I have a questions about Capacitors. Seeking help from Electronics Gurus.

Problem Description:
I have a 850VA home inverter which works fine with anything and everything consuming a total of 800 Watts when there's no power from the grid.
As usual when the Power Fails (From the Grid) the inverter kicks in and provide the supply of power from the battery in home. Everything works fine.
But when i switch on my Laptop (connected to the Inverter with no power from grid), the CFL Lights suddenly starts to randomly flick.

This flickering is not continuous but Random and even may or may not occur.
Sometimes the lights keeps on flickering as long as there's no power from the grid.
Sometimes the lights don't flicker for few minutes, then flickers for 10-15mins and then vanishes away. And then resumes after a while.

Irrespective of the total load on the inverter (Usually not more than 100 watts excluding the Laptop) flickering occurs randomly.
If i put the inverter on the full load of 800 Watts (including the Laptop), even then the flickering occurs randomly.
Even if take off complete load and only let the Laptop and a CFL being powered up by the inverter, even then flickering occurs randomly.

BTW, the Laptop's Power supply is 100~240v 1.5Amps.

Question:
As far as i have heard, this could be rectified using a capacitor connected in Parallel.
Yes/No?

If Yes, What should be the Specs of the Capacitor?

Capacitors wear out with use. Take it to electronic shop and get the internal ones replace with same or one with more capacity.
Connecting in parallel also solves it but better to replace internal ones before they destroy other caps.
Sorry I cannot judge which cap u need.

Ps- I am no guru when it comes to electric stuffs but this is what I think.

Sir do you experiance this problem only on the Inverter ? or is it still there while using the Lines ?

Only with the Inverter Sooraj.

I face the same issue...subscribed. ..

A few years back, i wanted to install an External Capacitor to a 1.5KV Air Conditioner in order to make it run on a 2KVA Power Generator (which otherwise due to the high Inrush current of the compressor used to trip the Generator).
While researching on the subject, i did read about the bigger external cap degrading the smaller internal one over time.
Even at that time, due to lack of understanding on the Capacitors, couldn't conclude the specs for the required Capacitor. Hence, had to abandon the idea at that time.

Well, in the current case instead of letting the Capacitor stay connected all the time, i can use a relay in order to make the capacitor get connected to Home (Load) only when the electricity fails from the grid. (Which is less than an hour per day at the moment but will increase as summer approaches.)
To further reduce the usage of the external capacitor, i can also put in a manual switch in series and switch it on only when the flickering start.

Actually that was an Inverter or UPS? 
Some have both functionality interchangeable using a switch behind them, if that was in UPS mode then switch it to Inverter mode.

hello,
actually. the inverter and ups we use produces square wave( if UPS than modified sine wave..)but the supply from grid is pure sine wave form... as we all know most of the electrical/electronic load is inductive load... which cause lagging power factor... which changes the angle between current and voltage. affect amplitude of sinewave but this is negligible (which can be corrected by connecting capacitor) but in case of inverter/UPS it is square wave/modified sine wave (slightly clipped in square form)Modified sine wave is initially more economical than true sine wave but with today’s technological advancements and the rapid proliferation of sensitive electronics that require true sine wave power to operate correctly, when we supply them from inverter( doesn't affect resistances ) the components like transformers or semiconductor devices has different affects and noise created in circuits which will create fluctuations etc... (which also create humming sound in fans transformers etc)

if you want to get rid of this put 440v capacitor at the output of inverter... and also earth the body of inverter
( for better result you have to add some filters )

regards