Best damn balance charger I ever had

[BrianG]

I agree with Arct1k; most balance wires/connectors are good for around 1.5-2A max. The wire size and connector type have relatively high resistance due to their size, so when you start pumping higher currents through them, you get more voltage drop across the wires/connectors. This would cause the charger to think the cells are at a lower voltage than they really are and could overcharge them as a result.

However, this type of charger is a really good idea IMO, but only if the wires where changed to something like 18GA and then a use different higher-current connector.

[zeropointbug]

Originally Posted by BrianG

I agree with Arct1k; most balance wires/connectors are good for around 1.5-2A max. The wire size and connector type have relatively high resistance due to their size, so when you start pumping higher currents through them, you get more voltage drop across the wires/connectors. This would cause the charger to think the cells are at a lower voltage than they really are and could overcharge them as a result.

However, this type of charger is a really good idea IMO, but only if the wires where changed to something like 18GA and then a use different higher-current connector.

Brian, unless I'm just tired right now, having the charger recharge the pack through the balance leads would read a HIGHER that actual voltage, then you would have a skewed CV phase than normal, but in the end the voltage of each cell would be spot on the money as current tapers off.

[zeropointbug]

BTW, where did you buy this charger Mister?

[A RC Dude]

Originally Posted by zeropointbug

Brian, unless I'm just tired right now, having the charger recharge the pack through the balance leads would read a HIGHER that actual voltage, then you would have a skewed CV phase than normal, but in the end the voltage of each cell would be spot on the money as current tapers off.

Actually, wouldn't the fact that the battery has the same wire and connection on both sides of the circuit make the resistance the same in front and behind the charger making the voltage read lower and lower when the internal resistance of the charger goes closer to zero (aka a high rate of charge)? In a since it's making a voltage divider circuit.



In this case the outer 2 resistances are the connectors/wires and the middle is the charger. But in all honesty, I doubt the wires have enough resistance to really matter enough considering that Lipo batteries can actually go slightly over 4.2v per cell. They just cut it at 4.2 for safety and most chargers are programed to read a just slightly higher voltage than actual so in production, the resistor values put in it don't have to be super extreme tolerances to still be safe.

Just my two cents and theory from what little electrical engineering know how I have.

[zeropointbug]

I'm not sure what you are trying to say. But I mentioned this before... say for instance you charge the cells at maximum 8amp, it's charging, it's charging, then nearing 4.2 volts, the charger would 'see' 4.2 volts, but the potential at the cell would be more like say, 4.17 volts, this is because of the losses in the small balance wire. Now, the current begins to fall, and as it's falling, the 'voltage losses' in the length of wire becomes less and less, so for example once it drops to 4 amps, the charger still 'sees' 4.2 volts, but now the cell is sitting at around 4.185 volts. This will continue until it approaches fully charged and the current drops to such a level where the charger voltage and cell voltage are indistinguishable, as the voltage losses are so minute.