La Crosse: Numbers Measured or Computed

Are some of the numbers displayed by the La Crosse charger computed rather than measured?

During charge, if I put the cells in and then plug in the charger, then the mAh readings for all the cell seem to always increment in lockstep, despite the current readings varying somewhat. Is that what other people observe?

(During discharge, this isn't the case - the mAh readings for different cells are close but often I have seen one increment before or after the others.)

I had a problem and got a replacement charger from La Crosse, and it was defective - the first slot didn't charge. The battery voltage never increased in that slot, and I measured almost zero current with an ammeter.

But the mAh reading for that slot kept counting up, just the same as all the others.

So I'm wondering if that number represents a real measurement, or if it's just computed based on the programmed charge current.

I'm hoping to hear that I'm mistaken and the mAh displayed during charge is real.

By the way, in the other slots my digital and analog ammeters didn't show anything near the charging current. Is the charger putting out pulses or some other fancy waveform?

its a computer whadayaexpect.
if you want to see any Pulses with a normal DMM, you can put it on AC, which will often show you any real ac, AND DC pulsing that is occuring. you wont get an acurate reading , but you can mabey see what you cant on DC.

with the 4 little tiny curcuits in the thing, i would not expect prefection.

your reject one, was probably SHORTED, as that is the only way it would think that it was putting juice in something.
weird though that it didnt detect a battery that would not charge.

ammeter LEADS can add in TONS of resistance, and change your results by large ammounts. change your leads for some hefty speaker wire, and shorten them, to have a more accurate representation.

that is all i dont know, i didnt build the thing, nor could i.

would you say your previous experience, of getting a fried, one has you looking closer than nessisary to charge a few batteries and have a guess as to how those battereis are working
so if it helps LIGHTEN UP , enjoy .

I think both charged and discharged capacities are computed based on the specified charge/discharge current and ellapsed time. It doesn't take into account differences in current and the fact that during discharge the current drops somewhat towards the end of discharge.

Charge mAh seems to be computed (I don't care capacity charge values).
Discharge mAh seems to be measured in "test" mode at least, and probably "refresh" mode also. But indeed it might be computed in "discharge" mode.

When selecting 100/200mA as D/C current in "test" mode, on some of my AAA the charger reported less than 800mAh after more than 8 hours discharge time. If the charger did only "selected current x time = mAh" it would have obviously reported more than 800mAh. So it takes the actual current into account.
Also, in "test" mode, there is no mAh value reported while discharging until it has finished. It shows "---". One more reason to think it's a measured value.

I had wondered the same thing about my BC-900 -- regarding the mAh display. mAh is ALWAYS computed as a product of measured time multiplied by measured current. I've checked mine during charge and this turns out to be accurate. The mAh value seems to be computed about once every 5 seconds. If you do your own check, remember the time display shows minutes as the right two digits, which must be converted to a fraction of an hour.

blr2005 said:

I think both charged and discharged capacities are computed based on the specified charge/discharge current and ellapsed time. It doesn't take into account differences in current and the fact that during discharge the current drops somewhat towards the end of discharge.

Click to expand...

does it? if it works like that computer thing, the current should stay the same, because its being current controlled instead of a resistive load . which would simulate a fully current controlled light discharge, and would not simulate a Direct drive, or incadescent direct load.


i also noticed that at the lower discharge rates, a battery is cycled "further" because it is a cutoff at a specific voltage, the less load that is on the battery at the time, the further down the battery is pulled.
I THINK
that is why the manuel suggests testing at the lower current values.
BUT
why would i test at a value that i am not going to be USING it at
SO
i use the "TEST" mode at the same basic rate that the item i intend to use it in would.
IF
my light ripps through a set of 2500s in 5 hours, i want to TEST the discharge rate at 500ma, not 100.
EVEN THOUGH
discharging slower, would depleate the cell further when cycling

Thanks for the replies.

blr2005 said:

I think both charged and discharged capacities are computed based on the specified charge/discharge current and ellapsed time. It doesn't take into account differences in current and the fact that during discharge the current drops somewhat towards the end of discharge.

Click to expand...

I suspect that discharge is measured, because if I watch the mAh numbers click over, it's not unusual for one number to increment a second before or after the others. Whereas during charge, they always increment in lockstep.