Charging dead battery, relay constantly clicking

[Cogman]

I have a ford edge 2012.

I came home after a long trip to a dead battery, so I purchased a 2Amp battery charger and have been charging the battery for about the last 8 hours. Inside the car, I could hear a relay clicking very quickly (~100 clicks/second), so I removed the fuse panel, and unplugged what I could easily get to, now I hear a slow clicking relay coming from the same fuse panel (~2 clicks/second).

So here is my question. Was the fast clicking relay preventing charging (using too much energy checking if there was enough energy to run things)? And should I worry about completely disconnecting the battery and charging to make sure nothing is draining it.

I'm hoping that the battery will be charged in the morning and just want to do everything I can to make sure it gets there.

 

[LTC8K6]

Probably too small of a charger to charge a dead battery in the vehicle given the parasitic loads and the relay. Probably the battery saver relay that was clicking?

I would disconnect the battery from the car if I had to use a 2A charger.

If you have AAA, get a jump.

 

[jlee]

A 2 amp charger should easily out-charge any small key-off power draw. I'm unsure if there's any odd anti-theft stuff (like 90's stereos) requiring some sort of reprogramming after power has been removed, but you could probably disconnect it and charge that way if you're concerned.

 

[jlee]

Probably too small of a charger to charge a dead battery in the vehicle given the parasitic loads and the relay. Probably the battery saver relay that was clicking?

I would disconnect the battery from the car if I had to use a 2A charger.

If you have AAA, get a jump.

It'd take a while to charge, but I really doubt parasitic draw will be that high. I could be wrong, though

 

[LTC8K6]

I'm thinking the car is never going to sleep with that charger connected and the relay tripping, so the parasitic load is staying high.

 

[Cogman]

I pulled off the connector from the negative terminal, replugged in the connections to the fuse box, and am going to let this thing charge overnight. Hopefully that is enough to get it rolling again.

 

[jlee]

I'm thinking the car is never going to sleep with that charger connected and the relay tripping, so the parasitic load is staying high.

Ah, good point. I've never owned anything that new before.

 

[Cogman]

Ah, good point. I've never owned anything that new before.

Yeah, this car has a ton of neat electronic features (the dashboard is an LCD screen, backup cam/nav box/etc) I'm thinking that LTC8K6 might be right here.

Thanks for the help guys.

 

[phucheneh]

Broken record/dead horse response from me:

Get a voltmeter and know with 99% certainty where you stand.

Repeated clicking from relays is common with a dead battery. Like, seriously dead. Well below the 11-12v range of what is generally considered indicative of 'fully dead' or close to it. I've seen it on batteries showing only 6-8v or so. A.k.a. 'dead dead'...for all intents and purposes, no charge present.

The relay coil gets just enough juice to pull the switch shut, but can't maintain it and the relay clicks back off. Rinse and repeat. If the relay(s) keep clicking, the battery is probably not charging or there is otherwise a power delivery issue (bad cable to fusebox).

First thing I would do is pull the battery from the car so that there is no draw on it. With the key off, there really shouldn't be, anyway, but sometimes in a modern car things get kind of stuck in a loop as the electrical system 'settles' after a shutdown. E.g. a BCM or other interior module is trying to manage basic functions like door locks, keyless/alarm stuff or whatnot. It cannot complete its task, but has just enough voltage to power up and keep trying, hence clicking relays.

First check 'open circuit voltage,' which simply means see what you're reading at the batt terminals while disconnected.

With a 'full size' batt charger, you can then generally just look for charging voltage somewhere in the realm of what your typical alternator would put out. With little benchtop trickle chargers, it can be a little harder- I'll usually periodically disconnect the charger and check the batt voltage to see if it's slowly building. It helps to occasionally put a small load on the batt to remove the 'surface charge' and get an accurate read. A spare headlight bulb/pigtail with some alligator clips on the end works nicely for this.

Once the batt is solidly into >12v territory, your relay clicking should stop. I suspect this is not happening. Either the battery has a bad cell (five charged cells and one dead one = ~10.5v battery) or it is simply not charging.

The relay clicking should not 'block' charging, but with only a 2a charger, it may be consuming electricity as fast as the charger can supply. Again, remove the batt, then let it trickle until you're reading a good bit over 12v. When you reinstall, your issue will probably be gone.

 

[tortillasoup]

I would fully charge the battery with the car disconnected, then hook up the fuses back to where they are and while that relay is clicking very quickly/loudly, try to locate which relay that is. You likely have a faulty switch of sorts that is triggering that relay to click on and then back off. The car is new, why not take it to the dealer to have them look at it?

 

[LTC8K6]

I would fully charge the battery with the car disconnected, then hook up the fuses back to where they are and while that relay is clicking very quickly/loudly, try to locate which relay that is. You likely have a faulty switch of sorts that is triggering that relay to click on and then back off. The car is new, why not take it to the dealer to have them look at it?

