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[devedsmith]

I've noticed some significant performance differences in using NiCad batteries vs alkaline in the Eagle Eye motion sensors. I have one in our closet - indoors of course (70deg year round), and one outside in our driveway (30 to 100 deg - Sacramento, CA weather).

Both exibit the exact same behaviors with NiCad vs akaline: When using NiCad they transmit perfectly when the ON/OFF buttons are used, but not at all when motion is sensed. If I swap for alkaline batteries (Energizer BTW) they transmit using ON/OFF buttons and when sensing motion.

Is there a reason for this? I'd really like to use rechargeables but they just don't seem to work as expected.

[-Bill- (of wgjohns.com)]

NI-CAD batteries typically have .25 volts less output than normal batteries even when fully charged.

Have you considered trying the rechargable alkalines or lithiums?

[steven r]

NiCd and NiMH rechargeable batteries have a typical cell voltage of 1.2V compared to the 1.5V of alkalines. So your pair of rechargables give you a total of 2.4V compared to the 3V of a pair of alkalines. I believe someone made a post saying they had examined the Eagle Eye and determined that 2.4V was below the minimum threshold voltage for reliable operation of the components used in the Eagle Eye.*

The other issue with using most NiCd and NiMH rechargables is that they have a charge shelf life. i.e. They drop a significant level of voltage in just a few months even if not used. The only exception to this are the new pre-charged NiMH batteries such as enelope. This makes NiCd and NiMH batteries more suitable for heavy current use applications.

Also NiCd batteries are subject to a condition known as "memory" which make them less suitable than NiMH batteries.


*I believe this is the topic I remembered.  http://forums.x10.com/index.php?topic=36.msg82408#msg82408