Parasitic Draw

[lapedrera]

Hi all,

I'm in the process of trying to find the draw(came accrosee the forums in searching).

I've have measured the draw in series from the - terminal.. 11.6A.
I've pulled all the fuses / relays in the engine bay box 1 x 1 to check if the draw drops.. no change.
I'm next going to pull the fuses in the cabin box to try the sazme thing..

Problem here is the fuses are those tinly type B ones..

Can I also measure the voltage on the fuses determine the one that may be causing the draw? (I'm not fully certain of this).
They're in a very difficult spot to remove without the correct tool.

 

[SC Maintenance]

Hi all,

I'm in the process of trying to find the draw(came accrosee the forums in searching).

I've measured the draw in series from the - terminal.. 11.6A.
Ive pulles all the fuses / relays in the engine bay box 1 x 1 to check if the draw drops.. no change.
I'm next going to pull the fuses in the cabin box to try the sazme thing..

Problem here is the fuses are those tinly type B ones..

Can I also measure the voltage on the fuses determine the one that may be causing the draw? (I'm not fully certain of this).
They're in a very difficult spot to remove without the correct tool.

11.6A is a HUGE amount of parasitic current. If it truly is that much, its not an accessory - its likely a fuel pump or something like that, or possibly a short?

How exactly did you run your draw test. Did you wait an hour and not touch anything - no door, key light, anything, to take that measurement?

 

[lapedrera]

That is what I am coming to understand.

Over an hour. Nothing at all.

How would I go about tracing it for an open?

 

[ka9mnx]

11.6A draw would pull the battery dead within minutes. There's something wrong with your testing method. I use volts not amps when testing.

 

[SC Maintenance]

If its really 11.6A, I would start by unplugging things that can actually use that much current first one at a time. Fuel Pump. ABS actuator. Things that have 12 gauge or heavier wires going to them.

If your pulling 11.6A on a 16 gauge wire its going to be warm. Also there are not many things that can pull 11.6A continuous without letting the smoke out.

What car?

 

[lapedrera]

It certainly seems to be via my multimeter. I'm just goign to go install the battery as it's been on my charger all night.

I think this may be more advanced than I'm going to fix.

 

[lapedrera]

11.6A draw would pull the battery dead within minutes. There's something wrong with your testing method. I use volts not amps when testing.

It certainly is not dying withing minutes currently. It was dead when I tried to start it a few days ago. After I got a boost(on Friday) it has been ok since then.

I suspect that it may be the battery.. I've had it tested 3 different times and each place had to charge it before it was tested -

Comes back at 500CCA (measured) vs 550CCA (rated).

 

[SC Maintenance]

It certainly is not dying withing minutes currently. It was dead when I tried to start it a few days ago. After I got a boost(on Friday) it has been ok since then.

I suspect that it may be the battery.. I've had it tested 3 different times and each place had to charge it before it was tested -

Comes back at 500CCA (measured) vs 550CCA (rated).

550 CCA battery likely has maybe a rating of at most 100Ah - likely less. So at 11.6A it would be stone cold dead in 8 hours just from sitting.

 

[supton]

11A won’t kill a battery in minutes, but it only has a few hours, if that.

In the 200mV range you can measure drop across a fuse. Thing is, 11A across a 50A fuse might be smaller than 0.5A through a 5A fuse—but both should have a voltage, not zero volts.

Sounds like something stuck on. Do not know what vehicle this is, but is there a bunch of fuses on the battery, or nearby, or is this old and using a fusible link? am wonder if there are several fuse boxes. Or something tapped in.

 

[lapedrera]

550 CCA battery likely has maybe a rating of at most 100Ah - likely less. So at 11.6A it would be stone cold dead in 8 hours just from sitting.

I do not know what the Ah rating is.

 

[lapedrera]

11A won’t kill a battery in minutes, but it only has a few hours, if that.

In the 200mV range you can measure drop across a fuse. Thing is, 11A across a 50A fuse might be smaller than 0.5A through a 5A fuse—but both should have a voltage, not zero volts.

Sounds like something stuck on. Do not know what vehicle this is, but is there a bunch of fuses on the battery, or nearby, or is this old and using a fusible link? am wonder if there are several fuse boxes. Or something tapped in.

I am not following you (just not exerpeiced enough to follow).

There a fuses / relays in the EB and a fuse panel inside the cabin.

 

[lapedrera]

Ok. it's not 11.6A on the load.. it's 11.6 Volts.

I did some of my own measurements after installing the battery (fresh of charger)

12.79 Vots(not installed) accross battery
12.79 Volts(installed / not running) accross battery
13.04 Volts(vehicle running) accross battery - I was told that this check is done to check the charging system (but not sure how it works if the batter yis already fully charged of a charger or what the numbers should be)

 

[nomas]

Are you sure that's not milliamps ?

 

[zrxkawboy]

Your ammeter needs to go in series with one of the battery cables.

 

[kschachn]

If its really 11.6A, I would start by unplugging things that can actually use that much current first one at a time. Fuel Pump. ABS actuator. Things that have 12 gauge or heavier wires going to them.

This here. Pull ALL the fuses a s see of there is still a draw. If there is then it’s an unfused component, usually the alternator. If there is no draw then start plugging the fuses back in one at a time until you see the draw again.

Also find out in the FSM what the draw graph looks like. Generally there is a higher initial draw that will reduce in steps until you reach a quiescent value.

 

[GSCJR]

Wouldn't the DVOM internal fuse blow if the A were that high?

 

[Nukeman7]

Ok. it's not 11.6A on the load.. it's 11.6 Volts.

I did some of my own measurements after installing the battery (fresh of charger)

12.79 Vots(not installed) accross battery
12.79 Volts(installed / not running) accross battery
13.04 Volts(vehicle running) accross battery - I was told that this check is done to check the charging system (but not sure how it works if the batter yis already fully charged of a charger or what the numbers should be)

The OP mistakenly reported the current draw measurement as Amps; however, in reality, he was measuring the voltage. Sounds a bit like he is not very experienced at electrical diagnostics with a multimeter.

Based upon the latest measurements above, I would suspect that it is an old battery depleting the charge overnight and there is no parasitic draw in his vehicle.

OP, what is the brand, type & age of the battery and what is it's history? Have you/can you check the electrolyte level in each cell or is a maintenance free it sealed unit?

 

[lapedrera]

Are you sure that's not milliamps ?

Yes.

 

[lapedrera]

Your ammeter needs to go in series with one of the battery cables.

I do not have an ampere meter.

 

[Quattro Pete]

OP may want to invest in a DC clamp meter to better measure parasitic drain without having to disconnect the battery. Every time you re-connect a battery in a modern car, a bunch of activity gets initiated - various systems coming back on-line, and it may take a while for things to settle down again.