With this unseasonably warm weather in the NE, I pulled out the MINI this past weekend, changed the oil, checked fluids, and charged the battery up. To my surprise the car started on the first crank. The next morning I went out, opened the door saw the interior light pop on, crank and nothing. After that not even the interior light would turn on.

I charged the battery again, started no problem. The next day same thing. I took the battery in and had it checked, it was fine (12v 550cca, etc.). So I am thinking the alternator is bad... my one question is though is it strange that I have electrical in the morning, try and crank and then have totally discharged the battery so much that the interior light no longer works? Could it be a short? Bad starter?

I plan on charging the battery tonight, removing the ground and seeing if the car still runs. That's the old test I know of for the alternator. Is there anything else I should be checking?

Thanks!

 

Doesn't sound like the alternator to me. The symptom of a bad alternator is starting with a charged battery, drive the car for a long period of time and have the battery voltage drop until the lights dim and the accessories no longer function. If you charged the battery and it started, then didn't drive it and the next morning it wouldn't start, the alternator didn't even get a chance to charge the battery. Nah, not likely the alternator.

Could be a number of things. On day 2 (after charging, starting, then sitting overnight) did it crank fast then nothing or crank very slowly then nothing?

To me it sounds like battery cable clamps, the battery, or even a dodgy starter solenoid (although unlikely). Do yourself a favor and pull both battery leads from the battery and give them a good cleaning. Inspect the clamps on the ends of the cables and make sure they're good and tight (meaning the cable is secured well in the clamp.

I had a similar problem with a no-start situation and it turned out to be the positive battery cable clamp at the battery. The PO used a cheap replacement clamp that was too big for the cable. I replaced the clamp and the problem went away for good. I couldn't reason it out completely but it was an easy fix.

Good luck. Don't rule out your alternator until you confirm the other stuff: battery (likely), cable clamps (likely), starter solenoid (maybe).

 

Thanks. Good questions.

On Day 1, after charging I did drive it for a good 45min or so around town. So the alternator had a chance to run and charge the battery.

On Day 2, there was nothing, not even a crank. I don't even hear the starter motor, as soon as I advance the key to ignition the dash lights come on and then immediately turn off and the battery is discharged. I charged the battery again and did start driving it around. On my way home it was starting to get dark and I noticed that my dash lights and tail lights were flickering on and off. I figured it was a loose connection (same fuse/circuit) for those lights. When I got it home and the car was idling I could not reproduce the flickering. I am not sure it is related or not. But perhaps there was not enough voltage or intermittent voltage?

I'll check the battery connections. Like I said, I took the battery into an autozone and they tested the battery and said it was fine.

Anyway to check voltage coming off the alternator?

 

with the engine off and the battery surface charge removed (headlights on for ~ 5 mins) a good battery should read about 12 volts post to post. with the alternator charging it the battery should read about 13.6 volts. if the battery voltage doesn't go up with the engine running the alternator is suspect.

jeff

 

Awesome. Thanks

 

I assume you checked the fan belt to make sure it wasn't slipping. Maybe you have a constant drain from some component when the car is shut off which causes it to slowly drain the battery, but you did mention that as you dove, the lights began to flicker. That shouldn't happen if the alternator is charging. I once had a TR3 that had lights dimming as I drove-turned out to be a loose belt. Good luck!

 

I would also check the cables that go to the battery as well your ground strap. The may be loose or corroded.

 

any decent parts store (chain) or mechanic should have a 'charging system tester' which will tell you if the alternator is putting out properly.

unfortunately I've had part staores "test" my battery and tell me it was 'good' and still have problems which eventually were solved by a new battery. Their test typically looks for a bad cell and does not determine if the battery HOLDS the charge, just is it chargable. And IME if the battery is a gell or mesh (like an OPTIMA) forget about it, their testers are no better than a toaster.

