Parasitic battery loss - advice from auto elecs please
Moderators: timk, Stu, zombie, Andrew, -alex, miata
- davekmoore
- Speed Racer
- Posts: 4681
- Joined: Thu Apr 30, 2009 1:53 am
- Vehicle: NC
- Location: Esprick, UK
Parasitic battery loss - advice from auto elecs please
Alternator charging oat 14.25 volts. Nearly-new battery charging ok on the car and holding charge at 13.05 volts when disconnected.
Took the globes out of the boot/rego plate lights. Clamped the driver's door plunger closed. Keys not in ignition. Nothing switched on. Multimeter wired in series between negative battery post and negative lead.
Shows 0.53-0.54 amps loss initially then drops to 0.49 - 0.50 after about half an hour of testing. Still showing 0.49 - 0.50 a further half an hour later. I'm told this is 490-540 milliamps and is 10 times too much. This would account for the battery giving up the ghost every 3-4 days unless charged overnight after each very short drive to work.
Checked the recently installed Haltech first - no change. Amazingly, after that the very first big square 40 amp fuse I removed at the front of the under hood fuse box dropped the loss to 0.41 - 0.42 amps. Three further back from that, the square yellow 60 amp fuse dropped it to 0.12 amps. Removing both of those dropped it to 0.01 amps. Putting them back in caused the loss to go up to 0.63 for a while then to settle back down as before. There's a click from something under the hood near the motor when the yellow 60 amp one goes back in.
The blue 100 amp fuse in the black box under the hood appears not to want to come out so that's not been tested.
While checking under the hood also discovered the wiring to the new EFI relay was so loose it could have fallen out of its connectors at any time (IF ONLY I HAD THE SKILLS, TIME AND PATIENCE TO DO ALL THE WORK ON MY CAR INSTEAD OF EXPECTING "PROFESSIONALS" TO DO IT WELL!).
All good in the fusebox by the driver's right knee except removing the "room" fuse reduces the loss to 0.39 - 0.40 amps when only that is removed. If the other two are already removed, removing the room fuse makes no further difference.
Removing all three of those mentioned reduces the loss to 0.01 amps.
What are the next steps?
Took the globes out of the boot/rego plate lights. Clamped the driver's door plunger closed. Keys not in ignition. Nothing switched on. Multimeter wired in series between negative battery post and negative lead.
Shows 0.53-0.54 amps loss initially then drops to 0.49 - 0.50 after about half an hour of testing. Still showing 0.49 - 0.50 a further half an hour later. I'm told this is 490-540 milliamps and is 10 times too much. This would account for the battery giving up the ghost every 3-4 days unless charged overnight after each very short drive to work.
Checked the recently installed Haltech first - no change. Amazingly, after that the very first big square 40 amp fuse I removed at the front of the under hood fuse box dropped the loss to 0.41 - 0.42 amps. Three further back from that, the square yellow 60 amp fuse dropped it to 0.12 amps. Removing both of those dropped it to 0.01 amps. Putting them back in caused the loss to go up to 0.63 for a while then to settle back down as before. There's a click from something under the hood near the motor when the yellow 60 amp one goes back in.
The blue 100 amp fuse in the black box under the hood appears not to want to come out so that's not been tested.
While checking under the hood also discovered the wiring to the new EFI relay was so loose it could have fallen out of its connectors at any time (IF ONLY I HAD THE SKILLS, TIME AND PATIENCE TO DO ALL THE WORK ON MY CAR INSTEAD OF EXPECTING "PROFESSIONALS" TO DO IT WELL!).
All good in the fusebox by the driver's right knee except removing the "room" fuse reduces the loss to 0.39 - 0.40 amps when only that is removed. If the other two are already removed, removing the room fuse makes no further difference.
Removing all three of those mentioned reduces the loss to 0.01 amps.
What are the next steps?
UK since return: Standard NC2 (horrid), C200K, ND2 BBR, NC2 BBR200 (loved it), NC BBR300 (better than BARMY), V-Special, turbo NB8B (my 84th car)
-
- Speed Racer
- Posts: 7468
- Joined: Fri Feb 11, 2011 12:49 pm
- Vehicle: NA6
- Location: Purga, QLD
Re: Parasitic battery loss - advice from auto elecs please
Put a kill switch in and use it when you stop. It is what I do with mine, however I don't have a radio to worry about.
