Charge 6v Battery with caps loose or tight

[Ziffer]

I've always thought you were supposed to charge with caps loose for expanding gasses. Parts guy says caps should be tight while charging. What is correct?

Thanks
Z

[52merc]

ive been doing the loose caps for years now for acid batterys, i seen one explde a # of years ago that the caps were left tight my 2 cents worth

[ford38v8]

Some batteries have a check valve that works only if the valve is tight.

[toby]

Caps off with a shop rag over the openings. Saw one that exploded - the guy did not have the caps off. It really messed up the engine compartment.

[Scott H]

Ask the 'parts guy' to explain his reason for the caps being tight.
Auto industry in general has always been caps loose, or better yet caps off and a shop towel over the holes.

Where is the 'parts guy' from? Meaning a traditional full service auto parts store or one of them new-fangled big-box places that cater to rice burners?

[34billct]

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They charge in the car with the caps tight dont they? thats the way their designed.

[Old Henry]

I've charged batteries for 45 years without loosening caps and without any problems. All of the caps on my batteries have been vented to allow escape of gases (I can hear the gas escaping while I'm charging). Doesn't the generator/alternator charge the batteries with the caps tight? Why should it be any different with an external charger?

[Chris Nelson]

A side note about charging batteries. About 50 years ago, I was charging a battery in my garage with the caps off. At that time, I smoked and happened to flick an ash of the end of a cigarette and it landed in the battery. The battery fumes exploded, imbeding one of the posts in the roof of the garage. Needles to say, I learned a lot that day about exploding batteries. How I escaped injury, I don't know other than my gaurdian angel was on my shoulder. Now I am very careful when charging a battery. Lots of ventilation and NO OPEN FLAMES.

[G.M.]

Don't charge at high charge rates, better with less amps for a longer time. This way there is less fumes and you won't warp the plates and the battery will last longer. G.M.

[Rich Overton]

I had been in the auto Parts business for the better part of 50 years. The caps were always loose when charging, as most have already stated. I would say that the generator charge is governed by the cut out or voltage regulator that's why the caps can remain tight. As a precaution we always left the caps loose not off. Another precaution is to never loosen or remove the caps until the cables are attached and tight. A spark from one of the cables can and will explode the venting gases. When the battery is charged, replace the caps tightly before disconnecting the cables for the same reason. That was always the instructions from the battery manufacturers.

Rich O.

[Jim in Wisconsin]

I am retired from maintaining a fleet of 160 electric lift trucks - did it for 35 years. These trucks are powered by lead acid batteries just like in a car, only much bigger, like from 500 pounds up to maybe 2 tons. We had many hundreds of batteries being charged at high rates and we certainly didn't take the caps off, except to add water. The batteries were maintained by the battery company, (C&D, Exide, etc.) and they know their batteries and the correct procedures- it's their business. The caps are vented to let the hydrogen gas escape - the only way a battery explodes is if there is a spark during the gassing phase of charging. I've seen (and heard) it quite a few times.
Our operators changed their own batteries and I've seen them take a fresh battery off the rack - it's still bubbling and making hydrogen - and get the cables pinched in the machine which makes a huge spark, then lights off the gas. The guy usually screams like a girl and runs like hell. Gee, I miss that part of working!
Let the caps on, charge in a ventilated area, and no smoking!

[Dave D]

The only SAFE way to charge a lead acid battery is with the caps ON.

[sturgis 39]

I have had batteries explode. They will freeze in the winter time and the vents will freeze shut. The explosion is not caused by a spark. This happens a lot when the temperature is below zero. I try to bring them into a warm place first before charging them. Then I charge them outside with the caps loose.
They always say to hook the positive jumper cable to the battery post and the negative cable to a good ground. This will eliminate the spark on top of the battery when you disconnect the negative cable first.

[Kurt in NJ]

Charging with the caps off is a good way to get acid all over the battery and nearby things, it also helps to create a combustible mixture inside the battery(allows air in, hydrogen gas without oxygen won't burn)

Do not fill a battery with water before charging, if the level is below the plates just fill to cover the plates ---the electrolyte level rises as the battery is charged, if you fill it before charge it can cause it to bubble over and make a big mess.

the batterys most likely to explode are the ones you keep charging to try and get that last season out of ---they gas more than they charge --a bad cell can boil, if you feel the battery while on charge and it is huffing and puffing, very hot, don't touch the charger clamps --turn off and or unplug the charger and walk away for a while.

[Graeme / New Zealand]

I have a battery charger/ maintainer/conditioner. It is a fantastic device and is switched on all the time. The caps do not have to be off. I swear by these things. It keeps the 6v fully charged and stops the sh*t from accumulating on the plates when the car is not in use.

Link below

http://shop.saveabattery.com/6-48-Vo...tainers_c7.htm

GB