alternator?

[Jon Wildsmith]

11.5v is quite low really meaning they're quite discharged from what you'd expect, had it been standing for a month or two since it was last given a good run or charge? 45 mA is quite high, I would expect it to be much lower on an 80. It could be a faulty alarm, ECU etc but it could also be the mismatch in the state of your batteries if e.g. the passenger side is past its best it will drain the other battery and that's why it's usually recommended to change them in pairs.

If you get Dave to test them he will warn you that drop testing can finish a dieing battery off and if he does it at arms length it's because the last one exploded and covered him in acid!

 

[frank rabbets]

Thanks again Jon. I think I will drop test them onto the concrete floor.
I have always replaced in pairs. Hasn't been standing that long, perhaps a week at a time then starting several times and not going anywhere.

Frank

 

[frank rabbets]

Both passed. So I'll check all the earths alternator etc. Alternator is able to keep up with all ancillaries on. I had to drive for 1 hour before the LC voltmeter needle went back up to it's normal place so probably lack of use and too many startings but that does not explain 0 volts for a second.
I'll do the PSP and Tappets. Also clean out the inlet and turbo manifolds whilst I've got the bonnet open.

Frank

 

[Dave2000]

After charging them fully I would install them in the car but disconnect the alternator, then take a reading after 12 hours. Then reconnect the alternator but do not start the engine, simply check the voltage a further 12 hours later.

The first 12 hours lets the surface charge dissipate, then in theory if there is no drain from the alternator (or other device) then the readings should be identical. Remember to make sure the interior lights ect are set to NOT come on at all during testing period.

Hope that helps?

regards

Dave

 

[frank rabbets]

Thanks Dave I'll report back.

Frank

 

[frank rabbets]

I've tested the leakage from both batteries, now both showing 12.3 volts each, which now shows 0 from the nearside battery and 25 milliamps from the offside battery. These are with the non testing battery connected. Interestingly if I increase the sensitivity of the meter the reading drops dramatically. Less resistance in the meter? I hope not a faulty meter. It's the old fashioned moving coil type Avometer.

I have also taken the alternator apart and found that the brushes are in a watertight container which itself comes apart. Perhaps the earlier alternators are not like this. No chance of sticking brushes with my design.

I did find that there was a lot of rust between the alternator body and it's engine mounting bracket which is a poor earth.

There are also TWO battery earths; one each side of the block. Both very difficult to get to but offside one easy now the alternator is out of the way.

I also found a disconnected earth; one which I mistakenly left off 12 months ago when I had the offside battery off. It is by the offside battery earth and comprises a twin black and white wire on a single connector. Anyone know where it goes? I have not noticed anything not working without it.

Frank

 

[frank rabbets]

I think voltage dropping to zero could be a dirty contact in the crossover relay thus isolating the battery which supplies the voltmeter, from the voltmeter ?

Answers on a ten pound note.

Frank

 

[Dave2000]

I've tested the leakage from both batteries, now both showing 12.3 volts each, which now shows 0 from the nearside battery and 25 milliamps from the offside battery. These are with the non testing battery connected. Interestingly if I increase the sensitivity of the meter the reading drops dramatically. Less resistance in the meter? I hope not a faulty meter. It's the old fashioned moving coil type Avometer.

Frank

12.3 is way too low Frank. You should see 12.6 from a pair of healthy batteries or 12.6 even if separated. I know that 12.3 compared to 12.6 does not sound a lot but in battery terms its way too much loss, IIRC that 12.3 reading indicates batteries down to about half charge. If you are sure nothing is connected and your meter is accurate the batteries could be toast. Now I would recharge them fully and let then stand overnight completley disconnnected from each other and any possible drain which includes keeping the top of the batery dry. Measure again the following day and compare them, you are really looking for 12.6v or more.

regards

Dave

 

[frank rabbets]

Thanks Dave. I'll try again. What shall I say to Halfords ???? They are still under guarantee. Should make an interesting one sided conversation, with blank stare coming back.

Frank

 

[Jon Wildsmith]

How accurate is your meter Frank, needs to be quite accurate to be meaningful but 12.3 on a battery that has only been alternator charged and stands for long periods of time is not unusual IMO. Brand new batteries hold the charge well but after 6-12 months of use like that they will have started to sulphate and that reduces their capacity so you should expect to see lower readings. Did you charge them with the alternator or off the car with an intelligent charger?

 

[Towpack]

I've tested the leakage from both batteries, now both showing 12.3 volts each, which now shows 0 from the nearside battery and 25 milliamps from the offside battery. These are with the non testing battery connected. Interestingly if I increase the sensitivity of the meter the reading drops dramatically. Less resistance in the meter? I hope not a faulty meter. It's the old fashioned moving coil type Avometer.


Frank

Frank,

The old Avo meters were top dog in their day and still have their uses but for accurate resistance or voltage/current measurements they are no match for a good, modern digital multimeter. Try and get hold of one if you can and compare the readings.

