# inverter dilema



## KRO (Feb 27, 2006)

after some excellent advice via this website i'm still a bit confused regarding which inverter to purchase for my van, maplins seem to be the place to buy at the moment but ......................

they have a 150w with only a ciggy lighter type plug for 19.99 or a 
300w with both ciggy plug and crocodile clips for a special of 14.99

so which would be best for me, i only wish to run my 15" LCD TV from it, which i think runs at 50w, could i use the 150w and plug it into my 12v power socket (or should i change the wiring on this, croc clips or direct to liesure battery) or would the 300w be a better deal for me, i'm really more concerned obviously about saftey and also maximising the running time available to me.
sorry for my ramblings but i would rather be clear about this matter, any advice will be gratefully received, thanks.


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## 88724 (May 9, 2005)

Hi Kro

The Power supply says 50W reality will be about 26 Watts.

100 W would be Ideal so 150W is nearest.

If its going to be a fixture get rid of ciggy plug and put an inline fuse in, keep it close to the battery.

Running time will be best on a matched Invertor size wise so the 150W is the best (of those two choices)


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## KRO (Feb 27, 2006)

hi george, i thought you would reply on this one, you seem very knowlegable in these matters, thankyou very much for your help, i'm now off to purchase one to use this weekend hopefully.

ps do you think i would be ok to use the 12v power socket in the TV area in my van for a while or should i make it instantly more permanent ??


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## KRO (Feb 27, 2006)

....


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## 88724 (May 9, 2005)

Hi Kro

_*ps do you think i would be ok to use the 12v power socket in the TV area in my van for a while or should i make it instantly more permanent ??*_

Thats a dodgy question to answer, most of these power points are under wired, it may work as a stopgap. Best is to do it right.


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## KRO (Feb 27, 2006)

ok george i understand, if i'm very lucky i may get some hookup this weekend where i'm staying that'll sort me, many thanks again.


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## 98172 (Mar 16, 2006)

KRO said:


> maplins seem to be the place to buy at the moment but ......................
> 
> they have a 150w with only a ciggy lighter type plug for 19.99 or a
> 300w with both ciggy plug and crocodile clips for a special of 14.99


I have seen this mentioned in other threads and I cannot find one in Maplins at this price, the nearest is £39,99.
Can anybody elucidate?

Regards

Frank


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## 88724 (May 9, 2005)

Hi Frymer

150W at £14.99 is Bgrade (ie returned stock with warranty)

http://www.maplin.co.uk/

Type Invertor in search box (top right hand corner)


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## 98172 (Mar 16, 2006)

Thanks for the prompt reply George, however, it is the 300W that I am interested in and I can't find it on the Maplin site for the above price.

Regards

Frank


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## 88724 (May 9, 2005)

Hi Frymer

When someone posts a Maplins invertor price, do not take time to reply in the thread, do not sit down for a cuppa, do not think thats a good price I'll get one next week

Correct proceedure is order online immediately or proceed to your nearest Maplins toot sweet.

Your snooze you lose (till next time)

They have rolling sales on these things, so next time it may be the 1000 Watt then the 600 Watt.

When Maplins are at 39.99 If you need to get now, I would spend the extra £10 and get a Sterling 350W, its a better quality product.

I always look at it has the Maplins are pretty unbeatable value when on offer, when they are not on offer pay a touch more and get real good quality.


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## 98172 (Mar 16, 2006)

Thanks for that George, it clarifies the situation.

I am looking at a couple that interest me, Nikkai 600W any good?

Kro; Sorry to hijack the thread!

Regards

Frank


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## 88724 (May 9, 2005)

Hi Frymer

_*I am looking at a couple that interest me, Nikkai 600W any good? *_

Well that depends, I thought you wanted a 300W? 600Watt is becoming a serious installation.

First you need to sort exactly what you hope to power............


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## 98172 (Mar 16, 2006)

GeorgeTelford said:


> Hi Frymer
> 
> _*I am looking at a couple that interest me, Nikkai 600W any good? *_
> 
> Well that depends, I thought you wanted a 300W? 600Watt is becoming a serious installation.


I was looking for a 300W George, just noticed the 600W in my travels so to speak and thought that I would ask advice.
You seem to be saying that there are installation problems that are not associated with sub-600W converters, if this is the case I may well stick with my original plan since I only need to power, laptop, satellite system and various battery chargers (not all necessarily at the same time!).