The relay will almost certainly not be clicking any more once the battery returns to normal.

It is likely only clicking due to low voltage and the battery charger not quite having enough power to both charge the dead battery and run whatever is trying to run in the vehicle.

 

[tortillasoup]

The relay will almost certainly not be clicking any more once the battery returns to normal.

It is likely only clicking due to low voltage and the battery charger not quite having enough power to both charge the dead battery and run whatever is trying to run in the vehicle.

but why was the battery dead? Seems odd. Also never heard of this behavior and I have a LOT of experience with cars with undercharged batteries of varying degrees of voltage... However it is true that newer cars are highly sensitive to low battery voltage and when I say low battery voltage I mean a resting voltage of like 11.9v being enough to trigger all sorts of check engine codes and what not.

 

[LTC8K6]

but why was the battery dead? Seems odd. Also never heard of this behavior and I have a LOT of experience with cars with undercharged batteries of varying degrees of voltage... However it is true that newer cars are highly sensitive to low battery voltage and when I say low battery voltage I mean a resting voltage of like 11.9v being enough to trigger all sorts of check engine codes and what not.

It was dead from sitting for a long time. Nothing odd about that.

I came home after a long trip to a dead battery

 

[Cogman]

Worked, Hopefully it starts again after work.

 

[Zenmervolt]

but why was the battery dead? Seems odd. Also never heard of this behavior and I have a LOT of experience with cars with undercharged batteries of varying degrees of voltage... However it is true that newer cars are highly sensitive to low battery voltage and when I say low battery voltage I mean a resting voltage of like 11.9v being enough to trigger all sorts of check engine codes and what not.

Considering that a battery voltage of 11.9 volts indicates that the battery is completely dead, I'd say that's more than just "low."

At 100% charge, an automotive SLI (Starter/Lights/Ignition) battery shows 12.6 volts across the terminals. A reading of 12.3 volts across the terminals means you're only at 50% charge. A reading of 12.0 volts is around 10% charge.

Not only that, but once a car is running, the alternator puts out between 13.0 (rather low) and 14.0 (rather high) volts. A reading of 11.9 volts while running would throw all sorts of codes (even ignoring the fact that it represents a completely dead battery) because it would mean that the goddamn charging system wasn't working. Most automotive systems are designed for 13.5 volt (nominal) input. The sensors used by the ECU typically use regulated voltage (5 volts is common) that is first conditioned by the ECU itself.

ZV

 

[tortillasoup]

Considering that a battery voltage of 11.9 volts indicates that the battery is completely dead, I'd say that's more than just "low."

At 100% charge, an automotive SLI (Starter/Lights/Ignition) battery shows 12.6 volts across the terminals. A reading of 12.3 volts across the terminals means you're only at 50% charge. A reading of 12.0 volts is around 10% charge.

Not only that, but once a car is running, the alternator puts out between 13.0 (rather low) and 14.0 (rather high) volts. A reading of 11.9 volts while running would throw all sorts of codes (even ignoring the fact that it represents a completely dead battery) because it would mean that the goddamn charging system wasn't working. Most automotive systems are designed for 13.5 volt (nominal) input. The sensors used by the ECU typically use regulated voltage (5 volts is common) that is first conditioned by the ECU itself.

ZV

I wholly agree, however starters will work down to about 10V, and trying to explain to people that a 11.9V battery is "dead" when most things like the lights and starter will work at that voltage is quite difficult to say the least.

 

[Zenmervolt]

I wholly agree, however starters will work down to about 10V, and trying to explain to people that a 11.9V battery is "dead" when most things like the lights and starter will work at that voltage is quite difficult to say the least.

Uh, no... A starter will not spin the engine if it's powered from an SLI battery that reads 10 volts with no load. A battery that far dead will not be able to deliver anywhere close to enough amperage to crank the engine. Hell, if the battery reads 12 volts with no load it's not going to spin the starter.

There's a difference between the voltage drop from having a load on the battery and the resting voltage. A weak battery may drop to 10 volts while cranking, but there's no fucking way that a battery showing only 10 volts at no load will crank an engine.

ZV

 

[tortillasoup]

Uh, no... A starter will not spin the engine if it's powered from an SLI battery that reads 10 volts with no load. A battery that far dead will not be able to deliver anywhere close to enough amperage to crank the engine. Hell, if the battery reads 12 volts with no load it's not going to spin the starter.

There's a difference between the voltage drop from having a load on the battery and the resting voltage. A weak battery may drop to 10 volts while cranking, but there's no fucking way that a battery showing only 10 volts at no load will crank an engine.

ZV

I disagree. Maybe you should do some tests of your own and report back, you may be surprised.

 

[phucheneh]

You're both half-right.

I've seen a battery with a completely dead cell, reading 11v or less OCV, start a car.

