Starter draining battery?


#1

1990 Dodge Grand Caravan, 3.3L

Three weeks ago, I had the starter rebuilt locally by a shop I’ve used confidently for years, most of their business is rebuilds like this. Besides a substantial coating of oil on the starter which was no benefit to the contacts, the tech also found a broken insulator which presumably was the primary issue. I installed the starter and have had no problems since (three weeks).

Yesterday morning, the battery was dead - no click, no lights, no horn. I could be wrong, but I don’t think the interior lights were left on overnight.

I put my 1 amp trickle charger on it for several hours and when I reconnected the battery, the horn sounded right, interior lights looked good…until I tried the starter. In an instant, I got the chattering clicky sound of a starter with inadequate power , then nothing, and the lights and horn were gone too.

After charging overnight -almost 24 hours now, that same scenario has repeated: first good horn and lights, then clicks from the starter, then very weak lights and horn.

Is this simply that the battery is down and needs more charge? Or could there be something wrong in the starter causing this rapid discharge? A few months ago the same electrical shop load tested the battery and it was surprisingly good considering its age. I don’t want to put a new battery in the car if the starter is somehow damaging the battery. I do have another battery I can swap in, but for the same reason I’m reluctant to install that without some better idea of what’s happening.

Does this point conclusively to the starter? Or is this clearly the battery?

Is there some way to diagnose the starter without removing it? I’m sure the shop would fix any mistake, but I don’t want to pull the starter again for no reason. The cable connector on the starter looks normal.

Thanks for any insight into this.
Roadtripper


#2

You will need a couple of days on a 1 amp trickle charger, but try removing the battery from the vehicle, or at least removing the battery cables while charging and see if that helps to get it charged up faster.


#3

Thanks Keith. I did have the cables off the battery, but even so probably had less than 20 amp hours, maybe much less. And as I suspected, simply trying to start it a couple times probably drained most of what I’d replaced.

After opinions from a knowledgable friend, I’m going to swap in my other battery - he said I won’t risk anything. It seems the battery is probably expired, based on the date mark, and I can accept that. But I’ll have it tested in the interest of “science”.

That said, there may be a small parasitic drain to trace, the ammeter showed .22 amps draw with the meter connected in series (between neg battery cable and neg post. My newer Caravan (1996) showed .10 amp for the same measurement. My friend thought that .22amp seemed high for just the computer, and there were no other obvious draws, though it’s an older computer. I’ll see if I can find a parasitic drain.

But at least the hunch is that I don’t have to mess with pulling the starter.

I appreciate the reply.


#4

Yes, that drain is too high. It might point to a problem with the alternator diodes. Is the alternator slightly warm to the touch?


#5
Is the alternator slightly warm to the touch?

Can’t tell now since the battery is disconnected since I have the charger going. Would that have been enough to drain the battery overnight, say 14 hours?

There’s a possibility that my trailer wiring may be implicated. When I discovered the dead battery, I immediately pulled the plug on the trailer. It had been connected for several days, and started many times during that period.

Today, after I swapped in the other good battery, the van started fine several times over a span of an hour. I rechecked the drain and found it as before, about .24 amp. Then I repeated that measurment with the trailer plugged in, and got the same drain, .24 a, presumably excluding the trailer wiring from the problem. BUT…immediately after that check, the starter would only give the click click rattle sound.

Ergo…battery on charger.

I don’t need the trailer anytime soon, so I can at least try to determine if the problem occurs without it, and proceed from there.

Thanks @NYBo.


#6

@WesternRoadtripper

If you don’t mind me asking . . . how old was that first battery, the one that tested surprisingly good for its age?

Anyways, if you’ve still got a 240 milliamp draw without the trailer hooked up, you can leave the trailer unplugged. It’s got nothing to do with it.

My advice is simple: Leave that DMM hooked up and start pulling fuses one by one, until the draw drops to something acceptable, 50 milliamps or less

After each fuse you pull, wait a few seconds to see if the draw drops. If not, put it back and proceed to the next one. It may take awhile. And it may be something unfused . . .alternator or some module


#7

@db4690
Fair question, no I don’t mind you asking…It’s time was up, just over 7 years, so I got my money’s worth. That’s why I was surprised when the tech told me it had a lot left in it, I can’t now remember the number he said.

However it’s curious, or hopefully instructive, to note that the other battery was working fine in another car, and then, when I installed it in the problem vehicle, it started the car a few times in an hour. Then, immediately upon re-connecting the trailer wiring, that battery also failed to energize the starter. Also an old battery, I admit. But my point is that something in the vehicle in question (or the trailer) seems to have sucked power from it in a short time. I wish I’d gone for a little ride to continue charging the battery…instead I just shut it down, but by that point, I was presuming the problem had been resolved.


#8

@WesternRoadtripper

I’m confident you’ll find the cause of the draw


#9

@db4690:
My newer Caravan measured a draw of .10 amp (100ma) which a friend thought was about typical to power the computer - memory I guess. But you say it should be 50 milliamp or less. How significant is that difference?


#10

@WesternRoadtripper

If you have a 50 milliamp draw, the car could literally sit for months and still start

If you have a 100 milliamp draw, I don’t believe you’d get away with it


#11

Did they give you a cranking amps on the battery test? I noticed my daughters car battery sounded a little lame, had it tested for cranking amps, and it only had 35 amps cranking power, she did not have a problem, got a new battery on the spot, but I think your battery is the prime suspect.


#12

Thanks @Barkydog

I saw the battery tester reading when the tech did the load test, then promptly forgot the number. All I remember was that it was better than it should have been, given the age.

For other reasons, I think it’s more complicated than just the battery. I’m thinking the cables may be the issue, and then there seems to be something which abruptly drains the battery, perhaps something intermittent. I’ve just not had time to pursue it today.

The first clue is that the starter would only click/rattle after I’d charged the battery for 20 + hours on a 1 amp charger, but when I moved that battery to my other Caravan, the car started fine.

The second is that the previously non-starting car cranked fine with the donor battery three or four times over an hour, but immediately after I reconnected the trailer wiring, the starter would only click/rattle.

Today I drove all over town, making several stops, in the newer Caravan powered by the battery which was dead as a doornail on Saturday morning, the one with more cranking amps than a seven year old battery is supposed to have.

So I have to believe there’s more going on here than just the battery. I’m going to start with cleaning or replacing the cables.


#13

Car batteries tend to have about 30 amp hours of capacity, so if it was totally dead and you charged it at the 2 amp rate it would take, what, 15 hours, so it seems like 24 hours should have been enough to charge the battery fully. Probably what I’d do is take the battery in for a load test. If the battery tests ok and you still get clicks, then I’d measure the voltages at both terminals of the starter motor (compared to the case ground). Both should ideally be above 10.5 volts during attempted cranking. If you got this voltage ok on the starter motor and it isn’t turning the engine, then there is almost certainly something wrong with the starter motor.


#14

Trailer wiring? If it worked before hooking up the trailer wiring and then stopped when you hooked up the trailer wiring, I would start with the trailer wiring.


#15
I would start with the trailer wiring.
--@knfenimore

Thanks.

Yup, I immediately suspected the trailer, and disconnected it as soon as I discovered the dead battery. That much was obvious. But after extended time on the 1 amp charger, the starter only clicks. And in the intervening time, I’ve just not had time to do a systematic investigation - higher priorities have prevailed. Maybe tomorrow.

At this point, I don’t know if the battery has enough charge…I just know the starter isn’t spinning but horn and lights seem fine. Bad cables, bad ground, phantom draw, starter problem, or ???..all remain to be checked. I hope I find something simpler than pulling the starter for the second time in a month.