Classic cars forum & vehicle restoration.

[MVPeters]

There's really no current / amperage of any consequence passing through those points.

It's the one place you might be able to kick the voltage up just a little bit.

As I said earlier, a 10/- note or very very fine sand-paper is all that's needed to clean the oxidation off them.
_________________
Mike - MVPeters at comcast.net
2002 MINI Cooper 'S'

[jp928]

So 16A is not really significant to you? Thats what my ammeter reads to. Down here the normal std household socket and plugs are rated 10A, more than that you need bigger conductors and pins.
jp 26 Rover 9

[Ray White]

This charging question is still a mystery. The car has stayed in the garage for a week now and started on the button this morning. I would have thought that if the battery was at fault it would have failed to hold a charge. Last week the battery had dropped to 4volts after a run out and I recharged it just to get the car back in the garage. I haven’t needed to touch the battery since.. I sat the car on the drive while I watched the ammeter at different engine speeds. At tick over the reading is in the charge range (it fluctuates with the electric petrol pump which is not original equipment) At no point does it swing into discharge teratory and at higher revs the the charge rate increases a few amps but the instrument reads 30 amps and an accurate reading is difficult. I would have thought that a failure to charge the battery would have shown up as a discharge reading but I am unsure about this. Truth be told I don’t know what is going on.

I have yet to take the car out again but I wouldn’t like to run out of sparks in the middle of nowhere!

[jp928]

Cant fault your logic re battery holding charge, but...I have a garage queen also - lucky if it gets used once a month for 100km. One month - battery dead as a dodo. Charged up, has been fine for last 4 months.
Check your fluid level, check the SG (spec gravity, indicates the acid strength ~= charge level) if you can (2.1=fully charged, <1.9 50%). Finally get it load tested at a battery shop. The battery in my Rover (6v) is now over a year old, gets run maybe every couple of months for < 20mins (~8A on meter), never fails to start, hasnt been charged for at least 6months now. Also carefull check all your earths for clean, free of corrosion, especially the actual earth lead, and the poles are clean, shiny, maybe very lightly greased.
jp 26 Rover 9

[Ray White]

Unfortunately my battery is a sealed unit so I can’t check th sg. I can confirm the terminals are clean and tight and the battery leads are correct heavy duty ones suitable for 6 volts. There is an extra earth that I added to the gearbox. All the wiring and accessories are quality new or refurbished as I have just completed a mammoth rebuild.

Incidentally, something which I learned when I worked in my late Father’s garage was to not use grease on battery terminals; rather, petroleum jelly (like Vaseline.)

[Ray White]

I seem to be on a learning curve these days. My 6 volt battery which I bought last June has “maintenance free” on the label. I assumed this was the same thing as “sealed for life” but no, it can be topped up if required. The caps were very tight like they had been glued on but eventually with the aid of a pair of grips they came off. The electrolyte was well above the plates so didn’t require topping up. I had charged the battery the previous night and after a few hours I tested it with a volt meter and it read 6.5. I then checked it with a hydrometer but the float didn’t’ even get off the bottom of the instrument. I tried again with another hydrometer in case the first one was faulty and I got the same result. Maybe both are faulty - I haven’t used either in years.

Being confused by these results and the fact that the ammeter on the car shows “charge” l contacted Alpha batteries who said they will collect the battery on Monday and check it out. If they find nothing wrong then at least I will know the fault lies with the car. If all else fails, I can get the car checked out by an auto electrician.

[47Jag]

JP,

THE 16A you quote isn’t really a problem because once the points are closed that is it until the engine is switched off. The damage to any type of contacts is at make (connect) and break (disconnect) time. Cut-out points are generally softer but more conductive compared to ignition points.

Art

[MVPeters]

Ray

I don't really think you've got much of a problem! Although I can't work out why the car wouldn't start, mentioned in your first post.

You've established that after a charge the new battery holds 6.5 Volts - that's fine.
You've got a healthy Amp rate of 8A - that's fine too.
All that's left is to persuade the Voltage up a little bit, which cleaning & a minute adjustment to the cut-out should achieve.

It all sounds very similar to the early Austin system (which I'm 50 years away from!). You may need to find an auto-electrician nearing retirement.
_________________
Mike - MVPeters at comcast.net
2002 MINI Cooper 'S'

[47Jag]

Wind back the 3rd brush and reduce the charge rate. Does the battery not need constant topping up with this charge rate?

Art

[Ray White]

So I have two conflicting pieces of advice. A) over charging or B) undercharging. Presumably both can't be right?

[MVPeters]

[47Jag]

Ray,

I said pull back the 3rd brush because 16A will boil the battery in no time.

Art

[Ray White]

[47Jag]

Apologies Ray,

I’m mixing your charge rate up with JP928’s contact current rating.

I’m old, I’m allowed

Art

[Ray White]

That's O.K. Art. Perhaps you could iron out a question I have been pondering.
(Remember, I plough quite a lonely furrow here in the wilds of Derbyshire so not really anyone to call on). If the dynamo is producing a healthy charge and the cut out contacts are closing as they should, and the ammeter gives a positive reading, is it possible that there could be a current leakage so as to starve the battery? Or will the short show up as a discharge on the ammeter.?

My ammeter seems to work normally ie. it swings into discharge when I turn the lights on and also when I operate the starter. Everything seems just as you would expect. I can't recall if the amps drop off after a mile or so as you would expect. The ammeter is a replacement for a non working instrument that was on the car when I got it but it seems to have been working O.K. as far as I can tell.