I am so sorry to ask this stupid question, I have been googling for hours I can't find the answer I hope people in here are friendly enough to answer.

I have a 7.2V battery pack (6 batteries) in total, each one of them has different voltages, some at 1.2V, 1.1V, 0.6V, 0.011V, etc.

I found some schematic on how to build a cycler, it has two terminals + and - to insert the battery pack

Am I suppose to insert the 7.2V battery pack to a cycler and then each one of the battery will go to 1.1V?

How is the cycler going to know the voltage of each one when the battery pack is in series???

Please help

G'day Mate,
You will have to charge the pack first, then cycle, also known as discharge, the battery pack.
The cycle looks at the pack voltage, as it decreases, & stops discharging when it reaches, in your case 6.6 volts.
If you have all good cells it will take a certain time, to discharge the pack.
As an example, if it is a 1000Ma pack & you discharge it at 500Ma, it should take 2 hours to discharge, if all cells are good, it it takes 1 hour, then you have one or more cells that are at less than full capacity.
So charge again & then discharge, if at the same discharge rate, they take longer to discharge then they are getting better, if the don't get better, they are possible stuffed.
That is basically what a cycler does. It puts the pack through a charge then a discharge cycle.

A battery cycler is nothing but a load that discharges your battery to a certain cutoff voltage and measures the amp hours or milliamp hours of capacity. It is mostly used to test battery packs to see if they are still good.

It doesn't know. It only assumes each cell is at 1.1 when the voltage of a six cell battery is 6.6 volts. A bad cell will show up as a low milliamp hour reading for the battery. For example let's say you have a 1200 mAh six cell pack and one of the cells goes to 0.6 after only 500 mah of discharge while the other 5 are still at 1.2 volts. This gives a battery total of 6.6 volts and the cycler cuts off after only 500 mah of discharge.

It's just a handy to have diagnostic tool, it doesn't repair bad batteries and I wouldn't over cycle them either. If it's a power pack for an electric plane, the plane will let you know when the battery is no longer good. Cyclers are mostly used to see if reciever and tx packs for gas planes are still safe to use. That's why most of them are designed to check 4.8 volt (RX) and 9.6 volt (TX) batteries.

Wait a second.
From what you have shown, you have a few bad or questionable cells.
The cells that are 0.9 volts or higher should be fine. The others are suspect.
The one that is 0.011 volts may be dead.
You can try a cycler, but I would just purchase a new pack.

BLE has it almost correct.. well, half correct. CYCLE means to go around in a cycle or a circle. Discharge then charge. If it only discharges, then it's a discharger. If it only charges, well, I guess you would call it a charger, right? A cycler will discharge THEN recharge appropriately.

There are several commercial cyclers on the market that will help you with this little project. The batteries in a pack are connected as a pack by the manufacturer and are usually 'sealed' in a form of shrink wrap. Then they are treated as a pack not as an individual battery.

Cyclers 'look' at the condition of the pack by discharging them to a preset level then re-charging them. They usually (often) have some sort of digital display that shows how much amperage was removed when discharging. Then they repeat the process after the battery pack has fully charged.. which will cycle down to a set point, display this amperage, then recharge to the set charge, depending on the number of cells attached and the type of batteries in use. Repeated cycling usually, often, will restore a questionable battery pack to normal. Battery packs with bad batteries are just thrown away, they you buy a new battery pack. They are cheap enough that you can do that. It is not worth it to keep a questionable pack just for the sake of a few dollars. It can cost you a lot more in destroyed aircraft and any damage they may do when crashing.