I have 2 lipo 3s 5000mah batteries and I want to connect them together in parallel to produce a voltage of 12.6v and 10000mah, then I will charge them through a type C 3s charger circuit with a charging voltage of about 13v.
Besides, I need to ensure the health of each battery, so I decided to use an active balancing circuit to balance the voltage in the battery cells through balancing connectors, It basically is a type of battery management system that uses energy transfer to balance cells in a battery pack.
So, what I want to know before testing is is this connection really safe? Is it necessary to use 2 lipo 3s active balancing circuits on each 3s battery? Or just need a single active balance circuit and connect each battery cell in parallel via the balance connectors on both batteries?

 

Welcome to AAC.

You could do it either way, it will be faster to balance with two balancers, but more accurate for paralleling with one. What concerns me is the lack of comms between balancers and charger. What slows the charge rate down as the balancers do their work? Can you post links to both devices?

 

Batteries in parallel always stay balanced, assuming the wiring between them is adequate.

 

Cells in parallel will, but the TS isn't planning to connect them together at the cell level, except during balancing. Anyway,IMHO, the balancing wires aren't heavy enough to run the cells together.

 

Welcome to AAC.

You could do it either way, it will be faster to balance with two balancers, but more accurate for paralleling with one. What concerns me is the lack of comms between balancers and charger. What slows the charge rate down as the balancers do their work? Can you post links to both devices?

Thanks for your comment, but I want to know what is the specific solution to this problem, below is the information I have about the 2 devices I am using

 

 

Basically, it would look like this when I just used one active balance circuit on both of my 3s lipo batteries with each cell on each battery connected in parallel.
Which method can I use? Is it enough to use 1 active balance for all or just one for all parallel connections or is another solution better for this? Will these connections lead to voltage spikes or anything that could damage my batteries?

 

The single balancer will work. Not sure about 'goodness' of the charger, can't find much detail on it - no info on what chips it uses - can you read them? The concern I have is the charge rate on the upper cell as the balancer goes into action... it will push charge up from the lowest cell to the top one, which could already be receiving 2 or 3A from the charger (what size charger did you get?) Also a charger without thermal monitoring is potentially a risk as you have no idea if the cells are overheating or not. Some would argue that a 1A charge rate on a 5Ah cell is not critical, but with balancing it could be 2A+. What's the C rating of the cells? Also what what ESC is that, what's your expected loading on the cells?

 

First, for the charging circuit, I can see the current parameters from the place of sale
- Input current: 2A
- Charging current: 0.74A
about active balance
- Adjacent battery cell voltage difference > 0.1V (current about 0.5-0.7A)
- Adjacent battery cell voltage difference > 0.2V (maximum balance current 1.2A)
With each 3s 5000mA lipo battery, I get 25C, and I need to provide a maximum discharge current to my Quadcopter which is about 80A through a 4in1 45A ESC