[aim120]

Originally Posted by Guite

I


There was uninterted power for last 24 hours till this evening. So the battery should have been fully charged, the on-charging mode light was not blinking anymore. Mains power went off about 8 pm this evening. The plasma TV (285 watt) continued on for sometime and then powered off on its own. We tried restarting it again, even switching off all other loads, but to not avail. For the record there is nothing wrong with the TV, it turned on when mains power came back.

Why is this inverter, apparently higher load rating, not able to power the TV? Moreover ceiling fan speed is very low when on this inverter power. Is voltage low?

Another odd thing: even if load is constant the inverter load indicator lights (50%, 75% and 100% respectively) sometimes changes on its own. Is this normal?

Did you set the charge current to 15A.

This 850va ups has a power factor of around .588, your earlier BI800I ups despite being 800va has a power factor of .625 because its runs on 24v ,so basically means that both UPS have the same max load of 500watt its just that your old one is more efficient.It could be that your old UPS could can handle a higher surge current better for a short duration of time.

Now the load indicator is not constant because just because you have switched on a tv and desktop doesn't mean the load is the same.For example the actual load of a plasma tv will vary it consumes more power if its average picture level increases and the power consumption will be at its peak when its showing a full white screen.Where a Lcd/LED(except local /global dimming tv) will have the same power consumption irrespective of the what is being shown on the screen.
In your PC just by moving a mouse will cause the power consumption to vary.

All UPS/inverter makers show the rating based on a resistive load such as your incandescent bulb.Your CFL,Tv,computer or any electronic device is a inductive load.

[Aroy]

Check both the output voltage and the frequency of the inverter. TV not switching on points to either of these parameters not upto specification.

Literature of our 47" LC LCD does not recommend running on inverter/UPS due to waveform distortion.

[Guite]

Originally Posted by aim120

Did you set the charge current to 15A.

Yes.

This 850va ups has a power factor of around .588, your earlier BI800I ups despite being 800va has a power factor of .625 because its runs on 24v.It could be that your old UPS could can handle a higher surge current better for a short duration of time.

Power factor must be at play then. Surge current applies for starting an appliance, right? However in my case the TV stays on just after a power cut and then powers down after sometime. There does not seem to be any surge current at play to effect the self power down.

I did a small experiment by running plain colour slides on the TV. It did not turn off by itself even on white slide, which as you have stated consumes maximum power in plasma TV.

Originally Posted by Aroy

Check both the output voltage and the frequency of the inverter. TV not switching on points to either of these parameters not upto specification.

While I do not have any equipment for checking frequency, I did a crude and not very accurate measurement of voltage using the inbuilt voltmeter of a stabiliser. Reading off from a wall socket, inverter output is shown to be 200 volt. This is the same output reading when this stabiliser is connected mains. In fact this stabiliser used to supply to the old 24v inverter.

[Aroy]

Originally Posted by Guite

Yes.
While I do not have any equipment for checking frequency, I did a crude and not very accurate measurement of voltage using the inbuilt voltmeter of a stabiliser. Reading off from a wall socket, inverter output is shown to be 200 volt. This is the same output reading when this stabiliser is connected mains. In fact this stabiliser used to supply to the old 24v inverter.

Does this mean that both the Inverter and the stabilizer show 200V in your meter. If yes, then it may be the frequency or waveform. If the mains voltage is higher then get the inverter output adjusted so that it gives a higher voltage.

[aim120]

Originally Posted by Guite

Power factor must be at play then. Surge current applies for starting an appliance, right? However in my case the TV stays on just after a power cut and then powers down after sometime. There does not seem to be any surge current at play to effect the self power down.

Yes surge current applies when starting an appliance.
If your tv power downs after that must be that your battery isn't giving out sufficient current.Check the battery voltage during the load like your plasma.

Originally Posted by Guite

I did a small experiment by running plain colour slides on the TV. It did not turn off by itself even on white slide, which as you have stated consumes maximum power in plasma TV.

So now its not turning off in battery mode? even when its displaying white color ? Then that means there is not issue in the battery

Originally Posted by Guite

While I do not have any equipment for checking frequency, I did a crude and not very accurate measurement of voltage using the inbuilt voltmeter of a stabiliser. Reading off from a wall socket, inverter output is shown to be 200 volt. This is the same output reading when this stabiliser is connected mains. In fact this stabiliser used to supply to the old 24v inverter.

I doubt frequency has anything to do with it power down.I also doubt the voltmeter in the stabilizer.Get yourself a multimeter it available for as low as 400.

[Guite]

Originally Posted by Aroy

Does this mean that both the Inverter and the stabilizer show 200V in your meter. If yes, then it may be the frequency or waveform. If the mains voltage is higher then get the inverter output adjusted so that it gives a higher voltage.

The stabiliser when connected to mains show its output as 200 volt. This same stabiliser gives input reading of 200 volt when connected to inverter supplied socket on inverter mode. The stabiliser has toggle switch for reading voltage of input and its output.

What I am deducing from this is that the reading may not be accurate (because it is not returning a reading of 220V) but: (A) output from stabiliser when connected to mains and (B) inverter output, are same. I never had problem with output from this stabiliser.

Incase the output voltage from the inverter is low can it be adjusted by self or by company technician? I had planned to finally buy a multimeter but could not go out today. Planning to get an accurate reading. Recommendation on good brand of digital multimeter welcome.

