Voltage drop...

aussie_paul · Guru

Voltage drop...

PeterD · Guru

Your inverter appears to be supplying approximately 95 W. That's a hell of a lot for a small TV. In this day and age why don't you use a TV designed to run off 12 V. They are mostly more efficient in the first instance and you don't have the power losses in the inverter on top of what the TV draws.

-- Edited by PeterD on Monday 2nd of February 2015 11:15:46 PM

03_Troopy · Guru

From the Caravans Plus website

Onyx Sphere 19.5" LED TV

Specifications

Screen Size: 19.5 inch TFT LCD
AV Playback: PAL / SECAM /NTSC
Down Firing** Stereo Speakers
DVD Player: DVD,VCD,MP3,Audio CD, CD R/W, JPEG,CDDA, WMA,CD-G,DVD-R,DVD-RW,DVD+R,DVD+RW,DVD-5,DVD-9,DVD-10,DVD18, HD-CD
Inputs: AV, 3 x HDMI, USB 2.0,
Tuner: HD Digital (MPEG4 HD ready)
DC 12V Cigarette plug included , AC power adapter 240V included
Power Consumption at 12V: 1.8A , 21.6W
Dimensions of Screen: 467W x 281H x 49D (mm)
Dimensions with stand: 467W x 318H x 176D (mm)
Net Weight: 3.3Kg
Native Resolution: 1600 x 900 pixels
Mounting holes: 75mm x 75mm (VESA Standards)

So yes, it seems to be drawing way to much current.

Jaahn · Guru

Hi Aussie Paul smile

The other answers have said it all, allmost wink

A feature of 240v inverters is that they just draw current as necessary to get the the required 240v voltage output. So if the supply from the battery is poor and has excessive resistance the current draw at 12v just goes up as the voltage goes down. This will continue up to the point when the inverter cuts off due to low voltage. However if it is just enough voltage to continue the 12v losses can be high. furious

My suggestion is to check the 12v supply wiring, both the +ve and the -ve wiring. Get rid of any sockets and plugs in the system too as they are a disaster. hmm

Jaahn

aussie_paul · Guru

PeterD wrote:
Your inverter appears to be supplying approximately 95 W. That's a hell of a lot for a small TV. In this day and age why don't you use a TV designed to run off 12 V. They are mostly more efficient in the first instance and you don't have the power losses in the inverter on top of what the TV draws.

-- Edited by PeterD on Monday 2nd of February 2015 11:15:46 PM

Hi All, we always run it off 12 volts, BUT I now have enough monitors to see there was quite a voltage drop half way along the 12 volt circuit to the TV when the TV was on. That is why I measured the DC voltage drop. I then found the AC supply for the tv and tried that off the inverter rather than connect a mains lead to the van. That is how I ended up with the measurements. I need to know if the TV is drawing too much current OR is there a problem with the 12 volt wiring.

Is the current draw excessive on both AC and DC?

Aussie Paul. smile

aussie_paul · Guru

I have just measured the current draw of our 48" Panasonic led TV.

Aussie Paul. smile

aussie_paul · Guru

I have now measured the amps drawn from the battery by the inverter running the TV off the inverter. Readings were 8.9 to 9.1. I scanned the specifications. Can't seem to load them atm.

The tv is 22" and requires a 12v 5 amp supply and power consumption under 60w. AND it is a LCD not a LED!!!

It is beginning to look like the DC wiring is too light, thus the voltage drop. Anyone disagree?

Aussie Paul. smile

-- Edited by aussie_paul on Wednesday 4th of February 2015 03:11:11 PM

-- Edited by aussie_paul on Wednesday 4th of February 2015 03:11:42 PM

-- Edited by aussie_paul on Wednesday 4th of February 2015 05:57:45 PM

-- Edited by aussie_paul on Wednesday 4th of February 2015 08:23:01 PM

Cruising Cruze · Guru

all depends how far your power point is from the battery Paul
If it has to travel from your battery halfway around the caravan on a cable that is to light to a power point
you can have some times a loss
My volt meter ( cheepy ) half way around the caravan gives a lower reading than what the battery is sometimes more than .2 volt

