PDA

View Full Version : Putting inverter near Battery



markland
24-12-2013, 10:22
Hi all converting a citroen relay into a campervan.

Ive built a box out of plywood under the passenger seat roughly 16" x 16" x 10" with lots of holes drilled for ventilaton to accomodate the leisure battery, fuse box for the ceiling lights and a cigar lighter.

Now ive left room for an inverter which i have not bought yet and will be permanently connecting it with ring terminals.

Am i ok to put the inverter inside the box or will there be flammable gases from the leisure battery?

vespalien
24-12-2013, 10:27
Do you really need an inverter? Most stuff will run off 12v these days & what can't is easily left behind. Inverters get hot because they are inefficient. Remember that whatever current is drawn out of the inverter at 240v, there will be over 20 times that current being sucked from the battery.

markland
24-12-2013, 10:33
Thanks for fast response.
All i will really need to run is a macbook pro which i also use for tv with a usb freeview. It would just be nice to be able to have the option to run other items.

Buy Silverline 263764 Inverter 700w at Argos.co.uk - Your Online Shop for Adaptors. (http://www.argos.co.uk/static/Product/partNumber/7154014.htm)
Inverter i will probably go for as it comes with terminals and not crocodile clips! will have to make a mount to keep it in place though.

francophile1947
24-12-2013, 10:41
Thanks for fast response.
All i will really need to run is a macbook pro which i also use for tv with a usb freeview. It would just be nice to be able to have the option to run other items.

Buy Silverline 263764 Inverter 700w at Argos.co.uk - Your Online Shop for Adaptors. (http://www.argos.co.uk/static/Product/partNumber/7154014.htm)
Inverter i will probably go for as it comes with terminals and not crocodile clips! will have to make a mount to keep it in place though.

Get one of these instead 90w LAPTOP MAINS & CAR POWER SUPPLY 5000ma 5A 12-24v with 12v cig lead & 240v | eBay (http://www.ebay.co.uk/itm/90w-LAPTOP-MAINS-CAR-POWER-SUPPLY-5000ma-5A-12-24v-with-12v-cig-lead-240v-/231049087456?pt=UK_Computing_LaptopAccessories_Pow erSupplies&hash=item35cb9949e0) - cheaper and more efficient:cool:

Siimplyloco
24-12-2013, 10:42
Do you really need an inverter? Most stuff will run off 12v these days & what can't is easily left behind. Inverters get hot because they are inefficient. Remember that whatever current is drawn out of the inverter at 240v, there will be over 20 times that current being sucked from the battery.

??? 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

noarlunga
24-12-2013, 10:46
Thanks for fast response.
All i will really need to run is a macbook pro which i also use for tv with a usb freeview. It would just be nice to be able to have the option to run other items.

Buy Silverline 263764 Inverter 700w at Argos.co.uk - Your Online Shop for Adaptors. (http://www.argos.co.uk/static/Product/partNumber/7154014.htm)
Inverter i will probably go for as it comes with terminals and not crocodile clips! will have to make a mount to keep it in place though.

Word of warning. I bought an inverter to run a couple of things including my MacBook Pro on my recent trip to Europe and the first time I plugged the charging cable in the computer didn't work. It hasn't worked since. On a previous trip I'd run the Mac successfully for three weeks on a 12v cable, using it to watch movies and use occasional wifi.

I don't know if it was the inverter that fried the computer or whether the lack of function was a coincidence but I wouldn't be tempted to try it when there is a 12v option available. Luckily my house insurance covered it and I got a replacement.

I'll try and find a link to purchase the 12v cable.

I'm completely 12v now, including the tv.

Johnny A

noarlunga
24-12-2013, 10:48
Here's a starting point.

http://www.amazon.co.uk/In-Car-Charger-MacBook-13-inch-Unibody/sim/B002LN67VK/2

J

markland
24-12-2013, 10:50
http://www.amazon.co.uk/In-Car-Charger-MacBook-13-inch-Unibody/dp/B002LN67VK/ref=cm_cr_pr_product_top

Seems good to me..

Think ill just see how i go with just the cigar lighter, prob put another in with a separate connection on the fuse box.

Just worried about putting the inverter inside same box as battery?

noarlunga
24-12-2013, 10:52
Get one of these instead 90w LAPTOP MAINS & CAR POWER SUPPLY 5000ma 5A 12-24v with 12v cig lead & 240v | eBay (http://www.ebay.co.uk/itm/90w-LAPTOP-MAINS-CAR-POWER-SUPPLY-5000ma-5A-12-24v-with-12v-cig-lead-240v-/231049087456?pt=UK_Computing_LaptopAccessories_Pow erSupplies&hash=item35cb9949e0) - cheaper and more efficient:cool:

Sadly that's not a solution for a MacBook Pro. As usual the solution is a special cable at a special price. :confused:

John Thompson
24-12-2013, 10:58
Make sure you have drop vents below the battery to allow any gassing to escape and not enter the living area.

