Parasitic Battery Drain – Hyundai i30 2015 model
Hello everyone, I wanted to post about an issue I found with my 1.4 petrol Hyundai i30 to help anyone else with the same issue.
The problem: First the start stop – stopped working. Then we discovered on several occasion that the battery had run flat after four or five days. Initially a bad battery was suspected so this was replaced and everything seemed fine for about 6 months (although the start stop never re-activated). Then once again the car was left sitting for five days and the battery was flat. As it was pretty much a brand new battery I did some investigation.
Important: The car MUST be locked with the bonnet open to do this test. I set the a multimeter to measure AMPs in the 10AMP range and connected it inline between the negative terminal of the battery and the car. Then I made sure that the button that checks the bonnet is closed was depressed. You can do this with a small clamp or just press it with your figure. Wait two minutes.
What should happen: You will see the amps being drawn will fall to about 0.45 amps as the car begins to shut down. After two minutes the amps will fall again to approx 0.03 to 0.05 amps. This is the car going into sleep mode. I can’t stress enough that to achieve this the car must be locked and the bonnet button depressed to fool the car into thinking the bonnet is closed. Some people will say it takes 15 minutes or longer but on a Hyundai i30 its 2 mins. There’s another post of someone demonstrating the same thing on a diesel so I’m pretty sure that’s standard.
What was happening: The amp draw was not dropping as expected and was staying at around 0.5 to 0.45 Amps. Doesn’t sound like a lot but that will drain a 70Ah battery in less than a week and it will definitely affect it performance even over night.
It seems likely that this is a common problem with this model. There are a couple of other feeds that talk about similar issues and one that covers this topic but not in as much detail.
What happened?
So first of all I tried pulling fuses and relays and even measuring for a voltage while the car was in shut down (you can put a multimeter on the micro fuses Hyundai use while in place – if there’s a voltage then there must be a current). Basically – if there’s a draw on the circuit you should be able to pull the fuse associated with that circuit and watch the current drop. However, despite pulling every fuse and relay I couldn’t seem to isolate the issue, There was no obvious circuit that was causing the issue. This is also a massive pain to do because not only are there a million fuses but you have to clamp all the door close buttons and keep the car locked to fool the car into thinking it can go to sleep. Anyway – I got nowhere.
So I took the car to two garages including the Hyundai main dealer. Both confirmed there was a problem but neither could work out what it was. ODB showed no errors. Hyundai charged me £250 for the privilege and said there wasn’t a lot more they could do. Wonderful.
The solution: Due to some digging on here and some helpful pointers by other people I eventually worked out that the trunk switch was the cause of the issue. When I say trunk switch I mean the little black weather proof rubber button you press to open the boot.
This is the video I used to work out how to get it out.
How to Replace Hyundai i30 Boot Release Button - YouTubeLong story short – the weather proofing had gone on the switch. This I believe, meant that water had got inside and there was just enough resistance on the circuit to stop the car going into sleep mode. Hence no real draw on the power from the button itself but enough resistance to stop the car going to sleep which was draining the battery. Simply disconnecting this switch and doing the same AMP test as described above proved that the car would now enter sleep mode after two minutes as described. A ten pound replacement part from ebay and I’m back up and running and it only took me about 6 hours to figure out and £400 in garage fees. LOL.
Hopefully this will help someone else and maybe save you some cash.
