MX5 ND - *Fixed* Parasitic battery drain from Fuse17 - audio

  1. My model of MX-5 is: 2016 Sport Nav 2.0
  2. I’m based near: East Yorkshire
  3. I’m looking for technical help or recommendations on: Battery

Hi All,

I’ve been having battery issues over the winter, due to using the tesla more, didn’t think much of it. However I had no idea about the age of the battery, so I replaced with a new Yusa 5000 (or however you spell it). Perfect and the spare is in the garage incase I need to jump-start.

One week later, and after using the car for 20-30 miles a day, it’s dead this morning. After ruling out the battery, I wanted to see what could be causing a high battery drain, Dropping to 10v from 12.5v in 14 hours, seems to make me think there’s something draining it hard.

The only interior mods are the installation of Android Auto and a replacement screen. No obvious lights on dash, no lights on, car locked etc.

I have tested the Parasitic battery drain by removing fuses one by one. It seems as if fuse 17, the audio system is at fault. Taking the draw from 1.05 down to 0.33 when removed.

Any help or advice on what could be causing this, common faults, issues with android auto etc?

Bump for attention :see_no_evil:

What are your drain readings in? Are you saying that the drain is 1.05 Amps down to 0.33 Amps? 0.33 Amps is still way to high, you should be seeing around 0.06 Amps.

You’re not parking it with the Cruise control switched “on” are you?

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Nope, I believe the cruise control issue was isolated to some RF models. Never use the limiter or cruise. Its pulling around 1.05 with the audio fuse in,

Located and disconnected the bose amp - No change (for anyone looking for it, it’s behind the driver’s eat under the plastic cover, near the hood).

Updating firmware to V74 (as I updated to V70 for AA)
Checked the alternator, no issue!

My last resort is to chase my AA install to ensure no “nicked wires”

Really running out of ideas now!

Rich

Hey,

Ok so ive managed to fix this and thought i’d share if anyone was in the same situation.

When I installed android auto, I took the software from v56 > v70. I just updated the firmware from v70 > v74 (latest and final). Somehow this has fixed the problem and my battery drain is now down under 0.4. Must have been a bug or setting leaving the audio system or power outlet on beyond the ‘sleep’ period.

All confirmed by a bluetooth battery monitor I also fitted. Definatly worth the £30 from euro car parts if you are struggling and want piece of mind.

Definatly worth a try if you are experiancing similar issues!

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0.4A is still high and would drain your battery completely in about a week.

The manual actually states 0.3-0.5 to be the normal range

Well a standard 45A battery would only last ( 45 / 0.4 ) hours / 24 to give days = 4.68 days, to completely flat and probably wouldn’t start a car after 3 days,

I have an old MX5NC (getting an ND soon) , but the NC will last for 3/4 weeks and still start fine.

A quick google says most cars use 40-50mA = 0.04A (which sounds about rights to me)

Totally agree - I’ve miss typed - 30-50mA which makes a lot more sense when calcuating battery duration!

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Mine has started doing this ….. I’ve had OS Version 74.00.324 EU N for ages without a problem.

Maybe i’ll get the old digital clamp tester out and take a good look for a parasitic drain :thinking:

Maybe my android auto is playing up ….. probably worth unplugging it to test