732A Battery Life

[johnny sparks]

According to the Fluke manual, the batteries in the FLUKE 732A should last 5 years.  I just had to replace my batteries (3 failed batteries; 5 failed cells)after 4 years (AJC-C5S 6V 5AH Emergency Light Batteries for a theoretical 15 hour backup).  I was wondering if other have found 4 year battery life to be typical.
Also, has anyone considered switching from SLA to Lithium in the same footprint ($$)?

[Hawaii596]

I recently changed a bunch of mine.  I think if they are allowed to completely discharge, and left discharged for a time, it can reduce battery life.  I had batteries in a 734A system (chassis with four 732B's in it) where one of them was bad, even though it had a label saying it had been changed in Aug 2012.  I am guesstimating that leaving it discharged (which did happen) may have been the culprit.

What are the details regarding the Lithium's you're considering?  I'll have to look but the mAH is pretty important.  The job is to keep the oven running up to 24 - 48 hours when power is lost (shipping to other location for calibration, etc.).  What are the comparative mAH of the lithiums you're looking at versus original type SLA?

[johnny sparks]

When I googled Lithium replacements, this store came up (no recommendation; have not bought from them):
http://www.batteryspace.com/lifepo4-battery-6v-5ah-30wh-10a-rate---replace-sla-with-5-times-longer-life-and-lighter-weight---un38-3-passed.aspx

The data sheet for the batteries are there as well.  As you can see, they are ~5x the price of SLA batteries.   But, they talk of longer life. 

[Bryan]

I just replaced a set that were dead as dead gets.  They were installed in Mar 2012 so I got about 2 and 1/2 years from them.  This piece had line voltage for the duration except when moving to another bench so they didn't get much if any exercis.
Not sure of the brandname but NP-4-6 that I got from Newark for about $13 each, replaced with same, probably a product of the peoples liberation battery factory.