BC6DX-II for MCPX batteries...parallel charge ?

[mixfisto]

Hey all, I just bought this Bantam Charger and before I do anything stupid, I wanted some help

I have spent a lot of time reading up on parallel charging, etc, but as I was about to start my first charge, I realized I don't quite "get it" just yet.

What I want to do is:
- parallel charge 5 300mah Nano-techs at the same time (for my stock MCPX) and
- parallel charge 6 550mah Hyperions at the same time (for my BL MCPX)

Could anyone give me some settings or advice? I'd like to charge these as fast as it safely doable!

I would highly appreciate it

[dtabuenc]

It's really not difficult. I assume you have a parallel charge cable already? All you do is plug the cable to the charger plug all the batteries you want to the cable and then add up the mah. You can mix capacities no problem. The only thing you want to make sure is that they are around the same state of charge/voltage (don't try charging a fully charged battery with an empty one).

For example you could hook up all 6 of your 550mah batteries. Then you would multiply 6*550 = 3300. So for charging at 1C you would charge at 3.3 amps. If you want 2C it would be 6.6.

You could easily mix the 300mah batteries with the 550s. That's not a problem. For example if you charge 3 300mah and 3 550mah just add it all up (3*300+3*550) = 2550 so you would charge at 2.55 amps.

There's nothing to it. Just be careful when you are plugin in the batteries that you get the polarity right. Never plug in the batteries if the cable is not plugged in to the charger (the connectors could touch and sparks would fly.

[mixfisto]

Thanks dtabuenc, just saw this!

I think one of the most confusing things about getting into elect heli's is the charging... but like all things, after awhile you figure things out, move on, and find new problems to conquer

[petertha]

Dumb question, but for people like myself who already have a 6S capable Bantam charger & want to charge/discharge a batch of say 6 MCPX type 1C cells.. why is there no harness available that plugs into the charger side like a standard Bantam balancing board, but has & 6 individual lipo plug adapters for each cell to be charged? Kind of like these but with a charger balance plug vs 4mm banana input.

http://www.aircraft-world.com/shopexd.asp?id=6943

http://www.hobbyking.com/hobbycity/s...dProduct=18867

Would this not do a better job of sensing different cell voltage states like a multi-S pack & presumably charge/discharge safer/faster/more consistent over the paralell method that treats it as one pseudo cell?

[dtabuenc]

It wouldn't really do a much better job. When hooking up many cells in parallel they essentially self-balance. The charger sees an average voltage back from all the cells and calculates how much voltage it needs to apply to send the total current you programmed your charger to charge at.

Once that voltage is applied, each cell will consume different amounts of current depending on the state of charge. Cells that are slightly lower voltage will charge faster, cells that are slightly higher voltage will charge slower. Fairly soon, all cells will be balanced at the same voltage since the faster-charging lower-voltage cells catch up with the slower-charging higher-voltage cells.

Once they are all the same, they will remain balanced throughout the charging process. If one cell starts to get higher voltage it will slow down automatically, and if one cell falls behind it will speed up automatically.

There is no need for special balancing logic. The reason why a balance board and logic is needed when charging a multi-cell battery is because you can never really disconnect the individual cells to charge them in parallel (which would be the ideal). Instead, the balance connector taps into the joints between each cell and manipulates the voltages to control the current and voltages charging each cell.

The only concern with parallel charging is that the cells are not TOO far apart in voltage. You don't want to charge a fully charged pack along side an empty one because the empty one would get all the current in an attempt to "catch-up" with the full one and so might exceed it's charge current "C" rating. You don't have to bee perfectly close though. I charge 3.75Volt cells with 3.90 volt cells all the time. They equalize fairly quickly and the currents involved are not high enough or for long enough duration to affect anything.

Originally Posted by petertha

Dumb question, but for people like myself who already have a 6S capable Bantam charger & want to charge/discharge a batch of say 6 MCPX type 1C cells.. why is there no harness available that plugs into the charger side like a standard Bantam balancing board, but has & 6 individual lipo plug adapters for each cell to be charged? Kind of like these but with a charger balance plug vs 4mm banana input.

http://www.aircraft-world.com/shopexd.asp?id=6943

http://www.hobbyking.com/hobbycity/s...dProduct=18867

Would this not do a better job of sensing different cell voltage states like a multi-S pack & presumably charge/discharge safer/faster/more consistent over the paralell method that treats it as one pseudo cell?