How is the Haltech wired in, does it keep power when the car is turned off?
How is the Haltech wired in, does it keep power when the car is turned off?
- hks_kansei
- Speed Racer
- Posts: 6154
- Joined: Tue Feb 03, 2009 10:43 am
- Vehicle: NB8A
- Location: Victoria
Re: Parasitic battery loss - advice from auto elecs please
the 100amp fuse is the main fuse, and is usually bolted in. (one 10mm bolt, sideways, dead centre of fusebox)
Removing that should drop everything down to nil (it's the main power from the battery if I recall)
as for the current draw, something is wired wrong.
look up what the 40 and 60 amp fuses power (should be written on the fusebox lid), there is probably somehting on at least one of those circuits that's on that shouldnt be.
Removing that should drop everything down to nil (it's the main power from the battery if I recall)
as for the current draw, something is wired wrong.
look up what the 40 and 60 amp fuses power (should be written on the fusebox lid), there is probably somehting on at least one of those circuits that's on that shouldnt be.
1999 Mazda MX5 - 1989 Honda CT110 (for sale) - 1994 Mazda 626 wagon (GF's)
- davekmoore
- Speed Racer
- Posts: 4681
- Joined: Thu Apr 30, 2009 1:53 am
- Vehicle: NC
- Location: Esprick, UK
Re: Parasitic battery loss - advice from auto elecs please
Magpie wrote:Put a kill switch in and use it when you stop. It is what I do with mine, however I don't have a radio to worry about.
How is the Haltech wired in, does it keep power when the car is turned off?
Yeah, I'd prefer not to lose radio memory.
Disconnecting the Haltech doesn't reduce the draw. However, another forum member who'd just collected some wheels from me, helpfully noticed the boost controller is actually hot (44 degrees C) while everything else is switched off!
UK since return: Standard NC2 (horrid), C200K, ND2 BBR, NC2 BBR200 (loved it), NC BBR300 (better than BARMY), V-Special, turbo NB8B (my 84th car)
- davekmoore
- Speed Racer
- Posts: 4681
- Joined: Thu Apr 30, 2009 1:53 am
- Vehicle: NC
- Location: Esprick, UK
Re: Parasitic battery loss - advice from auto elecs please
hks_kansei wrote:as for the current draw, something is wired wrong.
look up what the 40 and 60 amp fuses power (should be written on the fusebox lid), there is probably somehting on at least one of those circuits that's on that shouldnt be.
See comments about the boost controller. Presumably if that's getting hot it must be drawing current so must be wired wrong?
Nothing on the lid about what those fuses do. Google not helping much so far.
UK since return: Standard NC2 (horrid), C200K, ND2 BBR, NC2 BBR200 (loved it), NC BBR300 (better than BARMY), V-Special, turbo NB8B (my 84th car)
- hks_kansei
- Speed Racer
- Posts: 6154
- Joined: Tue Feb 03, 2009 10:43 am
- Vehicle: NB8A
- Location: Victoria
Re: Parasitic battery loss - advice from auto elecs please
I would expect warm = powered
Not sure on how those controllers work, if they need constant power, or if they draw a lot of power.
BUT, I would be checking if it's supposed to be wired to switched power or to constant>
sounds like whoever wired it may have got lazy and wired it to constant instead of wiring in a relay to only power it with ignition on.
Not sure on how those controllers work, if they need constant power, or if they draw a lot of power.
BUT, I would be checking if it's supposed to be wired to switched power or to constant>
sounds like whoever wired it may have got lazy and wired it to constant instead of wiring in a relay to only power it with ignition on.
1999 Mazda MX5 - 1989 Honda CT110 (for sale) - 1994 Mazda 626 wagon (GF's)
- davekmoore
- Speed Racer
- Posts: 4681
- Joined: Thu Apr 30, 2009 1:53 am
- Vehicle: NC
- Location: Esprick, UK
Re: Parasitic battery loss - advice from auto elecs please
hks_kansei wrote:the 100amp fuse is the main fuse, and is usually bolted in. (one 10mm bolt, sideways, dead centre of fusebox)
Removing that should drop everything down to nil (it's the main power from the battery if I recall)
It is just remove the pesky bolt? Because the fuse still doesn't seem to want to shift, and the draw is still 570 milliamps, gently dropping over time.
