Question for battery experts

Can I assume that if a CR2016 is rated at 80mAh and a CR2025 at 170mAh that when connected to say a Nichia 5600 LED that the 2025 will last double the time than the with the 2016? (Of course I would be using 2 of each to get 6v).
Are there no internal resistance considerations?
I am sure the drop of curve would have the same shape for both just that the one for the 2025 will be strecthed over a longer time period.

Your comments please.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Streak:

Are there no internal resistance considerations?
I am sure the drop of curve would have the same shape for both just that the one for the 2025 will be strecthed over a longer time period.
<HR></BLOCKQUOTE>

There are _always_ internal resistance considerations. The CR2025 has higher internal resistance than the CR2016 (at least for Sanyo cells, based upon info on their datasheets) which means that at 'high' drains the CR2016 might possibly be able to deliver more total energy to a load.

Both the Sanyo CR2016 and CR2025 have a maximum continuous current rating of 5mA. Sanyo's definition of maximum continuous current is 'The level at which 50% of nominal capacity is obtained to an end voltage of 2V per cell.' If you current limit to 5mA, I would expect double the run time with the CD2025.

The datasheets also have a 'pulse current' rating. This is the current that causes the voltage of a fresh cell to drop to 2V. For the CR2016, this is 50mA, but for the CR2025 this is only 40mA. This means that if you need 50mA (for a high brightness application), that the CR2025 might not supply sufficient voltage to run your load.

-Jon