Frank


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## 88724 (May 9, 2005)

Hi Frank

600 Watts requires more thought for the installation suddenly you have the possibility of 150 Amps being drawn.

With you list of products a 150Watt would probably do the Job, are you certain you need 300Watt?


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## 98172 (Mar 16, 2006)

Hi George. 

The simple honest truth is that I have no idea what I will eventually want to power since I am new to MH’s.

The rationale (originally) was to go for a 300W inverter so that it gives the possibility of running several appliances at the same time using multi-socket extension lead and ensuring total load is below inverter capacity.

I figured that there would be no particular penalty (other than financial) in buying a 300W inverter over a 150W, although I take your point on wiring considerations when looking at â‰¥600W inverters.

For example I am intending to use my laptop as navigation aid during a run so no power needed from leisure battery. When parked up I will use it as a computer and also TV/DVD player, the laptop draws ~90W. 
Should I want satellite TV then the satellite system (Digibox) will be taking power also, haven’t bought it yet so don’t know the consumption but maybe ~60W?

These are appliances powered only through the inverter of course and do not include other power-drawing sources on the leisure battery such as lights etc.

Cheers

Frank


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## DJP (May 9, 2005)

*Inverters*



> ps do you think i would be ok to use the 12v power socket in the TV area in my van for a while or should i make it instantly more permanent ??


I did that initially and found TV would go off after 15 minutes due to inverter shutting down. Not sure of the teccy explanation, but to put it simply, the wire to the Tv area of the MH supplying 12v cig plug (to which the inverter was plugged into) was not of sufficient size to run the inverter.
Something to do with resistance. No doubt George can tell you the exact reason. Got the dealer to rewire the socket (which they put in originally) using a heavier grade cable.
So, make sure the ciggy/tv cable is up to it, or wire directly to battery with a fuse in the supply line.


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## 88724 (May 9, 2005)

DJP's Problem was voltage drop due to inadequate wiring, most invertors tell you not to wire any further away from the battery than the length of the leads supplied, ie plugging into further length of wire is not good.


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## KRO (Feb 27, 2006)

hi frymer,

when i rang maplins they told me they had the 300w inverter on special at the moment (old packaging or something it also comes with 2 leads, ciggy plug & crocodile clips £14.99) 

hi george, although i got my inverter at the weekend i couldn't actually try it as i had the incorrect aerial patch lead for my TV, so now i can concentrate on some sort of permanent installation, when you say it's not recommended to use any leads longer than those supplied, would it be acceptable to fit and wire in the inverter near to the liesure battery and then run an extension lead from the inverter to the TV, or would it be better to check out / or replace if neccesary heavier wiring to the 12v supply in the TV area of the van :?: :?: :?: thanks again.........


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## 88724 (May 9, 2005)

Hi

Best solution is to wire the Invertor as near to the Battery as is practical (but not in the battery box)

Losing one or two volts at 240 Volts is not as serious as losing one or 2 volts at 12v, so if you need an extended run always try to make it the 240v lead.

If you really must extend the 12v definately increase the cable's copper cross section (post here first for "advice")


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## Jean-Luc (Jul 21, 2005)

Forget about inverters, get a stabilised 12 volt to 12 volt d/c power supply for the telly and an adjustable 12 volt to 16volt/24volt power supply for the laptop. This way you are not wasting precious battery power through the inefficiencies inherent in going up to a/c mains and back down d.c for the appliance. I only use a 150 watt invertor for the Sat box which are prohibitively priced for 12 volt units.


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## KRO (Feb 27, 2006)

Forget about inverters, get a stabilised 12 volt to 12 volt d/c power supply for the telly

hi midleton,

please tell me more, is a 12v to 12v d/c power supply the same as a 12v voltage stabilizer, where can they be obtained and what do they cost ??


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## 88724 (May 9, 2005)

Hi Midleton/KRO

The regulators actually waste more power than using an Invertor and going up and down, I have been saying this for ages after measuring the inefficiencies of both.

DAB also found that the 12V innards on 12v TV's used more power than the same TV run via an invertor.

These 12v regulators are definately far more wasteful of battery power, they cost more to buy and are not as useful as an invertor.


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## sallytrafic (Jan 17, 2006)

midleton said:


> Forget about inverters, get a stabilised 12 volt to 12 volt d/c power supply for the telly and an adjustable 12 volt to 16volt/24volt power supply for the laptop. This way you are not wasting precious battery power through the inefficiencies inherent in going up to a/c mains and back down d.c for the appliance. I only use a 150 watt invertor for the Sat box which are prohibitively priced for 12 volt units.


