Sulavaca has a clean rag and some WD40 for that.[/quote]
As long as he doesn’t offer his tongue.
Sulavaca has a clean rag and some WD40 for that.[/quote]
As long as he doesn’t offer his tongue.[/quote]
I’ve heard he’s recruiting an assistant.
Think about how a series circuit works and why it’s not a good idea to run a 3,000W device off a cable rated for 1,000W.
Just use the right tool for the job, an ammeter will tell you right away if you have a problem without waiting for the battery to discharge every time.[/quote]
So you’re saying a test light might pull too much extra current and damage delicate electronics?
Hmm… Fair enough. I suppose I wasn’t thinking of modern computerised cars, but then I wouldn’t buy one if I could avoid it. Dunno how high tech/delicate the Accord is.
I use a multi-LED test light which I think is supposed to pull a max of about 20mA, which I think is fairly safe for my kinda car, but maybe not all. OTOH I suppose it could easily get fried itself if the load is too high.
I have a multi-meter but I don’t use it much because it seems to generate random numbers unless it has a brand new battery, and I don’t really trust it even then. Next time I need one I should probably try and buy a better one.
I’m thinking more that exploding bulbs and engine oils don’t mix. Why don’t you try putting that LED in series with the rest of your vehicle electronics and see what happens 
Sulavaca has a clean rag and some WD40 for that.[/quote]
As long as he doesn’t offer his tongue.[/quote]
I’ve heard he’s recruiting an assistant.
[/quote]
Sulavaca is a professional, I’m more just an ammeter.
A typical battery in a 90s Honda is 30-50Ah so ~2days is roughly a 1 amp draw.
Slow drains like this are usually caused by some solid state device like the radio or alarm not turning all the way off or a short in the wiring harness between a live wire and another wire with some fixed resistance to ground. The reason why is if you had an actual short to the chassis, the battery can and will supply enough current to blow a fuse or worse, smoke the harness and light the car on fire.
Your best bet is to go about it systematically at or near the fuse box, since that’s the only place on the entire car where you’re going to have the wire harness organized in a fashion where you can pinpoint the branch at fault. The easiest way to do this is to put an loop type ammeter AROUND the positive battery wire. You should see your 1A draw.
Now systematically remove a fuse at a time until the draw goes away. Look up what’s on that fuse’s circuit and check it out. If its still drawing, remove relays systematically. If that doesn’t help, the draw is before the fuse box, which fortunately is not that many things. Voltage regulator / alternator, starter / solenoid are often culprits in this case.
Doing the ammeter and/or test light in series should also work assuming you’re only measuring leakage but if something goes wrong (eg: you accidentally try to start the car or your cooling fan turns on) your ammeter or light (or tongue) are likely to get smoked. Loop type ammeters are much better for this sort of thing and bonus is you don’t have to disconnect anything to use one.
If you really want specifics, Honda-tech.com should have details for your specific car and if you get really feisty, how to swap your motor with a “Red Top K20R” or something. 
mabagal forgot to mention that if you do find a high draw in current when first starting this test then wait for over an hour and then go back to check your ammeter. The car’s computer systems will draw a high current until they go into rest mode. Of course its sometimes the computers themselves that are at fault too and they won’t stop even if you pull all the fuses out.
There’s a decent single page article on parasitic draw here.
So, for a series test, the choice is between buying a loop ammeter, risking a multimeter, or risking a light bulb/neon tube/LED test light.
Um…light bulb.
I can live with the limitation that it can’t apparently be mixed with my engine oil while its actually exploding (?)
The cheap Draper neon one I had before was fuse-protected anyway.
Technically speaking, the loop ammeter is not series, although it does appear as an inductor in the circuit. The test light is perfectly good, but a drawback with the test light is that it’s binary. This means if you have something that is doing an acceptable drain of say 100mA, your test light may still stay on after you’ve eliminated the bigger draw. It also makes it harder to diagnose the situation if there are multiple branches at fault.
[quote=“Chris”]
Stopgap fix: disconnect battery before letting the car sit for a while.[/quote]
This provides the extra benefit of Anti-Theft.
I love reading threads like these which I pay attention to about as much as all of the engineering classes that I skipped/slept in/ignored during college. But there is some really good stuff here and I would be looking for this info if I had a similar problem.
Makes sense. I suppose I’d normally start with one of my test lights, (because they don’t need a battery and are already in my tool box) and then go to a multimeter if I needed to.
I’d never really thought of this as recce with the more expendable asset, just convenience, but it does seem to have that collateral benefit.
