I have a Frabill insulated minnow bucket (cooler, really). It has a small electric pump that oxygenates the water in the insulated cooler that the minnows swim around in. I have attached a picture, below. This pump can be powered by 2 D-cell batteries, which provide 3V and a total of around 24 watt-hours. The pump also has an input for a 110v source, which uses a 5.5mm plug that provides 3V at 500ma. If I'm doing my math right, this means it uses about 1.5 watts, so the D-cell batteries last about 16 hours of continuous run-time. This might be 3 days of my normal fishing trips, if I remember to turn the unit off...and therein lays ONE of the problems!
The other problem is that replacing the batteries requires you to unscrew the pump from the top of the cooler, disassemble the case for the pump, replace the batteries, and then put it all back together. The nut that the screw goes into is inside the lid of the cooler, so this is not a fun job when you have water/minnows in the bucket. I don't have a 110 outlet on my boat, although I do have a small (Energizer) portable power station with a 150w inverter and LiFePO4 battery. It could run the minnow bucket for a hunnert years...or so. I'd rather not have to bring that on the boat to run the 110v plug, but that would "work", for sure. (I've tested it and it's not a horrible solution.)
In learning about various lithium batteries, it has become obvious to me that most of the cells used in lithium batteries are somewhere in the 3.0 to 3.65 volt range. You put four in series and you get a 12v battery...but my device actually uses just 3 volts. So, is there any reason I couldn't use one or more 18650 cells, wired in parallel, to provide the ~3V used by this little air pump? The output of an 18650 is 3.5v (nominal) and they can easily cover the 500 milliamps drawn by this little pump. I guess my main question is whether or not the pump could be damaged with a 3.5v power source, versus a regulated 3 volts?
Thanks in advance for any replies.
The other problem is that replacing the batteries requires you to unscrew the pump from the top of the cooler, disassemble the case for the pump, replace the batteries, and then put it all back together. The nut that the screw goes into is inside the lid of the cooler, so this is not a fun job when you have water/minnows in the bucket. I don't have a 110 outlet on my boat, although I do have a small (Energizer) portable power station with a 150w inverter and LiFePO4 battery. It could run the minnow bucket for a hunnert years...or so. I'd rather not have to bring that on the boat to run the 110v plug, but that would "work", for sure. (I've tested it and it's not a horrible solution.)
In learning about various lithium batteries, it has become obvious to me that most of the cells used in lithium batteries are somewhere in the 3.0 to 3.65 volt range. You put four in series and you get a 12v battery...but my device actually uses just 3 volts. So, is there any reason I couldn't use one or more 18650 cells, wired in parallel, to provide the ~3V used by this little air pump? The output of an 18650 is 3.5v (nominal) and they can easily cover the 500 milliamps drawn by this little pump. I guess my main question is whether or not the pump could be damaged with a 3.5v power source, versus a regulated 3 volts?
Thanks in advance for any replies.