Stabilisers are often more inefficient than inverters and how do you think the 12V to 16 V 'power supply' works without inverter technology?

Regards Frank


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## DJP (May 9, 2005)

*Inverters*



> Best solution is to wire the Invertor as near to the Battery as is practical (but not in the battery box)


May I ask "Why not in the battery box?" :? :? :?

I have my 600w in the battery box and a mains lead running to 13amp socket by the TV.

My battery box contains 2 x 110amp acid batteries with sufficient room for another 85amp battery. It's probably 3 ft long by 15" wide. The inverter is fan cooled and there are vents fom the box to outside the MH.


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## 88724 (May 9, 2005)

Hi DJP

For several reasons

1. Its not good to have spark generation equipment alongside a producer of gas, a gas that is far more explosive than petrol vapour. A lead acid bomb can seriously ruin your day

2. Free air around the generator this enclosed space restricts the cooling of the Invertor

3. Due to condensation, the unit will heat up when in use and then when cooling will draw in cold damp air (in your case with the outside venting)


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## DJP (May 9, 2005)

*Inverters*



> "If my answers frighten you . . .then you should cease asking scary questions."


Thanks George 

I did such a neat instalation too! Oh well, more work to move it before it moves itself nfire:


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## Jean-Luc (Jul 21, 2005)

About staying with dc current. Inverting up to mains ac and transforming back to dc must be more inefficient than staying with dc current. apart from the energy dissipated as heat as you go up and back down there is also the energy used by the fan in the inverter. 
For the telly the unit is only stabilising the '12 volt' supply from the battery to a true 12 volts which flat screens require, they don't like 13 or 14 volts, the unit doesn't even get warm so it must be the most efficient method ( where does the inefficiency arise if there ain't any heat or light generated, the stuff doesn't even require heat sinks, unlike inverters). Regarding the laptop power the same applies allbe it that there is a slight warmth if the setting is at the upper end of the scale, say 19 to 24 volts. I got my telly unit from AMPERE and the laptop unit at Brownhills.


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## 88724 (May 9, 2005)

Hi Midleton

I have done tests on Regulators you are lucky to get anywhere near 80% eff

Invertors sized correctly get 95% eff 

Overall when Measured TV and Laptop using Regulator they used more power from the battery than using the invertor and normal power supply.

DAB did tests with a TV when powered directly via 12v even without a regulator it used more power than running same TV via invertor.


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## KRO (Feb 27, 2006)

right sorry, another dumb question, the TV area in my van has a 12v socket that actually has 120w written on it, (theres also another in the cab of the van that says 180w) now will my 150w inverter actually draw 150w when plugged in or only what is required to run the appliance / TV because i did hook it all up last night for about 30-45 mins and all seemed fine, nothing getting hot etc, it would save me a lot of awkward wiring work if this was ok :?: :?: :?:


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## DABurleigh (May 9, 2005)

Only what is required to run the appliance. This will be the appliance's maximum consumption plus ~10% for losses in the inverter. You will need to be sure the current consumption is less than 10A (120W) to use that socket. If you don't have a multimeter, check the rating plate on the appliance.

Dave


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## KRO (Feb 27, 2006)

right on the back of the tv (15" LCD) it says power: DC 12v 4a and in the booklet it tells me 50w, also there is a built in 10/15a fuse in the invertor 12v plug so worse case scenario it should only blow that....................... shouldn't it
:?: :?:


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## DABurleigh (May 9, 2005)

It will work fine. Enjoy.

Dave


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## 88724 (May 9, 2005)

Hi Kro

My Goodmans says similar on the power input for a 17" actual consumption ? is 26 Watts even with everything on full blast I could not get near 50Watts.

While you are using that TV you should not have a problem its within the sockets rating, dont forget and use something over 120w through there though.


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## KRO (Feb 27, 2006)

ok guys thanks for all your help, thats brilliant, it'll just make things so much simpler for me.
:lol: :lol:


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## Jean-Luc (Jul 21, 2005)

George, 
You seem a knowledgeable guy on the question of inverters Vs. transformers (regulated). I take your point about the latter being more inefficient than the former. Can you explain where the 'lost' power is going 
to in my transformers as it does not seem to be leaving through either significant heat, light or motion. Whereas my inverter (250 watt)has a fan whirring away to vent heat generated.


