Battery Box Cooling and Venting - Is This Safe?
I have a wooden plywood battery box. I insulated the box, and cut four 2x13 vents in the top (covered with foundation vents) and one of the same in the bottom to draw. The battery box is outside in a carport. I used foam insulation and saved the insulation cutouts so I can close or open any combination of the 5 vents. There does not "smell" to be any battery gas build up inside the box.
In the winter my 4 L16 batteries were pretty happy. Never getting much above 26C at any time. But now summer is here and I have seen a hi of 33C on the batteries while charging on a 95*F day with all 5 box vents open. I wanted to keep the batteries cooler.
Since the temp under my house is warmer in the winter and cooler than the outside air in the summer, using a 4" PVC drain/toilet connection and 2 ft of 4" PVC, I added a 4" x 2ft long vent pipe to the back bottom of the battery box that drew air from under the house. This worked pretty well, but still not good enough to keep the batteries below 30C when charging during the 3-4 hours a day temps were hi.
So I Added a 5" computer fan ... under the house, attacked to the 4" vent pipe to blow air IN from under the house. The fan is 2 ft away from the battery bank and blowing air in from under the house into the bottom of the battery box. The inlet into the box is at the bottom back of the box blowing at the bottom of the batteries. I can feel air blowing out all 4 top vents of the box. I closed the vent other vent (looks the same as the 4) in the back bottom of the battery box. So the battery gasses are being blown out the top (NOT drawn out past the fan and under the house)
The fan is on a timer and comes on at 6am before charging begins and stays on until 9pm long after charging and gassing has ceased.
Question: is this safe given the explosiveness of battery gasses and the potential for a spark from the fan? The fan is DC 12v and is using .5 amps. It is controlled by an AC wall wart converter sized for the fan loaded and plugged in to an AC receptacle under the house controlled thru an AC timer.
Here is the vented battery box
Here is the location of the Vent looking down into the box behind and at the bottom of the battery bank
Here is the vent pipe under the house 2 ft away from the box before the fan was attached. The fan is attached to the furthest open end of the pipe.
Thanks for the feed back.
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