Lockylockwood Posted December 29, 2023 Share Posted December 29, 2023 Hello all, me again Im having an issue whereby my defender won’t start. I’m not sure if it’s the battery or something else? When I turn the key I hear a slow cranking which gets slower the more I turn the key. I should mention that I’ve had issues with the starter motor making a grinding sound in the past but it has always worked. With this current issue when I hook it up to starter pack (which plugs into a wall socket) it eventually starts after about 10 tries. I have tested the battery with a multimeter and it reads at 12.65v. I have also done a basic test for a battery drain using a multimeter but it’s reading 0.00 (I appreciate that isn’t the best way of testing it) I don’t know if it’s the battery, the starter motor, the alternator or a battery drain? Im tempted to replace the starter motor anyway as it needs changing. Maybe that is the best way to start? Any ideas? Quote Link to comment Share on other sites More sharing options...
Lockylockwood Posted December 29, 2023 Author Share Posted December 29, 2023 I’d also like to add that whenever I have started the car (before this issue and now) the battery light stays on until I start driving. I am told the battery light doesn’t always mean there’s an issue with the battery itself and could be that the alternator is not working correctly. Quote Link to comment Share on other sites More sharing options...
Filbee Posted December 29, 2023 Share Posted December 29, 2023 How old is the battery? Quote Link to comment Share on other sites More sharing options...
Lockylockwood Posted December 29, 2023 Author Share Posted December 29, 2023 13 minutes ago, Filbee said: How old is the battery? About 2 years old Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted December 29, 2023 Share Posted December 29, 2023 What voltage does it dip to on cranking? Sounds most likely the battery or possibly poor connections. Is it a good brand of battery or a random cheapy? Quote Link to comment Share on other sites More sharing options...
Lockylockwood Posted December 30, 2023 Author Share Posted December 30, 2023 9 hours ago, FridgeFreezer said: What voltage does it dip to on cranking? Sounds most likely the battery or possibly poor connections. Is it a good brand of battery or a random cheapy? It was one of the cheap ones from Halfords website that showed as compatible for my defender 90 200tdi (retro from 2.5TD). This one: Halfords HB072/HCB069 Lead Acid 12V I tried to charge it overnight and it is still showing as charging this morning after 8 hours. I think you’re both right. I’ll get a new battery. I don’t want to make the same mistake again so I think I’ll buy a decent one. People are recommending 1000amps and 115ah Whats your thoughts? Anything wrong with having a stronger battery? Quote Link to comment Share on other sites More sharing options...
Escape Posted December 30, 2023 Share Posted December 30, 2023 The only reason not to fit the biggest battery possible is price, as weight isn't an issue on a Land Rover. 😉 But do check the wiring to the battery and starter motor, including the earth strap to battery and engine. And make sure your alternator is actually charging and you get at least 13.5V at the battery with engine running. You don't want an existing problem to affect your new battery. 1 Quote Link to comment Share on other sites More sharing options...
Shep The Disco Posted December 30, 2023 Share Posted December 30, 2023 If the battery light is staying on until you rev up then the alternator is not working correctly. This will be because either the belt is not at the correct tension or the actuator is worn out. First make sure you have the correct alternator set up with regards to belts and pulley sizes. The alternator should charge on tick over straight away from start. Then you can see how weak your battery has become. Once you get it working correctly and the battery is fully charged you can work out weather the battery is holding charge enough to have enough power to start. If it doesn't then the battery probably needs either reconditioning or replacing. 1 Quote Link to comment Share on other sites More sharing options...
Lockylockwood Posted December 30, 2023 Author Share Posted December 30, 2023 Very strange - I just bought one of these and it started immediately. https://www.amazon.co.uk/gp/aw/d/B015TKUPIC?psc=1&ref=ppx_pop_mob_b_asin_image I checked the volts straight away and it was 13.5 whilst the engine was running I took it for a drive and it was fine. I’ll leave the battery connected all night and see what happens tomorrow. I feel like almost everything needs replacing in this old banger 🤣 Quote Link to comment Share on other sites More sharing options...
Shep The Disco Posted December 30, 2023 Share Posted December 30, 2023 SO you boosted it and it started? If it's no crank In The morning and it's charging then nackered battery. Just check the alternator is charging on tick over without revving it up after starting it. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted December 30, 2023 Share Posted December 30, 2023 As Filip says, the general rule is buy the biggest battery that will fit in the space - just beware Defenders have the terminals the wrong way round to normal so sometimes the leads won't reach if you get the wrong one! 1 Quote Link to comment Share on other sites More sharing options...
