do you really need a pure sine wave inveter?

raggie33

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sorry to ask here but spent all night on the internet looking for ansswers but one website says yes then another says no lol. im looking to charge my ebike with one the bike uses a ac to dc adapter. also what about laptops? wont the charger of the laptop convert it to dc anyways? explain it to me in a homer simpson way please
 

orbital

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Wonder if something like this would be better,, less middlemen
Is the connector a standard type, (like an Anderson)


If not, I'd get a pure sine with all the electronics involved for your charging

 

PhotonWrangler

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sorry to ask here but spent all night on the internet looking for ansswers but one website says yes then another says no lol. im looking to charge my ebike with one the bike uses a ac to dc adapter. also what about laptops? wont the charger of the laptop convert it to dc anyways? explain it to me in a homer simpson way please
Square wave and stepped-sinewave inverters generate lots of harmonics. This shows up as spikes and noise, which can produce excess heating in some loads. An AC battery charger may or may not filter out this noise. If I was using this to charge lithium batteries, I'd stick with a true sinewave inverter as it duplicates the power from the electric utility.

We just bought a bunch of UPS units at my workplace and we went with true sinewave units. We confirmed this with an oscilloscope before connecting any sensitive loads to them.
 

raggie33

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i want a scope not even sure how to use it but they look cool i cant find pure sine wave units local any where and online man they are costly lol. and with today who knows if there real
 

orbital

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raggie, I was assuming you were using a 12V input for your inverter.
..often. more input voltage is a good thing.

I mainly use 24V inverters, it's just easier having 2x12V in series
(you only need a short heavy gauge cable for connecting the two batteries)

Series Wiring diagram~ connect the Pos. from one battery to the Neg. of the other battery.
easy

1707055952452.png
 

PhotonWrangler

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I dug up a couple of scope pictures comparing the square wave output of a cheap UPS (technically an SPS) with a good quality sinewave output UPS. The sine wave output is what comes from the power utility so it's good to be able to mimic this when you're generating backup power locally. The spikey edges of the square wave output can cause a downstream surge suppressor to think that it's seeing a continuous series of surges, causing it to go into "crowbar" mode and throw a short across the line. This can cause overheating and maybe some smoke as the MOV surge suppressor starts to burn. This happened to me with the combination of a square wave output UPS and a downstream surge-suppressed power strip that started to smolder during a power outage.

square_wave.jpg



sine_wave.jpg



In short, squarewaves are problematic but sinewaves are good.
 
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