zb in parallel.

Well,

For faster capacity testing the whole pack i bought this one a while ago.
https://www.aliexpress.com/item/32883863452.html?spm=a2g0s.9042311.0.0.27424c4diPQNck


I does have a set v cut off, it gives a warning signal, when it reached your setting, but does not stop discharging
Its not accurate enough to get the capacity.
But oke.

I connected 3zb2l3 in parallel to discharge.
The first one in line hasa resistor of 5.6 ohm.
The other two have two parallel resistor(2x5.6 ohm)
When i connect them to the batteries for a discharge, they all discharge at ~1A.
Started them right after each other.
I would expect that the one with just one resistor, would discharge at 600ma.

When i set up everything again, and this time i only use the the one with one resistor, he does ~300ma.
Wait 10 seconds:
Set up the second one with two resistors, he does 600ma?!?!?!?
wait 10 seconds:
when i want the third one, it goes into overload/not properly wired?(error 5).

Can this be a proper way to measure capacity, for a whole pack?


Thanks in advance

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I was also wondering recently if using multiple testers in parallel to test completed packs would work.
Would there be any problem with the power supply to the testers being from the same source?

No, you won't have any problem with your psu.
I had 30 zb's running and they consumed a total of 0.8ah.
With charging its a different story

For my testing i have now 5 zb's running with each 3 resistors (paralel)connected to it.
I have a steady 2.1a discharge per zb. AND a cut off at my set voltage.
I am going to change the resistors to scramble up the falue's.
I have a suspicion that they will connect as one big resistor.
If that is the case then, i will order a large 2 ohm 100w resistor and just connect 5 or 10 zb to it.
The zb's can handle 3A max.
I would like to know the total capacity from a pack before i am going to build my wall, so i can adapt before plugging them in.

If i add one resistor the total discharge goes up.
Apparently this works very good.
Oke you must count up all the numbers, but you get a good idea of the total capacity in the whole pack.

I think i found myself a easy way, to figure out the total capacity of a pack.
Also for maintenance it will come in handy.
But can those numbers be trusted?

Thanks

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I soldered some resistors parallel to a board, to add up the numbers.
Every zb has two 5,6 ohm 5w and two 6.8 5w ohm resistors in parallel.
They act like ~6.2 ohm at 20w? right?
I gives me a average of 2.7a discharge, nice, BUT

Question number one:

When one zb is done the discharge goes down.
If 4 out of 5 are done the last one will discharge at 900mA
They act like they are in serial?
If i add, no matter on which parallel string, an extra resistor, (for example: 4,7 ohm)all five go up in discharge with 100-150mA
Every parallel string is connected to one zb, and are on the board not connected to each other.
How can i prevent this?
Adding a diode will give more resistance cous the diode's must have extra v to work?

Question number two:

Is it possible to connect one large 5.2 ohm 100w resistor to all of the zb's?
I was calculating with ohms law and clearly i got the numbers or calculations wrong: 22 ohm at 25w
Or can i buy 5 25w 5.2 ohm resistors?
I don't like the chaotic look of the soldering board, and yes there is a ventilator on it.

Other solutions?

Thanks in advance