Minor battery explosion- '99 F250.

[jmc]

Hadn't started my 7.3 diesel for a few months but it's been on a battery tender most of that time. Hood had been up. Fired it up and got an immediate boom and heard something hit the barn wall. Turns out, it blew a (3 cell) battery cap off one battery. Looks like one cell is barely covered with water. Replaced the cap and it started/ran per usual. Never happened in 25 years. Only thing different this time was I cycled the glow plugs several times before starting. All theories welcome, please!

 

[5030]

Low on water (not electrolyte) but water and the hydrogen sulfide exploded, probably from a spark generated by a corroded (high resistance) battery post. I always check the fluid level in my flooded cell batteries before cranking them after sitting all winter on the battery tender.

I always use conventional Fluid Film as a corrosion protector on my battery terminals as well. Good stuff.

 

[Roadworthy]

The process of charging generates hydrogen gas which is highly explosive. I suspect you had a build up in the cell which was low on fluid. It then ignited when you attempted to start the truck. Check your fluid levels periodically and refill as needed.

 

[Chilliwack Murray]

We see this a lot on standby generators and fire pumps where batteries are on continuous charge. It’s usually caused by low electrolyte level exposig the plates and cell connectors. This has become more common with many suppliers only offering maintenance free batteries now. All flooded lead acid batteries use water and if you can’t replace it, you will have a failure or greatly reduced capacity. There’s usually very little difference if any between a maintenance free and a serviceable battery construction. If you have a choice, especially on equipment get a serviceable battery.

It can be caused by a spark at a battery post but much more likely from a spark inside the battery where the cells are connected together or to the post. Inside the battery the concentration of hydrogen is much higher than outside the case.

This is a good reminder of how dangerous batteries can be even when used as designed. I’ve witnessed several battery explosions over the years and cleaned up the aftermath of dozens. Wear PPE or cover batteries, acid in the eyes is almost always a sure ticket to partial or complete vision loss.

 

[5030]

Even with maintenance free flooded cell jars, you can pop the tops and determine if the plates are exposed and top off with DISTILLED water only. Do that all the time actually. Even a battery tender can and will drop the electrolyte level in a flooded cell battery. Always good to check ahead of time.

 

[jmc]

OP here.

Thanks, All. Easy fix!

 

[5030]

 

[Gregster613]

Even with maintenance free flooded cell jars, you can pop the tops and determine if the plates are exposed and top off with DISTILLED water only. Do that all the time actually. Even a battery tender can and will drop the electrolyte level in a flooded cell battery. Always good to check ahead of time.

5030, That's good info to hear...I didn't know if it was all right to pop the tops off of maintenance free batteries; they make it quite difficult to get to them. Thus, I assumed they were okay to go without "ever" needing to add water. I have several that I keep on a tender all the time and have "never" checked the water level. Guess I'd better get to checking!!
Chilliwack, Thanks for the info you posted on "trying" to obtain "serviceable" batteries whenever possible; I never thought about it that way before! I assumed the new maintenance free batteries were the newest/best option to have and haven't ever thought about checking/adding water to one of them. Guess I've been making a "Large" mistake!! I'll try to correct that mistake as soon as possible.

 

[5030]

I use a small flat blade screwdriver to pop off the integrated cell caps to check the fluid levels. All maintenance free batteries are about is planned obsolescence as the water in them percolates out and the plates are exposed and the battery dies.