Parasitic drain, an automotive short circuit that may cause a recurring dead battery

[sxr951]

Batreee..

[hailapeste]

I doublewatch your video coz it contains more the one tutorial inside. My question is can you elaborate on Cold Cranking Amps and Reserve Capacity numbers on battery coz I want to understand more of my battery 55A with 255DIN (GM) I know what 55A means but 255DIN dont. tnx

[spelunkerd]

@hailapeste That's a GREAT question. But it will take me a few weeks to find a good answer, ha ha. I googled 'car battery comparison', and came up with a few links. CCA is the important one here in Canada, since new cars are using more and coming close to the limits of cold usage. Thanks for your input! If you find out more, please post it here.

[hailapeste]

Very useful video, keep going. I thank you especially for 1ohm good explained method coz I have a cheep multimeter and I need to use it for this purpose. Still I'll try to find a little strong resistor cca 15-20w.

[spelunkerd]

@hailapeste You're welcome. And you also make a good point that the power rating on the resistor is very important. A higher wattage resistor would be better, but they aren't sold in many electronics stores, whereas the one Scotty uses is readily available. Just remember that you just let the juice flow long enough to get a reading, then quickly take it off before it gets hot.

[worldstream]

@spelunkerd You're right about calculated 10w should be enough according to this time span. I was thinking to actually build one resistor from NiFe leftovers. :) Your channel has allot of good quality infos. thx

[spelunkerd]

@worldstream Thank you. I had a look at your stream as well -- are you from Romania? Youtube is my chance to meet intelligent people from all over the world.

[worldstream]

@spelunkerd I've spent quality time with quite some of them. Many romanian peoples have entrepreneurial mindset but don't know where to start. I just explain them the basics. I'm looking for the next episode.

[jayguy173]

i got several shorted circuits improper terminology

[Toltecatl]

OK so now that I've seen your video and both Scotty's and Eric's videos I still don't fully understand the real world practical advantages and disadvantages of the 2 methods. According to what I've gathered Scotty's method of using a resistor is to protect the multimeter from getting fried but at the same time the resistor got so hot that Scotty Kilmer burnt his fingers while filming the video. In Eric's video, the multimeter remains connected except when opening a door, etc to prvent big spikes

[spelunkerd]

@Toltecatl The big problem with ammeters inside multimeters is you can EASILY fry your meter. Each fuse of my Fluke is $20, and on a cheap meter you may not be able to fix it. The commonest problem is to forget you were just measuring amps and then you decide to try and measure voltage across a battery. Sometimes a built in ammeter will fry with no warning light, then giving inaccurate low readings, and if you don't have a fuse you will want to use the resistance method.

[Toltecatl]

so which method is better in terms of practicality? I like the fact that in Eric's method you can see the AMPS change the moment you find the drain source. While with the resistor method you check the VOLTage drop but have to be wary of the HOT RESISTOR. So what are your thoughts of the the two methods?

THANKS FOR YOUR TIME AND ALL THE VIDS

[spelunkerd]

@Toltecatl Above all said, I still prefer to use the ammeter function of my multimeter, but I'm very wary not to overload the current draw. If I think the current may be too high, I'll use my induction ammeter which will not die if current is high. The resistor method is cool and interesting but I don't often use it. If I had an older multimeter, or one with a blown ammeter fuse, than I'd use Scotty's method.

[EdgarLopez]

good job

[hp11208]

nice

[TheFred1952]

very good video

[eurokid83]

Is that the 400 amp or 1000 amp current clamp your using in the beginning?

[spelunkerd]

@eurokid83 it's the (now discontinued) 1010i. I had to fix the switch once, when it failed to shut off. I believe it's 1000A, 600V, Cat III.

Fluke have some new, stand alone clamp meters that seem better, though some of that may be advertising. I don't find it great for the low amperage use in most automotive applications, though maybe it will be of more value with electric vehicles.

[eurokid83]

@spelunkerd You need a special low current clamp for anything in the mA range. Fluke makes a few.