Cheers John

oldtrack123 · Guru

Cruising Cruze wrote:
all depends how far your power point is from the battery Paul
If it has to travel from your battery halfway around the caravan on a cable that is to light to a power point
you can have some times a loss
My volt meter ( cheepy ) half way around the caravan gives a lower reading than what the battery is sometimes more than .2 volt

Cheers John

HI

Yes, that is exactly what happens , the voltage is affected by current multiplied by distance

But 0.2V drop under max load current should not present any problems with ,12V gear IF the battery is in a good SOC

oldtrack123 · Guru

aussie_paul wrote:
I have a Sphere roughly 20" led tv in the van. I measured the dc current draw today of 9 amps, because I thought that a voltage drop of between .5 and 1 volt was excessive. The AC current draw off the inverter was showing .39 amps. Thoughts??
Aussie Paul.

Hi Paul

Those AC figures simply mean the TV is drawing 93.6 VA at a PF of 0.xx[ NOT 93.6W]

What was the PF reading??

Certainly , it cannot be,what I see ,16 [on your meter]??or is that 0.16??

The actual Watts for the TV would be more like 40<50W=4A @12V

Also HIGH volume levels encrese the current

Even with inverter losses, 9A @12V current draw ,seems excessive

What are you measuring the DC current with??

What is the inverter, Brand ?model???

Have you tested the VOLTAGE AT the inverter DC input with the inverter under load &not loaded??

How long are the cables [distance of the cable run]& what sized cables[ dia of copper core]??

-- Edited by oldtrack123 on Wednesday 4th of February 2015 11:53:46 PM

-- Edited by oldtrack123 on Thursday 5th of February 2015 12:00:50 AM

aussie_paul · Guru

oldtrack123 wrote:
aussie_paul wrote:
I have a Sphere roughly 20" led tv in the van. I measured the dc current draw today of 9 amps, because I thought that a voltage drop of between .5 and 1 volt was excessive. The AC current draw off the inverter was showing .39 amps. Thoughts??
Aussie Paul.

Hi Paul
Those figures simply mean the TV is drawing 93.6 VA at a PF of 0.xx[ NOT 93.6W]
What was the PF reading??
The actual Watts for the TV would be more like 40<50W=4A @12V
Even with inverter losses, 9A @12V current draw ,seems excessive
Have you tested the VOLTAGE AT the inverter DC input with the inverter under load &not loaded??
How long are the cables [distance of the cable run]& what sized cables[ dia of copper core]??

-- Edited by oldtrack123 on Wednesday 4th of February 2015 11:35:28 PM

-- Edited by oldtrack123 on Wednesday 4th of February 2015 11:44:03 PM

Hi Ralph, what is PF reading?

I will check battery voltage under load to the inverter.

I will see if I can get some idea of the DC cable run and the wire copper diameter. It is the original Jayco wiring.

Aussie Paul. smile

Sphere TV.JPG

-- Edited by aussie_paul on Thursday 5th of February 2015 12:37:39 PM

aussie_paul · Guru

I ran some more tests today, and will try and get to the DC cable to see how thick it is tomorrow. I am beginning to think that this particular TV is drawing excess current for some reason.

Aussie Paul. smile

Cadpete · Guru

Looking at that table I wonder if it's actually the quality of the connection to the battery. Maybe corrosion built up under the terminal? Also how did you measure the votage halfway - insulation piercing probe or is there a join there, if a join did you check both sides of the join.

Just my 2c worth, but for you I'll round it down to free! biggrin biggrin

aussie_paul · Guru

Cadpete wrote:
Looking at that table I wonder if it's actually the quality of the connection to the battery. Maybe corrosion built up under the terminal? Also how did you measure the votage halfway - insulation piercing probe or is there a join there, if a join did you check both sides of the join.
Just my 2c worth, but for you I'll round it down to free!

Pete, connections to Battery are ok. Half way along to the TV is the Wineguard antenna booster that also has a cig socket where I plug my volt meter in.

