Sulphur odour suspected from battery

[cbm8880 Senior Member Find all posts View Profile Close cbm8880]

Hi all,

I have a 2010 GX with dual batteries. Over the last couple of days we have been camping and my second battery has been getting a workout (Engel fridge, but nothing it hasn't down comfortably in the past). Accordingly I have noted slightly lower charge voltages (around 0.5v lower than normal and fluctuating around +/- 0.4 v).

Today I have started to smell a sulphur smell under the bonnet and noted my second battery has started to leak a little. It is a sealed type, so is leaking around the side of the top panel. I have disconnected it for now.

So for the electrical gurus, does this point to an alternator problem or a battery problem?

Thanks.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

If your camping what are you charging the battery with and what is the charge
voltage?

Also sulphur smell, sure it is not wiring burning?

[cbm8880 Senior Member Find all posts View Profile Close cbm8880]

So I put the multimeter over both batteries tonight. The main battery is still at 12.5v, and the second battery reads 10.35v so it's cactus.

I ran the car again with just the main battery connected and it's charging as expected (14.4v fairly constant with the diode). I'm assuming that because the main battery is unaffected (I regularly check the resting voltage and it's mostly around that 12.5v mark), it's unlikely to be an alternator problem?

It's definitely a Sulfur like smell, as it happened initially when we (slowed down) entered a car park and initially the wife and I both assumed it was a car in front of us with a malfunctioning catalytic converter. After it followed me for the rest of the day, it warranted further investigation.

Ps. The batteries are both just over 5 yrs old, so it's not surprising that it has failed.

[AK7 Senior Member Find all posts View Profile Close AK7]

We got caught out camping with a bad battery years ago. On the drive back, the fumes wafted into the cab long enough to make all five occupants violently ill. Just a heads up if you still have to drive home.

[cbm8880 Senior Member Find all posts View Profile Close cbm8880]

Thanks leighW and AK,

I've disconnected it and am going to get it replaced today.

[Corigator Avid PP Poster! Find all posts View Profile Close Corigator]

A Sulphur smell is not surprising as the battery uses Sulphuric Acid. You are probably smelling H2S, released as the battery over charges when dying.