[Vwdiesel] HELP-Battery voltage when glow plugs kicking in.

[Mike & Coreen Smith]

Hello Diesel Dudes,

Tested my battery voltage today (about 12' C outside at the time)
12.65VDC (no load, car been parked 6 hours)
Ran glow plugs (just 1 cycle) and voltage went down to 11.6VDC while under
load.
After the single cycle, battery voltage was sitting back up @ exactly 12VDC
Started car (of course, one more cycle automatically) and voltage slowly
crept up to 12.04, 12.05. etc. to 12.1VDC after around 30-40 seconds. (then
I had to stop "test" & run back into work, LOL)

Does that voltage seem a bit low to you all?

I checked the voltage directly on the glow plugs 2 weeks ago and could've
sworn it was around 9.75 volts or something. I posted it, but now can't find
the message.  Must be a lot of voltage drop in my busbar, etc.

Think I have a soft battery or is it about right?

It's the biggie. Group...71?  Rats....I forget exactly.  Whatever that
recommended group # is I think I have....

Sorry for my rambling. Been an extremely hectic day and my head hurts.  Car
goes in shop tomorrow for a block heater install, and I'll get a new battery
based on your comments and a possible load test.  If you all think it sounds
about right, I'll skip the load test.

Mike in NB...home of whitetail deer, Atlantic salmon and cold temps !...brrr

P.S.- Car won't be driven all winter. (have a 4x4 Pathfinder for that.), but
I'd like to get OCT/NOV out of it if possible.