Aussie Paul. smile

IMG_3536 edit.jpg

IMG_3539 edit.jpg

IMG_3547 edit.jpg

Cadpete · Guru

Looking at the photos you have just posted you have 13.2 at the battery, 12.5 at the booster (midway Winegaurd power point) and 13? at the TVsocket - is that the correct understanding? ie lost and then gained, may be different circuits?.

oldtrack123 · Guru

HI Paul

PF is the "powerfactor" which seems to be showing as 16 on your meter which cannot be correct[usually ranges from 1.0 > 0.4]

It only applies when measuring AC loads ,current , volts, Watts OR VoltAmps with a PF number.

Watts & voltAmps are only the same value when the PF is 1.0

In all other case with lower PF> the VAmps will be higher than Watts

THe specs say <60W ;at 12V= 5A plus inverter losses

That would be at max volume & brightness

Your 12V dc draw from the battery to the inverter should not be much more than 6A

BUT if you do not have 12V at the inverter with the TV turned on ,it will draw more current

You need to check the actual voltage at the INVERTER DC input terminals with the TV both running & not running

If there is a significant difference you will need to check back towards the battery with the TV still running until you find a point where the voltage suddenly changes [encreases], the problem will lie between that point & the previous lower voltage point.

ps you should use the same DC voltmeter to do all the dc V measurements smile

Your are aware that the power meter you used in first pic is AC only?

It will have a significant error on DC

-- Edited by oldtrack123 on Friday 6th of February 2015 12:12:16 AM

aussie_paul · Guru

oldtrack123 wrote:

HI Paul
PF is the "powerfactor" which seems to be showing as 16 on your meter which cannot be correct[usually ranges from 1.0 > 0.4]
It only applies when measuring AC loads ,current , volts, Watts OR VoltAmps with a PF number.
Watts & voltAmps are only the same value when the PF is 1.0
In all other case with lower PF> the VAmps will be higher than Watts
THe specs say <60W ;at 12V= 5A plus inverter losses
That would be at max volume & brightness
Your 12V dc draw from the battery to the inverter should not be much more than 6A
BUT if you do not have 12V at the inverter with the TV turned on ,it will draw more current
You need to check the actual voltage at the INVERTER DC input terminals with the TV both running & not running
If there is a significant difference you will need to check back towards the battery with the TV still running until you find a point where the voltage suddenly changes [encreases], the problem will lie between that point & the previous lower voltage point.
ps you should use the same DC voltmeter to do all the dc V measurements
Your are aware that the power meter you used in first pic is AC only?
It will have a significant error on DC

-- Edited by oldtrack123 on Friday 6th of February 2015 12:12:16 AM

Hi and thanks Ralph, yes I knew that was an inline AC meter. I removed the solar input to the solar regulator to run these tests.

Battery voltage at inverter input 12.79.

Battery voltage at the inverter input with Inverter on and running TV was 12.72 using same meter.

DC amps at inverter input with TV running a little over 5 amps on an analogue gauge I have.

DC Amps running all the van lights was 3.8

DC Amps running TV on the DC system was 4.2

I have found that the inverter can make my cheap multimeter give crazy readings, and affects the tv signal in poor reception areas!!!!

I can now draw an electrical circuit as to how it is all laid out.

Can't beat getting in there amongst it all to learn what you have!!!!

The DC wiring is shown in these pics. There seems to be parallel DC cables running through the van.

Aussie Paul. smile

Rear of Wineguard amp and 12 volt socket disconnected..jpg

IMG_3596 edit.jpg

Rear of TV 12 volt socket ad TV cable.jpg

-- Edited by aussie_paul on Saturday 7th of February 2015 08:40:16 PM

oldtrack123 · Guru

Hi Paul

[Quote]Hi and thanks Ralph, yes I knew that was an inline AC meter. I removed the solar input to the solar regulator to run these tests.

[1]Battery voltage at inverter input 12.79.

[2]Battery voltage at the inverter input with Inverter on and running TV was 12.72 using same meter.

[3]DC amps at inverter input with TV running a little over 5 amps on an analogue gauge I have.

[4]DC Amps running all the van lights was 3.8

[5]DC Amps running TV on the DC system was 4.2

[6]I have found that the inverter can make my cheap multimeter give crazy readings, and affects the tv signal in poor reception areas!!!!