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## 88724 (May 9, 2005)

Hi Midleton

I would say heat, but I never bothered checking the temps when I tested, all I looked at was the amperage being drawn from the battery.

I found it was higher via the regulators, my invertor never gets hot enough when running a TV to set the fan off (on a 150 or less then generally dont have fans anyway)


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## 98735 (Apr 17, 2006)

Just to say hi, new to this forum, albeit an old hand in caravans and motorhomes.

I installed a 2.5Kw sine inverter from Victron Energy (Multi-Phoenix) along with 540Ah Carbon Fibre Batteries. Wiring is absolutely critical along with crimping and cleaning of connectors can see the difference in losing a few watts against losing 100's of watts and potentially starting an unwanted fire! I've done just that, on a modified-square-wave inverter, the predecessor to the Phoenix! I wouldnt recommend modified-square-wave inverters (they call them modified sine wave, but there square), because some electronic equipment is very sensitive to non-sinewave supplies.

I use a Lambda 80Amp AC-12V supply unit, modified so that the fan only runs according to heat dissipation. This unit supplies the stabilised 12V for all circuits, excepting motors (ie. pumps). The unit is tweaked to 13V to allow for line drop using the standard MH wiring and the 3 LCD's in the MH are quite happy with the supply (even though the 23" is receiving 13V).

All that George is saying is very correct and all I can add is that you should never underestimate your requirements for mains, always get more than you think you need, budget limiting. Each caravan Ive had, has had a bigger inverter, and I would have duelled up the Phoenix's, but I have a 4Kw Genset with auto-start when power is needed - ie. Aircon, Microwave, Sat systems will strain a 2.5Kw inverter, switch on the kettle, and all is dead without the Genset. Explain to your wife that you have to turn the TV's off just to make tea!


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## 88724 (May 9, 2005)

Hi Road demon

I dont agree with a couple of your points at all

1. Very few things actually requires Pure sine wave, below is the complete list as far as I am aware to date, pure sine wave is not as efficient as Quasi, not much in it but why waste power uneeded?

Washing machines 

Some dual unit TV DVD (actually very few have any problem, it depends on their internal power supply)

Electric toothbrushes (its the charger part that causes a problem, suffering brain fade at the moment and cant remember what the no electrical contact type charging is called)

Some power tools with speed controls

Ie generally not a lot that a motorhomer will worry about, I have tried virtually every other type of appliance on a Quasi sine wave with no problems at all.

2. Do not budget or fit an invertor any bigger than you need (ie for the best efficiency the one you need is twice the size ie if you need 50W buy 100w, but do not buy more capacity just for the hell of it.


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## 98735 (Apr 17, 2006)

Hi George,

We'll have to agree to disagree. A motorhome is just that, a home away from home and you have to be prepared for most events. As you rightly mention, power tools etc, along with hifi-hum, TV's (line scan) etc. Try using your Dremel on a modified-sine-wave inverter, or your flourescent inspection lamp (which will blow up)!

I started out on the 300Watt route in a caravan in 1993, soon went to 600W, then 1000W, then 1500W. When I bought the MH, I fitted the best I could afford, and it was the right decision, I've stayed well away from campsites on many occasion, and the power is just needed. The Genset is nice, but unsociable, so can only be used whilst camping outback.

The Phoenix is highly efficient and capable of recharging the batteries at a whopping 120Ah, meaning if Im away from a supply, I dont have to run the Genset very long. The MH is perma-mains, no more power-outs because someone trips the communal RCD etc.

If you think you only need 100W now, I can assure you, it will grow, and with each 'growth', it will cost you in time re-modifying and extra purchases.


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## sallytrafic (Jan 17, 2006)

RoadDemon said:


> ......
> 
> If you think you only need 100W now, I can assure you, it will grow, and with each 'growth', it will cost you in time re-modifying and extra purchases.


Unless you are like me haven't fitted a TV of any description or any of the rest of the baggage that a home contains my power consumption falls not rises especially now that my iPod provides the radio and music when not driving.

Frank


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## 88724 (May 9, 2005)

Hi Road Demon

We'll have to disgree because you are wrong, this is not a difference of opinion, we are talking fact's here.

Hi Fi hum? No it doesnt happen, not on the ones I have tested anyway (and I even tried a couple of cheapo's too)

TV line scan Not on any TV I have ever tested and I have tested loads of TV's 20 + at least and never once had a line problem.

