Balance adapter 3x 2s - 6s?

[BrianG]

Originally Posted by lincpimp

I am still not sure how the balancer reads the individual cells voltage in order to match them. I am sure that is is a simple circuit, but having trouble visualizing it..

Most balancers I've seen aren't using isolated inputs for each cell, so I imagine they simply measure each wire referenced to ground. For example, to get cell 3 on a 4s pack, it probably subtracts the voltage on cells 1 and 2 from the voltage on cell 3 to ground. There really isn't much to a balancer. Most of the resistors on it are used to apply a load to any high cells. All of the measurement and logic must be done via a PIC or something.

Originally Posted by lincpimp

Not sure how to explain this but how does the balancer know the voltage of the 3rd cell(1st one in the 2nd pack) as it appears that not using the red wire on the 2nd pack would eliminate the ability to measure across the pos and neg of that cell, the purple circle in the attached pic.

I know exactly what you mean, but let's see if I can explain it.

A pack's main black wire is electrically the same point as the most negative balancer wire.

A pack's main red wire is electrically the same point as the red balancer wire.

I think we can both agree on those two points, right?

When you use a Y cable jumper on the main power leads, you are effectively tying the most negative cell on pack1 to the most positive cell on pack2.

[lincpimp]

BrianG "Most balancers I've seen aren't using isolated inputs for each cell, so I imagine they simply measure each wire referenced to ground. For example, to get cell 3 on a 4s pack, it probably subtracts the voltage on cells 1 and 2 from the voltage on cell 3 to ground. There really isn't much to a balancer. Most of the resistors on it are used to apply a load to any high cells. All of the measurement and logic must be done via a PIC or something."


Ok, this makes sense. I was not sure if it measured individually or did somesort of subtraction. By leaving out the pos wires of the 2nd and 3rd pack I was having trouble inagining the circuit being complete to measure the cells seperately. However if the balancer subtracts tem to determine the voltage differences your wiring diagram makes sense. Thanks, now I can charge and balance my 2s 5000 packs as if they were a 4s pack, which is how I will use them. I just want to have all 4 cells balanced to each other.

[nativepaul]

Thanks very much for taking the time to knock that up for me Brian, it is as I suspected from your 2x 3s diagram, just remove the red wire and plug the blacks into the next slots but I wanted to be sure.

I use bullet connectors so I will be plugging the cells directly into each other to series them rather than using a main power harness and ziptieing them to the balancer harness, electrically this seems to be the same can you see any problems doing it this way (assuming I mark the balance plugs so they go into the right pack)?

[nativepaul]

Thanks again Brian, I made up the adapter this morning and just tested it out, it worked fine and after 5-10 mins my 3 new 2s packs where balanced together.

I also tried to balance my buggy's 4s flightpower 4350 pack for the first time, but the balancer switched itself off right after I plugged it in, after about 50 runs in the buggy and charging on my cheap Apache 2500 at 2.5Amps no balancing was needed at all, Flightpower rock!

Unfortunately my 1210/LBA10 combo didn't come with the dataport cable that it was supposed to Does anyone know the wiring layout of this? it looks like it uses standard Futaba servo plugs at both ends, is that right? I hope to get charging with my new combo before I receive the dataport cable in the post which will probably be weds or thurs if they get my E-Mail on Monday.