C.Net5000 and C.Net2000+ Battery Guide

The C.Net5000 ambulatory ECG monitor requires two AA batteries and the C.Net2000+ requires four. The capacity of an AA battery varies between manufacturers, and between particular battery types from the same manufacturer.

In order to perform a 24-hour ECG test, the ECG monitor requires a continuous supply of battery power over the 24 hour test period. If the batteries run out of power, the monitor will stop the test in an attempt to conserve power so that the test report can be downloaded. If the batteries run completely flat, the monitor will automatically shut down and the test report will be lost.

The batteries you use must have enough capacity to perform a full 24 hour test, and have some capacity spare at the end of the test to prevent the report being lost. The C.Net2000+ requires good quality alkaline batteries with at least 2400 mAh capacity.

Carbon-Zinc Batteries

Carbon-Zinc batteries (often labelled “heavy duty”) include well-known brands such as Ever Ready Energizer, and other low-cost batteries. They are designed for use with low-power devices such as portable clocks and television remote controls, and have much less capacity than alkaline batteries. Carbon-zinc batteries do not have sufficient capacity to run a full 24-hour ECG test, so should not be used with the C.Net5000 or C.Net2000+.

Alkaline Batteries

Alkaline batteries have much higher capacity than carbon-zinc batteries. We have tested a range AA batteries from different manufacturers and found that the most reliable and consistent are Varta Industrial and Panasonic Gold Line, either of which can be obtained from Cardionetics, depending on availability from the manufacturer. These have a capacity of 2400 mAh, which allows a 24-hour test to be run reliably.

We do not recommend using batteries from any other manufacturer with the C.Net2000+ ECG monitor, due to reliability problems found during testing. Problems include tests not running for 24 hours, losing the test report, and not being able to print or download the report after a test.

The pictures below illustrate the cause of the problem. With some types of battery, a black “ring” can be seen around the battery terminal (below, left), which prevents the battery from making a good electrical contact. Compare this against the picture on the right, where the battery terminal is clean and uncontaminated, giving reliable and consistent operation.

The black deposit can cause the battery contacts inside the ECG monitor to become dirty. If this happens, you can continue to get problems until the contacts are properly cleaned, even after changing to a different brand of battery.

Dirty Battery Terminal (do not use)

Varta Industrial (recommended)


Always remove the batteries from the ECG monitor when not in use. Alkaline batteries may leak if left inside the ECG monitor for a long period of time.

Rechargeable Batteries

Rechargeable batteries cannot be used with the C.Net2000+. With the C.Net5000, Nickel Metal Hydride (NiMH) rechargeables are preferred over Nickel-Cadmium (NiCd), provided the power rating is 2400 mAh or higher.

If rechargeable batteries are used, they should be fully charged before each test. Rechargeable batteries will discharge naturally if left unused for a long period, so they should always be recharged just before starting each 24 hour test.