UK since return: Standard NC2 (horrid), C200K, ND2 BBR, NC2 BBR200 (loved it), NC BBR300 (better than BARMY), V-Special, turbo NB8B (my 84th car)
- hks_kansei
- Speed Racer
- Posts: 6154
- Joined: Tue Feb 03, 2009 10:43 am
- Vehicle: NB8A
- Location: Victoria
Re: Parasitic battery loss - advice from auto elecs please
can't guarantee it's jsut that bolt.
But that's the only one I saw when I was wiring up something in mine yesterday
I think the easiest way to check would be to unplug the boost thingo.
leave the fuses in place, then measure draw
if it drops, you've narrowed it down to the boost thing.
But that's the only one I saw when I was wiring up something in mine yesterday
I think the easiest way to check would be to unplug the boost thingo.
leave the fuses in place, then measure draw
if it drops, you've narrowed it down to the boost thing.
1999 Mazda MX5 - 1989 Honda CT110 (for sale) - 1994 Mazda 626 wagon (GF's)
-
- Racing Driver
- Posts: 1125
- Joined: Thu Jul 26, 2007 5:46 pm
- Vehicle: NA6
- Location: North Brisbane
Re: Parasitic battery loss - advice from auto elecs please
Dave,
Don't go and unbolt and pulling fuses,with your luck, you'll end up stuffing something and it will cost you a bomb to repair.
The only parasitic draw will be from alarm, radio, clock and probably immobiliser.
If your not running the factory ECU then you can guarantee that something is wired to BAT power and not through the ignition switch.
The radio, clock and alarm will probably pull a couple of milliamps an hour, certainly not enough to flatten a battery in under 4 to 6 weeks.
If you have found the boost controller is hot then thats your problem and it needs to be wired up to the ignition side of the fuse box.
Don't you work in the industry????? If so WTF go and ask the workshop foreman who who is good and does foreigners, mate in every shop I've
been in thats one of the first things that you get asked, " do you do foreigners and how much $$$$ or how many cartons????"
Terry
Don't go and unbolt and pulling fuses,with your luck, you'll end up stuffing something and it will cost you a bomb to repair.
The only parasitic draw will be from alarm, radio, clock and probably immobiliser.
If your not running the factory ECU then you can guarantee that something is wired to BAT power and not through the ignition switch.
The radio, clock and alarm will probably pull a couple of milliamps an hour, certainly not enough to flatten a battery in under 4 to 6 weeks.
If you have found the boost controller is hot then thats your problem and it needs to be wired up to the ignition side of the fuse box.
Don't you work in the industry????? If so WTF go and ask the workshop foreman who who is good and does foreigners, mate in every shop I've
been in thats one of the first things that you get asked, " do you do foreigners and how much $$$$ or how many cartons????"
Terry
"Racing shouldn't be for rich idiots, but for all idiots"
- davekmoore
- Speed Racer
- Posts: 4681
- Joined: Thu Apr 30, 2009 1:53 am
- Vehicle: NC
- Location: Esprick, UK
Re: Parasitic battery loss - advice from auto elecs please
tbro wrote:Dave,
Don't go and unbolt and pulling fuses,with your luck, you'll end up stuffing something and it will cost you a bomb to repair.
The only parasitic draw will be from alarm, radio, clock and probably immobiliser.
If your not running the factory ECU then you can guarantee that something is wired to BAT power and not through the ignition switch.
The radio, clock and alarm will probably pull a couple of milliamps an hour, certainly not enough to flatten a battery in under 4 to 6 weeks.
If you have found the boost controller is hot then thats your problem and it needs to be wired up to the ignition side of the fuse box.
Don't you work in the industry????? If so WTF go and ask the workshop foreman who who is good and does foreigners, mate in every shop I've
been in thats one of the first things that you get asked, " do you do foreigners and how much $$$$ or how many cartons????"
Terry
Didn't unplug the main fuse. Got away with the unplugging and testing so far and everything is still working. In doing so, discovered a couple of loose connections and that the new rattle from the engine bay was where the auto elec had also not properly reattached the fuse box. I can see why, as it's a b*ggar to do, but it also shows why I'm trying to do some work myself so .....
