Bubbling battery

[Chippy Addicted PP Member Find all posts View Profile Close Chippy]

Quick question for the elec - techies ....

I have a dual battery system with a Redarc isolator and identical Exide batteries. The second battery is showing small pools of fluid around the filler plugs - usually after a decent run - but many of my recent runs have been through puddles and mud so it's a little hard to tell.

Is this a sign of overcharging or is it over full ?
What is the best way to check for overcharging - apart from reading the credit card receipt :lol:

Cheers
Chippy

[120GXV6 Member Find all posts View Profile Close 120GXV6]

Sounds to me like it has been overfilled!

Next problem is that decanting some fluid will dilute the acid solution and reduce battery life.

To overcharge would require a higher than normal voltage output from regulator - easy enough to test with a voltmeter. Should normally be no more than 14 - 15 V.

This has some good info!

[Chippy Addicted PP Member Find all posts View Profile Close Chippy]

Thanks Matthew

I may be better off letting it find it's own balance point. Surely if it's been over filled, and is bubbling off the excess, it will reach a point where there is no more excess ?? Hopefully.

Cheers
Chippy

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

Hey Chippy, im guessing it is a good battery ? I put a used battery in as my second battery and after a couple of weeks it started bubbling itself dry, no matter how often you topped up its cells it kept bubbling and drying out, apparently it " dropped" a cell or "shorted" a cell and so kept bubbling and drying out, changed the battery to a new one and has never skipped a beat. I originally thought overcharge, but my start battery was not affected. Stick a multimmeter accross the terminals with the motor set at fast idle ( 1500 to 2000 ) and watch the voltage, as mentioned earlier in the posts should be 14 to 15 odd volts. From memory 17 is overvoltage and would start cooking batteries, both obviously.

[Chippy Addicted PP Member Find all posts View Profile Close Chippy]

Thanks Speedy, I'll check that. This second battery is about 4 months old and hasn't skipped a beat. About time to dust off my old multimeter :shock:

Cheers
Chippy

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

It sounds like over-charging...however check the fluid level first.
Note you will have to wait until the charging module 'switches over' to check the charge voltage on the second battery.
I would check the charge voltage on the main battery just after starting the vehicle, then compare the reading with the second battery when on charge.
If the charge voltage is much higher it could indicate a crook battery as you normally only get a trickle charge as the sensor for the battery charge (alternator output) is from the main battery.
You could also charge the aux. battery with a battery charger and then see what happens when charging normally from the alternator.
Note I would recommend charging the aux. battery BEFORE going on any trip and at regular intervals with a decent battery charger.

[Chippy Addicted PP Member Find all posts View Profile Close Chippy]

Thanks for that Jon - next question ... what about regularly swapping the batteries (they are identical) ... say on a monthly basis ??

Cheers
Chippy

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

Changing batteries over would be a pain...losing the radio settings, etc....
Normally, the main battery is used for starting and is designed to do that, unlike a deep-cycle battery used for fridges, etc., which are designed to be discharged nearly fully.
There is a huge amount of info (and opinions) out there. I just give my auxillary battery a good charge from a battery charger before any trip where I will be using the fridge....this is what I was advised to do from an old bloke from a battery shop who seemed to know what he was talking about. Have done this on my vehicles for many years and seems to work ok.

[plucker Advanced Member Find all posts View Profile Close plucker]

How rough are the roads you travel on.
Last trip to Cape York, I travelled over pretty bad roads and about half way through the trip I checked the water level in the battery and it was down to half full. The battery acid had leaked out the air vents.
I topped it up and had to do the same quite a few times.
Checked the volts and it was not overcharging.
When I arrived home and stayed on bitumen roads the problem went away. Now the car (hilux) has corrosion problems below the battery.

A true indication of the battery charge is using a hydrometer. About 10 bucks from supercheap. Dont add any water to the batt before you use it or the reading will be incorrect.
A fully charged battery will read from 1220 to about 1260/1280. If it is overcharged it will be more like 1300.
Each cell should read above 1200. If one cell collapses, that cell will be under that.
First signs it will be at 1180 and eventually down the track it will be 1100 or less. The volts will start to drop at this stage also.
If used regularly (Once a month) the hydrometer gives an early warning of battery failure

Overfilling batteries can also lead to discharge through air vents.

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

Sounds like you need to change to a GEL battery.
If the battery is leaking, both the acid/water mix will be lost.
Topping up with just distilled water will result in an incorrect mix ( I think it is 33%) and failure of the battery.

[Chippy Addicted PP Member Find all posts View Profile Close Chippy]

Thanks for all the tips guys.

2 weeks later and there doesn't appear to be any more leakage .. and no, the battery's not empty :lol: .. the fluid level is fine. So maybe it was just a little overfull.

... and yes, some of the roads were fairly rough .. I was using them to help the suspension settle :shock: :lol:

Cheers
Chippy

[StormyKnight Advanced Member Find all posts View Profile Close StormyKnight]

... and yes, some of the roads were fairly rough .. I was using them to help the suspension settle :shock: :lol:

You probably did that when your car was new, and a week later, & a week later, & a week....

Cheers
Richard