Do I need a new alternator?

[BDA]

I'm worried about the battery, too. I'll see today when I (try) to take it out. Thanks for the tip about the Lucas alternator. It looks like a great fit and I found a source in the US! I'll see if I need it.

[BDA]

If the ammeter is pegged at +30A, and is at 0 when off, then you know the alt is charging.  However, it doesn't look as though the alt output is being regulated.  Hook up a voltmeter across the battery and start the engine.  Rev it up to 2500 or so and see what the voltage is.  13.8v to 15.0v is just fine.  more than 15.2v will overcharge the battery and boil it dry.

I replaced the voltage regulator a while ago and the ammeter needle became much better behaved (it had been bouncing around quite a lot but now it's pretty steady) but it still showed about +5 -to +15 without headlights and it pegs the plus side with headlights on. I checked the voltage at the battery and it was pretty erratic. The voltage bounced as high as 15.5, but it was only momentary. In general, it bounced around but rose as rpms rose. I probably didn't rev it over 3000 rpm and most of the time it was in the middle 14 volt range.

The "correct" voltage regulator is NLA but I adapted the one for the US version by bending the lugs and putting an extension on them so the wires hook like they are supposed to (the orientation of the lugs is the only difference between the "correct" VR and the one you can get that I'm aware of). I have two "correct" VRs that I don't trust so I don't know how or if I can compare them to the one I have.

I'm guessing that the almost unused VR I put in the alternator needs replacing, but I wonder if there is something else that is going on, maybe some other electrical component needs to be changed or the alternator is truly junk... The alternator pulley that Dave Bean put on my engine was a much smaller diameter one but I replaced it with one that is the stock diameter. I could put the smaller pulley on and that seems like it could at least lessen my problems since it would reduce the speed of the alternator.

Does anybody have any ideas?

[EuropaTC]

Hi BDA,

Whenever I've measured voltage at the battery to check the charge rate it's always been rock steady, maybe fluctuating by 0.1 or so but that could be down to me rather than the electrics. I wouldn't expect it to change markedly from say 1,500 rpm upwards unless you have a very large pulley on the alternator.  A smaller pulley on the alternator generally makes it go round faster/give higher output at tickover so I don't think that would solve the problem. If you want to reduce the speed of the alternator it's either a smaller pulley on the cam or larger one on the alternator. (think racing bicycle gears    )

14V is about right I think but again I'd expect it to be constant rather than moving about. 

Hmm, what next ?  My checklist would start something like this;

1. Does the alternator need a separate earth lead (like the original on mine) or does it earth through the alternator body itself ? If the former, check that lead or make up a new temporary earth lead to tick that box.

2. Battery. I can't recall if you've had a new one but earlier you mentioned you'd had to put a lot of water in. I've no idea if previous overcharging could damage the battery but it would be on my list. I would take it off and charge it on the bench.  After charging let it settle & measure the voltage.  Leave it on the bench & repeat after several hours or even next day, it should be the same. If it's dropping steadily by 0.1v as you measure, it's bust and that might be why your alternator is trying so hard to charge it up, it even might explain momentary 15V readings. 

3. I'd check the leads/connections on the charging circuit, just in case although I doubt that's the cause. Either clean all connections or with the engine running/charging, check the voltage between the +ve battery terminal and the heavy charge lead at the B+ connection at the back of the alternator. Ideally it should show nothing for perfect connections but I'd go with 0.1/0.2V.  I'd be very surprised if this is a problem having seen your car, but it's a box ticked.

4. If those check out then despite the lack of trust I'd be tempted to change the VR just to see what happens with another unit.

Actually, if I'm honest I wouldn't change the VR again, I'm so lazy that I'd just go out and buy another alternator !  Yeah, I know, that's not proper engineering but that A127 I fitted to mine has been a really neat solution....  and it was silly cheap as well.

Brian

[BDA]

Thanks for all that, Brian!

I wasn't clear, the cam pulley was the standard size (the alt. pulley was never changed). The motor was delivered to me with a small cam pulley so put the small on one back on. I also soaked the plugs in vinegar for a half hour or so (maybe I should have soaked them for longer... The larger wires (including the ground) no longer fit securely in the plug so it could be that the ground was not properly secured to the lug in the alternator. I made sure that both wires were secured to the lug when I assembled it with the small pulley. I'm using the original TCS alternator - a Delco Remy unit with four wires.

