Question about Pure Sine vs Modified Sine for DC 12V to 110V AC power inverters

[TnDronePilot]

So I'm looking into a inverter for my SUV that I can charge 1-3 batteries with and was wondering if I have to get the one with a pure sine wave verses the modified sine. I have this 4-port charger for my MA2 which has individual outputs of 13.2V 2A each. I love it because it charges all batteries at the same time which would benefit me while on a job. I did some forum research on sine but it wasn't specific to an inverter and, the thread starter's issues seemed to be that he was trying to use his repurposed UPS to charge without the car being on and simply wasn't drawing enough voltage so, the question never really got answered.

True sine inverters are a lot more money than ones with a modified sine wave so I was wondering if anyone knew if true sine is the bare minimum for charging DJI batteries. a Google-Fu search suggested that pure sine is needed for devices that cannot have varied voltage levels and also for sensitive equipment. Are MA2 batteries considered sensitive or will a modified model work? Thanks.

 

[Rich QR]

Many modern electronic devices like chargers use switching power supplies, which are very tolerant of non-sine waveforms. If a device accepts input of "110-240V, 50-60Hz", it will almost certainly work well with a "modified sine" inverter. Check the tiny print on the label of the charger.

BTW, the batteries themselves use DC, and can't work directly with any form of AC, neither from your utility company nor an inverter. They need a charger to convert the AC into the properly regulated DC that the battery can accept. So the question isn't whether the batteries themselves tolerate the inverter's output, but whether the charger you're using tolerates it.

 

[TnDronePilot]

Many modern electronic devices like chargers use switching power supplies, which are very tolerant of non-sine waveforms. If a device accepts input of "110-240V, 50-60Hz", it will almost certainly work well with a "modified sine" inverter. Check the tiny print on the label of the charger.

BTW, the batteries themselves use DC, and can't work directly with any form of AC, neither from your utility company nor an inverter. They need a charger to convert the AC into the properly regulated DC that the battery can accept. So the question isn't whether the batteries themselves tolerate the inverter's output, but whether the charger you're using tolerates it.

So if it has a hyphen/slash between the numbers indicating "a range of", it basically means it can handle non-sine? In my case it's 100-240v and 50/60hz. Thanks.

 

[Rich QR]

So if it has a hyphen/slash between the numbers indicating "a range of", it basically means it can handle non-sine? In my case it's 100-240v and 50/60hz. Thanks.

Yes. It will run fine on anything from 100V to 240V and from 50Hz to 60Hz. It can run on the standard AC power of any place in the world, without any sort of electrical conversion (but a simple plug adapter will be required to make the plug fit into various sockets around the world).

More importantly for this thread, it is extremely likely to run perfectly fine on any inverter. However, since there's no standard definition for exactly what kind of power a "modified sine wave" inverter might produce, it's impossible to provide an ironclad guarantee. Still, I've personally used dozens of such devices on modified sine inverters, never with a hint of problems, and I'd have no hesitation in plugging it into a modified sine wave inverter.

 

[natgild]

So if it has a hyphen/slash between the numbers indicating "a range of", it basically means it can handle non-sine? In my case it's 100-240v and 50/60hz. Thanks.

This may not be the same situation. I have an RV with what I assume is a non sine wave inverter. I regularly blow out my toothbrush chargers if I leave them connected when I switch from shore power to inverter. They are labeled 110-130V 50-60Hz ????

 

[Camino Ken]

A modified sine wave is a poor term as a descriptor. The better term would be unfinished or raw or noisy sine wave. They typically look like a staircase as opposed to a smooth waveform. The biggest drawback is a significant amount of harmonics at multiples of 50 or 60 hz. Most electronic equipment has some filtering on the power inputs or the equipment is not sensitive to noise so this usually doesn’t cause any issues. It is a bigger problem on audio and video equipment where some of the noise could bleed into the audio or video causing audible or visible degradations. Sensitive measurement equipment can be adversely affected as well.

Batteries, electrically look like huge filters and do a very good job of absorbing the noise so “modified sine waves” rarely cause any issues.

The toothbrush failures could be due to a voltage difference between the two power sources causing a surge/voltage spike zapping the very cheap/simple charger circuit of the toothbrush.