My latest project is a 12 VDC battery box to power my astro-imaging equipment for operation in the field. This battery box powers my imaging camera, autoguiding camera, motorized focuser & controller, powered USB hub, primary mirror fans, laptop, and includes expansion capabilities for added equipment in the future. A separate dedicated battery is used to power my mount. Here is a short list of requirements I had for the battery:
- 100 Ah LifePO4 battery (not lead-acid!) to support several nights of imaging on a single charge
- Anderson power pole connectors
- Power pole, USB, and cigarette lighter ports to support multiple 12VDC connections
- Fuse protected outputs and charging line
- Current/load monitor for both imaging and charging
- Integrated charging posts and ability to switch from imaging/charging mode without needing to open the box.
- Robust, mobile case for frequent travel to dark skies
- Lid and current/load monitor secured by magnets for quick installation/removal
- Storage of current/load monitor within box for travel
I decided to construct the box from Baltic Birch plywood despite the increase in weight compared to off-the-shelf plastic battery boxes. This should improve the durability, and I also prefer the way it looks. I used the BB plywood in three thicknesses:
- 3/4″ – Two end panels
- 1/2″ – Two longer side panels and lid
- 1/4″ – Bottom, inserted into dado routed in sides/ends
The 1/2″ thick side panels fit snugly into rabbets cut into the end panels. The 1/4″ thick base is installed within a dado cut into the end & side panels. There are a total of 12 neodymium magnets installed (epoxied) into recessed holes in the tops of the box sides and bottom of the lid for quick & easy removal of the lid. An additional 6 magnets are used to mount the current/load monitor on the top of the lid (during operation) and inside the box (during storage or travel). The current/load monitor is mounted to the lid during operation and can quickly be switched from imaging mode to charging mode without needing to open the box. During imaging I mainly use the cigarette style output for my laptop with a 12VDC/18VDC adapter and a single 12 VDC Anderson Power Pole line from the “Scope” output to a RIGrunner mounted on my OTA. The RIGrunner then distributes fuse protected power as needed to my imaging equipment. For charging mode, an external charger is simply connected to the charging posts and the current/load monitor is switched to the second set of power pole connectors labeled “Charge” to monitor charging progress. The box also features a couple of handles, small decorative/protective corner brackets, and rubber feet (not shown). I ended up with a bit more interior space around the battery than I needed, but it makes working in/around the battery a little easier and provides expansion space if needed in the future. Total box weight is 43 lbs, which is slightly heavier than I originally desired, but still manageable.