I have a thermal label printer that eats through 4xAAA 1.5v alkaline batteries in 15-30 minutes on average.
I have read of people using rechargeables and getting a low power warning, so my plan is to connect it up to one of the many spare AC adapters I have lying around.
I’m having a lot of trouble working the power needs out though.
I’ve googled for a couple of days and even hit up reddit electronics channel, I still can’t seem to get any decent knowledge.
Also please note, I’m a complete n00b, I only started reading books and watching youtube videos about electronics a couple of days ago. I’m learning as fast as possible.
This seemed like a good beginners project…
I can’t even actually find what mAh a AAA 1.5v alkaline battery is supposed to rate at, for a ‘heavy duty’.
Even if I do, the time it takes to run down the battery group is not precise, so the calculations would be guess work at best, ( and I can’t even be certain I didn’t get a couple of dud packs, event though they are EveryReady, new from OfficeWorks… )
How do I measure what mA the device is drawing from the battery? Or “should” draw. There is no rating on the device.
I read on Jan’s great “understanding battery capacity” page, that a circuit will only draw as much as it needs from the batteries. Is this true of an AC/DC adaptor too, or will it quite easily potentially pump in too many Volts/mA and fry the circuit? Would I be better off trying to find a 5v or 5.5v adapter just to be safe?
The only two 6v adapters I have run at 320mA and 500mA respectively, which seems a lot, even if the device is sucking 4 batteries dry in 15 mins…
I’m assuming I can put a resistor or something in there to choke the mA ?
Assuming I can work out what my target is.
Also any tips on making it ‘removable’, so that I can have it plugged in when I’m at home, and running on batteries when I’m out in the garage or somewhere else.
Maybe installing a socket to plug the adapter into would be better than wiring it straight onto the circuit board, so I can just plug in it. I think I have some old electronics with the female for the adapter plug…
If anyone has the patience, can help me out, also give advice and recommendations, that would be awesome. if not, I’ll keep on trekking…