Jack Hartshorn Posted November 26, 2022 Share Posted November 26, 2022 (edited) Hi, I ran into a problem where my battery was going flat every time I come back from a drive, we have tried to resolve it to no avail, would anyone know what I could do to fix this? So far we have replaced the voltage control box, dynamo and the battery is only a month old. Thank you. hi everyone, thank you for all the help, I’ve swapped the dynamo got a new battery and a new control box and a new earth and it’s finally running again, thank you for all of the help. It’s very much appreciated! Edited December 3, 2022 by Jack Hartshorn Quote Link to comment Share on other sites More sharing options...
standardthread Posted November 27, 2022 Share Posted November 27, 2022 You haven't by any chance got an alarm or blue tooth radio fitted have you? My daughter purchased a retro blue tooth radio for her classic car. All was fine if the car was used regularly, if not, the battery went flat because the blue tooth (not radio) is always on. Eventually it wrecked the battery, a very large tractor size version fitted by a previous owner. Quote Link to comment Share on other sites More sharing options...
Wendy Dawes Posted November 27, 2022 Share Posted November 27, 2022 As far as I know Steve Jacks herald has no additional electrical extras which may drain the battery, or prevent charging I have seen the car and don’t recall seeing any extras Quote Link to comment Share on other sites More sharing options...
glang Posted November 27, 2022 Share Posted November 27, 2022 I think a bit of investigation is required so start by charging the battery with it disconnected from the car. After a day or so remove charger, measure battery voltage and put it back on the car however before connecting the second terminal set your multimeter to DC amps and measure between it and the battery terminal (should read zero). Set the multimeter back to DC volts, start the car and measure the volts again across the battery. You might have to wait a few minutes and rev the engine a bit but the reading should be higher than the previous one. With these tests youre trying to prove the battery is good, theres nothing draining it and the cars charging system is working so let us know the results.... 1 Quote Link to comment Share on other sites More sharing options...
standardthread Posted November 27, 2022 Share Posted November 27, 2022 I agree with glang on testing the battery off the car. An additional very indicative test you could do is test the electrolyte in each cell with an hydrometer if you are lucky enough to have a battery that isn't 'sealed for life'. A bad move for classic car owners, but good for making more money for the battery manufacturers. Quote Link to comment Share on other sites More sharing options...
Dave Clasper Posted November 28, 2022 Share Posted November 28, 2022 (edited) All relevant earth and supply connections clean/good condition. There is info in most manuals about checking the various aspects of the charging system. One thing I did find with this, was (if memory serves), when checking dynamo voltage direct from dynamo, it should be giving out about 13v(this is from memory so maybe not exact) when the car is at around 1000rmp(again this from memory), according to the manual. My original dynamo was only giving out around 6v, so thought it must be faulty. Tried two others and similar v readings!. in the end it was the control box that had failed!. Quite a lengthy thread I started with my problems around this, maybe about a year ago? Good luck, Dave Edited November 28, 2022 by Dave Clasper Quote Link to comment Share on other sites More sharing options...
Dave Clasper Posted November 28, 2022 Share Posted November 28, 2022 I may have interrupted a bit Glang, as your maybe giving "one step at a time" advice (which is good) Quote Link to comment Share on other sites More sharing options...
glang Posted November 28, 2022 Share Posted November 28, 2022 No problem, need all ideas possible as it looks like Jack has already replaced all the main components😯 Quote Link to comment Share on other sites More sharing options...
Wendy Dawes Posted November 28, 2022 Share Posted November 28, 2022 He’s popping it along to a local Triumph enthusiast and hopefully they’ll get to the bottom of it for him Quote Link to comment Share on other sites More sharing options...
Velocita Rosso Posted November 29, 2022 Share Posted November 29, 2022 First, do a drop test on the battery to s3 if a cell has gone. Second, has the red light ever come on ? Has the bulb gone in the red light dash warning. This will stop any charging. Try a continuity test on the thin wire from dynamo/ alternator to red light bulb holder. This, if broken will also not allow a charge.. It's amazing how many people do not realise how much is dependent on that red light. 2 Quote Link to comment Share on other sites More sharing options...
Wendy Dawes Posted November 29, 2022 Share Posted November 29, 2022 Hi Mike, I think Darren has asked him about the red charge light on his Facebook page Quote Link to comment Share on other sites More sharing options...
glang Posted November 29, 2022 Share Posted November 29, 2022 16 minutes ago, Velocita Rosso said: First, do a drop test on the battery to s3 if a cell has gone. Second, has the red light ever come on ? Has the bulb gone in the red light dash warning. This will stop any charging. Try a continuity test on the thin wire from dynamo/ alternator to red light bulb holder. This, if broken will also not allow a charge.. It's amazing how many people do not realise how much is dependent on that red light. Are you sure about the need to have a good bulb cos my dynamo will generate an output ok without one? One of the tests of a dynamo in the workshop manual is to disconnect all external wiring from the dynamo and install a jump wire between its two terminals so that when running you can measure its self generated output.... Quote Link to comment Share on other sites More sharing options...
