Battery replacement compatability L55 to L62

Anglebert

Member
Join Date
Apr 2021
Location
Bulawayo
Posts
19
Hello everyone,

Have a quick question. Can i safely replace a controlLogix 1756-L62 with a controlLogix 1756-L55 battery and vise versa. I have a client with an L62 that has a failing battery and he has a spare L55 processor with a healthy battery.

Thank you
 
Looking at the picture of the L5 BA1 & L6 BA2 the connectors are different but as I have found in the past the batteries from other Mfg's are so similar if the voltage is the same it will probably work if the connector is changed, I have replaced a few (SLC & other PLC's) with non original supplier batteries & never had a problem, but knowing Rockwell they could do something different. so be cautious.
 
Looking at the picture of the L5 BA1 & L6 BA2 the connectors are different but as I have found in the past the batteries from other Mfg's are so similar if the voltage is the same it will probably work if the connector is changed, I have replaced a few (SLC & other PLC's) with non original supplier batteries & never had a problem, but knowing Rockwell they could do something different. so be cautious.
Hi, so I switched the batteries and changed the terminal connectors over the weekend and so far the processor is working fine with the L55 replacement battery.
Thank you
 
L6x series B battery is higher capacity when it comes to current and this replacement should not be done. Ser A L6x uses the same battery as L55
 
Rockwell literature specifies that you should only use their recommended battery (surprise surprise). As Contr_Conn notes the difference is because the L62 is a series B, if it were series A then it would use the same battery.

In general, as long as the voltage matches and the capacity is at least as large, such a replacement will work. Significantly increasing the capacity creates the potential for excessive current in case of a fault however.
 
In reality, it means the battery will not last as long, as these only supply enough current to keep the memory otherwise it would not last the 2 or 3 years or even 5-10 years (had a stored FX2n for 4 years & battery was still good).
 
There is a difference how battery used in L55/L6x Ser A and L6x Ser B

With Ser A, battery is keeping RAM data alive while power is OFF.
With Ser B battery used just for a few seconds during the shutdown to copy RAM to the internal NVRAM memory.
As a result Ser B battery needs to be able to provide a higher current on demand, while Ser A battery has a higher capacity. I don't remember if voltage is the same.
I have seen many failures when someone swapped connector. Are you willing to risk with expensive processor and production instead of buying a correct battery?
 
Let's get this in perspective, In the old days memory was small the battery backup would only be enabled during power down, it would depend on many factors i.e. size of memory, type, battery capacity etc. during power up the battery drain is almost non-existent, so in theory the battery would last somewhere in the region of 10 years, as volatile memory has increased, & hardware platform became smaller the battery life (when powered down) has become shorter, most systems have a large capacitor so when replacing the battery it will hold the memory for about 10 - 20 minutes so it can be replaced with power off.
Any that copy to NVRam will obviously require higher capacity but the amount of times it is likely to be powered down in normal circumstances it should last, in saying that, like any battery backed system with non-rechargeable batteries will last for a shorter time if the system is powered down frequently.
I worked at a plant where I replaced the backup batteries on over 100 PLC's & HMI's of various makes i.e. AB SLC, Siemens, Omron, IMO, Mitsubishi Koyo & a few others (I know a lot of different makes I did over time move many to Mitsubishi), A PPM schedule was in place to replace all batteries, not once did I power down any system all were replaced live using compatible batteries in most this goes against the mfgr's recommendations but never had a failure.
this was over a period of 16 years so must have replaced over 1600 batteries, only loss of program was when an engineer removed the PSU of an S7 400 system (the batteries are located in the PSU & not in the CPU + one other Mitsubishi PLC that nobody even knew existed, this had been running for nearly 19 years before the battery failed & the system had a power outage.
I had one Mitsubishi A1 processor where it was PW protected, this was replaced with a Q series, I removed the battery assuming it would lose it's memory within about 20 minutes, 2 days later it still retained it as it did 4 days later, went back 9 days later it had finally lost the program.
I currently have an FX2N that must be at least 12 years old originally used for testing, the battery has never been replaced, been powered down for over 5 years & last week I powered it up for a friend to borrow & it still retained it's data.
Many now have battery-less memory I know that some use what they call a super capacitor that charges up when under mains power, these are often used in small cameras & can power the camera for about 2-3 hours.
Getting back to the OP's question, as others have stated, I suggest it is a get out of jail card, but get a correct replacement.
 
Thank you all for your contributions. We placed an order for a new L62 ser. B battery at the beginning of the week. Should arrive early next week so we should be fine.
 

Similar Topics

Hello Everyone, I have a Mitsubishi PLC FX3U According to Mitsubishi PLC manual we have to power off the plc and change the battery in 20...
Replies
2
Views
1,609
Hi guys, I’m having a problem with programming an Elektronikon mk3 with DFM4WIN. The compressor type is ZR425. Since the battery was dead...
Replies
1
Views
1,912
I cut apart a 1756-xx memory battery and it turns out to be a 3 volt battery. So has anybody ever gotten a dual AA battery holder to series...
Replies
8
Views
2,326
Where is the battery located ? Is it on the left side of the cpu hidden by the power supply? Thanks
Replies
1
Views
1,654
Back
Top Bottom