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Marcin, you really did some good research here; however, we have to be careful when comparing the two sets of curves when talking about battery longevity. You came to the conclusion that the 'SE' battery will die in 140-160 days. I'm not sure if that is the correct conclusion to draw, for the following reasons:
1) We don't know what the steady-state current draw of the siren module is. The data sheet links you provide also show that the 'SE' battery can last as long as eight years, *IF* the load is only 20 uA. It's quite possible that the siren module only draws this small amount, as normally the module would operate from the main battery, correct? Without having SAAB circuit diagrams (or spec sheets) available, it's hard to say. You picked the 505 uA (half a mA) load for the 'minimum load' the alarm sees. I'm not sure if we can justify that guess without having circuit schematics, etc.
Here is a more fair comparison of 'SE' versus non-'SE' battery longevity:
For the CR17335
http://sanyo.wslogic.com/pdf/pdfs/CR17335.pdf
The CR17335 is stated to be a 1400 mAh battery. The lower left curve shows a DC discharge rate over a 200 ohm load. The discharge current (Volts/Resistance) starts around 15 mA and trails to about 10 mA. The time to fully discharge (Sanyo-defines this as 2V) is 105 hours. Note: data taken at 23 degC.
For the CR17335SE
http://sanyo.wslogic.com/pdf/pdfs/CR17335SE.pdf
The CR17335SE battery is stated to be a 1800 mAh battery. The closest comparison we can make is from looking at the top-left graph, which shows a discharge over a 280 ohm load, resulting in about 9mA of DC current draw. The 'SE' battery (1800 mAh) appears to last about 85 hours (for 23 degC) before hitting the Sanyo-defined 'discharged' point of 2V. It's safe to assume that if this 'SE' battery had the same 200 ohm load as the non-'SE' battery tests, it would have lasted even less, maybe around 50-60 hours. This is slightly confusion as I would have thought this 1800 mAh battery would last longer than the 1400 mAh battery. Then again, I've also seen manufacturers provide incorrect info in their data sheets as well (I'm a career E.E.).
All that said, I still believe you found the most important difference between these two batteries: The 'SE' battery has a nominal discharge current of 1 mA, a continuous max discharge of 10 mA, and a pulse max discharge of 100 mA. The regular (non-SE) battery has a nominal discharge current of 10 mA, a continuous max discharge of 1500 mA, and a pulse max discharge of 3500 mA.
Thanks for the great post. My alarm has started to act up and I'll need to perform this repair fairly soon.
Thanks,
KevinH
'00 9-5 Aero 116K
posted by 76.111.3...
, Tue, 11 Aug 2009 12:53:19
, Thu, 24 Jan 2008 07:31:36
, Thu, 24 Jan 2008 07:58:33, Wed, 23 Jan 2008 17:38:41, Wed, 23 Jan 2008 14:50:36
, Wed, 23 Jan 2008 12:38:35
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