WildCamping - Electrics

hairytoes

Guest
As you may deduce from my dumb questions, I am in fact a complete Newbie!

Here's the latest offering:

When I am not connected to 240v, (which I intend to be for most of the time) do I need an inverter to run the laptop (watch the odd movie, upload pictures, connect to net if any WiFi).

Laptop is an IBM T42 Thinkpad. Input 100-240, Output 16v

If I can get 12v appliances, such as kettle - do they come with a cigarette lighter attatchment?

I doubt I'll use much leccy, I have a 80w solar panel & 115a lesuire battery, the lighting is flurescent tubes (8w, each). The water pumps are electric & I'm not sure about the water heater (hopefully on gas).

Is it just a case of going away for a few days to see what happens, or is there a method of predicting your consumption v's production of electricity?

I understand the laptop can be charged via the alternator with a maplins 20 quid charger.

Bit long winded & fragmented, apologies in advance - I'm not really all that technical, but I'm hoping to learn!;)
 
Hi there

An inverter is a useful piece of kit to have onboard if you are not plugged into the mains!! It sounds like your covered for keeping your leisure batteries charge up through you solar panel.. Working out the rough electrical consumption of you appliances can be reasonably straight forward by the following; Voltage X ampage = Wattage and consequently Wattage divide by voltage will give you the ampage.....

So if you add up the ampage consumption of the 240v appliances that you want use on a regular basis whilst not plugged into the mains 240v you should be able to work out what size inverter you need. i.e If you use TV (2amps), Satellite (2 amps) and the kettle/microwave (4amps) total 8 amps ( 8A X 240v = 2000W) you'll need a 2000w inverter. Remember you may not have to use all at the same time so you could just switch them on and off when needed. If you’re watching the telly, boil the kettle using gas!!!

My wife has a range of hair dryers and bits that she insists on bring out when we go away, so we need the 240v even if where not plugged in. There is a wide range of 12v gear on sale these days, but why have two different voltage hair dryers, kettles etc...

Anyway I hope that made some sense for you, there is a wealth of information and really knowledgeable folks on the site and I'm sure that they can add to what I put down.

All the best Andy.:)
 
Just remember every amp at 240v is 20amps at 12volts for the example of 8amps it would be 160amps at the battery
regards
Alf
 
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Output of my laptop is 4.5A (printed on back of power pack), so if I multiply this by 20 = 90A on the invertor.

So I need an invertor that can cope with 90A?

My Leisure battery is 115A, I doubt I'd get much from that if the laptop battery was dead.

I guess if I charge the laptop via the alternator whilst driving (next question, how do I do that?) I'll have enough power to watch a movie, using leisure battery - when laptop battery runs out.

Bloody complicated - I tell ye!:confused:

Can I plug the laptop into the invertor whilst the van is running & it'll charge from the engine?

A 150w invertor should do the job then.
 
Hi hairytoes
About the laptop; seehttp://www.wildcamping.co.uk/forums/showthread.php?t=5546
Thus have an adaptor 12V> 16V (if 16V is the imput of the laptop). If you use a convertor you go from 12V>240V>16V you have to convert twice.
You can load the laptop when the engine is running.
Don't try to put an electric kettle (or anything else converting electrical power into warmth) on 12V - the easiest way to have a flat battery in no time.
Leo
 
Belgian said:
Hi hairytoes
About the laptop; seehttp://www.wildcamping.co.uk/forums/showthread.php?t=5546
Thus have an adaptor 12V> 16V (if 16V is the imput of the laptop). If you use a convertor you go from 12V>240V>16V you have to convert twice.
You can load the laptop when the engine is running.
Don't try to put an electric kettle (or anything else converting electrical power into warmth) on 12V - the easiest way to have a flat battery in no time.
Leo
Click to expand...


Alright Dude!

Thanks for your reply, I seen the earlier part & did wonder about it - as my batpack from the laptop says it's input is - 100-240V 1.2A-0.5A 50/60Hz

Seems a long way from your average of 18V:eek:

My output is 16V = 4.5A
 
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Hi.

I think you are confusing yourself by assuming that it's more complicated than it really is.

First you must mental "seperate" you laptop from its power pack, the laptop requires an input of 16V, in order to run this from a mains supply you have a power pack, 100V - 240V input 16V output.

In order to gauge power usage use the formula Volts X Amps = Watts (power), therefore 4.5A X 16V = 72W.

However all electrical devises will use power so assume 20%:- 72W + 20% = 86W input power, (or approx 0.4A at 240v). Therefore a 150W inverter should do.

To achieve 86W output from an inverter again assume 20% loss, = 105W, or approx 9A at 12V. Therefore a power usage of 9AH per hour of use.

Please note these figures are VERY approximate but will hopefully help you to gain a rough idea of how much power you are likely to use, and should represent a max, i.e. 4.5A is the power pack max output, I doubt the laptop actualy requires that much.

That all said I must agree that a 12V to 16V stepper is the best course of action if you can source one.
 
For electrical items such as laptops try to use a 12v adaptor rather than an inverter. Otherwise you are going from 12v - 240v - 20v and incurring a power loss on the invertor as they are about 85% efficient (they do vary)

My laptop has input of 20v at 3.25A = 65W 65 / 12 = 5.41A at 12V

having run the laptop for several hours last week wilding in Scotland the current consumed by it varied between 3.7A - 5.1A depending on the load on the CPU

Paul

PS remember to remove the battrey if using for long periods connected to an external source, otherwise overcharging occurs and shortens the life of the battery.
 
hairytoes said:
Alright Dude!

Thanks for your reply, I seen the earlier part & did wonder about it - as my batpack from the laptop says it's input is - 100-240V 1.2A-0.5A 50/60Hz

Seems a long way from your average of 18V:eek:

My output is 16V = 4.5A
Click to expand...

Hi,
Laptops have an adaptor+wire to put in the 240V. It converts 240V AC to about 16 to 18V DC input for the laptop. (depending of the make -usually 18V DC) Have a look at the adaptor which V.
You should use a convertor 12V > 16 or 18V from the cigaret lighter and put it in directly in the laptop (they come with all possible connectors).
If you use an invertor 12V > 240V you will loose power like Sparks said.
 
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