[Soekris] RTC battery discharge/recharge time

[Jan Hoevers]

I'm planning an application in which part of the equipment (4501 and/or
4801) will be powerless for extended periods of time.  Because network
availability is uncertain at time the equipment is needed, system time
may rely on the battery backed up RTC (taking the inevitable inaccuracy
into the bargain).

The 4501/4801 manuals on the soekris website specify that the
rechargeable lithium battery on the board can supply power to the RTC
for minimal 1 month, so I will specify a monthly recharge (and resync)
procedure.

The manuals don't say anything about recharge time, so I need a way to
estimate or test this.  Any suggestions on how to do this would be
appreciated.

thanks,
Jan Hoevers