Alberto, you can connect as many same S batteries in parallel as you like.
Voltage will be the same as a single cell and capacity will be the sum of all. To connect 3 cells you can simply use 2 of this product. The thing is 3 cells plus 2 harnesses will probably be more expensive than one bigger cell. Also the wiring might heat under full C.
Ok thanks, I understood, one thing* doesn't matter that I put a 3000ma battery with an other of 5000ma? If the 3000 battery goes empty before the 5000, it will have any damage or something? Because the 3000 one is going to continue discharging until the one of 5000 goes empty?
Hooking batteries in Parallel will not change the Voltage. Series is when the voltage is changed. You should make sure that the batteries are of the same mAh and cell value though. What the Parallel does is double the mAh rating. So if you connect two 3s 1300mAh batteries in Parallel you will end up with 11.1V and 2600mAh. I hope this helps.
To be picky, it does not double the capacity but add the capacity of the connected batteries to each other. I used one 2800 and one 1300 mah to get 4100 for example. My bixler barely took off with it but it gave me about 20 min flight time anyway.
That's true, I was incorrect in saying that the two batteries have to have the same mAh rating. They just have to have the same voltage or number of cells. Series connection needs to have the same mAh rating. Thank you Martin.
Technically when you plug two 2200 in parallel, the total capacity is 4400 and should provide more flight time. Having said that, your setup is another factor (weight, motor, props) because your plane will have to carry the extra load. The benefits may be just a few to many minutes extra.
I use it to charge two batteries in parallel 3S 2650mAh. My charger does not support simultaneous charging. It is necessary to let the two batteries to inner balance and allow both have the same voltage before starting the charging process.