832ark Posted November 28, 2023 Author Report Share Posted November 28, 2023 (edited) So, just got around to a longer parasitic load test. The meter hovers around 45-55mA with occasional spikes to 65mA. I stood and watched it for a good half hour. I’m really stuck with this, based on that load, a fully charged battery should last for some time before it has insufficient juice to start the car. I last drove the car yesterday and lo and behold it wouldn’t start this morning. Edit - to add, I’ve taken a look at the discharge curves for a typical car battery and I seem to lose 60% of charge in approx 24hrs, that equates to a current draw of approx 2A based on an 85Ah battery if I understand the physics correctly. Edited November 28, 2023 by 832ark Quote Link to comment Share on other sites More sharing options...
Paul P Posted November 28, 2023 Report Share Posted November 28, 2023 3 hours ago, 832ark said: So, just got around to a longer parasitic load test. The meter hovers around 45-55mA with occasional spikes to 65mA. I stood and watched it for a good half hour. I’m really stuck with this, based on that load, a fully charged battery should last for some time before it has insufficient juice to start the car. I last drove the car yesterday and lo and behold it wouldn’t start this morning. Edit - to add, I’ve taken a look at the discharge curves for a typical car battery and I seem to lose 60% of charge in approx 24hrs, that equates to a current draw of approx 2A based on an 85Ah battery if I understand the physics correctly. THinking out loud - so a bit random.... not trying to teach you to suck eggs - where/how are you measuring the draw? When it doesn't start - whats the output of the battery ? - is it actually flat or is it that the juice isn't making its way to the starter / starter faulty etc.? Other thoughts - try the "known candidates" - pull the bulbs on the front and rear lids - doest that change things, or try the d9 / d10 fuses ( pcm and amplifier) ? I am thinking something is going into high draw later in the cycle - after you have lost the will to live watching the meter. The other thing I have had on a different car is the regulator pack on the alternator going bad and draining the battery - not so easy to simply pull the cable off on these cars but it's another area of "maybe" Quote Link to comment Share on other sites More sharing options...
BBB Posted November 28, 2023 Report Share Posted November 28, 2023 I have one of these attached to the battery. https://www.ebay.co.uk/itm/394413642374 That would enable you to look at a longer time period discharge curve on your phone. You’ll also be able to spot @Paul P suggestion of something with a higher drain kicking in later. Quote Link to comment Share on other sites More sharing options...
Menoporsche Posted November 29, 2023 Report Share Posted November 29, 2023 14 hours ago, Paul P said: The other thing I have had on a different car is the regulator pack on the alternator going bad and draining the battery - not so easy to simply pull the cable off on these cars but it's another area of "maybe" ISTR one or two comments on that on here. Wouldn’t rule it out. Quote Link to comment Share on other sites More sharing options...
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