I figure I post this here:

I thought I'd post this after discovering one of my LiPo chargers (a 'freebie' one) was the bad type. It's called a 'parkzone 2-3 cell balancing lipo charger' and it comes with some of their planes.

As background, there are three basic types of balancers.

1) The worst type, the 'cutoff' type, is often built into low-cost chargers, simply monitors the voltage on each cell as the charging is taking place. If any cell voltage goes above 4.2V, it stops the charge immediately. If not built into a charger, this type will sound an alarm or some other means to indicate the charging process should be halted immediately.

While this gaurantees you will never overcharge a LiPo, it doesn't do much else. If a cell is out of balance, you will lose useful capacity, and the Low-Voltage-Cutoff might not kick in soon enough as you are using the cell.

2) The next best type, the 'clamp' type, works like an electronic voltage clamp, drawing no current below 4.2V while drawing some current as soon as the voltage rises above 4.2V. Typically this has a light, buzzer, or some other device on it so that you can know when it is 'clamping'. The amount of current drawn is typically small, ie. 100mA, a blinking light means the device is working normally while a solid or non-blinking light means the device is being overpowered and you should lower the charge rate to it's maximum clamping current. This type typically only functions at the end of a charge, ie. during the Constant-Voltage portion and care should be taken to ensure it is not 'overpowered' at this point.

3) The best type is a true cell equalizer that will equalize cell voltages by discharging from any cell that is a certain threshold above the others. Since this type works throughout the charge, it will rarely get 'overpowered' and you will rarely need to lower the charge current.

In general, the only type to worry about is (1). The clamp type works fine in nearly all cases, and the equalizing type is generally unnecessary but still nice to have if you can find one.

The lesson is to not assume a charger is doing the job just b'cos it claims to be a 'balancing' charger or it charges through the balancing plug. If a charger indicates your batteries are fully charged or stops the charge prematurely (compared to another charger), this is one indication it might be the 'bad' type. One sure way to find out if it's doing it's job is to take a voltmeter and measure each individual cell voltage of a fully charged cell. If each cell voltage is very close to 4.2V, you're fine. If one is above 4.23V or less than around 4.15V, it's probably the bad type.

Example:

a) 4.15V, 4.18V, 4.16V -> This is probably fine if the cell was charged a day or two ago.
b) 4.23V, 4.20V, 4.17V -> This if fine, 4.23V is where some clamp-type balancers start to switch on.
c) 4.30V, 4.20V, 4.10V -> Whatever charged this cell is probably not using any balancing at all.
d) 4.23V, 4.17V, 4.03V -> The charger is using 'cutoff' balancing and should genenerally be avoided!

Again, case (d) is bad b'cos you will lose capacity, and Low-Voltage-Cutoff may kick in too late.
By the time the cell is 'fully' discharged, 9V, the individual cell voltages might be something like:
3.2V, 3.1V, 2.8V

And the cells are likely to get even more and more out of balance as time goes on.

If anyone wants I can post some pics of the 'cutoff' balancing charger and a clamp-type balancer.

As cheap ($25.), 'freebie', or 'kit' LiPo chargers become more and more common, it's likely 'cutoff' type balancing will become more and more common, so be aware and don't assume anything.

Source: http://www.rcuniverse.com/forum/m_8287688/tm.htm

Now does the Thunder Power 610C do all this mentioned? Druss? Anyone?