AlanO Posted July 7, 2021 Share Posted July 7, 2021 270R purchased 'new' couple of months ago (2019/20 car sold back to CC after self build and purchased by me). Have had battery replaced under warranty and still under warranty so will get in touch with CC. But in the meantime is there anything I can check? Had long runs always with sidelights but that surely won't run battery down? (Haven't left lights on etc) Next step is to jump start, long run and leave with battery disconnected? Also will check battery earth strap. Any ideas please as although under warranty would like to resolve. Thanks. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 7, 2021 Member Share Posted July 7, 2021 Private Message sent. Link to comment Share on other sites More sharing options...
ScottR400D Posted July 7, 2021 Share Posted July 7, 2021 Are you putting the battery on charge when it's not being used? Do you have an isolator switch?If the answer to those questions is no, then I would suggest that you get a conditioning charger, fit a 12v cig socket direct to the battery and always leave on charge. This is the best solution IMO.Other options are to lift the hood every time you leave the car and connect the charger, fit an isolating switch or, as you say, disconnect the battery. IME, the immobiliser drains the battery and it doesn't take many days before it won't start. By now your new battery may be damaged anyway but maybe not. Link to comment Share on other sites More sharing options...
Area Representative Iain McCallum Posted July 7, 2021 Area Representative Share Posted July 7, 2021 Going back to basics i presume you have checked that the alternator is ok? Battery voltage should increase to around the 14 mark when the engine is running.Iain Link to comment Share on other sites More sharing options...
ScottR400D Posted July 7, 2021 Share Posted July 7, 2021 The alternator or some other fault is always possible but these batteries really don't do well unless isolated or charged when the car's standing. IME.My first battery lasted about 2 years. I then fitted a 12v socket and leave it on the conditioner (or fully disconnect over winter) and its replacement is going strong 4 years later. Link to comment Share on other sites More sharing options...
Roy Blyth Posted July 7, 2021 Share Posted July 7, 2021 I've had the same problem and after getting advice on here, I fitted one of these which is plugged in whenever the car is not in use. I also check the battery fluid level every couple of months. So far, so good... https://www.tayna.co.uk/battery-chargers/ctek/xs-0-8/ Link to comment Share on other sites More sharing options...
MarkD Posted July 7, 2021 Share Posted July 7, 2021 I've had battery issues in the past (Banner in a k series) which I suspect is related to the immobiliser but these have so far gone away since I had an isolator fitted and a regular check on the water level, which in the last 18 months has needed one top-up. Link to comment Share on other sites More sharing options...
AlanO Posted July 7, 2021 Author Share Posted July 7, 2021 Thanks for comments, which I'll take on board. I don't have an isolator and haven't charged the battery but I'm talking about the battery going flat overnight, although not on every occassion which could point to a dodgy earth connection perhaps? Ie. Went for good run day before yesterday, not used yesterday, wouldn't start this morning. I've been advised not to charge via 12 volt supply but content to disconnect battery and charge overnight, but cannot believe this is functioning correctly if this is needed. Could understand if left for a few weeks. Link to comment Share on other sites More sharing options...
OldAndrewE Posted July 7, 2021 Share Posted July 7, 2021 Do you know that the battery is actually flat, i.e. have you checked the voltage across the battery terminals before and during trying to start (need some assistance there). A battery will not go flat overnight unless it is dud or there is a considerable drain on it. Link to comment Share on other sites More sharing options...
ScottR400D Posted July 7, 2021 Share Posted July 7, 2021 It wouldn't take a few weeks to discharge. A few days maybe, overnight is extreme but your battery needs to be fully charged in the first place, which running it may not achieve. Nothing wrong at all with charging via a 12v cig socket, (If it's good enough for Porsche.....) lots of us do it. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted July 7, 2021 Share Posted July 7, 2021 If there is no parasitic drain, I found my Banner could go for 3 months or so when stored around the freezing point in the winter without needing a charge (ensuring the electrolyte level in each cell was correct several times a year, too). With the AGM battery I currently use, it can go a full 6 months over the winter without a charge.Overnight or weekly need for charge would indicate a major parasitic drain or shorted cell in the battery. A 100mA parasitic drain would take almost a week to drain 50% of the charge from the Banner battery. Link to comment Share on other sites More sharing options...
AlanO Posted July 7, 2021 Author Share Posted July 7, 2021 Thanks. No, I can't be sure atm about voltages and will need to check. Link to comment Share on other sites More sharing options...
Tom_Arundel Posted July 7, 2021 Share Posted July 7, 2021 Had this happen to me and came to the conclusion that the alternator won`t keep up with demand if you run below 3000 rpm with lights on, so I run in 3rd/4th if necessary to keep the revs up. I think the alternator has a larger than standard pulley to reduce the stress at high (track) rpm. which makes it run slower at low revs. If you hit traffic or traffic lights etc on the way home you can spend enough time at low revs to take the edge off the battery and the immobiliser will drain the rest to a level where it won`t start. Link to comment Share on other sites More sharing options...
