sim303
Active Member
- Joined
- Jan 31, 2017
- Messages
- 63
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Hi all
Spring is here and it's high time I investigated why my battery fails to start the car after just a few days.... (and yes, it is just one battery - the other is no longer part of the main circuit and instead serves as a leisure battery for auxiliary gear).
...so I spent much of Saturday measuring current drawn from the battery with various fuses pulled etc. I have three pages of notes, having measured with each fuse pulled in turn (engine fuse box and passenger footwell box). But the pertinent findings are these (all are measured with the alarm armed):
Base reading (A) - Overall drain, everything connected: 75-78mA
ENGINE FUSE BOX:
as per (A), minus RADIO fuse: 72-73mA
as per (A), minus HAZ/TRN fuse: 32-34mA
as per (A), minus ALL engine-box fuses: 27mA
PASSENGER FOOTWELL FUSE BOX:
ECU-B drawing 15mA
All fuses present EXCEPT HAZ/TRN and ECU-B: 15mA (Which makes sense: (A) - HAZ/TRN - ECU-B == 75-45-15 = 15mA )
~
Thoughts so far.... A total drain of 75mA does not sound ridiculously high, and certainly not enough to kill a healthy battery in a few days. Therefore I conclude that my battery is in a bad way and needs replacing. That's why I did this exercise - as I don't want to splash out on a new battery only to kill it with a bad current drain.
BUT.... 75mA _is_ higher than the Toyota recommendation (35-50mA as I recall), AND, the 45mA draw measured on the HAZ/TRN fuse seems unexpected, assuming that fuse really does only do the Hazards and Indicators. Subtracting that 45mA would seem to put me back within Mr T's expectations. Any thoughts on that? Is there some other function for that circuit? Is it tied into the alarm perhaps? Or maybe some previous owner has tied in some piece of junk device into the HAZ/TRN line? Should I trace that line further?
Thoughts welcome, (and if anyone is bored/interested enough to measure their own HAZ/TRN fuse current, I'd be really grateful!
sim
Spring is here and it's high time I investigated why my battery fails to start the car after just a few days.... (and yes, it is just one battery - the other is no longer part of the main circuit and instead serves as a leisure battery for auxiliary gear).
...so I spent much of Saturday measuring current drawn from the battery with various fuses pulled etc. I have three pages of notes, having measured with each fuse pulled in turn (engine fuse box and passenger footwell box). But the pertinent findings are these (all are measured with the alarm armed):
Base reading (A) - Overall drain, everything connected: 75-78mA
ENGINE FUSE BOX:
as per (A), minus RADIO fuse: 72-73mA
as per (A), minus HAZ/TRN fuse: 32-34mA
as per (A), minus ALL engine-box fuses: 27mA
PASSENGER FOOTWELL FUSE BOX:
ECU-B drawing 15mA
All fuses present EXCEPT HAZ/TRN and ECU-B: 15mA (Which makes sense: (A) - HAZ/TRN - ECU-B == 75-45-15 = 15mA )
~
Thoughts so far.... A total drain of 75mA does not sound ridiculously high, and certainly not enough to kill a healthy battery in a few days. Therefore I conclude that my battery is in a bad way and needs replacing. That's why I did this exercise - as I don't want to splash out on a new battery only to kill it with a bad current drain.
BUT.... 75mA _is_ higher than the Toyota recommendation (35-50mA as I recall), AND, the 45mA draw measured on the HAZ/TRN fuse seems unexpected, assuming that fuse really does only do the Hazards and Indicators. Subtracting that 45mA would seem to put me back within Mr T's expectations. Any thoughts on that? Is there some other function for that circuit? Is it tied into the alarm perhaps? Or maybe some previous owner has tied in some piece of junk device into the HAZ/TRN line? Should I trace that line further?
Thoughts welcome, (and if anyone is bored/interested enough to measure their own HAZ/TRN fuse current, I'd be really grateful!
sim