Ground strap is a good place to check including the engine block ground strap, not just the one at the battery. On my car the block ground strap comes off the block above the clutch end at the engine steady and runs along the engine steady connecting to the firewall end of the steady at the bottom of the holding bolt. If the nut comes loose you don't see it because it is on the underside of the steady. If loose here, the alternator can be functioning 100% but there is no good circuit to charge the battery when the car is running; & if the strap is loose there is no complete circuit for the battery to start the car. It can be flakey as the loose strap moves around and sometimes connects and sometimes not - this one drove me nuts for the first 6 months of ownership on my 79 - once found and tightened I never had another starting problem

When the battery is kaput, can you jump start the car? Does it continue to run?

 

No, I did not check the fan belt for slipping. I will check that as well.

I did check the cables to the battery and did not see corrosion or wear, nor with the ground strap. When the battery is charged, it cranks strong and without issue. I would expect issues with starting even if charged if the cables were the culprit. But since it always starts on first crank with a charged battery, I think I can eliminate cable issues around the battery.

Have not tried to jump the car so I cannot answer that. I am planning on charging the battery tonight, disconnecting the ground and seeing if the car still runs. I'll also check voltage across the battery with car on and off as suggested. If the car stalls or voltage doesn't pick up past 12v running I think its going to be a bad alternator, alternator connection, slipping belt.

thanks everyone!

 

OK, something odd happened. This morning when I left the battery was dead, no interior light, nothing. I just got home from work, wanted to grab something from the car, opened the door and the interior light turned on... I flipped the switch for the headlights and the interior light went out and the headlights didn't turn on. I closed the door, reopened the door and no interior light anymore.

Some sort of short? Seems odd.

 

I'd be looking for a **** poor ground .... changes from good to bad depending on the tightness/corrosion ....

we've said it twice

let's try one more time

CHECK YOUR GROUNDS

 

Like I said, I don't think it can be a ground issue if EVERY time there is a charged battery it cranks. And when I jumped it cranked. If there was a sporadic cable issue it would have affected at least one of those attempts in my opinion.

But, I did check the grounds, cleaned the connections, etc. But nothing was loose or corroded.

I did remove the ground from the battery while the car was running. It did not stall right away, but did immediately when I turned on the headlights. Repeated again and was able to duplicate. The draw from the wipers, radio and flashers did the same thing and stalled the car. From what I've always been told this is a telltale sign of an alternator. (Btw the belt was not slipping)

Also, the voltage across the battery with the car running was ~12v, not the 13v+ I would have expected.

 

Just reporting back. A new alternator installed and so far so good. None of the issues before are present. I'll be keeping an eye on it though and will report back. Tanks for the help!!

 

So what did you end up buying? I have a GM 1-wire alternator waiting to be installed but haven't gotten around to it yet. Did you just buy a Lucas replacement?

 

I got an uprated 70amp one that was fitted to the MPI MINIs. It's a direct bolt on for any MINI with an alternator. It was only a bit more than the replacement 40amp one. Not sure I will ever have enough accessories to justify the higher amp one but... Model GXE2297

 

If you've got interior lights, then turn the key and everything goes out and doesn't come back, you've got a loose ground or battery post or something like that.

If you fixed this with a new alternator, you probably just got lucky and tightened the right ground or battery post or alternator connection or some other electrical wire. I suppose there's a chance the alternator had a short in it, but that's unlikely to cause this same sequence of events.

I've seen this with many cars and its almost always simply a matter of cleaning and tightening the battery posts. Battery posts corrode from the acid and that corrosion shorts out the connection to the battery wires. I've had cars where I just had to bang the battery posts with a "small" hammer. With these crazy little cars and their Lucas systems, the ground wires can cause this same effect, but without the acid its not as prevalent.

I hope the alternator continues to work for you.

 

Its true that some of the symptoms of were indicative of a ground short, and I did go through and clean terminals and connections and have not seen that same issue again.

The telling signs of the alternator issue were two fold 1) no increase in voltage across the battery with the car running. I saw just around 12v whereas I should have seen 13v-14v and 2) the car dying with any additional load once started and the battery disconnected. If it was the earth ground strip for example the car would have stalled immediately when I disconnected the battery. Seems like I was getting some charge from the alternator but not enough.

 

glad you got it sorted.

 

Yes, it certainly sounds as if you checked all the possibilities. Congrats!

I wish I had a 70 amp alternator. I might actually wire up the rally lights.