Lockylockwood Posted December 30, 2023 Author Share Posted December 30, 2023 16 minutes ago, Shep The Disco said: SO you boosted it and it started? If it's no crank In The morning and it's charging then nackered battery. Just check the alternator is charging on tick over without revving it up after starting it. Interesting! Because I only tested it with my multimeter after I rev’d the engine a bit to get rid of the battery light. I’ll take a look tomorrow and make sure I check it straight away. Thanks so much Quote Link to comment Share on other sites More sharing options...
Lockylockwood Posted December 30, 2023 Author Share Posted December 30, 2023 Ah ha! I just went out there (I couldn’t wait). It’s not charging at the right voltage when the battery light is on before I rev the engine. So that’s definitely the alternator yeah? Are they easy to swap over? I have a 200tdi engine retrofitted. Do you know which one I will need for it? Quote Link to comment Share on other sites More sharing options...
TSD Posted December 30, 2023 Share Posted December 30, 2023 (edited) If you normally have to blip the throttle to get the warning light to go out, then there's not much point measuring it before that, it won't be charging. That's not unusual for some defenders with some alternators, and it doesn't mean there is a 'real' problem. It just means the warning light doesn't feed enough current to the alternator to get it going. When you raise the revs the alternator 'self excites', and from then on it will charge normally. Normally the engine isn't left idling for long periods after startup, it's not a problem worth fixing, though a higher wattage warning light bulb, or a second bulb wired across it, will usually solve the problem. My 200tdi has the warning light glowing dimly until the first rev up, my 2.8 has it on at full brightness (and has since new). My 300tdi with disco 100A alternator doesn't have the problem. Edited December 30, 2023 by TSD 1 Quote Link to comment Share on other sites More sharing options...
Lockylockwood Posted December 30, 2023 Author Share Posted December 30, 2023 39 minutes ago, TSD said: If you normally have to blip the throttle to get the warning light to go out, then there's not much point measuring it before that, it won't be charging. That's not unusual for some defenders with some alternators, and it doesn't mean there is a 'real' problem. It just means the warning light doesn't feed enough current to the alternator to get it going. When you raise the revs the alternator 'self excites', and from then on it will charge normally. Normally the engine isn't left idling for long periods after startup, it's not a problem worth fixing, though a higher wattage warning light bulb, or a second bulb wired across it, will usually solve the problem. My 200tdi has the warning light glowing dimly until the first rev up, my 2.8 has it on at full brightness (and has since new). My 300tdi with disco 100A alternator doesn't have the problem. So what you’re saying is that the warning light is somehow blocking the alternator from charging the battery until it’s off? That’s really interesting So what I’ll do is give it a go tomorrow morning. If it doesn’t start then I’ll jump start it and buy a new battery I definitely want this issue with the warning light fixed so I will definitely follow your advice on a higher wattage warning light (although I don’t know what the wattage is of the current one) Where can I get warning light bulbs from? Quote Link to comment Share on other sites More sharing options...
Peaklander Posted December 30, 2023 Share Posted December 30, 2023 No, he's saying that it is working and it's OK. The warning light is fed with your battery's voltage at ignition-on and the other end is connected to a stopped alternator. So it lights-up. That current flowing through it also flows into the alternator and when you turn the key to start the engine and it turns over, the current is enough to get the alternator to start to generate power. Initially it is very small and the current keeps flowing and the warning light stays lit. As the engine speed increases the alternator power output increases and eventually the current stops flowing through the warning lamp and it goes off. That tells you that the alternator is working. Usually you wouldn't notice this delay as it is less than a second. So as @TSD said, it really doesn't matter too much if you have to blip the throttle to make it go out. Usually you are moving and the revs are high enough for the alternator to send power to the battery and all is well. By the way a charged battery will show about 12.8V. A charging alternator will give around 14v but that depends on its size and how much stuff you have drawing power, such as headlamps, heated windows, wipers etc. They can pull it down to less than 14v but it should be well over 13v. Quote Link to comment Share on other sites More sharing options...