Found the Manuel and a description of the fuses.
The 60 amps fuse is for "all ignition related circuits". That's the one that seems to be pulling 400 milliamps. Surely it should only be drawing any current if the ignition is on? Or has, for instance, the boost controller, been wired to somehow draw current from the ignition circuit with the ignition off and no key in the ignition?
The 40 amp one is for "headlights and heated rear window". Couldn't test the HRW but can confirm that without the fuse only the sidelights work. That circuit seems to be pulling 100 milliamps.
UK since return: Standard NC2 (horrid), C200K, ND2 BBR, NC2 BBR200 (loved it), NC BBR300 (better than BARMY), V-Special, turbo NB8B (my 84th car)
- Locutus
- Racing Driver
- Posts: 879
- Joined: Thu Jul 26, 2007 7:39 pm
- Vehicle: NB SP
- Location: Sydney
- Contact:
Re: Parasitic battery loss - advice from auto elecs please
Grab the service manual from the relevant section of the forum. This will tell which circuits are connected to which fuses.
The ignition circuit should be open (0A draw) when the key is in any position other than IGN or START.
The ignition circuit should be open (0A draw) when the key is in any position other than IGN or START.
- Okibi
- Speed Racer
- Posts: 10898
- Joined: Thu Aug 21, 2003 11:00 am
- Vehicle: NB SE
- Location: Perth, Western Australia
- Contact:
Re: Parasitic battery loss - advice from auto elecs please
When you unplugged the boost controller did it fix the issue? Seems it needs to be wired up to switched power not constant power then.
If you had access to a car like this, would you take it back right away? Neither would I.
- davekmoore
- Speed Racer
- Posts: 4681
- Joined: Thu Apr 30, 2009 1:53 am
- Vehicle: NC
- Location: Esprick, UK
Re: Parasitic battery loss - advice from auto elecs please
Okibi wrote:When you unplugged the boost controller did it fix the issue? Seems it needs to be wired up to switched power not constant power then.
Not found where to unplug it yet. Update Sunday
UK since return: Standard NC2 (horrid), C200K, ND2 BBR, NC2 BBR200 (loved it), NC BBR300 (better than BARMY), V-Special, turbo NB8B (my 84th car)
- davekmoore
- Speed Racer
- Posts: 4681
- Joined: Thu Apr 30, 2009 1:53 am
- Vehicle: NC
- Location: Esprick, UK
Re: Parasitic battery loss - advice from auto elecs please
Delighted to report that the tuner has changed the wiring of the boost controller to go through the ignition and the loss has dropped to 1 milliamp which I guess is just the radio memory. Boost controller naturally now doesn't get hot when the ignition is off.
Also showed him the ECU installation and he's agreed to order an install cradle and to modify the OEM bash plate to fit over the top of everything - all at his cost of course.
At last, something seems to be going right with the car!
Also, for the past several days, and on the way to the tuner, the airbag light has been flashing 6 times then pausing, indicating a fault with the driver's airbag. After the fix above was done the airbag light has not flashed. Co-incidence, or another good result?
Also showed him the ECU installation and he's agreed to order an install cradle and to modify the OEM bash plate to fit over the top of everything - all at his cost of course.
At last, something seems to be going right with the car!
Also, for the past several days, and on the way to the tuner, the airbag light has been flashing 6 times then pausing, indicating a fault with the driver's airbag. After the fix above was done the airbag light has not flashed. Co-incidence, or another good result?
UK since return: Standard NC2 (horrid), C200K, ND2 BBR, NC2 BBR200 (loved it), NC BBR300 (better than BARMY), V-Special, turbo NB8B (my 84th car)
- davekmoore
- Speed Racer
- Posts: 4681
- Joined: Thu Apr 30, 2009 1:53 am
- Vehicle: NC
- Location: Esprick, UK
Re: Parasitic battery loss - advice from auto elecs please
So the battery went from 13.00 volts to 12.92 overnight. Is that ok?
UK since return: Standard NC2 (horrid), C200K, ND2 BBR, NC2 BBR200 (loved it), NC BBR300 (better than BARMY), V-Special, turbo NB8B (my 84th car)
Return to “MX5 Audio, Electronics & Lighting”
Who is online
Users browsing this forum: No registered users and 27 guests