I’d like to connect a 12V light used as a truck side marker to an A23 12V Energizer Battery. I’m just wondering if I need a resistor in case the batteries provide too much power to the light and how I can connect it. I’m thinking I can just connect the wire to the battery. The attachment must be quick and something I can purchase in two days if necessary!
I wouldn’t worry about the battery providing too much power for the lamp. I would worry more about the other way around. It doesn’t work that way anyway. The load (in this case your light) will only draw the current it needs at the specified voltage.
The A23 is all good for door chime transmitters or anywhere 12 is needed to supply a couple of milliamps but not incandescent lamps. Those lamps are probably 5W or more which equates to about 0.5A. I doubt wether an A23 would supply this for more than 10 or 20 minutes if that. You might stand a chance of getting a bit more using LEDs but these little batteries are just not built for that. The other thing that will happen is if you try to draw too much current the battery will be destroyed very quickly. Maybe (I have not researched this) that 0.5A would fall into this category.
Are you sure that the battery can fail for the reasons described? I am currently looking for the problem of why my battery is broken. Thank you.
@Thomas201926 Batteries have a C rating.
This is how much current can be safely drawn from the battery without damaging it.
The rating is with respect to the capacity of the battery.
Most dry cells have a 0.5C rating. Drone batteries have a much higher rating.
The A23 has a 55mAh capacity. Maximum current therefore would be 25mA.
The smallest 12V lamp I can find is from Jaycar and has a 100mA current draw.
Conclusion the A23 is not suitable for 12V lamps.
EDIT: Draw too much current and the battery will be damaged over time. Worst case the battery can explode. But, is unlikely with dry cells as the capacity is so low. Lithium batteries are a different story though.
I am very sure.
And it will not take long trying that trick either. So called dry cells usually don’t explode but what happens is they “polarise”. Gas bubbles form on the anode and they are done forever as they will not produce any current at all.
James. Thomas wanted to use a truck side light which would be 5W (420mA) at minimum. That is the hot current. The cold current at switch on would be a few time that.
i did a similar project where i was getting my power souce from a solar. Check it DIY SOLAR LAMP - Share Project - PCBWay. My advice is you need an inverter to boost 12 vdc to 240 Vac which is good for the bulb.
An A23 battery would not even start the inverter