 

[frank rabbets]

Just 1 hour alternator charge then drop tested then 3 mile drive back home. Up to my neck in tappets at mo'. Stripped alternator and looks OK. Also cured power pump leak. Cleaned out turbo pipe and inlet manifold and she started a bit rough for 3 seconds. Carbon on inlet seats so it's checking clearances today just as a precaution.

My AVO' is stamped "HQ NATO". Wonder why they sold it ??

Frank

P.S. How do you decoke finger nails?

 

[Jon Wildsmith]

Just 1 hour alternator charge then drop tested then 3 mile drive back home.

In which case I really don't think 12.3 indicates a problem with either the batteries or the charging system, more like how it's not used much Forget the 1 hour alternator charge, the drop test will have mostly negated that, approx 600 amps for what 10-15 seconds?

 

[frank rabbets]

Yes the Toyota voltmeter was defo lower after the drop test and didn't recover much in 3 miles home.
Can't understand why my 2004 100 has it's original batteries [confirmed by owner from new]. He only used it on Mways so not much stick with starter. My 80 original batteries lasted 3 years only. 1995-1998.

Tappets are spot on. Now the time consuming bit. Degrease with acetone and put a thin bead of silicone sealer . It even works with the egr valve gaskets. I've had them off several times and never bought replacement gaskets. Never leaked.

Thanks

Frank

P.S. Now the lane is resurfaced don't suppose you'll bother coming up anymore!

 

[Jon Wildsmith]

P.S. Now the lane is resurfaced don't suppose you'll bother coming up anymore!

It's a bit smooth now isn't it, wonder what it'll be like by spring! I could call in with my meter one of the days if you like, it's only a Meterman so nothing special but might be worth a comparison.

 

[frank rabbets]

I'll get the tappets etc back together and give you a call.

frank

 

[Dave2000]

How accurate is your meter Frank, needs to be quite accurate to be meaningful but 12.3 on a battery that has only been alternator charged and stands for long periods of time is not unusual IMO. Brand new batteries hold the charge well but after 6-12 months of use like that they will have started to sulphate and that reduces their capacity so you should expect to see lower readings. Did you charge them with the alternator or off the car with an intelligent charger?

I'm inclined to agree Jon with the battery having stood for long periods however, I was saying the test should be carried out after a 12 hour period, I note reading further on and if my understanding is correct, that Frank has taken his readings not after a 12 hour period but after a charge/load test/drive home scenario which is a little different from what I suggested. Of course an accurate meter is good and the Avo IIRC has an adjuster to set the needle position for accuracy however, batteries should still show around 12.6. 12.3 (assuming meter is accurate) would indicate around a 70% charge, any battery in good condition if tested as per my earlier post would show 12.6 volts or higher however, I do not know how long Halfords guarantee the batteries but I assume that the batteries are around 1 - 2 years old so should be in reasonable condition assuming the alternator is doing it's job and of course there is no other fault as we have yet to see? I still have the two Toyota batteries I fitted in February last year and as you may/may not be are aware have been doing 'all sorts' with them, and they still show 12.6 plus in the morning after all night with the alarm set and the usual parasitic draw from the 80, these are the small 55 amp hr batteries as per Toyota's fitment. Way to small for me but I am still looking for alternatives, not easy out here I'm afraid. Keep coming with the information Frank,

regards

Dave

 

[frank rabbets]

The batteries are coming up to 3 years old and have a 3 year guarantee. They are 91 amp hours. I don't know what the original rating was for the 80 but I think it was somewhat less. Perhaps the alternator is a bit small. I've looked in owners handbook but it does not give battery specs; to put you off buying one elsewhere perhaps.

The more precise any reading becomes the more one ponders how to measure it accurately. That is why there is only one yard and anyone can go to it for comparison to their yard. If " your " yard is a millionth of an inch longer it is not a yard.

I make victorian replica weight driven pendulum regulator clocks based on those used in observatories at that time. At that time, and indeed up to the 60's with improvements, these were the most accurate clocks in the world. I have made 4 but if you run them after regulation and after a few days they all drift off at various speeds. As a friend at the BHI joked "if you have one clock you know what the time is but if you have two clocks you never know what the time is". There are 84,000 seconds in a day and my best clock keeps time to within +/- 1 second per month. I only know this because I have a radio controlled clock receiving the official time. Without this I would have no idea which was the best clock.

I expect the same is true of voltmeters. I expect somewhere in England there is the official volt. Any way I'll get the batteries charged up and test their voltage and then every 12 hours after disconnection. Better than being bored.

Frank

 

[adrianr]

Clocks: Thats quite a skill you have there Frank!!

 

[Dave2000]

Clocks: Thats quite a skill you have there Frank!!

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^X2!

As a kid I decided to take the 'Hunter' left by my late Grandfather to my dad apart........ya know...........just to see how it works? You can guess the rest!


regards

Dave