What can happen if you plug in the wrong charger! or a Guide on Chargers & Power Adaptors

February 22, 2020

Guides

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Using the wrong charger on your laser level

Plugging in the wrong charger with your laser level

Or a guide on Chargers/ Power Adaptors

Many laser levels are sold with rechargeable batteries together with chargers or power adaptors. Sometimes, users lose or misplace their chargers and might consider plugging in a charger for another device. There are risks involved in doing this as the image below highlights. This post looks at what you should look at before plugging in a non-original charger or power adaptor.

Ideally, you always should use the original charger/power adaptor that was supplied with your laser or other electronic devices. However, sometimes this is not always possible. The worst-case scenario is pictured above with the charger frying the charging circuitry in the laser level. Other times it will just not work or if you have done your research it may do the job.

What is the difference between a battery charger and a power adaptor?

Battery Chargers or Power Adaptors are not necessarily the same thing.

A power adaptor just transforms your mains voltage (240V or 110V depending on your country) to a suitable voltage for the device, for example, 6V or 12V etc. Often the device itself will have the charging circuitry built into it, either as a separate board or part of a mainboard. This regulates how the power is transmitted into the battery.

A battery charger may look pretty much the same as a power adaptor and in fact, it does partly the same job. A charger will also drop down the voltage to the desired amount, but, it also includes the charging circuitry.

It’s not always obvious to tell the difference between the two. So plugging in a power adaptor into a device that does not have the charging circuitry built into it may well cause damage to the batteries even if on face value the Voltage and Power output looks the same as the specification of the original charger. This is because there is no control over the flow of power into the battery. It could even cause a fire with Ni-MH or Li-ion batteries. So if in doubt do not plug it in, contact the supplier of the laser level for advice. Often a charger unit will have information on it indicating only to use on the original device or it may have an unusual voltage for example 7.4V.

Chargers and Power Adaptors Specifications

So far I have talked about Voltage but the current power in terms Amp or Milliamps needs to be considered along with Voltage. Its all well and good having a 12V adaptor or power supply but does it supply enough current? current for laser levels is generally measured in MilliAmps or mA. Keep in mind that there is 1000 mA in 1A. so, 800 mA is the same as 0.8A. If the device requires 800 mA a charger or adaptor supplying 400 mA will not do the job by not charging the battery fast enough, not working at all or overheating. Note that most modern power adaptors are Regulated meaning that they won’t oversupply the current. So, if you use an 800mA adaptor on a device that needs 400 mA it should be fine.

A few notes on the image above of a Power Adaptor. Most adaptors these days are auto-switching so they can be plugged into both 110V and 240V AC mains. The input section indicates this. It also indicates that its suitable for both 50 and 60Hz mains systems. Let’s unpack this a little, Mains electricity is AC or Alternating Current this is where polarity is switched rapidly on US mains and others this is at 60Hz frequency (speed of switching). For the UK and others its 50Hz. So, basically the adaptor above works in all places, note the actual plug itself may well be different though. Output on the example above is 12V at 1.5A or 1500 mA and DC (Direct Current). The symbol of a fixed-line over a dotted line indicates DC.

Plugs

Next thing to consider is the plug and polarity of that plug that inserts into the laser or device. Most these days are of the type pictured below, however, the dimensions of the outer diameter and inner diameter vary substantially. Therefore, even if you have the correct voltage and current it may still not plug into your device.

Even if it does fit into your laser it may have the wrong polarity. DC has a positive and negative terminal the same as your batteries. Some power adaptors and chargers have the positive terminal as the inner part of the plug and the negative as the outer. Some may be the opposite with the negative being the inner and positive being the outer. Plugging in an adaptor with the wrong polarity may well damage the device.

Again looking at the label on the adaptor in the example the symbol indicates the polarity of the plug. In the example below the inner is positive and outer negative.

Conclusions

If you are not sure that your laser’s original charger is simply a power adaptor if it does indeed have charging circuitry built into it, DO NOT try and plug a none original charger/adaptor into it. If the original was purely a power adaptor then you can look into using a non-original unit. However, you will need to match the following. Output Voltage must be the same. Output Current must either be the same or greater if a regulated unit. Size and Polarity of the plug must be the same.

You can purchase universal power adaptors where you can select the DC power output and select different sized plugs and also set the polarity. This can be an option for replacing a power adaptor but not a charger with charging circuitry.