Checking your batteries
A low battery on most radios is indicated by a low warning tone while you are transmitting. On standby a similar tone or double low beep is made every few miuntes. Some radios display the battery level on their LCD display as well but this is not an accurate indication.
Note: Battery life is usually quoted based on a use of 5% Transmit, 5%Receive, 90% Standby ratio. Transmit really drains the battery fast, receive less so and batteries will usually last a couple of days when only on standby.
Fail Modes.
Batteries typically fail on one of two ways:
- The total battery capacity becomes smaller and smaller to the point of not being able to supply enough power for the whole day. This is the common fail mode.
- An internal resistance develops which has no effect when the radio is on standby (no low battery warnings) but as soon as you transmit the battery cannot supply the increased power demand.
You can test batteries yourself with one of the simple tests below which will give you a good indication of your battery health. You should do this test before you dispose of them. Alternatively Wildtalk can test your batteries on a battery analyser which gives an exact value for the capacity of the battery and a demanding health check.
Battery Test Method 1.
Practical Test. (“Will the battery stand up to a normal days use test?”)
Fully charge the battery (while on the radio): Charge until the charger indicates fully charged (usually a Green light) or if you only have an old trickle charger (where the light never changes colour) leave it on charge overnight (at least 14 hours).
Use the radio for a normal days work. This is usually considered to be 8 hours, but what you consider to be a 'day' is what matters.
If the battery starts to go flat before the end of the 'day' then the battery is failing.
Battery Test Method 2.
Crude Test (“Does the battery have much capacity test.”)
If the above test is impractical, for instance you don't use your radio in a conventional 8 hour 5% Transmit basis then you can also use the following crude test.
Fully charge the battery (while on the radio): Charge until the charger indicates fully charged (usually a Green light) or if you only have an old trickle charger (where the light never changes colour) leave it on charge overnight (at least 14 hours).
Turn the radio to a channel you don't normally use. A channel that will not receive anything.
Leave the radio switched on for 24 hours.
Transmit for three 5 minute bursts.
Typical Current Consumption
of most handheld radios, analogue, digital, licensed and licence-free.
- Standby: <50mA.
- Receive: around 100mA (depending on volume level).
- Transmit: around 1A to 1.5A (depending on transmit power).
NOTE: Occasionally a failure inside the radio can cause the battery to go flat prematurely. This is often indicated by the radio and / or battery getting warm. If this happens send back both battery and radio for analysis.
Memory Effect
You may have heard of the memory effect regarding rechargeable batteries. The effect of only partially discharging the batteries reducing the apparent capacity of the battery.
Memory effect really only applies to NiCd batteries which have not been available for UK radios for over 10 years. If your radio is using NiCd batteries then the batteries will likely need replacing due to their age.
