Home made Battery box and vent?

[Al Swope]

I got a free heavy duty battery from my buddy who is a lineman for a cable company. The battery says it must be vented when charging. I was hoping to use this waterproof tool box. I bought this fitting from Lowes to route the wire (10-2 with ground) from inside the trailer and from the truck (10 gauge) thru to the battery. I was going to drill a hole in the back of the tool box and mount the fitting so It points down. With the wires running thru the fitting there won't be much of a vent.

How much venting is required while charging? Would this work or will the hole works overheat? Do I leave the lid open? I want to mount this on my tongue

[MtnDon]

Ventilation is not required for cooling; it is required to vent off the hydrogen that is produced when charging a lead acid battery. Hydrogen, being light needs a vent outlet at the high point. For that to work best, an inlet may also be necessary, mounted low. This is a necessity for safety's sake. That fitting mounted the way you indicate would not be of any use to vent hydrogen. Pointing the end down is desired to prevent entry of water. If you look at the battery boxes sold specifically to hold tongue mounted batteries you will see the lids incorporate many gaps between lid and box body. Hydrogen is the reason.

[Al Swope]

Dreams shattered, LOL. They sell the box you are describing at Walmart for $10. I was hoping to use the tool box to also store some misc. junk. Thanks for the explanation

[H.A.]

....

[MtnDon]

I never saw the pictures before (I was on my phone and it doesn't open pictures unless I want the,). Now I see them here at home. That is a Gel battery, not an AGM. The manufacturer does recommend a vented box even though hydrogen emissions should be low. They may be extra cautious.

OTOH, a spark could still cause big problems as hydrogen has the widest flammability range of all flammable gases; 4 to 75%. It also has thewisest explosive range and requires a very low ignition energy. A static spark from a persons body is sufficient. I've seen the aftermath of two different battery explosions and may be extra cautious myself because of it.

[drshoe]

The solution is easy as pie. Check out this sealed battery box kit NOCO sells:



That vinyl tube goes into a hole in the lid to provide a vent. Except there's no reason to pay what NOCO wants. Personally, I used a weather-proof file box.



The vinyl tube isn't in the lid but close enough. I wasn't convinced it was even necessary, but the wife insisted we go better safe than sorry on this matter.

By the way, I'm convinced that the vent does not need to be at the top to work - gas effusion doesn't care about gravity https://en.wikipedia.org/wiki/Effusion. It just means that there might be a (very) little extra hydrogen inside when you crack the box (extinguish all smoking materials first!)

[MtnDon]

http://www.arhab.org/pdfs/h2_safety_fsheet.pdf

http://www.zomeworks.com/battery-electr ... ng-system/

http://bdbatteries.com/hydrogenventing.php

[lrrowe]

Well shoot. In my attempt to do the right thing based on posts here, I am using Example 2 for the second link. But this all says I am doing it wrong.

How are you managing hydrogen MtnDon?

[MtnDon]

The BD batteries method which is similar to the zomeworks 5.... I used 1/2" OD soft copper tubing inside a 1" copper pipe that is epoxied to the usual RV style plastic vent cover. . I'd show you but it is built in and hidden under the bed.

Your plan is probably alright. It just has theoretical problems under some temperature conditions. I only know of two cases of battery explosions. Both were owner / operator initiated; 1 by smoking and the other by installing a charge controller in the battery box. A relay spark probably initiated that one. The smoker lost partial vision in one eye, the other just ended up with a hole blown out the RV side.

[lrrowe]

The BD batteries method which is similar to the zomeworks 5.... I used 1/2" OD soft copper tubing inside a 1" copper pipe that is epoxied to the usual RV style plastic vent cover. . I'd show you but it is built in and hidden under the bed.

Your plan is probably alright. It just has theoretical problems under some temperature conditions. I only know of two cases of battery explosions. Both were owner / operator initiated; 1 by smoking and the other by installing a charge controller in the battery box. A relay spark probably initiated that one. The smoker lost partial vision in one eye, the other just ended up with a hole blown out the RV side.

This is the sketch from the BD site.


If this is really a good way to go (I have no knowledge to say it is not), then I could alter my with flexible copper tubing on the inside, but for the outer tube, it certainly would prevent the flexible part of my setup, thereby defeating my the ability to move my battery box installation for access to the batteries.

[MtnDon]

Mine combines design from zomeworks #5 and the BD design. 1" copper pipe extends from wall vent horizontally with the soft copper tube inside the larger pipe and bent downwards. Maybe it is better to have a vertical rise from the battery box as BD shows, before changing to a horizontal direction, but I did not have the space required for that. Or didn't want it intruding on the interior space. They are soldered to each other near each end of the 1" pipe. JB Weld epoxy used to connect / seal the 1" pipe to the plastic wall vent. Pipe also supported inside battery box with pipe strap.

My batteries slide out the rear when the rear door is opened. Foam rubber used to effect a seal against the closed door.

[drshoe]

To each their own to research, decide, and determine that the sources aren't trying to sell something.

Using my method I suppose under some conditions the amount of hydrogen produced by a non-sealed battery could pose a hazard if exposed to a spark. Like the posted link says, you could end up with a hydrogen trap. Like I said, extinguish all smoking materials before opening the box.

The laws of physics state that gases move according to random brownian motion. Separation of gases by density only occurs if you can contain a gas, e.g. in a balloon. No matter what the temperature, pressure, etc. the hydrogen produced will eventually disperse throughout the entire atmosphere.

The question is do you ever foresee a situation where you'll be generating hydrogen faster than venting can occur? When it comes to an AGM , that could only happen with a seriously damaged battery.