Issue
Is there a way to tell if the battery is bad in a controller?
Product Line
Andover Continuum
Environment
- BCX - 4000, 4040, 9640
- ACX5740, 5720
- Netcontroller II 9680
- Infinet II controllers
- B3 controllers
Cause
Determine if a battery is good
Resolution
Battery health is tricky to measure. Open circuit voltage COULD look ok with a marginal battery. The only sure way is to pull the power on the Netcontroller and see if it holds the data for our specified time. Most sites will not want to take their controller down for that long. Take the battery out and measure it with a voltmeter, it should read not much lower than ---
- BCX and ACX model controllers 3.6V
- Netcontroller II, Infinet II and B3 controllers 2.7V
BCX Spec Battery section:
Replaceable, rechargeable battery. Provides 30 days typical accumulated power failure backup of RAM memory All data stored in Flash on power loss.
ACX Spec Battery section:
Replaceable, rechargeable battery. Provides 7 days typical accumulated power failure backup of RAM memory All data stored in Flash on power loss.
I2/B3 Coin type battery:
The small coin battery in the i2 / b3 is rated 41mAH; if you calculate based only on the SRAM and RTC current draw you get about 85 days.
Netcontroller II:
The battery type here and SRAM are typical of infinet II controller battery life and will maintain backup of SRAM down to 2.7v.
NOTE:
Backup Flash is non-volatile memory and once written will hold unless manually cleared. SRAM is a part of memory that holds information as to where to start programs when power is re-applied to the controller in cases of main power loss.
The problem is that battery life is highly dependant on number of charge / recharge cycles which is beyond our control. You don't find the battery manufacturers giving such specs either. Example: The coin cells in our i2 / b3 have a shelf life "up to 10 years". Day to day use it is suggested that batteries should be replaced every 5 years.