TSD Posted December 30, 2023 Share Posted December 30, 2023 25 minutes ago, Peaklander said: No, he's saying that it is working and it's OK. Thanks Peaklander... Sorry, I'm a slow typist... 11 minutes ago, Lockylockwood said: So what you’re saying is that the warning light is somehow blocking the alternator from charging the battery until it’s off? Yes and no. The warning light serves more than one purpose. Firstly, as a warning light.... When the ignition is on, there is 12V on one side of the lamp. If the alternator is charging, then the regulator in the alternator has 12V on the warning lamp terminal. As theres 12v on both side of the bulb, it doesn't light. If the alternator isn't charging, the regulator output falls and there now a voltage difference on either side of the lamp, so it lights up. When the ignition is shut off, the alternator is still turning and outputting 12V to the lamp, but the ignition circuit voltage is now at 0, so there's a difference and the lamp lights briefly as the engine stops. Secondly, as an exciter... The alternator uses a certain amount of power to 'excite' the magnetic field inside it before it can generate any power. When the alternator isn't turning, current flows through the warning light to the alternator, to kick-start the alternator into life. If this current isn't present, or is too low, then the alternator won't start up until it reaches a higher speed (the 'self-excitation' speed) where the stray magnetism is enough to get things going. Once it starts generating (by either method), it is capable of generating power even at speeds well below engine idle speed. You said your engine is a retrofit. Depending what was originally fitted, you're probably/possibly missing one or two parts from the wiring loom. 300tdi vehicles have a resistor wired across the warning light (the effect is the same as a higher wattage warning lamp), and a series diode to block current flowing from the alternator holding the stop solenoid open on the diesel pump when the ignition is shut off. I'm not sure what value resistor was fitted - the circuit diagram says 1000 ohms, but that seems far too high to me. Something nearer 150 ohms would be more likely I would think. The total load should be more than 0.1A (since we know that the 1.2W lamp often isn't enough) and less than 0.3A (Bosch recommendation for no more than 0.2A additional load be placed on the circuit, in the 'blue book' for those that remember it.) But anyway, if you've always had this behaviour from the alternator, but the starting issue is new, then ignore it until you've sold the bigger problem. 1 Quote Link to comment Share on other sites More sharing options...
Shep The Disco Posted December 30, 2023 Share Posted December 30, 2023 Change the pulley on the alternator would be my choice This will allow the alternator to spin a bit faster from starting without having to rev up and charge accordingly. The 100amp alternator I also have doesn't do it. It's a problem I don't like so I don't have it as a problem. If it's flat in the morning then the battery is either not holding charge or something is sucking it off.. Quote Link to comment Share on other sites More sharing options...
TSD Posted December 30, 2023 Share Posted December 30, 2023 53 minutes ago, Shep The Disco said: Change the pulley on the alternator would be my choice Remembering of course that increases mechanical wear on the alternator. It will also increase the output current available at low rpm, which might be useful in some cases. The single Vee belt setup on Defender 200tdi is often a bit prone to slipping, and a smaller pulley will make that tendency worse. (I don't remember it being an issue on my 200 Discovery). None of that is a big worry, but if it's just to make the light go out, then just correcting the electrics for less than 50p seems a better bet. But fix the real problem first... Quote Link to comment Share on other sites More sharing options...
hurbie Posted December 30, 2023 Share Posted December 30, 2023 my daily driver is a 110 with a retrofitted 200tdi from a disco , and does exactly the same , have to blip the throttle a bit to get it to charge , swapped alternators a while ago , and that didnt help . i just live with it 🙂 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted December 30, 2023 Share Posted December 30, 2023 2 hours ago, Shep The Disco said: something is sucking it off.. Quote Link to comment Share on other sites More sharing options...
Shep The Disco Posted December 31, 2023 Share Posted December 31, 2023 11 hours ago, TSD said: Remembering of course that increases mechanical wear on the alternator. It will also increase the output current available at low rpm, which might be useful in some cases. The single Vee belt setup on Defender 200tdi is often a bit prone to slipping, and a smaller pulley will make that tendency worse. (I don't remember it being an issue on my 200 Discovery). None of that is a big worry, but if it's just to make the light go out, then just correcting the electrics for less than 50p seems a better bet. But fix the real problem first... Sure . Alternator rebuilds are cheap enough. I also sit on tick ove with the radio on watching for pests so it's how I like to be set up. Quote Link to comment Share on other sites More sharing options...
Shep The Disco Posted December 31, 2023 Share Posted December 31, 2023 10 hours ago, hurbie said: my daily driver is a 110 with a retrofitted 200tdi from a disco , and does exactly the same , have to blip the throttle a bit to get it to charge , swapped alternators a while ago , and that didnt help . i just live with it 🙂 I'm going to measure the pulley sizes on different alternators and see The 200s like a tight belt forsure. I always used to carry a spare belt behind the seat . Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted December 31, 2023 Share Posted December 31, 2023 Mine does it too, and has done for the last 265,000 miles across three alternators and two looms. It’s never caused a problem! Quote Link to comment Share on other sites More sharing options...
Lockylockwood Posted January 3 Author Share Posted January 3 Update The following day I went out and it wasn’t starting again. I bought a new battery. One with a higher capacity and CCA. It seems to start every day since (although it takes a few seconds), however the battery light is still there and for some reason when I try to rev or even drive, the engine is lagging. Almost as if there isn’t enough power for something to engage the engine. Whereas before I was able to rev hard straight away. Not sure if that’s making sense to anyone? Quote Link to comment Share on other sites More sharing options...
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