Handheld Star marine radio

[jonlea]

I have tried everhere online to obtain a replacement battery pack for a Star M298 vhf radio without success. I decided to replace the 7 1.2 volt AAA batteries wired in series with just a PP3 9 volt battery on the grounds I only want to receive not TX. It works well. I understand branded 9 volt batteries rate at approx 850 mah. I then bought a new rechargeable PP31300 mah battery which show 9 volts on a voltmeter but the radio will not receive anything although the display shows the channel being used. What am I missing or doing wrong?

 

[justanothersailboat]

Most PP3 batteries are actually six tiny cells inside (much smaller than AAA) and have less current delivery capacity than a pile of AAAs. If you use a PP3 non rechargeable (1.5v per cell) as a substitute for seven nimh type rechargeables (1.2v for cell), the voltage works out about the same and probably holds up similarly when under load, though it won't last anywhere near as long.

It's possible that your rechargeable PP3 with six rechargeable cells has a high enough apparent voltage when unloaded but it probably rapidly drops to markedly less than needed under load.

 

[jonlea]

Thanks for explaining the difference between the two types of PP3s.

I have therefore decided to return the new rechargeable ones to amazon and stick to a non rechargeable Duracell which seems to work ok.