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arch2b
2011.02.16, 08:50 PM
if i understand it correctly, orion 900's are now peak 900's? i've had good luck with orion 900's so i bought a case of peak 900's to replace the orion cells i've been using for over a year now.

i've put 3 sets through the break in process and not one cell has topped 750 mah, 1.43v. is this common to get such low mah rating on a 900 mah cell?

ChiMiniRc
2011.02.17, 12:32 PM
if i understand it correctly, orion 900's are now peak 900's? i've had good luck with orion 900's so i bought a case of peak 900's to replace the orion cells i've been using for over a year now.

i've put 3 sets through the break in process and not one cell has topped 750 mah, 1.43v. is this common to get such low mah rating on a 900 mah cell?

I have one set I got. 750's

Traveler
2011.02.17, 02:08 PM
I picked the 12 best cells from 4 packs and my capacity ranges from a low of 766 to a high of 940 mAh, with voltages between 1.46 and 1.51v. Not too uniform I'd say :(

Deca
2011.02.17, 02:36 PM
I have two sets, I believe my range was from 730ish to 790ish

geeunit1014
2011.02.17, 10:59 PM
I picked the 12 best cells from 4 packs and my capacity ranges from a low of 766 to a high of 940 mAh, with voltages between 1.46 and 1.51v. Not too uniform I'd say :(

Unfortunately to get a truly "matched" pack, you must go through quite a high volume of cells. Also, side note, if you are trying to match your packs, voltage is the least important number to consider ;)

ChiMiniRc
2011.02.18, 11:07 AM
Unfortunately to get a truly "matched" pack, you must go through quite a high volume of cells. Also, side note, if you are trying to match your packs, voltage is the least important number to consider ;)

I was scratching my head there too. High voltage is nice but I usually go by capacity and or internal resitance. If I had the equipment, average voltage for the first 10 minutes (my longest race), under a race discharge load.

These 1.4x and 1.5x numbers you are getting. Is this your peak voltage at the end of a charge?

geeunit1014
2011.02.18, 12:22 PM
I was scratching my head there too. High voltage is nice but I usually go by capacity and or internal resitance. If I had the equipment, average voltage for the first 10 minutes (my longest race), under a race discharge load.

These 1.4x and 1.5x numbers you are getting. Is this your peak voltage at the end of a charge?

Voltage is a function of runtime. So if you have 2 cells, lets say with the same IR, and one has 100 sec more runtime but a slightly lower voltage, that cell will blow away the other cell on the track because it can hold its voltage much longer (also its avg IR is better as well b/c of the longer runtime). The only time voltage is relevant is if 2 cells have the same runtime and IR, but at that point id doubt if they were off by more than a few hundreths of a volt ;)

arch2b
2011.02.18, 01:08 PM
voltage figures were not provided for relevance to matching, just for illustrating the variation within the cells.

i'm just surprised that these 900's are providing such low true capacity numbers. the orions i have are much more consistent and higher capacity.

Traveler
2011.02.18, 01:26 PM
voltage figures were not provided for relevance to matching, just for illustrating the variation within the cells.

Thanks Arch. Couldn't have said it better.:)

i'm just surprised that these 900's are providing such low true capacity numbers. the orions i have are much more consistent and higher capacity.

I was too. I use these cells in mod and have been quite pleased with them lately, in spite of the poor capacity numbers. I used them last night to run race 2 of our Reflex series, and they gave me the power I needed for the entire 15 minutes (and the win). When charged at a low rate (200mA), the capacity is considerably more than the 900mA rating. The capacity numbers I sited earlier were at a charge rate of 700mA.

Try a slow charge and see if your numbers improve. ;)