| > I'm really more of a spectator in this thread, but since James Beck
| > has pointed out that his designs are used in millions of chargers (?)
| > out there, I think that's worth expanding on. If you think that's
| > baiting him (or arguing with him), then so be it.
| NEVER said millions of charger.
OK, you said millions of products. I did follow chargers with a (?)
to indicate that I wasn't sure that they were chargers. I assume
you're familiar with the convention of following something with a (?)
to indicate that you're not certain of it?
| Better work on that reading comprehension.
| I said millions of PRODUCTS, big difference.
OK, then tell us about the products. Since they're apparantly
relevant to the discussion, let's be specific about what they are.
| Besides, that's still not the point.
If you don't want to tell what your products are, that's fine too.
| Let's assume that I know NOTHING about battery charges and you are
| going to enlighten me. Show me the datasheets that would
| substantiate your claims.
I really haven't made any claims in this thread, except that chargers
do exist that don't do CC/CV for LiPos. Perhaps you're thinking of
somebody else's posts?
However, if you're looking for an example, you only need to look at
any of the adapters that are put on a NiCd/NiMH charger to allow it to
charge LiPo batteries.
Generally they just cut the circuit when it hits 4.2 volts/cell -- so
the current is constant (during the entire charge period, anyways --
of course the current is zero before and after.) There is no CV phase
Personally, I wouldn't bother with any of those adapters, but they do
exist. Here's an example for you --
Of course, the downside is that your battery will not be completely
charged. How close you get depends on your charge rate -- if it's
high, your battery may be far from fully charged, and if it's low it
will be close. But it's certainly possible to design a charger that
gets your battery up to 99% charged using only a CC charge regime (you
just charge at a low rate.)
Or you could design a charger that does multiple CC regimes (i.e. do
1C until voltage hits 4.2 volts, then 0.5C until voltage hits 4.2
volts, then 0.25C until voltage hits 4.2 volts, then 0.1C until it
hits 4.2 volts again) then you could charge your battery almost
completely and yet never have a true CV regime at all.
Or with a little smarts, your charger could calculate the internal
resistance of the cell and actually charge up to higher than 4.2 volts
(because the voltage would drop back to 4.2 volts once the current was
off) but you'd better not make any mistakes or you'll damage the pack!
Or you could take your basic cell phone charger -- a 4.2 voltage
source, run through a resistor to limit the current, into the battery.
The only time the current or voltage (at the battery) is constant is
at the end -- when current = 0 and voltage = 4.2 volts. (Though you
might want to label that as a CV charger, as the input voltage (input
to the resistor+battery, anyways) is a constant.)
Either way, I think CC/CV is so popular because 1) it works, and 2)
it's easy to implement, especially to companies who have already made
NiCd/NiMH chargers. But it's hardly the *only*