RobPearce Posted November 29, 2022 Share Posted November 29, 2022 1 hour ago, glang said: Are you sure about the need to have a good bulb cos my dynamo will generate an output ok without one? It may depend on the control box but I think dynamos normally work without the light, whereas alternators usually don't. Quote Link to comment Share on other sites More sharing options...
foshi Posted November 29, 2022 Share Posted November 29, 2022 could even be the starter going to earth , really needs to do some basic checks when he returns from his run out , battery may be ok is the dynamo charging is the wiring from the dynamo ok to be honest not hard to find the problem . bit of detective work required paul Quote Link to comment Share on other sites More sharing options...
glang Posted November 29, 2022 Share Posted November 29, 2022 1 hour ago, RobPearce said: It may depend on the control box but I think dynamos normally work without the light, whereas alternators usually don't. Yes looks like the bulb just earths down via the regulator through the dynamo windings and when it starts to generate the output opposes the battery voltage and the bulb doesnt have enough current flow to illuminate. I was going to change the bulb for an LED which wont affect the charging but it might illuminate brightly at strange times due to them working across a wide range of voltages... Quote Link to comment Share on other sites More sharing options...
drofgum Posted November 30, 2022 Share Posted November 30, 2022 17 hours ago, glang said: Yes looks like the bulb just earths down via the regulator through the dynamo windings and when it starts to generate the output opposes the battery voltage and the bulb doesnt have enough current flow to illuminate. I was going to change the bulb for an LED which wont affect the charging but it might illuminate brightly at strange times due to them working across a wide range of voltages... Glang, LED's won't light when the output voltage goes higher than battery voltage. Being diodes they only allow current to flow in one direction. So if wired so they light when there is no output they will only light when output is below battery voltage by a large enough amount to start light emission. Regards, Paul Quote Link to comment Share on other sites More sharing options...
Rosbif Posted November 30, 2022 Share Posted November 30, 2022 Am I right in thinking you have an LED as the charge warning bulb? If I am then I would swap it out for a standard one, when I bought Leds for my car the supplier specifically said NOT to use one as the charge warning light, I run a dynamo. Quote Link to comment Share on other sites More sharing options...
glang Posted November 30, 2022 Share Posted November 30, 2022 3 hours ago, drofgum said: Glang, LED's won't light when the output voltage goes higher than battery voltage. Being diodes they only allow current to flow in one direction. So if wired so they light when there is no output they will only light when output is below battery voltage by a large enough amount to start light emission. Of course youre right. However I do like the way an incandescent bulb can be an early warning of charging system problems because starts to glow when theres an output/load discrepancy and I wonder if an LED would be as useful... Otherwise as Rob said I think an LED will be ok for a dynamo but not alternator which of course is much more common these days and the reason why suppliers tend to recommend against using them for ignition warning lights. Quote Link to comment Share on other sites More sharing options...
foshi Posted November 30, 2022 Share Posted November 30, 2022 but said light was going out when i asked him Quote Link to comment Share on other sites More sharing options...
glang Posted November 30, 2022 Share Posted November 30, 2022 Unfortunately the ignition light going out doesnt necessarily mean all is well because when you look at the voltage regulator diagram the bulb is just connected to the output of the dynamo not the outgoing terminal. This means that the dynamo can be functioning perfectly with the regulator controlling the voltage correctly but theres another contact inside (cut out contact) which has to close before the output connects to the cars electrics. If this contact fails to make the ignition light is out but youre using the battery alone to power the car. However I dont think thats the case here as the battery would go flat pretty quickly and the car stop while driving. More likely is that the battery charge wire is broken or disconnected somewhere so the regulator gives an output and powers all the electrics to allow driving but the battery wont be topped up. This is why I earlier suggested testing the battery voltage before starting and then after - if the second reading is eventually higher it confirms the charging circuit is working. 1 Quote Link to comment Share on other sites More sharing options...
foshi Posted November 30, 2022 Share Posted November 30, 2022 yep and i said the same way back on the same page as you glang agree ignition light but a few basic checks need doing paul 1 Quote Link to comment Share on other sites More sharing options...
Wendy Dawes Posted November 30, 2022 Share Posted November 30, 2022 Jack has arranged to pop up to Andy Johnson’s workshop, he’s an electrician, as well as a massive Triumph fanatic got a Spitfire, Stag, 2 Heralds and a couple of 2000’s, - (some of which they are currently restoring.) I’m sure he will get Jacks car sorted for him 👍😊 Quote Link to comment Share on other sites More sharing options...
glang Posted November 30, 2022 Share Posted November 30, 2022 Be interesting to find out what the problem is but potentially tear making taking into account the money thats already been spent☹️ At least there might be some spares to keep.... Quote Link to comment Share on other sites More sharing options...
Wendy Dawes Posted November 30, 2022 Share Posted November 30, 2022 It will be interesting to find out, it’s certainly a puzzle, Jack is only 17 and it’s his first car, he’s very intent on getting it sorted, and is very patient with its gremlins. Will be a nice car when it’s fully reliable for him he loves it, I often hate mine lol 😊 Quote Link to comment Share on other sites More sharing options...
Wendy Dawes Posted December 4, 2022 Share Posted December 4, 2022 All sorted , bad earth to battery and caused battery to fail too all good now we’ll done Andy and Luke 👍 1 Quote Link to comment Share on other sites More sharing options...
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