I have a dual purpose 12v battery for my 45 thrust trolling motor. I recharge it at home after I go out fishing. My wife is very afraid of the battery & charger thinking it can blow up and/or spray acid all over at any given moment. I want to assure her its safe but I really dont know how to explain it or if it really is even safe.

1. What is the likelihood of a battery explosion/fire and what would cause it?

2. How can I be as safe as possible with the battery?

I just learned to take the vent caps off when I charge it, I had charged it at least 20 times with the caps on. I also filled the water cups in it with distilled water. The guy who told me how to do this told me not to put the caps back on too hard (he tapped them with the butt of a screwdriver) or the battery could explode. Now I am super worried when putting the caps back on. The battery says they have to be tight and level but Im afraid to tap them too hard.

I figured the only way to really get hurt was to somehow touch both terminals with a piece of metal. When connecting the battery to the charger, I will put the negative clip on first then the positive. Sometimes the positive clip will spark if I dont clamp it right on the first try. I also get sparks when I hook the battery to the motor and the motor is on. (only happened once!)

I have found that putting the positive on the neg doesnt do anything but I think thats a saftey feature.

The reason I am developing a fear of the thing is probably twofold. One, my wife is making me second guess my confidence in handling it and two, I really dont understand them. I never learned how batteries work, how rechargers work and how to handle them to avoid accident. I never really learned how to jump a car. I have been in some embarrassing situations when a female friend asks me to be the hero and jump her car. I was terrified that I would kill us both. After creating a huge spark when I tried to attach the jumper cables, I had to flag down a second guy to help me....doh! I believe that understanding something is the best way to get over a fear you might have.

anyway, hoping someone could take some of the mystery out of it for me so I feel more at ease. Surprisingly the battery came with no instructions or safety info besides the helpful "Caution: Shield Eyes, Can explode acid in your face!" ; )

Has the battery in your car ever blown up? What's the difference between an alternator charging a car battery and a portable charger charging a boat battery? Todays chargers are smarter than those of yesteryear. Set the charger for the proper battery type, plug it in and let it do its job. Tell the wife no need to worry.

anyway, hoping someone could take some of the mystery out of it for me so I feel more at ease. Surprisingly the battery came with no instructions or safety info besides the helpful "Caution: Shield Eyes, Can explode acid in your face!"

This is for the stupid people out there because we have a litigious society

Has the battery in your car ever blown up? What's the difference between an alternator charging a car battery and a portable charger charging a boat battery? Todays chargers are smarter than those of yesteryear. Set the charger for the proper battery type, plug it in and let it do its job. Tell the wife no need to worry.

This is for the stupid people out there because we have a litigious society

thanks for the reassurance. I actually did use that example!

dont really agree about warnings on products that can explode face melting acid being "for stupid people". Not interested in suing, just like my skin ON my face. ; )

DO NOT take the caps off a battery while you are charging it. It creates excessive water loss and actually increase the chances of exploding. Any body that thinks a battery CAN NOT explode is full of it. While it's not likely it will explode if the caps are left on and it's charged in a well vented place at the proper level, it can happen, the gases released by a charing battery are explosive. Usually, it only happens when one has just finished or not quite finished charging and someone disconnects the chargers cable and they cause a small arc. This possiblity bcomes much greater when one is charged at a high charge rate that's causing the water to boil in the batterty. Anybody that has ever worked at a place with a big charger and putting a one hour fast charge on one has seen or heard of them exploding. Another time it's subject to happen is when someone is hooking jumper carbles to one and they hook them backwards, that sudden, heavy current surge can explode one. I've seen them explode in boats where they were being charged by the onboard charger with the lid down on the battery compartment, someone opens the lid without give it time to vent out and start disconnecting the batteries, causing a small arc. So, don't think they can't explode, I've seen dozens of exploded batteries over they years.

Now, other than ruining the cloths you have on and possibly getting in your eyes, and making on big mess to clean up with baking soda, the danger of getting seriously hurt, or of it causing a fire is very slim. Add that to the fact that with a little proper handling and charging at the proper 10% charge rate, it's not very likely one will explode, I wouldn't worry about it.

At one time I did business with a battery manufacturer. They had a vent in all their batteries so there is no need to take the caps off. Most systrems (maybe all) today have a negative ground. You put the ground wire/connection on last.

Keith has it about right. The chance of a lead acid battery exploding occurs during fast charge because the battery generates excessive oxygen and hydrogen. Any spark to that mixture will cause an explosion. Under normal charge large vent space is not required. VW used to have the battery under the back seat. And always connect the negitive post last.

As an aside, battery acid is not particularly toxic. IIf one happened to explode in your face and you got acid in your eyes, you simply wash it out with water. On the other hand, it will eat holes in your jeans if not cleaned.