Thursday, January 22, 2015

On the Bench- Building a Bigger Plywood Battery Box
Scott Symmes11:41 AM


Project for January, 2015

With my birthday coming up, I wanted to work on a project of my choice. In this case, it was a bigger battery box made from plywood. This project has been lingering in the background for 6 months.
The box would hold up to ten 6 volt deep cycle batteries. The batteries are an important component of an off grid power system. The primary use is to store the power generated from the solar panels and wind turbines. An inverter is then hooked up to the batteries and it converts the battery electricity (DC) to regular household electricity (AC).

Batteries are expensive and should be looked after.
They can range from $90 - $240 each. Three years ago, I purchased (4) 6 volt Exide batteries for $98.00 each (on sale). In the Spring of 2014, managed to pick up another four, used, 6 volt US batteries (brand) off craigslist for $40.00 a piece.

If the batteries have a clean, ventilated, safe, dry place to sit, they will last many years. With my experience, it's best to take care of them as long as I can. Don't let the charge get below 60% and check the levels of acid. I felt a little bad, that I had left the batteries just sitting under the cabin and not being tended. Batteries will slowly lose their charge over time and die a horrible death.

Back to the box... for the last couple of outings to the cabin, the plan was to get started on the box. I had even pre-cut all the plywood, but it just sat in pieces, waiting to be assembled. The winter chill made it hard working outside using the cordless tools.


The other day when I was driving to work, I thought, why not work on it during my lunch hour and get it knocked off. So, a few days before an outing to the cabin, sat down at the kitchen table and sketched out some rough plans.
Next, I went to the computer and figured out how the get the best use of a piece of plywood and made a cutting guide. It helps if you have all the information from the battery manufacturer. Using this as a guide, designed a plywood box that measures 24 inches wide by 48 inches long by 15 inches tall.  I purchased a 4' x 8' sheet of 3/4" thick Oak plywood. It was a damaged on one side and got it for $10.00. Sweet! That saved me at least $50.00.

With the sweet tablesaw at work, I ripped all the plywood up and started to assemble the box. Used 1-5/8" screws and Gorilla Wood Glue for all the joints. Got 80% of the box finished on my lunch break. Came back after work and put in another 20 minutes. Took the box home and applied 2 coats of Kilz Odorless Primer on the inside and Varathane America Walnut Wood stain on the outside. It came out pretty sharp.

Next, was a stand for the battery box to sit on. I personally hate bending over to work on stuff, it eventually hurts my back. I came up with a stand made for 2" x 4" and 4" x 4' posts for legs. The legs will be notched to fit directly under the 2 x 4 frame. I might add a 2" x 6" to tie in the legs with the frame for some added support.
Below is some of the videos of making the boxes.