Putting inverter near Battery

[markland]

Thanks all for you helpful knowledge!

now got two 12v ports and i'll see how i go with that.

One more question... should i have a fuse between my main (under bonnet) battery and the relay? theres a fuse between the leisure battery and leisure fuse box. I have an unopened inline fuse holder but the wiring of it seems unsubstantial compared to that of my twin core battery cable which is very thick.

 

[sparrks]

Thanks all for you helpful knowledge!

now got two 12v ports and i'll see how i go with that.

One more question... should i have a fuse between my main (under bonnet) battery and the relay? theres a fuse between the leisure battery and leisure fuse box. I have an unopened inline fuse holder but the wiring of it seems substantial compared to that of my twin core battery cable which is very thick.

Whenever taking a feed/connection off of a battery it should always go through a fuse first.

 

[big tom]

1 amp at 12volts = 12 watts
1 amp at 240 volts = 240 watts

13 amps at 240volts = 3120 watts
13 amps at 12 volts = 156 watts

OHMS Law W V
A V A R

A TV using 35 watts at 12volts will take 2.9 amps
A TV using 35 watts at 240 volts will take .14 amps or 140ma

So to take 3120 watts from a 12volt battery you would draw 260 amps.

 

[rugbyken]

Can't give the technical reason I'm afraid but my inverter certainly drained my battery although it was switched off I went back to maplins and was advised to disconnect the crocodile clips or if wired in to fit an inline isolator between battery and isolator, did the latter & haven't had a problem since.

 

[Tbear]

Can't give the technical reason I'm afraid but my inverter certainly drained my battery although it was switched off I went back to maplins and was advised to disconnect the crocodile clips or if wired in to fit an inline isolator between battery and isolator, did the latter & haven't had a problem since.

The trouble with equations is that they do not take into account bad connections, small poor quality wires (resistance), leaks to earth etc. You can use a lot more electric than the sums tell you. Then add in less than perfect, cold batteries. You begin to understand why some folk have 300+Ah battery banks. As we do mainly short stays moving often, it does not seem worth the extra weight. So we use the minimum amount of electricity. We have one member that has fitted gas lights it his van.

Our inverter is buried at the back of a cupboard. Not used it since we changed from Laptop to Tablet.

Merry Christmas All

Richard

 

[WitchyOne]

Excuse me for popping in. The piece of kit Francophile1947 posted –

90w LAPTOP MAINS & CAR POWER SUPPLY 5000ma 5A 12-24v with 12v cig lead & 240v | eBay

Has anyone else used it? Would anyone else recommend it?
I use a small inverter, plugs into cigarette lighter and has 1 socket for a 3 pin plug, to charge either my laptop or mobile phone whilst driving.
Would I be better with something like this? I get confused trying to research and compare these things as I don’t really understand them and this looks as though it’s a bargain

 

[vespalien]

Excuse me for popping in. The piece of kit Francophile1947 posted –

90w LAPTOP MAINS & CAR POWER SUPPLY 5000ma 5A 12-24v with 12v cig lead & 240v | eBay

Has anyone else used it? Would anyone else recommend it?
I use a small inverter, plugs into cigarette lighter and has 1 socket for a 3 pin plug, to charge either my laptop or mobile phone whilst driving.
Would I be better with something like this? I get confused trying to research and compare these things as I don’t really understand them and this looks as though it’s a bargain

What is the input voltage of your laptop (or whatever device) you want to run? If it is 12v as many are these days, just buy a 12v plug & lead with enough capacity for the rated device current. You only need something like that if you have a non-12v device. I have not bought a none 12v lappy for years & all the phones & notepads etc run off 5v USB leads nowadays. 12v to 2xUSB plugs can be had for a pound or two & will reduce the load on your battery as far less losses than an inverter plus a transformer.

