Parasitic draw, .455 amps, fuse #25 the problem???

[J_C]

I just measured mine, the '98 XLT SOHC. Hadn't ran it since Friday, did not start it, just opened door for a couple seconds to pop the hood. There is no hood light.

235mA, higher than I expected it to be though I know of no other problems with it, besides that being higher than I'd like.

Had a few minutes today to look into mine more. I read that the battery saver circuit times out after 45 minutes so I waited and retested.

Turns out it's only at 235mA for the first 45(?) minutes after *activity* like opening the door, triggering courtesy lights. Letting it sit for an hour (hood already open so I didn't open the door again to pop the hood) it settled down to 20mA battery drain which made me happy.

 

[imp]

Had a few minutes today to look into mine more. I read that the battery saver circuit times out after 45 minutes so I waited and retested.

Turns out it's only at 235mA for the first 45(?) minutes after *activity* like opening the door, triggering courtesy lights. Letting it sit for an hour (hood already open so I didn't open the door again to pop the hood) it settled down to 20mA battery drain which made me happy.

@J_C The predecessor to today's EEC-V, EEC-IV, in the '90s was said to draw 5 to 10 ma. I've used that number over the years when searching out big "leaks". 20 is great! imp

 

[shucker1]

Stupid question.

Of course you zero out your meter before you remove the 8 Ga jumper.

Not zeroing out might skew your test results.

 

[J_C]

^ Not necessarily. Whatever reading your meter shows while connected in parallel to the jumper wire is just going to reflect the resistance ratio of the meter and leads to that of the jumper wire + contact to the cable and battery terminal, as a % of total current flow, meaning it is a valid reading already for the amount of current flowing through the meter at that point in time.

You'd have more error zeroing that out than leaving it, though if there were more than a single digit # of mA through the meter, it isn't likely that the jumper wire was making good contact at either or both ends, but it doesn't matter so much for the purposes of the test as all the jumper had to do was keep a surge current from flowing through the meter when it became the sole carrier of the current.

If you're just measuring current and don't need to walk away or have a free hand for anything else (pull fuses or relays or whatever...) then you don't even need the jumper wire, can just hold one meter probe against the battery cable clamp and the other probe at a 90' angle to the battery terminal and pull the clamp up and off with the meter still connected to both, though this assumes top battery terminals. Same thing with side terminals except shoving the probe in from the side against the terminal before the cable bolt is all the way out.

 

[1996BLKBauer]

Had a few minutes today to look into mine more. I read that the battery saver circuit times out after 45 minutes so I waited and retested.

Turns out it's only at 235mA for the first 45(?) minutes after *activity* like opening the door, triggering courtesy lights. Letting it sit for an hour (hood already open so I didn't open the door again to pop the hood) it settled down to 20mA battery drain which made me happy.

I honestly wish mine was the same, if it didn't take me almost 2 hours, to pull fuses, and unpin the connector on the GEM I would be worried about the 45 minutes, or an hour where the battery saver times out. but after 2 hours it was still at almost a half an amp. on the bright side the switch i installed has been working great for almost a week now, lol. Only left it on once for 30 minutes.

 

[imp]

^ Not necessarily. Whatever reading your meter shows while connected in parallel to the jumper wire is just going to reflect the resistance ratio of the meter and leads to that of the jumper wire + contact to the cable and battery terminal, as a % of total current flow, meaning it is a valid reading already for the amount of current flowing through the meter at that point in time.

You'd have more error zeroing that out than leaving it, though if there were more than a single digit # of mA through the meter, it isn't likely that the jumper wire was making good contact at either or both ends, but it doesn't matter so much for the purposes of the test as all the jumper had to do was keep a surge current from flowing through the meter when it became the sole carrier of the current.

If you're just measuring current and don't need to walk away or have a free hand for anything else (pull fuses or relays or whatever...) then you don't even need the jumper wire, can just hold one meter probe against the battery cable clamp and the other probe at a 90' angle to the battery terminal and pull the clamp up and off with the meter still connected to both, though this assumes top battery terminals. Same thing with side terminals except shoving the probe in from the side against the terminal before the cable bolt is all the way out.

@J_C Can I get clued in here WTH is being discussed? Maybe missed something above, but didn't see it. Sounds like a jumper inserted into a circuit to measure a voltage drop across it, to determine the current flow, the jumper resistance being known then I = E/R, and the current is determined? Actually, many Ammeters use the principle to achieve the same result; called "Shunt Type Ammeters".

For my wieners, if the current level is even closely known by guesswork, my Simpson VOM is all I need, up to 10 amps. Old school, old dog, new tricks suck. imp

 

[J_C]

@J_C Can I get clued in here WTH is being discussed? Maybe missed something above, but didn't see it. Sounds like a jumper inserted into a circuit to measure a voltage drop across it, to determine the current flow, the jumper resistance being known then I = E/R, and the current is determined? Actually, many Ammeters use the principle to achieve the same result; called "Shunt Type Ammeters".

