RCM6750 backup battery problem.

Rabbit
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1

Hi guys,
I’m using the RCM 6750 and backup its RAM with the CR2450 3V battery. But I found out that the battery’s life is very short and in 3 months can finish using. Is there anyway to increase the battery life?

2

May I know what determines the amount of current that rcm 6750 use on the backup battery

3

Hello, Did you check the section G.1.2 Battery-Backup Circuit in the user’s manual? If not, please follow that procedure to connect external battery.

http://ftp1.digi.com/support/documentation/90001191_E.pdf

Actually the drain on the battery is typically 120uA for the RCM6700 when no other power is supplied.

The RCM5700/RCM6700 does not drain the battery while it is powered up normally.

I hope this helps you.

4

Is there anyway we can reduce 120uA?

5

I do not think you can reduce this 120uA. I think it would be better to check with digi tech support.Send mail to tech.support@digi.com, they will help you.

6

There is another blurb in the User manual that states:

“Cycle the main power off/on on the MiniCore after you install a backup battery for the first time, and whenever you replace the battery. This step will minimize the current drawn by the real-time clock oscillator circuit from the backup battery should the MiniCore experience a loss of main power.”

This turned out to be very important for our customers using a different module, as we ship the product with an insulator strip between the battery and connection terminal. If that strip was pulled out without cycling power, the battery draw was doubled.

Something to remember…

7

Ok. May I know what is the procedure we need to take to perform “cycle the main power on/off”? Is it just power ON and OFF after we install the backup battery?
I don’t think this is the solution because when we are doing testing of the RCM6750 on our device, it will involve a lot of powering ON and OFF… And every time before our device is shipped out, we will need to test it in our factory here, so of course we will ON and OFF a couple of times. But the backup battery still drain very quickly.

8

RCM6700 with the most recent version of R6k processor (marked with “CC”) consumes no more than 50uA of current.

9

May I know how do you achieve that? I’m already using the RCM6750 with Rabbit 6000 processor.