I can now draw an electrical circuit as to how it is all laid out.

Can't beat getting in there amongst it all to learn what you have!!!!

[7]The DC wiring is shown in these pics. There seems to be parallel DC cables running through the van.

Aussie Paul. smile [end quote]

[1]That indicates a well charged ,& if a rested voltage ,a fully charged battery,tick OK

[2]Better than expected, tick OK

[3]around 64W input input for The TV which is rated 60W [depending on volume & brightness settings]

Not much wrong wth that, possibly 90% efficient

[4]that equals a total of around 45W seems a little low but depends on what lights you have

[5]Are you saying the TV is dual voltage 240 &12V?? If so why not just run it from 12V ? as you can see far more energy efficient!

& no inverter interference

[6]Obviously not a quality PURE sine wave inverter!

Yes, AC meters can give funny readings on other than pure sine wave

[7]No real problem with that as long as each pair are the same Dia& length & are terminated in a common terminal.

But perhaps they are looping cables from one outlet to another, that is quite normal practise

Yes best to get to know all you can about the van when ALL is going well & in the peace & quiet of home Then ensure you record & keep that info in the van,

Just in case you need it when well away & in a spot with someting wrong smile

Next check your fridge out

If a 3way have a look at what the flame should be like

What A good ignition spark looks like

If a compressor type ,what it actaully draws with YOUR meter when FULL ON & the voltage at it's input at the same time smile

PeterQ

-- Edited by oldtrack123 on Saturday 7th of February 2015 10:12:17 PM

aussie_paul · Guru

oldtrack123 wrote:

Hi Paul
[Quote]Hi and thanks Ralph, yes I knew that was an inline AC meter. I removed the solar input to the solar regulator to run these tests.
[1]Battery voltage at inverter input 12.79.
[2]Battery voltage at the inverter input with Inverter on and running TV was 12.72 using same meter.
[3]DC amps at inverter input with TV running a little over 5 amps on an analogue gauge I have.
[4]DC Amps running all the van lights was 3.8
[5]DC Amps running TV on the DC system was 4.2
[6]I have found that the inverter can make my cheap multimeter give crazy readings, and affects the tv signal in poor reception areas!!!!
I can now draw an electrical circuit as to how it is all laid out.
Can't beat getting in there amongst it all to learn what you have!!!!
[7]The DC wiring is shown in these pics. There seems to be parallel DC cables running through the van.
Aussie Paul. [end quote]

[1]That indicates a well charged ,& if a rested voltage ,a fully charged battery,tick OK
[2]Better than expected, tick OK
[3]around 64W input input for The TV which is rated 60W [depending on volume & brightness settings]
Not much wrong wth that, possibly 90% efficient
[4]that equals a total of around 45W seems a little low but depends on what lights you have
[5]Are you saying the TV is dual voltage 240 &12V?? If so why not just run it from 12V ? as you can see far more energy efficient!
& no inverter interference
[6]Obviously not a quality PURE sine wave inverter!
Yes, AC meters can give funny readings on other than pure sine wave
[7]No real problem with that as long as each pair are the same Dia& length & are terminated in a common terminal.
But perhaps they are looping cables from one outlet to another, that is quite normal practise

Yes best to get to know all you can about the van when ALL is going well & in the peace & quiet of home Then ensure you record & keep that info in the van,
Just in case you need it when well away & in a spot with someting wrong
Next check your fridge out
If a 3way have a look at what the flame should be like
What A good ignition spark looks like
If a compressor type ,what it actaully draws with YOUR meter when FULL ON & the voltage at it's input at the same time

PeterQ

-- Edited by oldtrack123 on Saturday 7th of February 2015 10:12:17 PM

Yes TV is both 12 dc and 240 ac and this is the only time I have run it of 240V. More for finding out info.

The inverter is supposed to be pure sine wave. pic attached.

In another thread I have checked the 3 way fridge gas flame and igniter.

What with my need to understand "stuff" the plumbing and electrical have been a little exhausting!! BUT I am getting there.. biggrin

Aussie Paul. smile

IMG_3568 edit.jpg

-- Edited by aussie_paul on Saturday 7th of February 2015 10:38:14 PM