For my wieners, if the current level is even closely known by guesswork, my Simpson VOM is all I need, up to 10 amps. Old school, old dog, new tricks suck. imp

Shucker1 was asking if the meter needs to be zeroed out to get a valid current measurement, as a method proposed by another member previously in a different post.

The purpose of the jumper wire is only to be able to get the meter connected in series with the battery and the cable while the vehicle stays in an energized state so there isn't a large inrush current flowing through the meter upon first completing the circuit from the cable to the battery after having had it disconnected, or at least that's what I took it to mean.

It is not to measure voltage across the jumper wire. The jumper wire should have the minimum resistance reasonably possible because there is no good reason to try to attempt to make a resistor out of it for the purposes of measuring such a low current when you have a multimeter capable of the steady state current.

A multimeter does in fact have a calibrated (though sometimes crudely) current shunt inside in order to measure resistance from the voltage drop across it, but one that does not vary from a dodgy connection at both ends and one the meter was calibrated to read with accuracy (and no further calculations required to arrive at the current rate).

Yes a VOM would work. I didn't mean to make things seem more complicated than they were, just answering Shucker1's question about zeroing a meter which isn't applicable to this type of reading.

 

[J_C]

I honestly wish mine was the same, if it didn't take me almost 2 hours, to pull fuses, and unpin the connector on the GEM I would be worried about the 45 minutes, or an hour where the battery saver times out. but after 2 hours it was still at almost a half an amp. on the bright side the switch i installed has been working great for almost a week now, lol. Only left it on once for 30 minutes.

But was this two hours with you never opening any of the vehicle doors and the battery stayed connected? I don't know all the triggers for the 45 minute timer, I didn't test whether the 45 min would start up again from 0 at the point of reconnection of the battery if it had been disconnected, nor whether pulling any particular fuses or breakers and putting them back in would reset it to another 45 minute period. Actually I didn't do anything else yet to test mine except wait the 45 minutes and measure at the battery.. well, that and I had ordered a spare battery saver relay just in case, that just came in the mail today so it figures I don't need it, lol. Can't hurt to have a spare I suppose.

 

[shucker1]

Actually it wasn't really a question but more of a suggestion. I actually work as an instrumentation and controls field service technician for General Electric.

Standard procedure for some of the gear we work on. Speed reading again I did't notice that IMP was using a Simpson 260 so no need to zero out.

I also notice a post somewhere in this thread about amp clamps not working on steady state current draw. I'll have to disagree. I do it all of the time with A\O and A\I circuits for calibrations and new install commissioning.

If the OP could get a hold of a Fluke model 771 or 773 process amp clamp there would be no need to break the circuit at all.

Like IMP said though the old Simpson Model 260 is darn near bullet proof.

 

[J_C]

There is no *standard* multimeter I'm aware of that should be zeroed out for a current reading when it is the typical type that completes the circuit rather than a clamp-on one sensing a magnetic field in the wire. That's the primary difference, that stray magnetic fields can make a clamp on type need that, especially around other electromagnetic circuitry, but not a standard multimeter where you break the circuit, then it completes it.

Even the multimeters that Harbor Freight has given out for free with a coupon or $3-$4 otherwise will have good enough accuracy to do this test, so with owning a basic/standard multimeter so useful for even our now old-tech Explorers (let alone newer vehicles with even more electronics), I can't see a reason to borrow a Fluke clamp-on instead of just buying a basic multimeter then having it for the next time one is needed for any of the multiple types of measurements it can do.

 

[imp]

@J_C I get it! I did not consider the possibility of a high inrush current when connecting the meter in series. Nowadays we have things like air bag circuitry which charge up a big capacitor initially when the battery is connected. OTOH, how high might the initial inrush be? Pretty high, for a very short time, limited by only the resistance in series with any capacitors, which might actually be only the resistance of the connecting conductors themselves. My Explorer battery terminal makes a small but visible spark when I connect the battery!

@shucker1 You have the kind of employment I would have given an arm for! Instead, I wound up building stuff like you work on! Now, too old to do much more than dream...... imp

 

[shucker1]

IMP.

Never too old brother.

54 and still going.

 

[shucker1]

J_C I understand what you are saying. No need to split hairs, it was just a suggestion.

However, sometimes we use written procedures, by engineers, to test and commission new equipment. A lot of procedures include this step.

Chemical process plants, some deviation from procedure is tolerated.

Try a deviation of written procedure in a nuclear plant and you can quickly find yourself in "Nuclear Jail".