[Nut-upsuser] false low battery alarm

[Vieri]

--- On Thu, 2/28/13, Manuel Wolfshant <wolfy at nobugconsulting.ro> wrote:

> Good batteries ( for instance Yaesu, as seen in APC UPSes )
> last 4 
> years. Normal ( usual ) ones last 2. Do the math yourself

Thanks for that information.
Just a side question:
Will the ups.mfr.date value be updated automatically by the APC ups firmware when I change the battery or will I need to set it manually? I'm asking because I'm not sure if the current battery was really installed at the time indicated by this field.

I also have another (maybe related) problem. I have another 2 APC devices I'd like to monitor (apparently same model and serial numbers). However, whenever I connect a serial cable to the port on the UPS, the whole device shuts down immediately. This happens only if I connect the other end of the serial cable to either a ttyS0 port on a running motherboard or a port on a rs232-to-usb adapter (even if the usb end ISN'T connected to a NUT monitoring server). What could be happening here?
This is obviously slightly off-topic because it doesn't seem to be related to the nut ups drivers.
I'm just wondering what could be happening and if old batteries on relatively high load (approx. 75%) could be a reason the UPS shuts down abruptly on connecting a serial cable on both ends. IT sounds really strange though.
Also, the UPS won't switch on while the serial cable is connected even if I press the UPS power-on button several times.
I have to disconnect it (or at least the far end of it) in order to "boot" the ups.

Thoughts greatly appreciated.

Vieri