ControlLogix battery replacement

JoeM1

Member
Join Date
Jul 2015
Location
Tucson
Posts
71
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 connect two 1.5 VDC batteries, extended/relocated the OEM wires to the holder and done the memory battery this way?

Thanks
Joe
 
They might have to be rechargeable AA batteries.

The ControlLogix CPU keeps the battery up while the power is on, that is why the life is rated 10 to 20 years under normal circumstances.

But, I have replaced AB batteries with cheap batteries and had them need replaced within 6 months. Buy good quality batteries - doesn't have to be AB, but the cheapies don't last in CLXs.

There is a certain forum member I already plugged today with good batteries.
 
And of course the charging current of the AA sized batteries will be the same as on the original mini-sized batteries. Because if it is charging, this current would come from the 1756-LXX. And it is sized for the original batteries. And for saving couple of bucks, you can risk couple of k-bucks (only the processor price, it's up to you to count production losses).

I, personally wouldn't
 
there are cheaper battery replacements than AB batteries. That is the route i have taken. they even come with the right connector and everything.
 
I actually had to do that years ago. It was an old Autolog controller (came from Europe) and for some reason I cannot recall, you could not replace the coin cell battery on the CPU board...so when it finally died I had to remove it and the holder from the board and in its place I soldered on the pigtail wires off a AA battery holder, and also installed a diode so the voltage on the board would not go into the batteries. It worked fine. Just wish I could remember why you couldn't just change the battery.
 
I cut apart a 1756-xx memory battery and it turns out to be a 3 volt battery.

I think it is a CR123 battery (with solder tabs), a fairly common style for cameras (without solder tabs).

I ran into problems with getting replacements shipped because you can't get ground shipments to an island. (Well, you can but a lot of the big sellers don't want to bother). Being lithium batteries they have restrictions as cargo on passenger aircraft (if properly marked they can be sent via air cargo, again most of the time sellers don't want to bother).

Just get a holder for a CR123, wire up the connector, walk into any big box store, drug store, etc. and buy one off the shelf and you are in business.
 
Hold it !!

The battery in a ControlLogix processor is NOT RECHARGEABLE.

It is a Lithium CR123A with solder tabs, quite hard to find, but i did find someone on eBay selling replacements years ago, which were much more reasonably priced than OEM batteries.

Now lets talk about battery life....

Up to and including the 1756_L5x series, the battery was used to maintain the contents of RAM during periods of no power to the controller.

On the newer 1756_L6x series, the battery is used to allow the processor to transfer the RAM contents to Flash RAM. Thereafter it is not used.

So, in a nutshell, series 5 processors would eat batteries if you powered down the controller for long periods, while a series 6 would eat batteries the more often you powered it down.

Series 7 and above controllers have a rechargeable "Energy Module", and, like the series 6, power from it is used to save the RAM contents to Flash memory.
 

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