Are cheap dc 24v to ac 240v inverters any good??

Phil2008

Phil2008

Phil2008

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17 Dec 2004
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We have just bought a caravan and I was wondering would a cheap inverter connected to a 12v car batt run a portable tv ok? If yes how noisy are they??
 
Depends on the power rating of the tv. If it's a portable one then I'd imagine so. And most are passive cooled, so should be silent.
 
and the power rating of the inverter

also i think some have a basic power rating, and a surge rating which is obviously higher. for tv watching you'll want to make sure your tv is a lower wattage than the basic rating of the inverter.

not sure what a small tv uses, but a cheap one from halfords seems to run a laptop happily enough.
 
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Just been cleaning the caravan today,, and I think it has a inverter, it looks like a pc's psu. Its screwed down under the seat and and a 3pin socket attached to the front of the seat. Im guessing its either works from the caravans battery or when the caravan is attached to the car. Also theres other sockets dotted about in the caravan, but Im guessing those will only work when connected to mains power. Im going to have a play tomorrow.
 
Might be worth getting a gel battery like this http://www.rapidonline.com/Electric...oc-gel-electrolyte-batteries/73327/kw/18-1124 if your going to run the inverter off a battery without the engine running.

Standard car batteries aren't designed to be constantly completely discharged and charged, rather kept at a steady charge via the alternator... These gel ones love it. We use them at work, they will run a laptop for a day, they get discharged fully once a week at least, and even a year later still have at least 50% of the original capacity. I'm not sure what the AH rating of ours at work is though.

You have to get a special charger for them though, standard car battery charger might not do it.
 
my mum wants to use the hairdryer on the inverter too. but I havent a clue what is the max wattage on this inverter that is fixed in the caravan, as it says nothing about the wattage.
 
Hairdryer i think probably not. they can pull between 600W and 2000W (from a quick look on google) and your average cheap inverter i.e. <£50 is going to be max 300W, probably 150W.

Laptops take between 60-100W, and another quick google shows portable TVs use upto around 50W.

Can't find anything about typical ratings for built in caravan inverters though.
 
I'd be suprised if you could, don't hairdryers pull around 2kW? An average inverter is probably only good for around 500W?
 
I tried the inverter yesterday without success, I tried it with a fan and it was completely dead, so sometime, I'll check all the fuses, just incase. What inverter do you guys recommend me to buy, if I have no luck with the caravan inverter??
 
Ive just come across this......

http://cgi.ebay.co.uk/Power-Bright-...ervan_Caravan_Accessories&hash=item35aa5ff112

But I find it hard to believe it can outout 1100 watts on a car/leisure batt, but I know very little about watts, amps and all of that stuff. So will it run a hair dryer if its no more then 1100watts and if so, how long for?? I see you can even buy 2000watt inverters too:eek:

Ah yeah, I checked the fuses today and there all fine, so the inverter is bust:mad:
 
Depends your car battery. Say if it's 100 Amp hours. It can provide a current of 1 amp for 100 hours.

Average hair dryer say 2kW.

P=IV. 2000=I*230.

I= 8.7A.

100/8.7 = 11.5

So around 11.5 hours :p

Extremely simplified result. But long story cut short, you'll be fine :)
 
I've had bad experiences with cheap car power adaptors from ebay.

Two of them I had blew up, one ruined my laptop Ac brick and one just failed outright. Cheap, mass produced Chinese tat, all were filed under B/I/N.

I'd say stick with a quality PSU.
 
DunK1 said:
Depends your car battery. Say if it's 100 Amp hours. It can provide a current of 1 amp for 100 hours.

Average hair dryer say 2kW.

P=IV. 2000=I*230.

I= 8.7A.

100/8.7 = 11.5

So around 11.5 hours :p

Extremely simplified result. But long story cut short, you'll be fine :)
Click to expand...

It can provide 1A for 100 hours at the rated voltage of 12V, not 230V. It can only provide 1A at 230V for 5.24 hours.
 
Whats the amps on a average car batt?

Id never buy a electric item from chana, The last item I bought from abroard was a mp3 player and it lasted about a month.
 
Phil2008 said:
Whats the amps on a average car batt?

Id never buy a electric item from chana, The last item I bought from abroard was a mp3 player and it lasted about a month.
Click to expand...

It will say on the car battery you are using. But typically between 40-95Ah.

Simply multiply the voltage by the amp hour rating and you will get the watt hour rating.

Then you can divide the the watt hour rating by the devices power rating to calculate how long you can run something for.

So for a standard 12V 40Ah car battery it's 480Wh. Which would power a 1100W hair dryer for 26mins.

As you can see, running a hair dryer off a car battery is not feasible.
 
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