There is a large difference between five charged cells and six dead ones. OCV should only be used as an indicator of state-of-charge with a known good battery. Which just brings us back to 'if you're going to work on cars, buy a decent voltmeter.' A combination of OCV (remove surface charge first) and a simple V-drop test across the batt terminals while cranking will, the vast majority of the time, tell you what you need to know.

The only thing I will 100% disagree with: 11.9v does not set low voltage codes in control modules. That's usually more in the 10v range; i.e. lower voltage than a module would ever normally see when the car is under heavy electrical load while not running. Like turning the starter. Or just being parked with headlights on and then opening a window or something. That brief light dimming isn't a loss of some measly tenth of a volt or some such.

 

[tortillasoup]

Well I've noticed on numerous vehicles that have a no load voltage of around 11.9 or slightly less have major computer glitching/check engine codes, pretty much a cacophony of warnings, lights, errors etc. all resolved by turning off the car and charging the battery for a few hours with a trickle charger.

 

[Zenmervolt]

You're both half-right.

I've seen a battery with a completely dead cell, reading 11v or less OCV, start a car.

There is a large difference between five charged cells and six dead ones. OCV should only be used as an indicator of state-of-charge with a known good battery.

Wasn't thinking about one dead cell and five good ones. Completely agree with this clarification. :thumbsup:

Well I've noticed on numerous vehicles that have a no load voltage of around 11.9 or slightly less have major computer glitching/check engine codes, pretty much a cacophony of warnings, lights, errors etc. all resolved by turning off the car and charging the battery for a few hours with a trickle charger.

A trickle charger (usually under 1 amp) isn't going to do jack shit for a battery that far dead in only "a few hours." A trickle charger would take at least 12 hours to charge the tiny battery on my motorcycle from an OCV of 11.9 volts. A very small car battery is going to need 40+ hours on a trickle charger to come back from that, more common car battery sizes would need between 60 and 90 hours at a 1-amp charge rate.

ZV

 

[natto fire]

You're both half-right.

I've seen a battery with a completely dead cell, reading 11v or less OCV, start a car.

There is a large difference between five charged cells and six dead ones. OCV should only be used as an indicator of state-of-charge with a known good battery. Which just brings us back to 'if you're going to work on cars, buy a decent voltmeter.' A combination of OCV (remove surface charge first) and a simple V-drop test across the batt terminals while cranking will, the vast majority of the time, tell you what you need to know.

The only thing I will 100% disagree with: 11.9v does not set low voltage codes in control modules. That's usually more in the 10v range; i.e. lower voltage than a module would ever normally see when the car is under heavy electrical load while not running. Like turning the starter. Or just being parked with headlights on and then opening a window or something. That brief light dimming isn't a loss of some measly tenth of a volt or some such.

Good point. I had a bad cell plague me for a bit when I had a fairly new battery in an '80 Toyota Corolla.

There are six cells in a battery, which chemically, produce 2.1v each. Because internally the cells are a series circuit, weird stuff can happen if one of them fails intermittently.

I learned the hard way that a battery test is an easy and cheap way to save some diagnostic legwork, even when common sense tells you to start at the load and work from there.

 

[tortillasoup]

Wasn't thinking about one dead cell and five good ones. Completely agree with this clarification. :thumbsup:



A trickle charger (usually under 1 amp) isn't going to do jack shit for a battery that far dead in only "a few hours." A trickle charger would take at least 12 hours to charge the tiny battery on my motorcycle from an OCV of 11.9 volts. A very small car battery is going to need 40+ hours on a trickle charger to come back from that, more common car battery sizes would need between 60 and 90 hours at a 1-amp charge rate.

ZV

That's true, but I figured a few hours on a trickle charger would be enough to get him over the hump with the relay but now that I think about it, it really would need at least 12 hours to do anything useful, preferably 24-48+ hours to go from 10v to 12v+ since most car batteries are at least 40+AH and lead acid charging is only 50% efficient. I use the Batteryminder 1500 which is a 1.5A trickle charger, desulfates the battery, temperature compensated...

 

[Scarpozzi]

Good that you got it going. I'd run it by Autozone or Advance Auto and have them test your battery to check the cells.

The fact that you were gone on a long trip makes me wonder if a light was left on or a door wasn't closed all the way. Testing the battery should at least give you piece of mind. I've seen a lot of batteries fail in less than 2 years lately (mine, friends, family)...which is crazy considering they used to be rated for 60 months.

 

[tortillasoup]

The batteries aren't the problem, the problem is the very high parasitic draw from all the electronics, alarms, keyless entry, push button start (RFID) crap. Disabling the SmartKey system on the Toyotas makes a huge difference in lowering this parasitic draw but you can't do that on the newer cars anymore which totally sucks. On the first gen cars with the smart key system, you could disable the system with a button under the dash but with the newer cars, you can't do this and you basically have to live with this very high parasitic draw which is a problem if you drive your car infrequently.