interesting battery puzzler

[Daktari]

So Saturday night I rolled onto the property around 9pm, killed the lights and turned off the truck. Sunday afternoon I hopped in to run an errand, and . . . no ignition light, and only a click from the starter button. This happened once . . . once . . . before (about 18 months ago) and I found that the negative earth cable was a little loose. Tightened it that time and all was well. So I took a look at that cable and found it tight and clean on both ends. Climbed back into the driver's seat and got the ignition light, but no sound from the starter. Had to get to work a different way.

Didn't have time to do anything on Monday or Tuesday, but today I jumped it and let it run for a little while before driving the mile or so to work. After work I had no ignition light, and no sound from the starter, and the darn thing wouldn't jump start either. Had stuff to do this evening, so there it sits overnight.

Some clues to consider: this is a '65 IIA with the integrated key switch and headlamp switch (negative earth). Both the headlamp switch and the ignition tumbler have been loose ever since I've had the truck (a couple years). Also, about a year ago the wire from the distributor to the coil went bad and I replaced it.

Any ideas what made the battery go flat?

I've ordered the replacement ignition/headlamp switch from our host (RNE831). Needed that anyway.

[Triumphdaytona2007]

i had the same thing happen to me yesterday when i got home from work, on mine the cable where it bolts to the starter was a little corroded, so i cleaned off the corrosion and dirt and it cranked fine, mine was a 64 109 with the ignition/light combo, it was doing the same thing just clinking instead of turning over, put a different battery in and nothing so checked the started and that was it

[I Leak Oil]

The battery cable routes to the push button start switch, from there it energizes the key switch and the other cable goes to the starter. If you have no dash lights and the starter won't turn (even with the key off it should still turn) then you are not getting power to the post on the starter push button. Could be the battery, could be the cable. Could be an unlucky combination of both! Check your battery ground as well. Use a meter to check the cables.

[Rineheitzgabot]

Clean all surfaces that the cables connect to. The battery, the starter, etc. Do this with both ends of the cables. Consider using big star washers to ensure continuity. This will more than likely fix the issue.

I discovered this a few months ago. That's how I know, and the well-versed members of this board nailed immediately.

Love this place.

-Gary

[RoverForm]

has anyone ever observed their battery voltage while running the engine?

i'm trying to understand the normal volt ranges of a batt with the engine running to see if my charging system is healthy.

here's a video of the results:
V43UIEufmZ4

i also have a chart below which leads me to believe that the battery is charging? but in the video you'll notice that the ammeter is reading ~ -5, and drops to almost -15 when the headlights are switched on... but the charge warning light is illuminated all the while.

Open Circuit V(12 V) [Approx. charge]
12.65 V [100%]
12.45 V [75%]
12.24 V [50%]
12.06 V [25%]
11.89 V [ 0%]

source (http://en.wikipedia.org/wiki/Automotive_battery)

[superstator]

I honestly don't know the series electrics that well, since I've got a Toyota alternator and custom harness. But those numbers would make me very suspicious of the alternator or regulator. What happens to the voltage if you rev the engine?

[Sputnicker]

If it were charging, you would see numbers in this range:

"Charge with 13.2–14.4 V" (from your source document).

As was already suggested, it might be idling too slowly. If you rev the engine and the voltage doesn't climb into this range, it's not charging.

[RoverForm]

with revs it climbs to maybe just over 13.

but i haven't tested while driving.