The starter battery on our coach came with a knife switch to isolate the batter when parked for a while. When I leave the switch closed it will kill a fresh battery in 2 days. I know it may become an agonizing exercise to locate the myster draw so thought I would see if anybody else has had a similar problem and solved it. Any ideas will be greatly appreciated.

Bill here's a pretty simple test you can do to check for the battery draw. If you have a 12 volt test light. Remove the negative cable
from the battery, connect the alligator clip to the cable end that you removed and then poke the negative terminal on the battery.If a light comes on you have a short,bad ground or etc. With the light still connected start removing fuses 1 at a time until the light goes out.Once the light goes out you then know which circut(s) to then check to hopefully narrow your problem down.If this is an additional battery turning off circut breakers while your test light is connected will do the same thing.I hope this will help you.It can be a little time consuming but hiring someone to troubleshoot it for you might be a little money consuming.

Hey Jay, thanks very much for the detailed tip. I'll be going to work on it as soon as I can find a volunteer to watch the light.
Bill

I hereby nominate Jay to be upgraded from the junior member status and accorded all rights and privilages due full members. This little tidbit will be copied and entered into my Barth Notebook for future reference.

------------------
Dan & Suzy Z
'81 Euro 28

The test light is OK if it is a small load. If the load is a little bigger, the light filament will act as a fuse and just blow. If the load is really small, the light might not even illuminate. All of this will depend on the lamp that is used and the current being drawn by the load.

I would suggest that every RV owner have a multimeter. It will do this test as well as many many other useful things.

Message for Bill H . Bill remember we are only talking about a 12 volt system . I have found that the test light can handle more than 15 volts without blowing. Also I have found that the bulb will light very dimly with as little as a volt going to it.Obviously if you try to send 115 volts to the test light it will in fact blow. I have used this test on numerous occasions with much success,And by positioning the light properly I am able to see the light myself thus not having to depend on a helper.Just F.Y.I.

quote:

Originally posted by Jay zabelny:
Message for Bill H . Bill remember we are only talking about a 12 volt system . I have found that the test light can handle more than 15 volts without blowing. Also I have found that the bulb will light very dimly with as little as a volt going to it.Obviously if you try to send 115 volts to the test light it will in fact blow. I have used this test on numerous occasions with much success,And by positioning the light properly I am able to see the light myself thus not having to depend on a helper.Just F.Y.I.

In this situation, volts mean nothing. Amps mean everything.

When a light bulb is in series between the battery and the load, it is acting as a fuse, and a fuse reads current. The lamp may either stay dark(on a light load), illuminate, or blow(on a heavy load), depending on the current rating of the lamp and the current drawn by the load.