[ltsgoyanks]

Well done! All the way around! Great instruction, methods, and video technique!

[jsnyara]

seen you around the etcg forums. great videos, subbed :)

[eeiko321]

Very good video. 10/10

[spelunkerd]

@eeiko321 Thanks.

[besman007]

So Document, Devide, and Conquer..Hmmm, kinda like the u.s wars in Afghanistan and Iraq..

[batterybank]

Reguarding the amp draw using the 1 Ohm 10 watt resister, couldent a 4 amp fuse be added to protect the resister sence its only capable of 3.1 amps?

[spelunkerd]

@batterybank That's a good thought. I guess it would be one more 'moving part' that could fail and confuse the user if it suddenly blew. A reversible circuit breaker would work best, but I haven't found one with such low amperage rating at my local hardware store. What I've built here seems to work pretty well. To me, the big weakness is a lack of ability to transmit a findable signal down a wire, a pulse wave modulator. But that adds expense and effort.

[batterybank]

@spelunkerd I went aheadand installed he 4 amp fuse, I know AdrenalineJunky96 burned both his up. I just need to make up the connecters for the detecter. I wish the buzzer was abit louder.

[spelunkerd]

@batterybank I think that will work fine. Since parasitic drain is by definition a drain that is low amperage, it usually isn't making a lot of juice because of circuit resistance. If circuit resistance is too high then a short detector may not have enough voltage drop to drive a buzzer. Higher amperage would probably blow the fuse in the fuse box, and so the problem would present as a recurring blown fuse.

[AdrenalineJunky96]

Yah I had tried googling but nothing yet for the schematics. I thought by disconnecting the plug connectors that ruled out that area as the buzzing didn't stop. So when I got to the fuse and it quit, I assumed it was between here and the wires running to the main fuse panel under the hood. Confused how 1 fuse in door locks and another is Lock Switch?

[AdrenalineJunky96]

So....... does this mean the problem is in a wire between this fuse and the larger 60 amp fuse in the engine bay? Is the "lock switch" between here somewhere? I appreciate your help as I know if I took to a mechanic i'd done spent a couple hundred bucks. I like doing things myself and though annoying it is good to see i'm on the right track..... MUCH THANKS! Look forward to more of your input!!!

[spelunkerd]

@AdrenalineJunky96 Regarding where the fault is, it could be anywhere in the circuit covered by the #2 fuse, probably distal to the #2 fuse. Once you isolate the area involved, plug the other devices back in to get back to normal elsewhere. Try to find a schematic of the circuit involved -- a google search might help. .

[AdrenalineJunky96]

@AdrenalineJunky96 So you are saying that the problem could be in the wiring even where I had disconnected the plugs/connectors? I thought by unplugging them and the buzzer continuing that it ruled out that area? So do I need to plug the detector device into the #2 fuse and start testing the connections again? Getting a little bit lost. Thx. Mike.

[AdrenalineJunky96]

@AdrenalineJunky96 O.K. had someone tell me that the short would be under the dash before the fuse! So can I plug the tester into this fuse panel and plug/unplug and shake wires to narrow it down further? I have a strong feeling that it has something to do with the power door locks just because I have been in there. Am I correct in using the tester further with the connections before the fuse?

[AdrenalineJunky96]

@AdrenalineJunky96 Well I just went out and plugged the short circuit tester into the fuse panel under the passenger dash and replugged the connectors and expected the buzzer but I am getting nothing. I inserted fuse and retested under the hood and buzzer goes off. Stumped as to why the buzzer isn't going off when inserted under dash?

[AdrenalineJunky96]

O.K. more progress but yet still so far away. I have a 94 Oldsmobile 88 Royale. I have unplugged everything I can find relating to trunk release, power door locks and horn as far as connectors go and shaken everything around them. I just found there is another smaller fuse box under the passenger side dash. There is smaller fuses for 1. Door Locks, 2. Power Antenna, Lock Switch, Trunk Release, and 3. Horns. I got to #2 fuse and WALAAAAAAAAAAAH, the buzzer quit!!!

