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Bl**dy alternator again!


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Ok John, I see where you're coming from. However, the alternator will self excite when the revs are high enough. Given that you've had 3 major failures from 2 new alternators, that your rev counter read out is erroneous and that your charging volts are varying outside of normal expected parameters I would be inclined to keep it simple and blame the alternator. That's why I suggest swapping it for a known good one. If it makes no difference, you've lost nothing but you will have ruled out the alternator as the source of the problem.

I hope that explains why I keep wittering on about changing the alternator ?

Good luck with resolving it ?

Mo

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5 hours ago, Peaklander said:

I should add that I only have a circuit diagram for a 300TDi and  the lamp wiring is different as the lamp has IGN +12v on it which then routes through to the alternator, with the diode in series and the resistor across the lamp. In your supplied image of the older wiring the lamp has 0v and the 'other end' has the IGN+12v running through the resistor first before splitting off to the alternator and the warning lamp.

Sorry John, this is wrong - my mistake. The older diagram shows that the lamp common connection is +12v not 0v as I said, so it is similar to the newer ones except for the diode and position of the resistor.

I don't think I'm adding much to the party but I'll have another think through a little later. It is really surprising that there have been so many alternator 'incidents' so something isn't right (says he stating the obvious).

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5 minutes ago, Peaklander said:

Sorry John, this is wrong - my mistake. The older diagram shows that the lamp common connection is +12v not 0v as I said, so it is similar to the newer ones except for the diode and position of the resistor.

I don't think I'm adding much to the party but I'll have another think through a little later. It is really surprising that there have been so many alternator 'incidents' so something isn't right (says he stating the obvious).

Thats ok! 

Two new batteries arrived by courier a couple of hours ago. I've put them in and ensured all connections are tight and clean. It's all fired up first time with all the appropriate lights lit on IBS battery controller, meter etc and the output from alternator at idle is 14.7 dropping to 14.2 with heater fan on and all the headlights and spotlights.

Battery light is on with ignition switched on, goes off when started and so far it *seems* to be behaving normally, but its only been running since five minutes ago! 

I'll leave it running for a bit and give it a good check over to ensure everything is acting normally, but so far it looks very healthy.

Is it possible that a duff battery has been the cause? 

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I don't know how a duff battery presents itself at the alternator in terms of how it can load it but I guess it could create havoc with the regulator, especially if in a dual system the other battery is OK. Maybe your IBS is very clever and properly isolates a charged battery and allows the alternator to see the second one and increase the output current (charge). Perhaps this is was was happening.

The 14.7v is very nicely high and I think if the alt can put that out, then your batteries should get fully charged. I really don't know if the batteries are the cause of the apparent output fluctuations from the alt. Maybe only time will tell.

The battery lamp is certainly behaving now :D

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The IBS is an older model but its still very clever with its charging protocols. Its interesting that in a resting state the IBS was showing a single green LED to indicate 13V with the old battery pair even though the actual metered voltage was way lower than that (at rest), but with this new battery pair it isn't doing that. So its perhaps something that the IBS was doing in response to the perceived battery states. I'll give it some time and see what transpires. Thank you VERY much indeed for your help thus far - greatly appreciated!

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Update. Charged new battery pair overnight. Left to 'cool down' and they showed a healthy 12.8v each later on at rest.

The IBS battery monitor LED indicator lights are now behaving normally - and the split charge relay clicks in and out when charging happens via the main battery (it prioritises the starter then switches to the aux battery when the starter is fully charged) and clicks out when off charge, with the associated LED lights doing as expected and exactly matching the metered voltage at the battery terminals.

The odd behaviour that the IBS has been doing for a year or so and that I could not resolve - showing a 13V charge current on the main battery despite there being no input - has ceased. I have a 'smart meter' attached to the system that *should* calibrate itself to the battery charge state and indicate in real time the remaining capacity and it was previously indicating a massive voltage drop when I fired up the Eberspacher heater - it is now indicating a drop of less than 3% of full charge on the aux battery after one run of the heater, which is more like I'd expect. 

Although its early days - its pointing to the charging problem being caused by the IBS battery monitor dropping off its charge cycle probably due to some weirdness it has been detecting in the batteries. 

Certainly driving about today the alternator is putting out 14.8V and under full load - lights, heater, stereo etc was still showing 14.3V. AND the tacho reading is rock solid 800rpm on idle and responding appropriately to rev increases as I drive. 

It'll be interesting to see what happens in the next few weeks! 

Thanks everyone for your guidance and suggestions!

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JJ, that's a really good result and I hope the batteries were the cause. I have struggled with my dual battery set-up which uses a Durite sensing relay to allow the aux battery to be charged once the main is showing enough volts. In practice the main is fairly well charged all the time whereas the aux can run right down (camping cooler). The problem then is when the relay clicks in, which is just a few seconds after start-up, the discharged aux is presented in parallel with the highly charged main and the alternator output is probably compromised.

I have to check this is more detail with a clamp ammeter to be absolutely sure that I know what's going on because then I will see the actual charging current passing through the batteries and out of the alternator.

