i new new to this forum and have a question about inverters. My husband and I are about to go on the road full time and wish to do a fair bit of free camping. We have a 22 ft caravan with duel batteries and 2 x 120 watt solar panels. We are not sure if we need an inverter or not . Any help and information will be greatly apricated.
We free camp wherever possible especially out bush.
Before anyone can reply we need to know battery capacity in amp hours (Ah) and what you would like to run with inverter,,, ie TV, set top box, VAST satellite box, Laptop, charge camera/phone batteries etc
Cheers Baz
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Why is it so? Professor Julius Sumner Miller, a profound influence on my life, who explained science to us on TV in the 60's.
I did have a pure sine wave inverter which I have now thrown out after it only lasted 12 months.
By that time I had adaptors to 12 volt for everything I use in the van. No point using a battery to an inverter which is changing it to 240 whereas a 12 volt battery stays at 12 volt. I have 12 volt points in the van and it all works fine.
As Baz said you need to think about what you want to run off the inverter - eg: what will you use that runs from 240v.
For your laptop - I highly recommend getting to somewhere like Jaycar and buying an in-car charger for the laptop and charging it as you drive along. Laptops can be a major source of power drain.
So, let's say you are set-up for the night and you have the TV going, laptop charging and maybe a camera as well. Add the wattage of all those items together. For example sake let's say you came up with a total of 500 Watts. It would be wise to buy at least a 800 or 1000 Watts Pure Sine Wave inverter to cover your power needs and surges. PSW inverters are not cheap so think carefully if you can get away without using one.
I have a small 300 Watt unit just for charging the cameras at night if needed (they are usually charged on the go in-vehicle).
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Stewart www.vkportable.com.au www.forums.vkportable.com.au
As Baz said you need to think about what you want to run off the inverter - eg: what will you use that runs from 240v.
For your laptop - I highly recommend getting to somewhere like Jaycar and buying an in-car charger for the laptop and charging it as you drive along. Laptops can be a major source of power drain.
So, let's say you are set-up for the night and you have the TV going, laptop charging and maybe a camera as well. Add the wattage of all those items together. For example sake let's say you came up with a total of 500 Watts. It would be wise to buy at least a 800 or 1000 Watts Pure Sine Wave inverter to cover your power needs and surges. PSW inverters are not cheap so think carefully if you can get away without using one.
I have a small 300 Watt unit just for charging the cameras at night if needed (they are usually charged on the go in-vehicle).
Good advice above.
As another practical example we run 19" TV, Vast OR set top box and Laptop on a 200W modified sine wave inverter. Draws about 150 watts OR 5-6 amps DC (depending on battery voltage obviously) with 3 on.
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Why is it so? Professor Julius Sumner Miller, a profound influence on my life, who explained science to us on TV in the 60's.
I seem to get by OK with an 800 watt inverter, usual usage ie laptop, TV. But inverters also draw power, I was advised that .1 of an amp per 100 watts, so my 800 watt inverter draws .8 amps per hour.
I hate to tell you this, but 150 watts @12v is 12.8 amps,depending on what voltage is in the battery.Even at 13+volts its over 10 amps.Volts devided by watts equals amps. Sorry, but its just maths. Bill
I hate to tell you this, but 150 watts @12v is 12.8 amps,depending on what voltage is in the battery.Even at 13+volts its over 10 amps.Volts devided by watts equals amps. Sorry, but its just maths. Bill
Yes Bill no need to be sorry. I plug ammmeter into circuit to measure,,, maybe it wasn't charging laptop battery when I did it, so not drawing th full 150 w I'll rechack as we are home tomorrow and heaps to do around the van.
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Why is it so? Professor Julius Sumner Miller, a profound influence on my life, who explained science to us on TV in the 60's.
The rule of thumb when using an inverter is to divide the power consumption of your 240 V device by 10 V and not 12 V. Using the figure 10 takes your converter and battery lead losses into account.
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PeterD Nissan Navara D23 diesel auto, Spaceland pop-top Retired radio and electronics technician. NSW Central Coast.
I was told a quick "rule of thumb" when doing calcs to run 240V appliances from an inverter is to take the wattage of the appliance and shift the decimal place.
e.g. An 1100 W microwave would use (drop the last zero) about 110 amps. So if you zap a meal for 15 minutes (1/4 of an hour) - figure on dragging your battery bank down by about 110/4 = as close as makes no difference to 28 amps.
You want to size your battery bank to NEVER drag them below 50% of their capacity. That is, if you have 200 amps at your disposal, do not drag more than 100 amps out of them as you may damage them or shorten their life.
I know, this will offend the purists, but it works for me.
BTW: I run a PSW 2500W inverter that runs an automatic coffee machine that drags 1600W to heat the boiler. I can make two cups of coffee for myself and my wife (four coffees) each morning which my solar array replenishes during the day.
I also can run the toaster if I sleep in and allow the bank to recover from the overnight drain. Makes us a nice quiet neighbor in the mornings
Hope my ramblings make sense.
Cheers
TC69
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