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Old 1st July 2019, 10:14 AM
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johnny_quattro johnny_quattro is offline
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Default 11.9 volts

I've been having quite a lot of trouble recently starting my car, and my recent purchase of a 600 Amp battery pack has been a very worthwhile investment, I can assure you. For those interested, it's a DBPower device which can start cars of up to 6 litres capacity. Booked the car in with the local garage to clean up the fabled battery/starter motor/alternator connection box on the chassis rail towards the front of the car. I last had it attended to around 7 years ago and as per usual, it was all crudded up with verdigris (that bluey/green stuff).

I still had problems starting the car so went up to Harry Halfords to get them to do their Yuasa battery test on my silver 019 battery. They told me the battery simply needed charging (showed capacity as 408 out of 800) which then led me to conclude that the alternator is on its way out. One minute it shows 12.3V with engine running, occasionally showing as much as 12.9V but if any accessories are on, voltage drops again. The aircon fan when it kicked in was enough to see it drop on occasion to 11.9V to 12.2V. That's never enough to charge, bearing in mind it's 2.1V per cell, so around 12.6V under ideal conditions. Before I attempted to start the car, it was showing 11.5V.

A quick emergency-type phone call late Friday evening to the forum sponsors, a nice chat with Maria and I have a replacement alternator on its way to me this morning - mileage from that S8 car when the alternator was removed should (in theory) give us another 50 to 60 thousand miles of electrickery....

I'm looking forward to getting this done tomorrow as I've been unable to use the aircon/stereo for obvious reasons.

Note - I obtained my voltage levels using the two-button push on the climate controls, using register 36 on the LHS to show the voltage on the RHS display. Another useful register to monitor is 102, which came in handy for coolant temperatures when my thermostat got stuck/old.

How to:
Press and hold the recirculation button, and then press the vent control up arrow. The left temperature indicator then displays a code number, and the right temperature indicator its value. Traverse the codes with the temperature + or - buttons.
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  #2  
Old 1st July 2019, 11:55 AM
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Default What voltage?

It would be interesting to know what other people see voltage-wise on the climate control display. Assuming 14.4V when the engine/alternator is running (ideal conditions), I would expect to see perhaps 13.8V, allowing for a sniff of voltage drop due to the battery location. Whenever I've measured the voltage connected directly to the battery terminals in the boot, it's approximately 0.3V lower when register 36 is selected, as per my previous post on how to obtain the voltage display on the climate controls.
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Old 3rd July 2019, 11:31 AM
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Default The saga continues...

This problem is bugging me. I'd had the car rigged up to a mains-powered battery charge the previous day for around 7 hours on a fast charge. I did this in preparation for the alternator replacement. It started up OK but not as quickly as I would have expected.

After the alternator was replaced yesterday with the supplied S8 alternator from a younger car, all seemed well as I was seeing 13.1 to 13.5 with my cheap LED thingy I plugged into the 12V socked on the centre console. Parked the car up for 10 minutes at a friend's house and it would not start. Jump-started myself with the aforementioned DBpower unit, and managed to make it to Harry Halfords for my second test of the week, with a handheld Yuasa-branded box of tricks - again it said that the battery was good and needed charging, this time it was showing 485 out of 800 or so. The positive battery terminal was certainly very warm, whilst the negative terminal was stone-cold. Worryingly, the tester unit was only reporting 12.6V under load, i.e. headlights on main beam and electric A/C fan in operation.

Summary:

[1] I have to start the car using the jump pack each time as there's not enough grunt to start it
[2] Connection block on front chassis rail has been cleaned up and reseated and is free from deposits of verdigris (bluey-green stuff)
[3] Alternator replaced with 150amp one from forum sponsors. Note that the 'new' alternator didn't have DF spade connector on it which was present on my 'old' alternator.

Does anyone have any pearls of wisdom to offer before I go down the detailed auto electrician route?
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Old 3rd July 2019, 01:07 PM
MikkiJayne MikkiJayne is offline
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It sounds like something is eating a lot of power when it shouldn't be then. The battery terminals certainly should not be warm. Is the terminal itself connected ok? A bad connection to the battery post could cause a resistance which then generates heat. Its quite common for people to over-tighten the terminals which crushes them, then they can't seat on the battery post properly. Is the top of the terminal flush or below the top of the battery post?