I should have mentioned that I got a new battery (the old one that was fried was replaced under warranty!  ).  I've driven maybe a couple of hundred miles or so and it needed a little water so was definitely over charging it.

After putting everything back together with the smaller pulley, the voltage between the battery posts was still a bit jittery, but never got much over the mid 14 volts. I thought the ammeter was looking good, but on my test drive, it behaved pretty much like it did before - pretty steady but on regular driving it was a bit over +10 amps (first line). On acceleration, or with the headlights on, it would get about to +30 amps - so it might be registering a bit fewer amps than it did with the bigger pulley.

I didn't test the voltage between the battery + and the big brown/white wire (to the ammeter) - I think that's what you mean by the "B+ connection at the back of the alternator". I'll look at that the next time .

So I made a minor improvement - and I expect a small improvement in HP to the wheels! 

I'm thinking for now that I'll run it like it is and watch the water in the battery. If I need water, I'll just unplug the alternator and run without it and recharge it over night. I can drive for a day on the battery. In the mean time, I'll keep my eye out for a small tractor alternator.

I looked around for a A127 and haven't seen any on this side of the pond yet. The ones I saw had the 'ear' on the wrong side so that would be difficult to set up.

[EuropaTC]

but on my test drive, it behaved pretty much like it did before - pretty steady but on regular driving it was a bit over +10 amps (first line). On acceleration, or with the headlights on, it would get about to +30 amps - so it might be registering a bit fewer amps than it did with the bigger pulley.

I looked around for a A127 and haven't seen any on this side of the pond yet. The ones I saw had the 'ear' on the wrong side so that would be difficult to set up.

There's definitely something wrong there if you're getting 10amps. Mine, with a 75amp alternator, will kick up to 10/20 amps immediately after starting and then settle back to just a needle's thickness over the neutral point.

I did a quick look through my notes and found this comment in relation to high charge rates;

"Symptoms here would include low battery electrolyte, damaged battery plates from overheating and/or burned out bulbs. The cause is usually a defective voltage regulator or poor regulator ground connection."

Most modern alternators ground through the body connection bolts but I'm pretty sure my OEM alternator required a separate ground wire.  I'm picking up on the comment about regulator ground connection so it would be worthwhile pulling it apart to make sure the regulator and alternator itself are grounded. I think in my case the ground wire went from the alternator to a point on the chassis where the engine bay cross pieces bolt on but I can't be sure as it's been several bottles of vino since I removed it.....

Maybe worth remaking the connections to tick another box ?

Brian

ps.....     more HP at the wheels ?  gotta love it !   

[BDA]

Thanks again, Brian! For a "lazy" person, you seem to keep pretty good notes!

The funny thing is that mine starts out at zero and after a little while, it goes to +10 - the opposite of yours!

I'll take it apart and with this grounding issue in mind, see what I can see...I'll also chase that ground.

I know I should have paid more attention in my electrical engineering classes, but there doesn't seem to be that much to an alternator that could go wrong after you change the VR.

[EuropaTC]

Thanks again, Brian! For a "lazy" person, you seem to keep pretty good notes!

 

Yeah, you wouldn't believe it. I have scrappy notebooks, A4 folders, all sorts of rubbish collated over the years.  All because I've a lousy memory;  I seem to be able to recall "bits" of things but never the complete picture and so in my job I relied heavily on my own filing system to keep at least an air of professional about me.  I'm slowly moving them to electronic these days but I doubt I'll ever throw away the scruffy paper.....  it's security blanket stuff.

[BDA]

I wish I were better at taking notes. When my car was 3/4ths finished (is it ever truly finished?) I finally started taking some notes. I wish I had started sooner. As it is, some of my notes just aren't as helpful as I would wish. I supposed I left out information because it was "obvious" or "didn't need to remember" it. Still, it's something I advise everybody to do when they build their car. I wish I had more pictures, too, but alas, digital cameras were not common then.

[BDA]

I thought I'd resurrect this thread rather than start a new one. I had a charging issue recently that you all might be able to help me with.

