Negative reading on the amp meter

[henk]

What will happen if the amp. meter on the dashboard gives a negative reading? Could it harm the battery?
Sometimes my amp. meter give a slightly negative reading when the engine is idling or a certain rpm when driving.
The regulator is set according to the manual from Lucas with a volt and an amp. meter.

[oehrick]

Hi Henk

I don't think its a problem as long as it is a small deflection, there is a certain amount of current drain when the dynamo is not charging such as the field coils and regulator coil or coils which will result in a drain on the battery. You can always turn the ignition off if you are idling for a long time.

If it stays like this quite a way up the rpm's to what might be considered working speed (we may have to wait until Brian or Pavel drop by for a figure, there's nothing in the workshop manual that helps, other than with the exciter wire from the regulator detatched you should expect output voltage to hit 24 volts by 1000 rpm and do not exceed 1000 ) you might have a charging or regulator adjustment issue. My old girl is still awaiting my fitting a new regulator ad while I'm wood wrangling spends a lot of time idling so I tend to turn off the ignition to stop it discharging.......

PS I'm assuming you are Diesel engined - not much help turning the ignition off if spark assisted Fordsoning

[Pavel]

I'm sure you are aware, Henk, that when you use a battery charger any reasonably good one will stop charging when the battery is fully topped up. When all's said and done the generator is just a battery charger and the regulator will stop it sending out more volts if it's not needed. The best way to check this is, when it happens again, to check the batt. voltage with a volt meter [with the engine off]. Depending on the battery's condition the reading should be in the high 12s or low 13s. If, in the above condition, there will always be a slight, very slight, drop in amps showing because of losses in the wiring and also that caused by the operation of the regulator cut-out mechanism.
All of that, of course, is the theory; it could be contaminated points in the regulator or a generator getting to its use by date.
The next time it happens try turning on the headlights -- this should soon cause a positive reading on the ammeter. If so, all is well.
As Rick says, turning off the ignition is an idea. Personally, I wouldn't worry.

Pavel

[henk]

Thanks lads.
I was a bit worried because I’m concerned my battery is broke again in a short time because last weekend it had a bit of trouble starting with a short rest after a long ride. The last time my battery failed it gave the same symptoms.
I will check it with an amp and volt meter.

[peter2]

Hi Henk,

check the voltage with 1200 rpm after running a longer time when the battery is fully loaded. I ruined a battery because my regulator switched off at 15V. Batteries don't like higher voltages than 14.3V - 14.4V.
I switched to an electronic regulator and have no problems since then.

Peter

[Pavel]

Peter makes a good point.
Two pointers to overcharging are (1) fuming from the filler caps [very EXPLOSIVE !] and (2) a white powdery substance around the battery posts -- this last can be got rid off by pouring very hot to boiling water over them. A dose of Vaseline on the posts and clamps, when dry, will stop corrosion and developing bad contacts.

Pavel

[Brian]

Does the battery meet the specs here Henk?



I have been using batteries from my local tyre shop and have found that some hardly last a year and they are not cheap. The 1 year old battery failed on the Rover just after I had the new computer fitted and they fitted a Land Rover recommended one. It now swings over very quickly.

The Major battery should be 144 ah which is more than the 128 ah of the 6X and 6Y 4, 5, and 7000 tractors.

[henk]

Ah. I have a 100Ah battery.

It's always on a loader (drip).
Normally it starts with no problems. This is my 3e battery in 10 years. And every time the problems start with a difficult start after it has been running normal hot.
It won’t go round the first time and at the second time it starts.

[peter2]

Hi Henk,

same here, I use a 100Ah battery, too.

I had the same start problems even with a new battery and the electronic regulator so I changed the starter, too. I don't know the exact current with the old starter but it was a lot more than with the new.
All wiring came new at the rebuild in 2013.

The new starter looks identical to the original Lucas but has not a single sign or number on it. It turns noticable faster than the old one.
Was about 240 Euros on ebay.
I want to test and repair the old one but had no time since.

My Super Major starts bad, she needs a lot of turns when cold (and a lot more when really cold), but with the actual combination of battery and starter I'm happy.

Peter

[henk]

Probably the regulator needs checking and re adjusting. As Brian shows, I need a larger battery and as Peter says, the starter motor could be a part of the problem.
And I just read an old post, saying a hot starter motor will work lesser.

Next weekend I’ll be busy.

Does anybody know how many Amp the starter motor will draw normaly from the battery while starting?

[Pavel]

On a seriously cold day, and with an engine in as new condition [unworn bores and p/rings], to initially overcome inertia the draw could be as high as 400 amps. After the first rotational movement this drops to around 200 to 250.
Whilst I would agree that the amp. hours description of a battery's power and ability is a reasonable guide, the modern designation of CCA [cold cranking amps] is a more reliable guide. For my recent purchase for my SMD I settled for 650 CCA -- but I suspect that for a colder climate 700 and above would be better.