Have you had a look in the access panel above the battery to see if the main fuse is also getting warm?
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Old 3rd July 2019, 02:56 PM
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Quote:
Originally Posted by MikkiJayne View Post
It sounds like something is eating a lot of power when it shouldn't be then. The battery terminals certainly should not be warm. Is the terminal itself connected ok? A bad connection to the battery post could cause a resistance which then generates heat. Its quite common for people to over-tighten the terminals which crushes them, then they can't seat on the battery post properly. Is the top of the terminal flush or below the top of the battery post?

Have you had a look in the access panel above the battery to see if the main fuse is also getting warm?
I'm going to check the car shortly for its daily starter test. Terminal connectors are on solidly with no movement. I'm fairly sure (from memory) that the terminals are both level with the battery posts. Will check the main fuse as suggested. Thanks, MJ.
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Old 3rd July 2019, 07:20 PM
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It's the simple things in life that count.

Battery terminals were level with the top of the battery posts but the voltage was still low with the engine running. My positive battery terminal (and the post) were warming up rather nicely which proved in my non-electrician's mind that there was some resistance causing the problem. I went to the effort of checking for parasitic drain whilst I was there, even though that wasn't the root cause of the problem. Nothing out of the ordinary when I checked the mA draw on the multimeter.

Took both terminals off the battery and inspected the battery posts. I noticed that there was a vertical ridge on both terminals which you could feel with your finger, let alone a nail. I suspect that this may have been down to the local grease monkey over-tightening the terminal - this may have been due to the work done where the local garage replaced my fuel pump recently. I managed to remove the ridge that was present on both posts and then applied some copper grease to the terminals.

End result - was able to start the car without my jump pack for the first time in a week or so. I checked the voltage and was now seeing 13.6V with the amp/stereo pounding away. Checked the posts after 10-15 mins of idling, and both terminals were 'cold'. I've just been on a good run in the car, with some spirited driving as they say. Famous last words and all that, but I think it's now sorted. Motto of the story - always double-check connections even if the terminal connections appear to be well secured to the battery posts.
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Old 3rd July 2019, 09:08 PM
ainarssems ainarssems is offline
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Glad to hear it's sorted but copper grease on battery terminals, first time I hear it. I normally file battery terminals and cable clamp inside shiny, attach and then apply general or anti corrosion grease on the outside after assembly.
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Old 4th July 2019, 10:42 AM
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Quote:
Originally Posted by ainarssems View Post
Glad to hear it's sorted but copper grease on battery terminals, first time I hear it. I normally file battery terminals and cable clamp inside shiny, attach and then apply general or anti corrosion grease on the outside after assembly.
My tube of copper grease must be about 20-25 years old now, only about half the size of a tube of toothpaste so therefore used sparingly but with great effect.
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Old 7th July 2019, 08:01 PM
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I was taught to use Vaseline.
I keep a special "garage use only" pot in the garage.
Of course I also use it when messing with water hose connectors.
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Old 13th July 2019, 10:52 AM
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Default Famous last words - goodbye Yuasa Silver battery

I started to have problems again where I'd left the car overnight and it would start up fine, but if I drove the car and left it for 10 minutes, it was flat as a pancake and only hinted at turning the engine for 1/4 of a second before the click of death from the starter motor solenoid. An auto electrician was employed and the subsequent load test of the battery (after being left on charge overnight) showed almost complete failure - 300 amp load was placed on the battery but before it had got to 180-200 amps, the voltage was showing as low as 8.4V-8.5V. Battery was therefore toast and a letter on headed-paper was given to me so that I could go and get a refund from Harry Halfords.

The auto-electricians involved mentioned that they had dealt with a fair few customers over the last year or so that had had issues with starting their cars and a high percentage of them were Yuasa Silver. Suffice to say, Johnny G now has a Bosch battery.
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