Battery Charging times?

You need the capacity rating of the battery pack in mA and then divide the battery's capacity (say 600mA for example) by the charge rate (200mA). Using the example above you're looking at 3.0 hours for a full charge. I'd try to find the battery part number and look it up on Tower Hobbies website

Of course you could blow $50 on a charger that will charge automatically if you don't want to guess............................

You can test the voltage of the pack with a DMM to get a rough idea how full or empty it is, but this is rudimentary at best, as an 80% charged pack will still read full voltage.

Doc

all your questions answered at:

The math skills are ok, BUT You have to also account for the fact that there are significant losses in the recharging process. quick and dirty, you usually have to charge about 150% of what you took out to come out approximately even.

| You have to also account for the fact that there are significant | losses in the recharging process. quick and dirty, you usually have | to charge about 150% of what you took out to come out approximately | even.

The losses are generally a good deal smaller than that. Though in the case of a very slow (C/10 or so) charger, you're also dealing with self discharge of the battery, especially with a NiMH cell. (With a faster charge, the self discharge rate can probably be ignored.)

In the case of a 1C charge rate, it seems like you need to put about

The real energy loss happens in the voltage difference -- you may charge your 8 cell NiCd pack with about 12 volts, but while you're discharging it you'll get around 9.5-10.5 volts for most of your discharge period. The difference goes into heat, both during charge and discharge. The difference gets larger and larger as your charge and discharge rates increase.

Though for a formative charge on a brand new NiCd/NiMH cell, putting in about 140% of the rated mAh capacity seems about right. But you don't need to do this every time, unless you're using a slow charger.

Ok, I stand corrected, ;-)

Any idea what the loss ratio is on the Li-Poly cells?

you need to know the capacity of the pack, that is maH. THAT is what determines what rate you can charge it at.