 

[sparrks]

What is the input voltage of your laptop (or whatever device) you want to run? If it is 12v as many are these days, just buy a 12v plug & lead with enough capacity for the rated device current. You only need something like that if you have a non-12v device. I have not bought a none 12v lappy for years & all the phones & notepads etc run off 5v USB leads nowadays. 12v to 2xUSB plugs can be had for a pound or two & will reduce the load on your battery as far less losses than an inverter plus a transformer.

Most laptops seem to be 19v nowadays

 

[vespalien]

Most laptops seem to be 19v nowadays

I wouldn't buy one that wasn't 12v, not had a problem finding them so far.

 

[maingate]

Maplin sell a 12 volt charger/power supply for laptops and netbooks. I have used one for a few years now. The output voltage can be set to a variety of voltages to suit the laptop. As has been said, many are 19 volts these days.

 

[sparrks]

I wouldn't buy one that wasn't 12v, not had a problem finding them so far.

Why?

 

[vespalien]

Why?

No need for any inefficient and expensive converters of any sort, just plug straight into 12 supply. Electronics today is generally designed well enough to cope with minor fluctuations, especially with the device battery in circuit too.

Why buy something that needs extra gear to make it work?

 

[WitchyOne]

Thanks ever so much for replying, it's kind of you but I have to admit I was lost after the first couple of sentences. My fault but I just don't 'get it'

I THINK the voltage of my laptop is 19v. I've no idea what it is for my mobile and don't know where to look to find out.
Giving it more thought, and reading a few more posts, I think I'm going to carry on as I have been doing with my little inverter. The laptop and mobile I tend to charge most times I'm out and about - I use my phone as satnav - but occasionally it's been handy to be able to plug other things in as in the time we had a power cut indoors and I was able to plug my printer in in the van. During the hot weather I've been able to plug in and use a small desk top fan to help keep the dogs cool and a small table lamp when I knew I was going to be parked up for a while in the dark.

My van isn't a 'proper' camper van it's mine and the dogs run-around that we shuffle about to suit whatever it is we're doing that day, hence I don't know very much about technical stuff like electrics.

Thanks again though, much appreciated

What is the input voltage of your laptop (or whatever device) you want to run? If it is 12v as many are these days, just buy a 12v plug & lead with enough capacity for the rated device current. You only need something like that if you have a non-12v device. I have not bought a none 12v lappy for years & all the phones & notepads etc run off 5v USB leads nowadays. 12v to 2xUSB plugs can be had for a pound or two & will reduce the load on your battery as far less losses than an inverter plus a transformer.

 

[Exu]

??? That is scaremongering. V=IR. A tv using 35 watts will use 3 amps + the losses in the inverter. An amp is an amp is an amp, whether it is drawn from the mains or a battery. Do not worry.......
John

Yes an amp is an amp BUT what stays constant is the power (watts), not the amps, the relevant equation being W= IV. So if the TV runs off the mains at 240 volts and consumes 36 watts then it would draw only 0.15A. If the inverter was 100% efficient then at 12 volts, as you say, the inverter will draw 3 amps from the 12v battery - however of course it is not 100% efficient so the current drawn will be a bit higher than that.

But for running things like computers it can be much more important to know if the waveform that the inverter produces is pure sine wave and if not (and the cheaper ones will not) then can the computer be damaged by all the harmonics?

 

[Exu]

I THINK the voltage of my laptop is 19v. I've no idea what it is for my mobile and don't know where to look to find out.

My Laptop is a Dell and, like yours, has an input of 19v DC. Like you I use an inverter for it. The fact that it is a cheap inverter that produces a lot of harmonics is taken care of by the power supply unit that isolates the laptop from them. However it is, I think, possible to buy a 12vDC to 19v DC converter from Dell, if you so wish.

Many mobiles nowadays seem to use a USB cable (both of ours do) so have an input of 5v DC. If yours is one like this then USB power supply units that plug into a 12v cigarette lighter socket are cheap and widely available - and are what we use now (we also use them for our Kindles). If your mobile is different then the power supply unit will probably have the output voltage marked on it - but in any case you can use the inverter (as we used to do with our older mobiles).