Another 85 300td alternator post. sorry
 

I'm struggling with my alternator/battery issue and I could use some help.

Bought new battery from autozone. At the same time, I installed junkyard bosch alternator with brand new voltage regulator. Autozone said the alt was good, but didn't provide numbers - just a pass/fail test.

Installed new battery and junkyard alternator with new voltage regulator. Used my multitester across battery terminals to get 13.5 volts with engine running.

I figured it was safe to go out, so I was out all day last sunday, wipers on, lights on. Toward the end of the day I noticed very slow wipers, windows, and fuel gauge dropping very quickly. Stopped for fuel. Couldn't get it to restart. Jumped it with one of those battery packs. Fired right up. Made it home, but battery was very low - slow wipers, etc.

I charged the new battery for two days with my 2 amp charger until reman bosch 65 amp alt. arrived. I installed the rebuilt alt on friday and charged the battery again overnight.

Took it for a spin today to see if it all worked. I ran it with my multitester attached to the battery poles.

Started out 12.4. Dropped a little when I cycled glow plugs. Fired up. Within 3 miles, I was up to 13.7. I ran blower on high, lights, fogs, brights, radio, wipers, all on and it stayed steady at 13.6.

Left it idling for a few minutes and it dropped down to 12.0. I pulled the glow plug relay supply plug and it bumped back up to 12.5. Does half a volt drop indicate the relay is staying on?

Took it for a drive with gp relay unplugged and it read 13.6.

Don' t you think I should be getting more volts? Is a 2 amp battery charger enough for a big battery like this one?

I checked my 95 and it puts out 13.9 after a minute of idling.

Sounds like your GP relay isnt cutting fully out. Once it cycles, it should have zero effect on the battery.

There sure is a gremlin in the battery/alternator/gp relay/ignition switch someplace. Seems like there have been quite a few issues lately.

gp relay
 

Thanks TnBob. Do you think my 2 amp charger is adequate to top up my new battery after I ran down?