Is a 150W MSW inverter safe for laptop chargers/mobile phone chargers ? - Page 1
Forum section: electronics / general

author: Darkslayer7
author_rank: Newbie
timestamp: June 29, 2013, 08:31:18 am
content: I just purchased a 12V to 230V 150W (up to 300W surge) MSW inverter (has a changable 25A fuse)mainly for my laptop to charge it on the go. My laptos charger is rated at 100-240V 90W. However it does not say that it reqires a pure sine. Should It be safe to use it on Modified sine? Also my little Samsung wall charger is a 5V 1A (5w) USB charger. Could I use that too with the inverter?Here is the Inverter :http://energenie.com/item.aspx?id=7591Also, Its my first post. Helo everyone

author: Psi
author_rank: Super Contributor
timestamp: June 29, 2013, 08:33:54 am
content: I've used generic 150W inverters to power laptop PSUs before without issues.Inside the psu the first thing it does is rectify the AC back into DC anyway, so it shouldn't be a problem.

author: SeanB
author_rank: Super Contributor
timestamp: June 29, 2013, 10:34:00 am
content: with a wide input range it could or could not have active PFC, but in any case it will work with either a square wave or a modified square wave. The USB charger will have no problems either, it is a simple bridge rectifier. The only things that complain are ferroresonant units ( from the input not being exactly 50/60Hz as designed for) and transformers that drive regulators where there is now insufficient headroom to maintain regulation. The other item that will complain is a colour CRT where you will get a colour set on the display as the degaussing circuit does not work well with a square wave input.

author: Psi
author_rank: Super Contributor
timestamp: June 29, 2013, 10:39:13 am
content: Things with AC motors, like desk fans, sound a bit weird on modified sinewave but that's about the only strange thing ive seen using those sort of inverters.

author: digsys
author_rank: Unknown
timestamp: June 29, 2013, 10:48:54 am
content: Quote from: Darkslayer7Hiya and welcome. I did a teardown (not here) on very similar ones from Jaycar.com.au Absolute rubbish and dangerous.Up to you, but there's no way I'd take a chance. I tested MANY "cheapish" inverters and in the end I found that a goodguidewas the weight of the OP Transformer. With a reasonable design, you'll also find a much nicer AC. Those 3/4/5 level switched DCOP types are pretty tired old technology and create a LOT of noise / spikes etc. But as always YMMV

author: Darkslayer7
author_rank: Newbie
timestamp: June 29, 2013, 12:19:47 pm
content: Quote from: digsys on June 29, 2013, 10:48:54 amCheapish? Yes. Was about 25euro.Hmm. Might have to dig out my old osciliscope, and see for myself how nice of a square it creates.The USB is good. Charged my Galaxy Nexus in about 80min.I tred a 135W air compressor for like 15min. Works good so far. The unit did not heat up much. And the cooling fan was not blowing out hot air either.

author: amyk
author_rank: Super Contributor
timestamp: June 29, 2013, 12:49:14 pm
content: Regular SMPS will be fine with square wave AC oreven pure DC, although ones with active PFC might have some issues.

author: tom66
author_rank: Super Contributor
timestamp: June 29, 2013, 08:55:53 pm
content: My Dell charger could not operate correctly from a 180W MSW. The power LED flickered and the laptop would not charge. I suspect the PFC circuit was not happy.

author: Darkslayer7
author_rank: Newbie
timestamp: June 30, 2013, 07:16:15 am
content: So I tried it in the car. plugged it in. started the engine. It charges. Left itt there for 15min to see how it goes. Went from 7% batt to 28. The charger got hotter than usuall. But I assume its good to go. Measured the output voltage. It was steady. Its suposed to be 20V. It did delivered 19.92 under charging. The Power brick was about 35c hot.

author: Stonent
author_rank: Super Contributor
timestamp: June 30, 2013, 07:39:12 am
content: Many years ago I tried to use an inverter with a laptop and got the flashing power light as well.

author: peter.mitchell
author_rank: Super Contributor
timestamp: July 02, 2013, 01:56:00 pm
content: For charging laptops and the like from 12V, just get a DC-DC converter, much more efficient usually, and only one box, not two.

author: wiss
author_rank: Frequent Contributor
timestamp: December 28, 2015, 07:22:48 pm
content: Sorry to wake up this old thread but I think I have a relevant question...I have experienced behaviour similar to the blinking power-led, the LED was on but the laptops (a eeepc and a HP) charged a few seconds and then stopped charging and then charged again. Using a modified sine 12 VDC -> 230 VAC converter._Why_ do the power supplies have problem with modified sine?

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 29, 2015, 02:03:28 am
content: A particularly badly designed PSU can be sensitive to EMI. If you know how to work on electronics, maybe try hacking the inverter to output 170V or 340V DC?

author: wiss
author_rank: Frequent Contributor
timestamp: December 29, 2015, 08:22:29 am
content: At least one of my p-sups are designed for 100 - 240 V, the peak voltage should not be a problem.I measured the inverters output and it is a double-square with a peak of +-340 V. I did not check the duty-cycle but it looked reasonable.Since this kind of problems seems to be very common I assume it is not due to specifically poorly designed laptop p-sups, or it is industry standard to deliver these poorly designed p-sups with pro-level as well as consumer-level laptops.

author: Seekonk
author_rank: Super Contributor
timestamp: December 29, 2015, 09:02:08 am
content: I have a few blown inverters I've picked up that I never fully repaired, just tore out the H bridge and connected outlet to the raw HV DC. These easily power electronic CFL, DVD players, and most electronic wall warts. In fact many of these still work at reduced power on my 50V raw solar panel feed. Lately I've found some good name fairly large power wall warts only use half wave rectification that are plug position dependent. Devices that use capacitive dropping seem to have trouble with MSW. Heard reports that some kill a watt devices go up in smoke and phase triggered tool charges have issues, but no direct experience.

author: necessaryevil
author_rank: Regular Contributor
timestamp: December 29, 2015, 09:33:04 am
content: You could use a rectifier and a capacitor to make 340v= dc. This is about the first thing your chargers do internally anyway. Doing this saves the input stages of your chargers, they wouldn't be exposed to the rapid change in voltage of the modified sine.I don't know if the PFC circuitry of the chargers is affected by the dc voltage. Could anyone confirm this isn't a problem?