Networked battery monitors

1. A battery monitoring system for simultaneously managing the batteries in 100 or more remote locations, each of said locations comprising a battery string with 100 or fewer cells, said system comprising:

a. an individual battery monitor operatively engaged with at least one of said cells;

b. a network access module in communication with said battery monitor, said network access module comprising a modem compatible with a machine-to-machine data communication protocol, said protocol comprising assigning a variable IP address to said network access module modem upon initiation of a connection to a battery manager; and

c. said battery manager comprising a fixed IP address that can be connected to via said a machine-to-machine data protocol upon said initiation of said connection,

wherein said network access module is programmed to periodically transfer battery monitor data, including ohmic measurements, to said battery manager at a frequency of not less than once per week and with a total rate of data transfer of not more than 1 Mb per month.

2. The battery monitoring system of claim 1 where which further comprises at least 100 of said network access modules, each located at a different remote location and each being programmed to call in at a scheduled time plus or minus a random offset in time.

3. The battery monitoring system of claim 1 wherein said network monitor is programmed to initiate a connection and download cell ohmic measurement data at a rate of between once per minute and once per 5 minutes during a battery discharge.

4. The battery monitoring system of claim 1 wherein said individual battery monitor measures ohmic measurement data at least in part using background perturbations.

5. The battery monitoring system of claim 4 wherein said background perturbations comprise ripple current of said battery string.