Edit:
Just read aim120's response. The TV does not power off on the white slide but still power offs on normal TV viewing on inverter power. Please recommend good and durable multimeter as posted above.

[aim120]

If the tv doesn't power off with a white slide at its max power consumption,then it can't be the inverters fault.

Well a good multimeter brands which are not that expensive are meco,Uni-t,Mastech although these cost around 1k or more.
I have a meco thats more then 15 years old still running fine.

The cheaper ones do get the job done,but it won't last that long but for some one who is using it rarely it should be a problem.

[Guite]

Wouldn't accuracy of reading be doubtful incase of cheaper products? Have found a Mastech for Rs.895 on eBay. Strangely there are other products of similar appearance and same model name but labelled different brand. A local brand Metravi also looks good but is costly.

[aim120]

Mastech are from the same OEM provider but i found they Mastech branded ones to have slightly better plastics.

Metravi is also good.

If one really wants accuracy then they will have to go with a TRMS meter which costs a lot.I have a TRMS Mastech Clamp meter and a normal Meco DMM one.

[Guite]

Tested voltage output of the inverter using a digital multimeter and it reads 225 volt. That's ok.

Power factor .588 x 850 VA is good for 500 watt load, right? The old inverter with power factor of .625 x 800 VA is also theoretically good for same load. So why is the new one not able to 'carry' as much load as the old one?

[aim120]

Originally Posted by Guite

Tested voltage output of the inverter using a digital multimeter and it reads 225 volt. That's ok.

Power factor .588 x 850 VA is good for 500 watt load, right? The old inverter with power factor of .625 x 800 VA is also theoretically good for same load. So why is the new one not able to 'carry' as much load as the old one?

I assume you checked it when it was running on battery so there is no issue in voltage.But do check the voltage when its running the plasma tv both in white slide and in normal viewing.

If the load was more then the inverters rating then the inverter should shutdown thats not the case in yours.

Both inverters have the same load rating ,its just that your older one was more efficient.

[Guite]

With multimeter probes on the plug going into the TV, voltage reading is 250 on mains power. Switch off MCB so that power comes from inverter + battery. Voltage reading fluctuates all throughout duration of reading. After about a minute inverter goes on over power mode (>100% load) and TV has to be turned off. When we try to restart TV on inverter power, voltage momentarily drops to about 170V. This is not consistent on every attempt, sometimes 180, sometimes 168, etc.

I also tried measuring current drawn by TV but power does not pass through multimeter. Connection is in series. Maybe multimeters cannot measure AC current?

[R2D2]

Originally Posted by Guite

With multimeter probes on the plug going into the TV, voltage reading is 250 on mains power. Switch off MCB so that power comes from inverter + battery. Voltage reading fluctuates all throughout duration of reading. After about a minute inverter goes on over power mode (>100% load) and TV has to be turned off. When we try to restart TV on inverter power, voltage momentarily drops to about 170V. This is not consistent on every attempt, sometimes 180, sometimes 168, etc.

I also tried measuring current drawn by TV but power does not pass through multimeter. Connection is in series. Maybe multimeters cannot measure AC current?

Most MMs can measure AC & DC voltages among other parameters such as current (Amps), Resistance (Ohms), continuity, transistor/diode checks, etc. They can also measure current - up to limits specified by the model - sometimes 10A or even 20A.

Which digital MM did you buy? Make sure that you switch the input knob to AC. A DMM is a useful tool and it is wise to invest in a decent model. Metravi is a good Indian brand but slightly on the expensive side. I use Fluke DMMs and Clamp meters but this will be overkill for you.

Do not buy the Rs 200/300 Chinese garbage. DMMs are used to measure hazardous voltages and there are corresponding safety standards that DMMs must adhere to. For for that kind of money I am sure the Chinese "brands" take the easy and inexpensive way out.

If you are getting flaky & low voltages from your inverter plus it cannot support a TV it means there's something wrong with either the input (Battery) or the rectifier stage. Please get both battery and inverter checked.

[aim120]

It depends on the make and model of your multimeter ,some don't have the capability to measure current.

To measure AC current you will need to connect the the measuring leads to the desired port and set the meter to Ampere mode or AC current mode.

Some meters have 2 ports one for upto 10ma or 20ma and other for upto 10A or 20A.You should connect it to the the 10A or 20A and then set the multimeter to 10A or 20A ac current mode.

Do also check the battery DC voltage under load.

Now the fact that the inverter indicates overload means the load is more then what the inverter can handle.

Does it overload on a white slide as well?

[Guite]

Thanks for being with me on this.

Originally Posted by R2D2

Which digital MM did you buy? Make sure that you switch the input knob to AC.

It's a brand named Mastech which I bought from Ebay for Rs.895. I put the knob on 10A. However there is no separate section for AC current, only section for DC marked A with straight line and dot dot dot.

Originally Posted by aim120

Does it overload on a white slide as well?

White slide makes no difference to the voltage reading and overload switch off. Whether on mains or inverter power, voltage reading at TV plug changes every second, ranging from single digit to 240V. It stabilises at 240 only on black slide and completely dark scene.

Another interesting point to note is that inverter does not indicate overload when supplying to desktop PC. Both PC and TV are more or less same load, not running concurrently.

Voltage reading at battery terminal is stable at 12.45V when power is drawn from it and supplying to TV. However I noticed something else, the battery cables are hot, though not scalding hot. Is this normal?