This battery is a LOW SELF-DISCHARGE type. This means that the battery will discharge very little by itself and you can leave your Honker (turned off, of course) for a long time without having to recharge it. (Just in case.) This also means that if you don't use the Earphone Amplifier, the rechargeable battery will last a very long time, running only the Honk electronics. (Like, over 200 hours.)
Turn the HEARAMP on every few months to check, and if the LED is flashing, recharge it overnight.
Recharging a FULLY DISCHARGED battery will take about 20 hours. If the blue LED is flashing (meaning it's NOT fully discharged) and you start charging when you get home, it will be fully charged in plenty of time for practice the next day. You can charge it anytime you've used it more than a couple hours.
These batteries do NOT have the "MEMORY" problem the early NiCads had.
If you need to use your Honker and the Blue LED has quit flashing (is out) YOU CAN RUN IT ON THE CHARGER with a very minimum amount of hum.
WHEN YOU DO THIS, THE RECHARGEABLE BATTERY MUST REMAIN IN PLACE.
DO NOT TRY TO RECHARGE ANY OTHER KIND OF BATTERY IN THE HONKER.
It could leak and wreck your Honker. (And, for the record, it could catch fire or explode.)
If you can't run it from the charger, YOU CAN USE ANY 9-VOLT "transistor" battery to run it.
Put the Rechargable Battery back in as soon as you can and recharge it overnight.
DO NOT TRY TO RECHARGE ANY BATTERY EXCEPT the 9-Volt NiMH.
When you are using a NON-RECHARGABLE battery, the Blue LED won't flash at the right time:
It will start to flash LONG BEFORE you are anywhere near running out of juice.
With an Alkaline battery, it will flash for about half of the battery life. (About 8 out of 20 hrs.)
Avoid extreme temperatures, especially long-term storage above 90°F.
Turn the HONK CONTROL OFF when you're not using it.
This turns off both the HONKER and HEARAMP.
Don't leave it charging for more than 24 hours.
Keep it charged between uses.