Clx Battery Issues

[Ken Moore 23]

I have a 1756-L61 with battery issues. The system was built last Sept. but not commissioned until November. When we went to start it up, the battery was dead, understandable since the system had been powered down for several week. I replaced the battery, and the new battery lasted one week. The system is powered by an industrial grade 12.8KVA UPS and never lost power. Raised heck with the local AB rep. and got a free replacement. Now that battery has died as well, it was in service for about 30 days. Is this typical, or have I experienced a bad batch of batteries? I would expect a battery in a system under power to last many months.

[DEVO 0]

What you described seems a little atypical. You did not list which battery you are using but I figured it must be a 1756-BA1. The AB literature recommends the use of the 1756-BATM which is an external battery pack. The worst case scenario for the BATM with a L6X processor is listed as 146 days versus just 21 days with a BA1. I would highly recommend using the BATM.

[Ken Moore 23]

I've been using the 1756-BA2

[DEVO 0]

Then you should be getting at least 8 or 9 months of battery life. Sounds like another AB issue to me. One other thing, is the L61 a Series B controller?

[Ken Moore 23]

Series B controller

[DEVO 0]

Well, then the battery should be lasting at least 8 months,

[ratcliffe_ic 2]

Just completed a project using a L61 processor myself, during the software writing stage I was out of the office for 2-3 weeks onsite so the test rig was powered down. On my return my battery was dead. Tech support (UK) recommended installing the 1756-BATM unit. Which I did for piece of mind. It seems the L6x CLX processors eat these smaller batteries if left off for a while. This is from tech note 21152 Battery life when using the L63/A is 4 weeks with standard battery, 213 days with batm.

[Ken Roach 194]

Here's the deal; the 1756-L1, -L55 and -L6x Series A controllers did eat up their batteries pretty fast compared to SLC or PLC-5 controllers. This was never a secret, but many users just assumed they could put a system on the shelf for months using battery backup and didn't install nonvolatile memory. The 1756-BATM, "BATtery, Monster" was one solution for users who couldn't use nonvolatile memory. The 1756-L6x Series B controllers redesigned the battery-backed memory to use an onboard NAND flash memory (not the removable CompactFlash card). The battery is only used for a few seconds (sometimes less) during system powerdown, during which it runs the whole controller while the program and current tag values are saved to the onboard nonvolatile memory. After that's done, the battery just runs the onboard clock. If the battery dies during power-off after that, the program should be retained, minus the onboard clock time. There was a small batch of -L6x/B controllers (Knowledgebase Article ID # 40779) that were found to drain their batteries faster than expected, so of course Tech Support can identify those and replace them. But if you had a controller come up with a dead battery after three weeks of continuously powered operation, there's something else wrong. 1756-BA2's should last for a couple of years when they aren't in use. Keep talking to your local office or Tech Support to figure out what else is going on.

[ratcliffe_ic 2]

Thanks for the info Ken, I am chasing this up right now with tech support. Our processors were purchased Mar 2007 so I am sure they are from the manufacturing dates on the article.

[Ken Moore 23]

Hat's off to Mr. Ken Roach, give that man a cigar! My processor was purchased in the time covered, looks like I need a new processor. In my case the processor is being used in a SIL-2 application, and I check the battery status every 60 seconds, and sound an alarm if it's bad. I thought there was a long shot that the GSV was killing it. Ken