Yes Mo if you disconnect the battery you will loose stored memory.
You can beat the rascal with little effort and cost.
Go to a Radio Shack Store and purchase one each:
cigarette lighter plug
9 volt battery terminal
9 volt battery
Solder the two leads or each together keeping the polarity correct.
The center of the plug is positive and is soldered to the plus wire of the 9 volt terminal.
You can tell which is positive by looking at the battery as you plug the terminal and battery together.
The remaining leads must be the negative or Ground.
Attach the battery to the terminal.
With the ignition "OFF" plug your little El Cheapo memory saver into the cigarette lighter plug.
Remove the battery.
The stored memory will remain for a short time.
Turn the ignition switch to the "RUN" position.
The reverse voltage flow will maintain the memory for you.
Pretty simple, huh?
Another El Cheapo!
Happy Trails Beep Beep from Houston!!!
Donald, El Cheapo