Thread: Exploding battery.

Originally Posted by 123rover50

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I thought gassing might have been the cause but that amount of current would hardly make gas would it?
Then what would ignight it anyway?

It does not take much overcharge to make gas - any overcharge will do it. And I would think that 10W is at least twice the size panel needed to maintain the charge on a battery, so if unused for some time, there could be a significant accumulation of hydrogen in and around the battery (hydrogen will ignite and explode over a very wide range of concentrations in air).

The ignition will have been from a spark when you tried to start, most likely from a bad connection at the battery, but also possibly from a connector within the battery that has deteriorated. Examination of the four battery poles is likely to find some evidence of sparking, or have a close look at the intercell connectors in the battery that blew its top off.

John

Could the battery have been low on water? I once had this happen long ago on a old Holden ute. I went to pull away from the lights and bang. Numerous lights on the dash and a very ordinary smell wafting through the vents after a huge explosion. Car appeared to still run fine. I drove off to the side of the road and opened the bonnet. Looking in, the motor was still ticking over fine, though there was molten plastic dripping from where ever it landed. Then I spotted where the battery used to be. Not much left, little more than the settling vapours and gas surrounded by that sulphur stink you describe. I put it down to me not checking the water levels in the battery and the plates inside touching and shorting.

Originally Posted by JDNSW

It does not take much overcharge to make gas - any overcharge will do it. And I would think that 10W is at least twice the size panel needed to maintain the charge on a battery, so if unused for some time, there could be a significant accumulation of hydrogen in and around the battery (hydrogen will ignite and explode over a very wide range of concentrations in air).

The ignition will have been from a spark when you tried to start, most likely from a bad connection at the battery, but also possibly from a connector within the battery that has deteriorated. Examination of the four battery poles is likely to find some evidence of sparking, or have a close look at the intercell connectors in the battery that blew its top off.

John

I get confused easily
Now a 12 volt 10 watt panel is producing just under 1 amp, is that right?
When in series to give 24 volts what does that do to the amps and watts?
I thought it might be half of 10 or just 5 watts.
Its a long time since I did this stuff but I could look it up.

Keith

Originally Posted by 123rover50

I thought gassing might have been the cause but that amount of current would hardly make gas would it?

Charging produces gas.

Originally Posted by 123rover50

I get confused easily
Now a 12 volt 10 watt panel is producing just under 1 amp, is that right?
When in series to give 24 volts what does that do to the amps and watts?
I thought it might be half of 10 or just 5 watts.
Its a long time since I did this stuff but I could look it up.

Keith

Solar panel outputs depend on a lot of factors but you should read up on how the current output changes with load. The "watt" rating of a panel is its peak output under specified conditions and you won't reach it unless you recreate those ideal conditions. Most panels used to have a helpful little graph on the back to work out the current at a particular voltage.

Example of a "12V" panel:



And that curve is only at one temperature. Note though how a typical panel can push up a battery voltage above its safe level quite easily.

Anyway, your major problem with a solar panel is that if left on too long it will electrolyse away all the water as their voltage isn't regulated. You should really get a solar panel regulator to suit the application.

Perhaps one terminal was a bit loose as it got blown off.
How does one check the water on this type of battery anyway?
Where one post was connected inside the battery looks corroded so it may have been broken due to vibration or somesuch, could have arced and sparked.

Keith

if you've had a cell fail or start to fail it will outgas excssively. if you leave it on a charge it will outgas further under load.

if the cell has boild to near dry drawing starting current will cause the battery to spark across the plates or the internal links

theres no real way of checking most sealed batteries. some you can see through by putting a strong light along side the casing but that only works on the ligher coloured batteries.

These two batteries are 5 yrs old. They are kept fairly cool under the tray.
So after this time the acid level is under the top of the plates and there is no way to check or top them up.
Why are we buying these?
I would be better off with the ones with plugs on top.
Imagine if it was under a bonnet when it exploded. Acid everywhere.
Temps hotter under there too so the water would evaporate from the battery faster.

Keith