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Hi all, I'm really sorry if this has been covered already, but I need to get my G/Fs car running before tomorrow.

There was a huge amount of corrosion on the positive battery post, it progressively go worse over 3 weeks from the first time it was noticed (5 weeks from the installation of a remote start[which I believe is causing this whole problem] and the only recent electrical work[I installed a hitch and wired the plug in over a year ago]). Well the Rav didn't start this morning, I popped the hood and the post had bubbling electrolyte coming out of it, I quickly removed the battery.

After purchasing a new battery and hardware to replace all the corroded parts, I went to work. As I'm wiring up the positive lug, I measured the wires resistance to ground. The smaller one running into the fuse box has a direct short to ground. This explains the battery problems, but why is it shorted in the first place? Hard ground, 0.01 Ohms.

I've spent the last two hours slamming my head onto this keyboard, searching the internet for a cause or explanation..... Any and all help is greatly appreciated!

The car is a 2007 Limited V6 4x4

-Will
 

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As I'm wiring up the positive lug, I measured the wires resistance to ground. The smaller one running into the fuse box has a direct short to ground. This explains the battery problems, but why is it shorted in the first place? Hard ground, 0.01 Ohms.
I don't think you have a short. According to ohms law, a 12 volt battery passing through a .01 ohm load would create 1200 amps of current flow. That would have surely melted the cables.

I think the resistance that you are measuring is the result of all the electronic devices that are on the circuit. For example the ECU, Radio, or even a dome light.

You know that if you measure the resistance of a 120v light bulb it will be almost 0 ohms but that resistance increases to about 240 ohms as soon as the filament heats up.

Electronic devices have capacitors that absorb an initial in-rush of current and then level off to very small amounts.

In an automobile, the only way to check for excessive current draw is to use an ammeter to measure the current traveling from the battery post into the cable.
 

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Rickl,

Thank you for that quick response. I was in such a rush to find the reasoning behind the corrosion that I quickly made assumptions. I verified that there is .01 amps on that wire, not nearly what it would be if it was shorted as you suggested. I'll check it again in the morning, but I think it's good to go.

Here's to self-induced panic :cheers:


Now why did the 18 month old battery self destruct:confused:
 

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I popped the hood and the post had bubbling electrolyte coming out of it, I quickly removed the battery.
Now why did the 18 month old battery self destruct:confused:
I'm not sure, but you may be misusing the terminology. Electrolyte is the liquid water/acid solution that surrounds the lead plates inside the battery, so I doubt if Electrolyte was bubbling out of the posts. The only way that could happen is if the plastic battery case was cracked around the post and if that was the case you wouldn't need to ask me why the battery didn't last long.

If the case was indeed cracked, then it was a manufacturing defect, or it was damaged during installation. Either way, that explains the short lifespan of the battery.

The blue/green corrosion is the result of acid contacting the lead battery posts. In most cases the acid is in the gases that escape from the battery, but if you did have a cracked case around the post, that would have accelerated the corrosion.
 

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I verified that there is .01 amps on that wire, not nearly what it would be if it was shorted as you suggested. I'll check it again in the morning,
When power is first applied to the system, all the on-board computers will reinitialize (i.e. boot-up) and draw larger than normal amounts of currents. After initial power up, many of the processors in a vehicle will return to an idling state. You should really be checking for current draw in this idling state.

This means that you have to interrupt the circuit initially to insert the ammeter, but leave everything for about a 1/2 hour before taking your readings. Your reading of .01 amps (10 milliamps) is already quite low and does not indicate any problems.
 

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Rickl,

Thank you for that quick response. I was in such a rush to find the reasoning behind the corrosion that I quickly made assumptions. I verified that there is .01 amps on that wire, not nearly what it would be if it was shorted as you suggested. I'll check it again in the morning, but I think it's good to go.

Here's to self-induced panic :cheers:


Now why did the 18 month old battery self destruct:confused:

The battery ordinarily would be under warranty and if it had, for example, a 24 month free replacement warranty it should be replaced for no cost by the seller. If the warranty is pro-rated from the date of purchase the warranty will cover the total cost minus the 18 months apportioned over the total months of the warranty, e.g, if the battery was warranted for 36 months the warranty ordinarily would reimburse the purchaser for 1/2 of the total cost (but see Dr. Dyno's experience regarding that situation by doing a search).

Without examining and testing the battery it apparently was defective, but to have electrolyte bubbling up from a terminal would be unusual although as a former battery RMA tech for a manufacturer I have seen electrolyte ooze out from a terminal location.
 

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This guy just experienced the same thing with is 4.4--a lot of corrosion on the positive terminal and a cracked battery--dealer replaced the battery and positive cable under warranty:

Battery Condition OK?
 

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Thank you all for the spirited responses. I checked current again this morning and it's at 30 milliamps, I'm happy with that.

The old battery had a 100 month warranty, we are looking for the receipt; if not we got it at Costco, hopefully they will have the purchase on file.

You should really be checking for current draw in this idling state.

This means that you have to interrupt the circuit initially to insert the ammeter, but leave everything for about a 1/2 hour before taking your readings. Your reading of .01 amps (10 milliamps) is already quite low and does not indicate any problems.
I have a fancy dc clamp meter that I used for the readings, but this process would work for anyone else who may not have one. Thank you for the break down how to.



This guy just experienced the same thing with is 4.4--a lot of corrosion on the positive terminal and a cracked battery--dealer replaced the battery and positive cable under warranty:

Battery Condition OK?
The pictures are very close to what I was experiencing, but 3 times worse. There was a large mound of corrosion on top of the battery post. As I tried to loosen the positive terminal it broke in half around the post.
 
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