Power Inverters

[syncropaddy]

Im looking to buy a 500w or 600w power inverter for the Syncro 25 trip in April. Anyone got one to recommend or one to avoid?

[axeman]

you planing on getting clamped and having to fire up a 4inch angle grinder and grind off the padlock over in germany?

neil

[v-lux]

Pure or modified sine wave?

[syncropaddy]

Modified sine wave will do. Its main function will be charge batteries for cameras, laptops, phones and power one or two other devices

[Mr Bean]

Maplin usually do good deals and I can't remember who but I recently saw someone is doing a 300W for something like £19.99. I use a 300W job for my internal mains slimline flourescents and also charging stuff. I find this adequate with a fairly low quiescent (off load) current. I assume this current would be higher on the bigger models and apart from a quick burst for a microwave for instance you may find the batttery current renders the big ones a no-no for any decent load. (1Kw at 12V = 1,000/12 = over 80Amps even at 100% eficiency says he probably teaching granny to suck eggs))
Regards
Wolfie

[boatdog]

hi i got my 600w inverter from maplins think it was 40 quidish works fine will surge to 1000 w for short periods runs a colour tv and all the other bits and pieces no problem.
also not a bad size so it fits in a cupboard out the way

[lloyd]

Wolfe is right. 600 watts is 50 amps draw on 12 volt battery...

[v-lux]

I wouldnt like to go any larger than 300w's myself.

Nothing i use it for needs anything larger, occasional phone, laptop here and there, all low consumption stuff (aside from a mates better half sneakily plugging in some hair straighteners when i wasnt looking)

As for what to go for, i reckon most of the chinese stuff around is much of a muchness. I know various people who have various different cheapo ones and none of them have had problems. I bought mine from a guy on BY, its still running fine.

Just get a cheap one would be my recommendation, from somewhere like maplins where you'd be able to return it should it ever go wrong.

[dissy26]

Hello V-lux
Was it any trouble running the hair straighteners or did it work fine?
regards

[boatdog]

would 300 w be enough? i use a 14" colour tv and it trips my old 300w inverter out because of its start up load (yes i know buy a flat screen) i switched to a 600 w and it runs everything fine, one battery lasts about 3 days of camping with tv about 3 hours a day. i used to have a narrow boat with a 3000 w inverter could run a flymo hover mower off it but i had 5 110 amp batteries running it!

[v-lux]

Surprisingly, it did run the hair straighteners, took the battery down to a hideously low voltage though......

[lloyd]

The battery draw is based on how much power inverter has to produce.. IE if drawing 120watt it will use 10amp at 12volts + one more amp to invert the power. Most specs say 80%-90% efficiency. I've been told the more wattage the inverter is rated, the less efficient it is at low wattage use... IE a 600w inverter may use 20amp + 3amp to invert 240watt while a while a 300watt inverter may only use 20amp + 2amp. I have not been able to find any statistics to back this up.

I suggest used large wire and hooking directly to battery as cig plugs are rated for about 15amp max.

[Mr Bean]

We ran a PC together with some outdoor video downstream equipment on a 300W Maplin inverter which supports the statement that fairly modern equipment such as PC's etc are fairly tolerant to the somewhat non-sinusoidal (Square) waveforms generated by low end invertors. I would suggest that hair straightenners are fairly low wattage. Of course the off load current for a larger invertor is likely to be higher. You need to remember that a 900W mocrowave on a lower setting achieves this by a low frequency pulse width modulation (i.e. by turning it on and off) this means that on say the 300W setting it runs in short bursts at the full 900W which clearly would defeat a 300W inverter. Unless you want to restrict the use to low wattage stuff then you need to think carefully about how you connect to the battery as Lloyd suggests. In my opinion the only way is to hard wire it in very adequately rated cable and proper connector lugs and isolate it using a proprietary battery isolator when not in use. Faffing about with crock clips/jump start leads etc. is not a good idea. There is also a question about the rated output in current of your liesure battery. I am brave (some say stupid) when it comes to electrikery but this is one area I tend to treat with care. In my fairly limited experience experience and on the safety front the battery voltage doesn't have to drop by very much to switch the inverter off and into an irritating noisy alarm condition. So in few words if in doubt uprate the inverter but remember you don't get nothing for nothing.
Good luck anyway.
Wolfie

[syncropaddy]

Thanks for all the replies guys. Ill nip into Maplins when Im up in Dublin and get sorted.

[jed the spread]

Got a 400w in the westy, charges all your phones, computers and stuff without going out and buying a 12volt charger for all your shnizel.

jed