Help with capacitance for a particular load

[M1keTh0mas]

I am new to both this site and electronics, and everything I know about components and how they work (which is near non-existent) I have learned in my spare time. I am planning on buying a modified sine wave inverter to have for emergencies and to power miscellaneous items in my car. I don't plan to use it on anything with electronics, because I know that they don't always play nice together. Knowing that capacitors help smooth voltage (at least I'm fairly certain anyways) how would I calculate the correct capacitance for a known load? This would be partially for increasing efficiency and also incase I am at a job site and need to recharge my power tool batteries. Also, if anybody could explain to me as to why I always hear that modified sine wave fries battery chargers, it would be greatly appreciated...actually any information even remotely related that is explained in laymens terms would be very helpful.

Thank you to anyone and everyone in advance that can help

 

[Harald Kapp]

I am new to both this site and electronics, and everything I know about components and how they work (which is near non-existent) I have learned in my spare time. I am planning on buying a modified sine wave inverter to have for emergencies and to power miscellaneous items in my car.

Dont! Please, dont!!!
An inverter is a dangerous beast, you're dealing with high and dangerous voltages and currents (even on the low voltage side). This is nothing to be tampered with by someone who lacks the necessary experience.

Knowing that capacitors help smooth voltage

That's for DC. An inverter creates AC. Capacitors alone will not smooth AC.

 

[M1keTh0mas]

That's for DC. An inverter creates AC. Capacitors alone will not smooth AC.

Then how would one do it for AC? I remember reading somewhere about passive filtering, and if memory serves me correctly, that's what I am trying to do, right?

And as for experience, I've been an electrician for years, so I know a little more about where not to stick my fingers. Lol. Complacency kills, but PPE will save you

 

[BobK]

Why get a modified sine wave inverter and then try to fix it instead of getting a true sine wave inverter?

Bob

 

[davenn]

I am planning on buying a modified sine wave inverter to have for emergencies and to power miscellaneous items in my car.

so what are these items in your car that run off AC ?

And as for experience, I've been an electrician for years, so I know a little more about where not to stick my fingers.

but, unfortunately, your earlier comments indicate that you have no idea what you are talking about

so we are struggling to know if you really do have the experience ?


Dave

 

[M1keTh0mas]

@BobK for a few different reasons.. its much cheaper to buy a modified sine inverter, because I can go down to the local gettin' spot and get a 750/1500w for under $40. Also, for as much as I plan on using it, I don't want to spend a lot of money. Lastly, most things that I buy I take apart at least once to see how they work, and to learn from looking, googleing, and forums. If I break a cheap inverter i wont be nearly as upset.

@davenn items that run off of AC are a small heater (I work construction and seeing as how it is coming into winter here, i wouldn't have to let my car idle for 15 minutes to be kinda warm), a few lights and mini fridge for back yard parties, and the occasional small corded power tool.
And as for experience, I've been through an electrical apprenticeship for residential, commercial, and industrial installations. But the teacher I had wasn't really teaching material. On top of being a teacher, he had 4 other jobs in the company, and the class suffered because of it. He really only taught about things that we installed and how to install them Ex. Transformers, ATS, motors, and some ac theory. Long story short, I have electrical experience, but have nearly no experience with small electronic components, hence the reason I take things apart to see how and why things work the way they do. I decided to come here for help so that I avoid stupid mistakes that cause damage/injuries. I'd rather have wise guidance than have a rousing failure (again )

 

[Harald Kapp]

Those items you mention imho will work well from the original inverter. No modification needed.
A filter, while possible, would be huge, expensive and will dissipate quite some energy, thus draining your battery faster than without filter.

 

[Harald Kapp]

Possibly dangerous content without the op showing a clear understanding of the risks involved.
Tread closed.

Sorry,
Harald