Very few power tools, maybe the Dremel? but on your track record on being wrong so far I would not take your word for it.

Flourescent lights do not blow up on quasi sine wave, thats an old wives tale I even did a picture showing one being run from a Nikkai invertor.

Nice sales pitch for the Victron ( a good unit not knocking that ) but the things you are saying to justify it are all totally wrong 

Whopping 120 AH ? I think you mean Amps.

If anyone wants to discuss a system Like Road Demon is suggesting its another topic entirely, Buy into it now for a TV etc and you will be wasting your money.


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## 98735 (Apr 17, 2006)

Sorry George, but your not as clued up as you make out. Leeds University, Chief Engineer, retired, repaired several Flourescent lights that the 1.5Kw unit, bought from Bull Electronics blew up! Caravan, with a 20" CRT, had line scan. Yamaha unit (I cant remember model, used to switch video and act as an amplifier) had hum, transformer based.

Your talking to a BSc(hons) Microelectronics and the Chief Engineer, Leeds University, retired. Whats your qualifications, other than slagging off new people on this forum?


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## 98735 (Apr 17, 2006)

Just to add a little more to this thread.

Forums are about helping people, using your experience and suggestions. My initial post was to advise others of my situation, as I once was looking into inverters, and how it progressed, not about knocking other people.

I could get technical with you George, ie. 120Ah - instantaneous charge current or meaningful amount of charge in 1 hour, but it does no one any good.

By all means put in a modified-sine-inverter, but read the manual, they warn you of potential problems, something they wouldnt do if there was not concern. Also, put in an inverter for the current job, but be prepared to keep on changing it as your requirements change.

Franks idea is a good one, keep it simple, but Ive gone the other way, too much time in tents on mud filled sites to blame.

Ill leave this thread here, as starting a flame war is not my wish.


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## 88724 (May 9, 2005)

Hi Road Demon

The Victron doesnt put in 120 Ah of meaningful charge in one hour, it cannot wothout a perfectly efficient battery Whethor you get technical or not thats not what the Victron specs say.

Forums are about sharing experience and Knowledge, but your post was full of inaccuracies, now you are claiming high Qualification to back up your post, it makes no difference you are still wrong.

Qualifications, not getting into that again, trolls had a field day last time, but I will say I can back what I say up with easy experiment that anyone can carry out and If you are qualified? (anyone can say that) but even if you are, I am not impressed as virtually everything you have said is actually and proveably wrong.

You must be extremely unlucky I have tested 20+ TV's and not one with line flicker. 5 stereo systems now with any hum, Only tested one flourescent light after this old wives tale was claimed before, again no problem.

Also you put my name against your inaccuracies on your second ever post? sorry that you think correcting your totally wrong info as a slagging off, I do not see it that way at all.


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## nukeadmin (Oct 10, 2003)

Admin Note: GeorgeTelford has been Kicked from this thread


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## sallytrafic (Jan 17, 2006)

Its perfectly possible for George and RoadDemon to be both 'right' there is a wide range of quality in a Quasi-Sinewave equipment see here Antares Quasi

Note Antares produce equipment at the top end of the market argueably too costly for private motorhome use.

Regards Frank


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## Jean-Luc (Jul 21, 2005)

Hi all'
Following George Telfords dismissal of RoadDemon's (and myself's) questioning of his opinions I ran some tests today to get some facts regarding the relative power consumption of inverters and regulated d.c supply, for power for electronic equipment, here are my findings.

Appliance being tested : Mitsubishi Black Diamond 15 inch LCD (Maximum power consumption 30 watts) supplied ex factory with an external transformer supplying 12 volt dc from mains supply.

1.Using 250 watt modified sine wave invertor and mains transformer
Current draw from battery - no load = 0.67 ah - powering tv = 3.81 ah

2.Using 150 watt pure sine wave invertor and mains transformer
Current draw from battery - no load = 1.56 ah - powering tv = 4.98 ah

3.Using Amperor regulated 12 volt supply
Current draw from battery - no load = 0.00 ah - powering tv = 2.80 ah

Conclusion (for me)
Staying with dc current is best, Mod. sine wave is second best and leave the pure sine wave switched off unless absolutely necessary for sensitive equipment.
Someone else can do the relative percentage efficiencies but staying dc seems to use at least 30% less battery than inverting.

Regards to all
keep with the program


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