A few months back I had purchased a new enclosure to hold the guts of the solar box. The original plastic ammo can was beginning to show fatigue at the bottom from lifting the box with the battery installed within. This wasn’t going to be good for a permanent field deployment of this box in the future, so I decided to upgrade to a Nanuk 905 to house everything. This upgrade benefits the project in two ways: Firstly, the thing is waterproof and extremely durable. Secondly, it allows for the installation of a secondary battery in parallel with the one already installed (as mentioned in a prior post).
Two issues with the new enclosure were how to charge the batteries without running the cables through an open lid and how to prevent the batteries from smashing all over the place when the box is being carried (the handle is on the side when laying on the ground vs. the ammo can having the handle on top of the lid).
I solved the first issue by drilling a 1″ hole through the side of the case and installing a weatherproof surface mount SAE socket with the included 4 screws and some black RTV sealant to retain some level of waterproofness.
The second issue was corrected by fabricating an aluminum frame to fit within the case. I was going to make it fit the full interior dimensions of the case, but the interior isn’t flat. The batteries sit side-by-side in the frame and are secured to it with 1″ wide Velcro straps. The edges are all curved inside. The finished product isn’t perfectly square, but it’s fairly close (and dare I say, not too bad for a first attempt at something like this). The only issue with not being fully square is that that the batteries are wedged together on one end. Not a deal breaker, but won’t be optimal when the warmer weather rolls around again.
I decided to instead make a frame that fit the dimensions of the outer part of the foam insert. This should allow for some slight shock resistance to anything inside and also some slight insulation to boot.
I added a standoff to prevent everything from sliding towards the lid when carried by the handle which seems to be working well so far, but it looks like a second one will need to be added on the side closest to the lid hinge. If carried at a normal walking pace by the handle, there is minimal movement of the battery/frame combination as is.
Further steps for this project include beefing up the battery section of the frame with some aluminum bar stock so that the batteries can be strapped down independent of one another which should be good if only one battery is needed for operation (most likely during the summer months where less power is needed). I’m also planning on mounting the charge controller to the inside of the lid using a piece of aluminum bar stock to keep it out of the way when the repeater and radio are installed later on. Another hole will also need to be drilled to run the antenna feedline out of the box, but I’m still researching how that will be done (possibly using a cable gland and sealed with RTV sealant).
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