[AdrenalineJunky96]

I just then went off the buzzer. I had recently replaced power window motor so thought it was probably the power door lock wires. I have disconnected the power door lock on the driver side door where I had worked. I unplugged the trunk release button and removed the plug in from the horn. I have wiggled the wires in these areas but nothing happens. Am I missing something? I greatly appreciate a reply.

[spelunkerd]

@AdrenalineJunky96 Two ways to approach this kind of problem. Most of us quickly go to what instinct tells us the problem is, like you did above. That approach is faster and often you get lucky. When that doesn't work, I find the second approach is better. Go right back to basics and start from scratch, by first investigating, slowly and methodically. The car will tell you what is wrong if you hone your listening skills. I could be more specific, if you can accurately describe what you have....

[AdrenalineJunky96]

O.K. I have used the resistor and found that a 60 amp circuit which includes power door locks, horn, and trunk release is pulling a little over 3 amps and every couple days the battery is dead. I made a short circuit tester but my buzzer only works and it only works 1 way. The spade terminals have to be plugged into a certain side or it doesn't buzz. The light doesn't come on though and only has a hot wire. I was looking at the diagram. Do you not have the negatives wired to the switch?

[spelunkerd]

@AdrenalineJunky96 Oops, I replied to your first message before I read this one. If you pull the fuse on that 60A circuit for a few days, does the problem go away? The circuit of that home made tester is wired exactly per the schematic on my video. Maybe the resistance of your short is too high to give enough drop voltage across the tester to light up. Does it work if you wire the tester straight across the battery? You could use a simple test light. Strange problems are often due to bad ground.

[captainbluejay]

Thanks for expanding on Scotty Kilmer,s tecnique for finding the parasitic drain.He did not explain why he uses that size resistor.Thanks for breaking it down in easy to under stand way.I have a large drain on my 85 Corvette and will be useing this method to day to try and start to adress the issue.

[spelunkerd]

@captainbluejay You're welcome. Good luck finding the problem -- these can sometimes be really obscure.

[captainbluejay]

@spelunkerd I could not see your multimeter very well to see the setting selection.Should my cheap multimeter be set at 20 on the DCV selection? The reading will be in volts, which is equal to amps beacuse of the resistor.Is that correct? When I test at that setting I get a reading of - 2.13 with all lights off and the computer at rest. Does this mean my drain is just over 2 amps?

[spelunkerd]

@captainbluejay Yes, if your resistor is 1 ohm, the amperage = voltage drop across that 1 ohm resistor. So, if you have it hooked up correctly then you are at just over 2 amps. Remember the hood light and the computer, and anything else you might have left on. If both of those are off (for long enough for the computer to go into sleep mode) you are way too high -- should be in the range of 0.045 amps. My meter uses automatic range-finding.

[bearing01]

I had a parasitic drain in one of my cars (1986 BMW). The instrument cluster had NiCad batteries to retain the oil change memory. The batteries died and wouldn't hold a charge and caused a parasitic draw around 150mA. This was enough to kill the car battery over the period of a couple weeks - or less if the battery is compromised. The off parasitic draw is around 60mA now. /John

[Tdfries]

Thanks for the reply. I've noticed that the digital readout multimeter's are significantly more expensive... I may just need an analog one for my uses. Thanks again for the reply and the video.

[Tdfries]

Hello, thank you for this helpful video. Just a quick question. What model and brand is the multimeter you are using? I'm just curious because I would like to purchase one that I have seen in use, as I would know that it is good quality. Thanks for any input and I appreciate the video.

[spelunkerd]

@Tdfries Fluke 88V. REALLY expensive, probably not worth it unless you do this for a living. Great connectors, and some added features. One fuse on one of these meters costs more than a low level meter from a hardware store. On the other hand, I've killed a few meters in the past, never killed a fluke, and fluke do offer a lifetime warranty with all their meters. If you go to the youtube site 'EEVblog', you will find an electronic engineer who does entertaining multimeter reviews.