On 30/05/2020 09:22, Smolley wrote:
Further to a post a few weeks ago, about the battery being flat in my car
after standing idle for a few weeks. I subsequently charged the battery in
the house using a laptop power supply and a couple of headlight bulbs in
series to deliver a charging current of ~2 amps over several days. I
eventually put the battery back in the car and fitted a knife switch
isolator. Yesterday I went out in the car and returned after about 10
miles. This morning after the engine fan had stopped I measured the
standing current across the open knife switch and was surprised to see the
meter was reading 3.26 amps. No wonder the battery flat!

That sounds like a wiring problem. A mate of mine had a similar problem
in the 70's with a 60's car, that turned out to be a failed on/off
switch on the radio (this had no lights to indicate it was on, and
didn't make a sound tuned between stations). IIRC it was drawing an amp
or so.

Slightly different, but the reason my ATV battery was going flat even
when used regularly was that the glow plug timer relay had failed, so
these were drawing 20 amps or so, well over the charging current on idle.