I can see the advantage of a clamp-on inductive meter, but I probably wouldn’t use it enough to justify what I assume is significantly greater expense. OTOH if it avoided melting one or two good multimeters I suppose it’d pay for itself.
I’ll bear it in mind if I go meter shopping. Thanks
After sitting idle for maybe 3 weeks, my car started, but the battery doesn’t seem to be holding a charge.
(EDIT: This seems a bit strange, since I’d have expected a knackered battery to fail to start the car in the first place. My best guess is that it was significantly discharged while standing, and then damaged by the high recharging current. ENDEDIT)
I bought a new one, but the guy in the battery emporium said, according to my translatorette, that the cars “electricity power” was a bit low.
(I assume this means the charging voltage was low, but I didn’t see the reading on his meter because I was in the car revving the engine, and she didn’t relay the comment to me until after we’d driven away.)
I think I now have an excuse/reason to buy myself a better multimeter to replace my cheapo random number generator.
It’d mostly be for automative use.
I had a Gunson one that had special automative functions (tach, dwell, etc), but I couldn’t find it when I was back in the yook this summer.
Any recommendations? I know of Fluke, (because they made a nifty hand-held network analyser that I used when I didn’t need a lot of detail) and assume you can get them here somewhere, but they are pretty pricy for an occaisional-use item, so a good-but-not-quite-as-expensive brand would probably make more sense.
Clamp-on inductive loop functionality would be nice, but not essential.
I have a very nice multimeter. It is Taiwan made and considered the best on the market here. I’m damned if I can remember the brand right now, but I’ll try to remember to check when I get back to the workshop. If you can avoid it, then try to stay away form Chinese meters of the cheap and cheerful variety. I’ve never had a Chinese gauge of any sort last longer than a week.
I love my multimeter. It’s one of the most used tools in my tool box, and perfect for parasitic drain testing.
As an addition to your meter, you should pick up some crocodile clips for the ends of your meter’s leads. They come in really useful when clipping into battery terminals or when fitting stereos or other auxiliaries to your car.
Edit: My multimeter’s brand is : YFE. It’s Model number is YF-3502
Thanks Mr S. I’ll look out for it.
Just put the car through its inspection (late) this morning, so I’m in celebratory (gadget buying) mood, a habit of mind ingrained by the UK MOT test, though of course that’s a significantly higher hurdle.
I’d be curious to know what the real (emission and braking force) numbers were, but didn’t think it was a good idea to rock the boat by asking.
If you went through a private testing centre then the numbers are likely meaningless anyway as their machines are mostly re-calibrated to allow crap cars to pass. That’s the reason they get so much business from local used car dealers.
I put my ex-girlfriend’s car through one the other day. They didn’t lift the bonnet to check the engine and chassis numbers, and their slip pan (wheel alignment gauge) was definitely not accurate as I had the alignment done half an hour after leaving and the suspension had to be changed as it was bent too far out of shape.
I’ve also taken a car through there with a destroyed front steering assembly and even though its wheels could float a full 5cm, it still passed with flying colours. It also had an illegal turbo and intake modification. It still made no difference. PASS!
Don’t worry chaps. I don’t recommend or even sell such a vehicle to anyone. This one I borrowed from a dealer, just to see for myself how lax a local testing centre could be.
[quote=“sulavaca”]If you went through a private testing centre then the numbers are likely meaningless anyway as their machines are mostly re-calibrated to allow crap cars to pass. That’s the reason they get so much business from local used car dealers.
[/quote]
That’s the reason they get my business too, though of course its wrong. Very very wrong. 
I don’t necessarily think I can rely on them being lax, though. A car that looks like mine screams “FAIL ME” irrespective of its mechanical condition, and I ain’t got no guanchi, so if they needed a victim to fill a quota, I’d likely be it.
I check what I can (lights, handbrake adjustment, pedal travel) before I go in. I considered temporarily removing the air filter, but since I don’t know the emissions are bad, I didn’t bother.
The batteries in Taiwan are the same batteries they use in Canada. They’re both made in China.
Your vehicle is losing it’s charge and it’s not a normal occurance.
Get a multimeter to check the charge of the battery. It could be the sparkplugs, or ignition coils/wires. Batteries do not lose their charge in 4 days, especially Taiwan’s mild climate.
[quote=“allperils”]The batteries in Taiwan are the same batteries they use in Canada. They’re both made in China.
Your vehicle is losing it’s charge and it’s not a normal occurance.