ScottR400D Posted July 7, 2021 Share Posted July 7, 2021 That makes sense, IMO. Link to comment Share on other sites More sharing options...
AlanO Posted July 7, 2021 Author Share Posted July 7, 2021 Ahh, you may be onto something as I'm still running it in so keeping revs low. Will do some further voltage checks tomorrow and give a decent run above 3000. Link to comment Share on other sites More sharing options...
AlanO Posted July 7, 2021 Author Share Posted July 7, 2021 Ahh, you may be onto something as I'm still running it in so keeping revs low. Will do some further voltage checks tomorrow and give a decent run above 3000. Link to comment Share on other sites More sharing options...
Area Representative Piers300 Posted July 7, 2021 Area Representative Share Posted July 7, 2021 I would check the battery charge voltage when the engine is running and if I recall, you should see around 13.6 to 14.2 volts dc. If the voltage is only 12 volts when the engine is running, then you have a problem with the alternator or a slipping belt. I would connect the charger directly to the battery, but make sure you are using a CTEK or similar Constant potential charger, I.e. fully automatic . With these chargers, you can leave it connected 24/7, as when the battery voltage and charger voltage are equal, then no current flows. Piers Link to comment Share on other sites More sharing options...
AlanO Posted July 10, 2021 Author Share Posted July 10, 2021 So I jump started and it fired first time. All good although at that point wasn't able to measure voltages. Went on good long run keeping revs up, no lights/wipers to drain power. Left for 24 hours with battery disconnected. Now able to measure voltages (drove home to pick voltmeter and stuff up). Battery has 11.8v, which drops to 11.4v when turned on (pump presumably). Engine won't turn over, starter just clicks (series of quick clicks). Battery now on charge (CTEK). Unable to confirm atm that there is a secondary earth strap to engine mount but earths that I have found are clean and secure and no difference between chasis and block voltage readings. My plan is to charge battery, start car, run and take voltage readings. Happy to hear what others would do in these circumstances. (yes, phone call to CC on Monday if not resolved is on my list). TIA. Link to comment Share on other sites More sharing options...
revilla Posted July 10, 2021 Share Posted July 10, 2021 At 11.8/11.4 Volts your battery is either completely flat or faulty. You really need to measure the voltage with the engine at say 3000rpm to know whether the alternator is charging it (in which case it's probably a battery fault) or not (in which case it's probably an alternator fault). Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted July 10, 2021 Share Posted July 10, 2021 Relatively new batteries can fail with an internal short between the plates that causes self-discharge, perhaps covered by warranty if the car has been on the road for less than a year? Usually an internal short will only affect one cell when the battery is sitting unused and disconnected, typically the battery voltage will start at 12.6V and stop decreasing when it gets to 10.5V as the faulty cell becomes fully depleted in charge. When the car is running the shorted cell can affect charging of the others cells, too. Link to comment Share on other sites More sharing options...
ScottR400D Posted July 10, 2021 Share Posted July 10, 2021 I wouldn't try to reach a conclusion until the battery has had a full charge from the CTek. I don't think CC have fitted the earth straps to the engine mount for some years now. When I built my car in 2015 that was the recommendation but I didn't want to damage the chassis at the mount point and I made up a short lead from the negative terminal to a screw insert just to the left of the battery near the air filter. Despite suggestions that it might not last very long, it's been faultless and I believe that is what is now recommended in the latest build manuals. Link to comment Share on other sites More sharing options...
AlanO Posted July 10, 2021 Author Share Posted July 10, 2021 Thanks all. Battery is currently on charge so bit of a wait. BTW, this is the 2nd battery car has had . Went on road 'new' in May but by time I'd got home from CC battery was dead. CC replaced it. Starting to think it's alternator problem but will know more when I run it. Link to comment Share on other sites More sharing options...
AlanO Posted July 10, 2021 Author Share Posted July 10, 2021 Battery voltage 13.4 when charged. 50min run and at 3,000 rpm shows 12v so suspect alternator issue. Thanks for your suggestions and help everyone. Link to comment Share on other sites More sharing options...
AlanO Posted July 10, 2021 Author Share Posted July 10, 2021 Battery voltage 13.4 when charged. 50min run and at 3,000 rpm shows 12v so suspect alternator issue. Thanks for your suggestions and help everyone. Link to comment Share on other sites More sharing options...
revilla Posted July 10, 2021 Share Posted July 10, 2021 Yes at 12V the alternator just isn't putting anything back into the battery. Link to comment Share on other sites More sharing options...
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