Huge electrical drain while running (intermittent)

Eric · **Posted:** Mon Sep 22, 2014 7:02 pm

Over the past 6 months I have had an intermittent electrical drain while driving.

The problem first showed up in April - lights dim, battery voltage steadily dropped from 12.3 to 10.6 or less over a 30 minute drive, but it frequently would start charging at 14.2V again for no apparent reason. I always made it home but once the battery drained to the point it stalled as I pulled in the driveway. The alternator OAD pulley was noisy so I installed a reman Remy from Rock Auto, and the problem seemed to be resolved.

Then in early June it happened again. I replaced the non-OEM spiral cell battery with an AGM battery & it seemed to solve the problem again. I ordered a replacement Litens OAD for the original alternator and set it aside as a spare.

Over the summer the problem happened once in a while, but only when I had the AC on, so I figured it was heat-related (I don't often use AC anyway).

It started again a couple of days ago (no AC this time). Coming home from nights this morning it dropped to 6.5 volts and died on the side of the road (quite the light show from the instruments at those low voltages!). CAA (Canadian AAA) boosted/charged it for me and did a roadside test. The battery was fine but the alternator is dead. I made it home, put the charger on the battery and went to bed.

I swapped in the spare this afternoon but before the swap the battery was at 12.3V. There was a plastic sticker on the stator frame on the reman Remy that was boiled and shrunk - ie cooked, and the OAD on it seemed fine. The original I swapped back in was charging at 14.1 at idle and 14.4 at increased RPM. However, it was sizzling hot within a couple of minutes. Since the battery was partly charged already this does not seem normal.

It has been idling a bit rough over the past couple of months, and I am starting to think there is a large electrical draw that only happens when it is running.

I still have the original 7V ceramic GPs. Could this be a bad GP controller? I have to go to work again in a couple of hours. Anybody have any suggestions for fuses or connectors to pull to isolate the GPs or anything else that would draw such a big load?

HELP!

Eric · **Posted:** Mon Sep 22, 2014 7:19 pm

And the old battery is ok too - it has been working great starting my tractor (3 cylinder Perkins diesel).

gmctd · **Posted:** Mon Sep 22, 2014 10:05 pm

Bad alternator will do this - start by looking at battery supply fuse\circuit breaker and cable connections, then have alternator tested at AUTOZONE

AC auxilliary fan could do this due to faulty motor bushings siezing up - use long screwdriver to rotate blades, noting spool-down time - should rotate easily

Faulty glow plug controller could do this - unplug controller and inspect connector for melted plastic

Eric · **Posted:** Thu Sep 25, 2014 12:37 am

Update:

I unplugged the glow plug control module & had a quick look at it. It does not show any signs of overheating. It has been disconnected for since Monday and the charging voltage seems more stable with it out (14.1 to 14.2 at idle & 14.3 to 14.4 while driving). Not surprisingly, the CEL is now on. When I arrived at work tonight, I left the high beams on for a few minutes to put some load on the alternator & it only felt warm to the touch - not sizzling hot like it was Monday. Of course, the battery is now fully charged.

I will check the fan and do a few more tests this weekend. I am curious to see how many amps the alternator is actually pumping out.

According to the FSM, the glow plug system will draw a maximum of 20 amps. I was really surprised - I thought it would have been much, much higher.

Huge electrical drain while running (intermittent)

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