Charging Proto 2 battery question.

You may need to replace the battery FIRST if it is a 5 Volt board.

We need the product number to further advise.

First, how old is the engine? Look on the bottom of the tender for the charging port. If it is round,I suggest you pop the shell off the tender and see what color the battery is. If it is a 9 volt green, you are good to go. If it is white, it is old, and likely to cause trouble. I would replace it before charging it. If you have a rectangular port with 2 pins, you are also good to go. To answer your original question, you do not need to have the engine connected.

Chris

LVHR

The model number is 20-3242-1. This engine has the blue 2.4 volt battery pack and the wireless drawbar.

I just bought a Christmas engine from 2005 never run brand new. I just bought a new battery and charged it first then put in in the engine.  If it’s an older engine with a 5 volt board or a PS-1 engine I won’t put voltage to it before I put in a new charged battery in it.

Your good to go with your 3 volt board.

Go ahead and plug the tender in.

When finished, you can do a test.  Your battery pack is 12 years old and may benefit from replacement, available thru MTH or hobbyshops.

With a charged battery, have your engine running on the track and remove all power.  If the battery sustains sounds for 7 seconds or more, your battery is okay.  You won't hurt the engine if your battery is poor but you would need to replace it.