Get a multimeter to check the charge of the battery. It could be the sparkplugs, or ignition coils/wires. Batteries do not lose their charge in 4 days, especially Taiwan’s mild climate.[/quote]
And I have never, ever heard of a battery drain due to its spark plugs or ignition coils and wires. nine times out of ten its the alarm system or stereo. Eight times out of ten its a door lock motor. One time out of ten its something else.
Pull the positive terminal off the battery and connect your multimeter between positive battery and positive wire. The multimeter at this point should be set up to be showing Amps, and this commonly requires that the leads on the multimeter be switched around. Use the 20A setting. Oh, and remember to have the vehicle switched off, all door lights off, and in the case you have a bonnet/hood switch, then depress the switch, or use a screwdriver to close the locking clasp and mechanism which holds the bonnet shut. You need the bonnet open to read your multimeter, but you don’t want any closed switches potentially setting off any computer systems.
With the multimeter connected, you should be getting a typical normal reading of around 0.03 amps. In this case you have no parasitic draw. Just to make sure you have set up properly, you can experiment by turning on the interior light to see if your meter readout changes. If nothing changes, or your screen is reading zero when your car has an electronic control unit, then you likely haven’t set up your meter properly.
If you have a reading over 0.05, then this is considered high (unless working on Fords) and you should investigate your vehicle’s systems to figure out where additional the drain is.
If you have a higher reading over 0.03 at the beginning of the test, then having checked all lights, stereo and auxiliaries are off, wait for up to twenty minutes with multimeter hooked up, and then re-check the multimeter screen. A few (very few, and mostly non Japanese) vehicles will show a high drain for up to half an hour as the vehicle’s ECU has taken longer to go into “sleep mode”. After the half hour point, then almost all vehicles should be reading around 0.03.
If reading over 0.03 after all is done, then you should begin disconnecting any alarm system first, starting with its siren, as that is often built with a backup battery which typically fails after around four to five years. Next disconnect any stereo system, and especially any amplifiers which may be permanently wired to the battery. In some cases vehicles may be fitted with additional T.V. boxes, GPS tracking units and other systems which sometimes require a backup battery. Any system which incorporates a backup battery will often fail and result in a direct parasitic draw from the vehicle’s main battery. These types of systems should always be investigated before any other as they are almost always the greatest common cause of significant battery drain.
If your vehicle’s systems are only drawing around 0.03 amps, and you are still loosing significant battery power over a relatively short time of around a few days, then the fault is most likely your vehicle’s battery or charging system.
First, in the event of a battery drain, check any system which has a battery backup, i.e. alarm, GPS Tracker
[quote=“sulavaca”]I have a very nice multimeter. It is Taiwan made and considered the best on the market here. I’m damned if I can remember the brand right now, but I’ll try to remember to check when I get back to the workshop. If you can avoid it, then try to stay away form Chinese meters of the cheap and cheerful variety. I’ve never had a Chinese gauge of any sort last longer than a week.
I love my multimeter. It’s one of the most used tools in my tool box, and perfect for parasitic drain testing.
As an addition to your meter, you should pick up some crocodile clips for the ends of your meter’s leads. They come in really useful when clipping into battery terminals or when fitting stereos or other auxiliaries to your car.
Edit: My multimeter’s brand is : YFE. It’s Model number is YF-3502[/quote]
Havn’t shopped around but I had a look in one of the local electronics places at the weekend. They have it, for, IIRC, 870NT. They also had a YF-3502T which apparently does temperature measurement too, for a little more. (I think 950NT).
I’m not sure if the model T comes with the thermocouple sensor or if that’s extra, but the online picture seems to have some extra wires so I’d guess/hope its included.
I dunno how useful that’s likely to be (oil temperature measurement? coolant? etc?) but for the small difference I’m inclined to get that one.
(I don’t quite see why one can’t use the “ordinary” millivolt scale to measure the thermcouple output, but then I know bugger-all about thermocouples/multimeters. EDIT: I suppose they just provide an additional scale to save converting the meter reading. ENDEDIT)
Any thoughts/experiences, anyone?
I’ve never needed the extra functions you mention. You should be fine with the basic multimeter I mentioned. The additional temperature gauge would usually be useful in a modding situation to measure changes in engine performance. Most cars which I come across on a daily basis will never require such testing. The only occasional times I come across a need for a temperature tester is for air con cool air output and radiator coolant temperature, but I use specific devices for those, the latter being a simple thermometer like a meat roast thermometer which sits in the radiator or expansion tank and gives me a manual gauge reading. This is good as its simpler to read and I don’t require temperature readout to within tenths of a degree.