This project was centered around a junk-yard find, a battery powered Quick-fill device for inflating inflatables. The goal was to improve its ability to quickly fill an inflatable raft using high discharge lithium instead of C-cell batteries.
- Soldering & Wiring
- Battery safety
The device originally ran on (6x) C-type batteries running at ~4.5V. So the first step was to determine what kinds of current the motor could draw using a high current power supply. To run this test I had the power supply voltage limited so that the motor could draw as many amps as its heart (Winding) desired. The main goal was to determine how many amps it could draw at a reasonable lithium battery voltage (~3.7-4V), which turned out to be ~10.4A. So based off of this measurement, there seems to be a lot of room for improvement based on the average current draw you can achieve out of regular old batteries.
Wiring it up: So I decided to wire it up using 14 gauge flexible wire, while keeping the switch and motor the same. I used a XT-60 connector to connect the battery pack and the motor/switch circuit together. And for batteries I had a handful of Turnigy ‘Nano-tech’ (NE-BA931) batteries which are 3.7V, 750mAh cells rated for 35-70C Discharge. I ended up being able to use 10 cells which I kept all in parallel (1S10P). But for wiring I chose to connect two batteries to a single pair of 20 gauge wiring, this was to limit how many wires were in the assembly. During this process I first cut the connectors ground cables and wired them-up then proceeded to do the same with the positive connectors. This is primarily a battery safety precaution because due to the high discharge rate of lithium cells, shorting a battery can be vary dangerous.
Once I had successfully wired up the batteries to a XT-60 connector, I packed it all together and tested it. Surprise surprise, it worked the first time with no issues. I ended up packing this in a pack with an inflatable donut and went for a hike and swim at a near by lake. All-in-All a pretty straightforward and useful device for all the boating outings we have.