Inverters

[Patriot]

Hi all,

I bought a cheapy invertor to run my laptop which needs 65 watts. I've plugged it in and all I get is a quiet ticking noise from the power supply

Does anyone have an suggestions/experience on a decent inverter?

Thanks

James

[Daz]

Got my inverter on e-bay. Its a 1200w modified sine wave type. It ended up costing about $180 and was a new item. Has been used only a couple of times and not on heavy consuming yet (most items 100-120w) but it works OK.
Hope this helps.

Daz

[jgcertified]

The ticking noise is the inverter cutting off from overload. I used to have a 120 watt inverter in my car, and when i ran a laptop off it (HP laptop, adapter needed 200-ish watts) the inverter would squeal

[BUSHNUT]

In regards to inverter, i would say that it may not be cranking enough juice to do what you are asking of it. I got one of those cheap Waecos 9 coke can Variety, it infers you can run a laptop on it, but it gets bloody hot, on asking around it indicates that it maybe allright for recharging batteries of the laptop but not running it direct. There is an old saying " It's generally cheap for a reason "

[Nickj]

bushnut. see PM sent.

[80landcruiser]

James

I don't have an inverter, but I do understand that you need an inverter with a sine wave. Whats a sine wave you ask? with any generators or power devices that produce electricity, it produces in "waves", if one was to graph it, it would look ike this high - low - high - low - high - low, like a roller coaster. These highs and lows can vary dramatically. With laptops, however, they require a constant, reliable flat line with very little variations.

Sherif

[aaronb]

It generally doesnt matter if its pure sine wave or not, as the transformer in the laptop power pack will still throw out the required voltage to run the computer. One thing to check when buying one is the watts, you need to make sure that this will run your power pack. With my laptop the input is 240v at 1.5 amps. Convert this to watts by multiplying the voltage by the current eg. 240x1.5= 360watts.
Just reverse it to work out the amps an inverter will throw out. eg. DAZ's unit 1200watts /240v= 5 amps

[tektrek]

Originally Posted by Patriot

Hi all,

I bought a cheapy invertor to run my laptop which needs 65 watts. I've plugged it in and all I get is a quiet ticking noise from the power supply

Does anyone have an suggestions/experience on a decent inverter?

Thanks

James

Without getting to technical, all computers (laptops, notebooks & desktops) have switched-mode power supplies to run all the various components within like disc drives, motherboard, monitor, modem etc. Switched-mode supplies run at efficiencies of 85% or better especially if the input voltage (220-240vac) is sine wave in frequency. Modified square wave/quasi wave power inverters have at best an efficiency of 60% due to their linear circuit design. They are cheap to manufacture, cheap to buy and should only be used for lighting, soldering irons and other resistive loads and power tools without electronic gear boxes. These inverters are rarely used in the UPS industry as they are considered too messy in output and unreliable for backup power systems especially with computers. They also interfer with anything containing a clock like microwaves, VCRs, DVD players/recorders, digital alarm clocks and so on.

The ticking sound you heard is most likely due to insufficient power entering the power supply from the inverter - ie the inverter doesn't have enough grunt and as the power power supply needs squeaky clean AC power it will go into overload trying to cope with the AC from the cheapy inverter. The overload is caused by the power supply circuit trying to start up to supply power to the laptop.

The simple solution is buy a sine wave inverter rated to at least 150 watts. This type of charger is kinder to your charger/power supply which could burn out if used with an inferior cheapy modified square wave inverter which you seem to have tried .

If you need more info PM or email me. I have been involved with DC-AC power inverters for over 20 years and use them in solar power systems I design and supply.

Good luck.

[BUSHNUT]

Originally Posted by tektrek

Without getting to technical, all computers (laptops, notebooks & desktops) have switched-mode power supplies to run all the various components within like disc drives, motherboard, monitor, modem etc. Switched-mode supplies run at efficiencies of 85% or better especially if the input voltage (220-240vac) is sine wave in frequency. Modified square wave/quasi wave power inverters have at best an efficiency of 60% due to their linear circuit design. They are cheap to manufacture, cheap to buy and should only be used for lighting, soldering irons and other resistive loads and power tools without electronic gear boxes. These inverters are rarely used in the UPS industry as they are considered too messy in output and unreliable for backup power systems especially with computers. They also interfer with anything containing a clock like microwaves, VCRs, DVD players/recorders, digital alarm clocks and so on.

The ticking sound you heard is most likely due to insufficient power entering the power supply from the inverter - ie the inverter doesn't have enough grunt and as the power power supply needs squeaky clean AC power it will go into overload trying to cope with the AC from the cheapy inverter. The overload is caused by the power supply circuit trying to start up to supply power to the laptop.

The simple solution is buy a sine wave inverter rated to at least 150 watts. This type of charger is kinder to your charger/power supply which could burn out if used with an inferior cheapy modified square wave inverter which you seem to have tried .

If you need more info PM or email me. I have been involved with DC-AC power inverters for over 20 years and use them in solar power systems I design and supply.

Good luck.

Can you give an indication of costing please

Bushnut

[rollywheeler]

A majority of 12/24v problems can be attributed to inadequacies in the supply lines and earth returns.
Voltage drop over undersized wires and poor connections can be quite considerable. There is often some confusion in the industry descriptions of wire sizes, e.g. an 'automotive' 6mm cable can have a core diameter of less than 4mm since the 6mm refers to the size of the total diameter inclusive of the insulating material. It's the cross section of the conductor that counts and a 50% reduction in diameter can produce huge voltage drop over relatively short distances.
Your average inverter is programmed to provide an audible warning when the input drops below a preset voltage and to shut off entirely at a slightly lower one.