Pavel

[henk]

Just made some measurement.
At idling no charging with about 12.3 V in the battery. Reverse up to half rpm's, about 5 Amp loading. Full rpm's regulator shuts, no loading. Going back to just above idling, minus 3.5 Amp and the voltage dropping to below 9 Volts. So that’s not good. Going back to idling, regulator shuts off.

Seems max load of 11 amp's can't be reached and the shut off is not set right. Going to try to fix that.

[henk]

Is it possible to use the regulator from the Super Major for New Major without changing a lot of wires?

[peter2]

Hi Henk,

I would say yes. It's a standard Lucas part which is used in cars too.

Peter

[Brian]

Henk,
On your Major the regulator is behind the lower instrument panel, on the Power and Super Majors the regulator was next to the air cleaner. It could be made to fit but not a simple job. There are regulators available of the same type but make sure they do not have spade terminals instead of the screw type. These will not fit, do not ask me how I know

[Pavel]

Henk; short answer is no -- some re-wiring would be necessary. Regulators on Majors before the Super had 5 wire terminals whereas the Super has only 4. May I suggest you disconnect the battery and then remove the regulator and, using glass/sand paper [NOT emery or wet and dry], gently clean the contact points. The points in line with connector E are the cutout, and those inline with the connector F are the regulator. On a petrol engine the points in the distributor transfer molecules of metal from one contact to the other. We used to clean them up with a 'points file', or on a machine, to give them a new lease of life. Given time the same metal transfer occurs on voltage regulator contacts.

Pavel

[henk]

Brian,

In 2005 I have to put a new regulator in. I could only get my hands on a spade one. It took me a lot of time and to convert it. There is not enough space in the little dashboard. But I made it fit.

Thanks for the help so far lads.

[Brian]

Henk,

I wil post this new one over to you in the next couple of days, it is only lying on a shelf gathering dust.

[henk]

Brian,

Thanks for the offer, but mine is not broke I think. It needs setting. And getting in a srew version would mean converting the wires back. So maybe you can make some else happy with it.
I was only wondering about the super version, because I think that one needs no adjustment. Or am I wrong about that.

[peter2]

Hi Henk,

on the Super is a Lucas RB108 regulator. It needs adjustment too.

Peter

[henk]

Today if het installed and tuned the regulator on the Major.
The voltage points were bad. I put replacements in from an old one I had and lined all thing out because it was out of line. That was one of the faults.
I made a study about setting the regulator with the help from you, you tube and a college.
I got it set on almost the right numbers.
There are two faults.
1: after starting and going up to high rpm's it will give about 18 Amp's. After a short time it will drop between 11 to 13 Amp's and then goes slowly further down.
2: when lowering the rpm the amp meter gives a negative reading from about 3 amp's. At that point the regulator should cut off, but it will only do this whit stationary running engine. But it's a lot better than first.
Big plus is that when using my lights the reading stays in the plus. Only when using high front lights and work light on the back it goes to negative.

I'm so far satisfied with the result.

Thanks for all the help.

[henk]

I was a bit optimistic.
Made a ride today and the loading for the battery is a mess.

Could it be that Lucas made different regulators while they look the same? Maybe charging a car or a tractor could have other parameters.
My old one say's E27N RB106/2 and has screws. And at the bottom there’s a gap between the line from A to the coil. Seems that some electrical part has disappeared there.
The new one has no numbers at all and has spades. And the A to coil line is strait trough.

I'm completely done with this problem, so I ordered an new age regulator. Something like you see on the link below.
Problem is that I need to change the system from plus on chassis to minus on chassis and polarise the dynamo and change the connection on the ammeter.
I was ensured that other than that there would be no problem. Starter engine should work normaly.
The regulator has four connection, but A1 and A can be connected together to the A terminal.

http://www.beckelektronika.nl/Lucas.html

[Brian]

That should be no problem at all Henk, change your battery leads over to give Positive output and Negative to earth. Then take a wire from your Positive battery terminal and just connect it to the Field terminal on the dynamo for a short time. It is called "flashing" and polarises the dynamo to the battery connections.

Then fit your regulator and change your amp meter connections.

The "A" and "A1" terminals on the regulator come from the same position in the regulator and are joined together anyway so you do not have to do it externally. "A" was normally used for a feed to the ignition and everything connected to the switch like lights etc. "A1" was used as an extra terminal for more functions if needed.

[henk]

So I have bought the electronic regulator and build it in. Changing from pos to neg was no big deal.

Works like a dream. It still gives a negative reading when idling, but that what it suppose to do according to the maker. It keeps giving a bit of power to the fields.

[oehrick]

That sounds to have worked out nicely Henk a little surprised they have not designed out the loss to the field coils when revs are low but it does just what the coils sort does

It would be interesting to see if others think it would be a good idea not to electric weld on the tractor without first disconnecting the device ?? I have always been wary of this with alternators but when I've had an exhaust fitted and they have welded a bracket or something on the car no one seems to have worried about this or any of the other electronic components - anyone had direct experience of auto-electronics damage by stray welding currents or is this a myth ??