As noted in a previous post, I had replaced the voltage regulator and things seem to settle down a little. My ammeter spends most of time above +20. When it's idling and just a little above, it shows 0. I've been keeping pretty close tabs on the water level in the battery and it seems to rarely need any and when I add some, it's very little. I've been driving like this for several thousand miles including some long trips (one about 4 1/2 hours each way and another about 8 or 9 hours each way) with no issues. Lights, radio, ignition, fuel pump, clock, etc. all worked without drama. One day a week or so ago, I turned on the ignition and the clock was blinking and the radio station was no longer on my usual station which implies that there was an interruption in the current to it. I didn't remember disconnecting the battery but I might have so I reset the clock and tried the starter. The electrics went dead without trying to turn the starter. I tried it again and it started right up. The car drove without incident for a couple of days IIRC. Then, after coming home from our MG club breakfast (without incident), I went to take it to the store and the same thing happened - the clock and radio indicated that electricity had been interrupted and everything went dead when I tried to start it. The battery voltage was about 12.75 volts. I put it on the trickle charger for a couple of days. The voltage now is a bit over 13 volts (can't remember exactly). It starts right up. The voltage across the battery with the engine revving slightly was about 14.6 volts. I checked the water in the battery and added a small amount to a few of the cells but only one of them really looked low.

The wires seem to be securely fixed, the belt is in good shape, and the battery is probably a bit over a year old. I have a new voltage regulator I can put in if thats indicated. After that I guess my next move is to a new alternator.

Comments anyone?

[jbcollier]

Just a few points to start:

14.6 volts across the battery with the engine running is fine.

13.0 across after charging just indicates a surface charge and is not an indication of battery health.  Turn the lights on for 30 seconds, turn them off and then check the battery voltage.

First check your connections: battery/clamps, battery/chassis, battery/starter, battery/alt, engine/chassis, alt/ammeter, etc/etc.  Make sure they are clean, secure and snug.  Physically remove the battery cable clamps and make sure they are not oxidized.  Clean and coat with petroleum jelly.

Check that your alt belt is adjusted correctly.

Use a hydrometer and check the state of charge of each battery cell.  They all should be within 50 points of each other.  If not, replace the battery.

If the hydrometer indicates the battery is charged then do a backyard load test.  Hook up a voltmeter across the battery, turn on the headlights and crank the engine.  If there voltage falls below 10 volts, have the battery properly load tested and replaced if need be.

[EuropaTC]

On the data you've got, I would have put the alternator at the bottom of the list to check. I would be suspicious if a single cell in the battery was noticeably lower than the others but at only a year old it's hard to imagine it's got faults.

The electrical gremlins seem to be alive and well in your car with those symptoms, I'll admit I'm struggling. It's the fact that it appears completely dead one minute and then starts up the next that's puzzling.

I had an intermittent fault on the Elise when new which resulted in it working one day and not the next. The dealer initially thought it was the alarm system which well known back then for draining the battery. Over a couple of weeks he replaced the battery, alternator, STACK instrument binnacle and IIRC starter motor thinking they had internal shorts, but the problem was still there.   It turned out to be corrosion on a plug connector which was keeping some relays energised - corrosion despite the car being less than 6 months old !   

From that experience I'd go round the car checking plug connections, I'd re-make the main earth/positive connections and any relays you have fitted. If the whole car is dead then I'd start off with the earth lead and move to the starter solenoid as the primary electrical inputs.  If it doesn't work one minute and does the next then it sounds very much like a connection, the problem will be finding it because the traditional voltage drop testing is really for a continuous circuit fault.

Brian

[Certified Lotus]

Here is a wild guess. Check to see if the alternator light bulb (warning light) is not burnt out. Sometimes this bulb is required in the circuit and if it’s not working the electrical system won’t charge.

By the way, I have no idea if a Europa has one (I’m still rebuilding mine).

[BDA]

Thanks everybody! I tried to remember everything that might be suspicious but there were a few things I forgot. I have painted battery clamps which have a cable clamp held down with two bolts and captive nuts. I replaced the nuts with nyloc nuts and filed the paint from under the cable clamps. In spite of all that, I will be looking for some better clamps. I have a gear reduction starter and very occasionally it will "grind" when I go to start the car - sometimes even if I've just gotten in the car. The second attempt is probably always good. I'll get a hydrometer and check the battery and start checking connections (whoopee!). There is no alternator light (it would have been nice if it were that easy!).


I'll report back with whatever I find.

[E Paul]

Another alternative alternator is the Denso widely available in the US (Toyota) and inexpensive.  Works with existing wiring. I made a drawing of the custom bracket I made for it. PM me if you want a copy of the drawing and pics of the installation. I went through several of the Delco's during my 43 years of ownership of 4525R...the Denso one is much better in terms of output, reliability, and size.
Paul

[BDA]

Thanks, Paul. I'll keep that in mind.