Post pictures of battery adapters you bought, 3D printed, or built.
This one should arrive today.
It is an adapter for Ryobi One+ 18V batteries.
This one should arrive today.
It is an adapter for Ryobi One+ 18V batteries.
I'm hoping that I don't burn out this little 12V pump with it.+
Whatcha going to make or run with that 18V DC Poppy?
...small Anderson connectors are very nice to work with.
I agree, thanks for your vote of confidence+
Doubt you'll burn out the little pump, 99% sure it'll just run faster.
I was thinking that it might be wise to put a resistor in line but I don't know what size.Personally I would caution against running a 12vdc pump off of what is likely 20.5vdc off the charger for 18v and 20v lithium ion batteries. I would suggest a simple solution of calculating a resistor to burn off the excess voltage figuring on getting rid of about 7-8vdc or I would instead consider using a 24V pump instead.
+I was thinking that it might be wise to put a resistor in line but I don't know what size.
snakebite, and xxo, would you please consider describing your adapters, which ones convert what to what?
I think that was a motor 12v 0.4A. A resistor that is dropping 8v at 0.4A using ohms law R=E/I which makes for 8/0.4 or 20 ohms. Then you need to calculate the wattage of 8v times 0.4A or about 3.2 watts, I would use 4 or 5 watts better to have a higher than needed wattage of resistor as more than needed doesn't do any harm. If you use higher ohms it will reduce the voltage to the motor more and lower ohms will have it higher. It is likely the motor/pump could handle 20% more than it is rated at so it may be fine up to 14-15v making you only needing to drop 5-6v at 0.4A which would make for a 12.5 to 15 ohm resistor of 2-3 watts. If you have resistors in this range you can use wiring them in series/parallel to get the voltage you need. Another better solution IMO would be to get a buck circuit module that can handle 24vdc as you could dial in the right voltage and it would be a lot more efficient converting the excess voltage into current which would increase the run time off a battery source. Resistors usually are a lot cheaper if you have them already or can source them locally.I was thinking that it might be wise to put a resistor in line but I don't know what size.
I was out getting my covid booster shot today, and on the way back, I stopped by an electronics shop and asked for a resistor. He recommended a voltage regulator. I asked... "what will that be? About $10?" He replied... "Nah... $3."I think that was a motor 12v 0.4A. A resistor that is dropping 8v at 0.4A using ohms law R=E/I which makes for 8/0.4 or 20 ohms. Then you need to calculate the wattage of 8v times 0.4A or about 3.2 watts, I would use 4 or 5 watts better to have a higher than needed wattage of resistor as more than needed doesn't do any harm. If you use higher ohms it will reduce the voltage to the motor more and lower ohms will have it higher. It is likely the motor/pump could handle 20% more than it is rated at so it may be fine up to 14-15v making you only needing to drop 5-6v at 0.4A which would make for a 12.5 to 15 ohm resistor of 2-3 watts. If you have resistors in this range you can use wiring them in series/parallel to get the voltage you need. Another better solution IMO would be to get a buck circuit module that can handle 24vdc as you could dial in the right voltage and it would be a lot more efficient converting the excess voltage into current which would increase the run time off a battery source. Resistors usually are a lot cheaper if you have them already or can source them locally.
Yes, a voltage regulator can be used that would allow you to use a wider range of input voltages without noticing output voltage drop that a resistor would have. Beware that unless your battery pack has built in voltage protection (I think most do but some may have the protection built into the tools itself I'm not totally sure) you could drain it below safe levels.I was out getting my covid booster shot today, and on the way back, I stopped by an electronics shop and asked for a resistor. He recommended a voltage regulator. I asked... "what will that be? About $10?" He replied... "Nah... $3."
Here it is.
View attachment 20169
@Lynx_Arc, I really appreciate you, for taking your time to do the math, and explaining it along the way.
Thank You.
Poppy