Australia' 🐸
Hahaha, zeker! Maar zoals gezegd, ik heb al redelijk wat ervaring met ZKETECH apperatuur en tot nu toe bevallen die ook prima!
Die is ook erg leuk, gave vent
Andy ♥️
impressive device though! thank you for sharing, and please make the video on topic the data acqisition of this charger-load.
Don't forget to check the individual cell voltages before you put them in parallel to further equalize them.
I used my 4x10A lab supply and a 400W electronic load. Cycling 16 40Ah cells took ages. 280Ah will take eras 🙂
What difference would the invidual cell voltage make if I'm going to equalize them anyway?
My idea is to put them in series, have them equalize between themselves a bit and the charge to like 85% to 90% of the way, lots more watts like that.
The disconnect everything, put it in parallel and then top balance them all. At that point, everything should be in the same state.
Once in series again with BMS and load, any outliers would pretty quickly become apparent I think.
I am doing individual tests right now, but that's more for the videos, so we'll see more about it in the future!
@@IntermitTech Well, when charged in series (even with an balancer) the cell voltages may (still) differ, and when next connected in parallel a large equalization current may flow. Best to check that the difference between the lowest and highest cell voltage is no more than 20mV or so. Keep in mind these large 280Ah cells can easily provide several kA.
Ah like that, yes Thnx, that's a good reminder! That I do understand though and I don't except them to differ too much if I let them equalize a little bit after charging and use thick busbars to minimize any voltage drop.
I have also planned a pre-charge resistor between the battery and inverters, maybe it could be useful here too if one of the cells is really out of balance.
Would be really cool if you could “close the loop” and charge low cells with full cells.
How do you mean exactly? In theory if you connect 2 sells in parallel the higher voltage one will charge the lower voltage one and in the end balance out.
@@IntermitTech I think I worded my original comment poorly. What I mean is that you’re powering the charger/discharge from the wall then burning off 280ah to heat. Instead of losing the 280ah to heat on the discharge test, it would be cool if transfer that energy into discharged cells. Of course there would be losses.
What some people on the internet do, guys and girls, is use a complete batterypack for that.
But that's the chicken and the egg:-)
So, one 48v 16S pack, inverter and then the ZKE to charge each cell.
Andries, as it looks like, you have enough cells for 6 batteries. (all for your self?;-)
I suppose measure 16 cells, create one pack and use those + the inverter and ZKE to measure the next 16 cells. Build a pack with those -and because they are fully charged, charge the next 16 cells, etc.
Afterwards you know all characteristics of each cell and can rearange the cells to create 6 optimal packs.
Would be nice to see you unbox every single one of those boxes, even if they're all the same!
seriously. lol