The reason I say this is because your experience has been remarkably similar in that you had a bad battery (and a good one?) and were charging them together - as you say above.

Could you just explain this though - what exactly is it?

20 hours ago, Jocklandjohn said:

I have a 'smart meter' attached to the system that *should* calibrate itself to the battery charge state and indicate in real time the remaining capacity and it was previously indicating a massive voltage drop when I fired up the Eberspacher heater - it is now indicating a drop of less than 3% of full charge on the aux battery after one run of the heater, which is more like I'd expect. 

Do you have a photo or something please?

Thanks

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5 hours ago, Peaklander said:

JJ, that's a really good result and I hope the batteries were the cause. I have struggled with my dual battery set-up which uses a Durite sensing relay to allow the aux battery to be charged once the main is showing enough volts. In practice the main is fairly well charged all the time whereas the aux can run right down (camping cooler). The problem then is when the relay clicks in, which is just a few seconds after start-up, the discharged aux is presented in parallel with the highly charged main and the alternator output is probably compromised.

I have to check this is more detail with a clamp ammeter to be absolutely sure that I know what's going on because then I will see the actual charging current passing through the batteries and out of the alternator.

The reason I say this is because your experience has been remarkably similar in that you had a bad battery (and a good one?) and were charging them together - as you say above.

Could you just explain this though - what exactly is it?

Do you have a photo or something please?

Thanks

Ha! Well I wanted something that would easily indicate ACTUAL power reserve so that the family could easily determine what was going on. Volts and % charge states are ok for geeks! And…this is fairly important I think - at some point we're building an eco house (I was a carpenter in a past life - proper 5 year apprenticeship, and did a year as a welder and gas-burner before that) but I know zilch about electrics so thought I could use the Land Rover conversion to learn about AC/DC and solar and all the associated battery malarkey. So what I've done may be overkill for a 26 year old LR camper, but I'm viewing it as another apprenticeship, and I've learned a hell of a lot by doing it, but I have to confess it's just made me realise how little I know about the complexities of electric installation and management.  However I have a very functional camper as a result.

You can use various devices for measuring appliance power drain and battery states but they all seem to involve installing a shunt and figuring out what your appliances are drawing. That seems like a colossal pain in the bum so I looked about and came across the Merlin Smartguage, which is a piece of electronic wizardry that seems to be in equal measure loved and reviled! Apparently they are fitted to various military vehicles so squaddies can see what the battery state is with absolute clarity, and many yacht owners have them. It's an easily installed three wire set up (on a split-charge system) and no shunts involved so you don't need to start messing about with cutting into your wiring looms. Two thin sense wires go to the aux battery and a third to the starter. Over time the Smartgauge determines power use and charge and works out the USABLE battery capacity of the aux battery as a %.  It can be set up to trigger alarms and chargers so is pretty comprehensive in its functions.

So my setup is a two battery system managed by the IBS split-charger & monitor. The IBS prioritises the starter battery and then charges the aux battery once the other one is 'full'. The solar controller (another ebay bargain) from Morningstar manages the aux battery. It has a dedicated 'Load' circuit for powering something - in my case it's a fridge. When the fridge is switched on and sufficient voltage comes off the solar panel it runs the fridge and surplus current is sent to the aux battery for charging. If solar input drops and stops, the fridge is then run off the aux battery alone. If the battery voltage goes below the 'safe' threshold (below which battery damage would likely occur) the solar controller cuts the fridge off, saving the battery. The Merlin can have alarms set to trigger when voltages in the system drop to 'unsafe' levels so it's a pretty useful system.

In real terms, on a sunny day the solar panel (3mm thick cheapie off ebay again) outputs almost 4amps and the fridge pulls approx 2.5 when running (intermittently) so in normal circumstances the panel is both running the fridge and charging the battery. Combined with alternator input this means efficient aux battery charging and when parked up and left the system is maintaining aux charge assuming sufficient light. 

The IBS is an old one - more than 15 years old now and detects ONLY alternator voltage but the more modern ones allow bi-directional control so can allow charging via both aux or main. So at present mine won't allow the solar panel to charge the main battery ONLY the aux battery. The  IBS can apparently be upgraded with a new controller and fancy diode but its not any kind of priority - what I've got works really well, well until I had this recent charging issue that is - perhaps the curse of complexity! 

Hope this helps.

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Oh that website you linked to is full of stuff and there's a lot to read. Thanks for that, I'll have a good read. I had a very quick look at what the Smartgauge actually measures and how it interprets the battery state. I think it measures voltage and holds some kind of map of the discharge state of various battery types in order to  match the two.

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57 minutes ago, Peaklander said:

Oh that website you linked to is full of stuff and there's a lot to read. Thanks for that, I'll have a good read. I had a very quick look at what the Smartgauge actually measures and how it interprets the battery state. I think it measures voltage and holds some kind of map of the discharge state of various battery types in order to  match the two.

Yes there's some clever software involved. But the website is pretty full-on, and the owner has been/is pretty active on various forums fielding questions and explaining all sorts of esoteric stuff about electricity - real enthusiast!

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