Hi All!
I have a handheld RFID scanner that I want to replace the battery with a power supply. I can easily spec the PS to the voltage of the battery, but I am not sure how to spec the current of the power supply. I can’t find specs on the battery, or the device. I need to figure out how much the device draws at max. I could get the max battery current (voltage / internal resistance), but I expect this is much higher than the device actually needs. CSL CS101 Handheld RFID Reader - EasyBadges It is basically this unit.
I have reached out to the manufacturer, but honestly, I don’t expect them to help me out.
Has anyone else tackled this kind of problem in the past?
Open to any suggestions or guidance!
Thanks!
Nate
Well, the voltage for the charger is different than the output voltage of the battery, so 19.8V X 2.5A = 50 watts. the battery charger is 25V X 2.5A = 62.5 watts. (I was thinking that the voltage would be equal, but it’s not). So I would maybe make sure the watts are higher than the battery charger. So at 19.8 V the for 62.5 watts, the amperage is 3.1 amps.
You can’t really go too large on amperage, anything over what you need is fine. I don’t know what the costs differences are for the different wattages of power supplies, but if the cost is negligible from 50 to 100 watts, go with the bigger one.
I thought I saw 19.8 but it’s 14.8. (and that might be dependent on which manual I found, you should look at the actual manual you have or the battery)
so 62.5 / 14.8 = 4.22 amps
but yeah, if the charger does 2 at a time, you should be able to cut the wattage roughly in half.
The earlier comment still stand though, excess wattage won’t hurt you if the voltage is spec’d correctly.
Can you believe the manufacturer suggested that it is not recommended to replace the ($100+) battery with a DC power supply? Can you think of any reason a battery would be recommended instead of a power supply? I always thought a power supply provided more stable voltage and current.
A battery would be a cleaner power source. Less voltage ripples, spikes, etc… But if they designed their power circuitry properly, that shouldn’t matter unless you’re using a noisy $2 AliExpress special…
It’s probably about designing for the power source too. I wonder what kind of circuitry is in the battery. There is going to be some kind of control system, and I am curious if you don’t have that if it will still work.