We have a 2kw inverter mounted above the batteries and drop vents below the batteries. We only need the inverter for odd things like charging my shaver, Joan's Hairdryer or the blender. Everything else electrical we run direct from the batteries at 12v. The leads from the battery to the inverter should be as short as possible to avoid losses.

I agree with you keeping the batteries at room temperature, as they are rated at 25c and lose power as the temperature drops.

I have the van wired with 2 mains circuits one powered by the EHU and the other from the inverter. I fitted caravan type cream sockets for the inverter circuit and while domestic ones for the mains hook-up.

John

Caz
24-12-2013, 10:58
I have a 300W inverter which I bought about 9 years ago and I have rarely used it. It is quite noisy, (modern ones are probably quieter and cheaper), but for most things there is a 12v plug option anyway.

To my naieve way of thinking - if a thing is so power hungry that it only runs on mains then it will probably take too much out of my battery anyway so I won't use it unless on EHU. For example the leccy kettle, fan heater, multi cooker, hairdrier ...............

Tallyman
24-12-2013, 11:18
Hi we're new on here and usually just read the posts, but couldn't resist sharing our experience with an inverter we had been advised to buy from a well known electronics store to run our laptop ( marine charts) on our boat .
It was our first night sail and with just a few navigation lamps , depth and the laptop running , the battery went flat an hour out of port the new alternator couldn't keep up with the power drain and went into meltdown and we had to rely on our rusty navigation skills heart in mouth to reach our destination . Still have nightmares so as non expert lay people we would stick with good old 12 v :-)

Andys
24-12-2013, 11:27
Our inverter sits beside the batteries in a locker on the outside of the van. Never been a problem.

Siimplyloco
24-12-2013, 11:35
Our inverter sits beside the batteries in a locker on the outside of the van. Never been a problem.

As with most things, especially electronic equipment, you get what you pay for. The Victron Energie 24v/35A 1800W Inverter/Charger on my boat is 16 years old, is left on all year round, and never misses a beat or cooks batteries!
John

Tbear
24-12-2013, 12:03
Hi all converting a citroen relay into a campervan.

Ive built a box out of plywood under the passenger seat roughly 16" x 16" x 10" with lots of holes drilled for ventilaton to accomodate the leisure battery, fuse box for the ceiling lights and a cigar lighter.

Now ive left room for an inverter which i have not bought yet and will be permanently connecting it with ring terminals.

Am i ok to put the inverter inside the box or will there be flammable gases from the leisure battery?

Some batteries have a vent tube/hole so you can run a pipe outside the box. Very little hydrogen is given off, hence the very small bore vent tube, unless you boil (overcharge) your battery. Make sure all contacts are good so there is no sparking.

Richard

Bigpeetee
24-12-2013, 13:48
Remember, Hydrogen is lighter than air (hence hydrogen used in early airships) so ventilation holes in the bottom of a box will only expel hydrogen when the box is full of hydrogen and has expelled all of the air!!

However as stated, you have to be mistreating the batts to get severe gassing.

I have my 2kw inverter above one of the leisure batts with a wooden spacer between the two so that if the inverter became detached, it won't short circuit the battery if it dropped onto the lugs. Now that would be spectacular, but not for me.

I use ordinary starter batts with my large inverter as they will stand the shock of a hair dryer at 1.5kw.

The batts are now 4 1/2 years old and getting towards the end of life, but that means replacing 3 batts all at the same time. Not at Christmas!!

I use 12 for everything except hairdrying and microwave (long story!!)

rugbyken
24-12-2013, 14:13
After getting a flat battery from my inverter I purchased the keyed isolator fitted between the battery & inverter stops the resistance which drains the battery even when not being used , works Jan's hair drier and various other items that I usually forget the 12volt adapters for. I normally keep the key tied on the hair driers cable to remind me to turn it off.

Tezza33
24-12-2013, 14:19
After getting a flat battery from my inverter I purchased the keyed isolator fitted between the battery & inverter stops the resistance which drains the battery even when not being used , works Jan's hair drier and various other items that I usually forget the 12volt adapters for. I normally keep the key tied on the hair driers cable to remind me to turn it off.Mine is fastened on top of a laptop safe which is next to one of the batteries, I also use an isolator switch for the big invertor, we use it for a 900w kettle when travelling, hairdryer and microwave but I isolate it when it is not in use, if the battery level gets too low it also switches itself off to avoid damaging the batteries

markland
24-12-2013, 16:54
After getting a flat battery from my inverter I purchased the keyed isolator fitted between the battery & inverter stops the resistance which drains the battery even when not being used , works Jan's hair drier and various other items that I usually forget the 12volt adapters for. I normally keep the key tied on the hair driers cable to remind me to turn it off.

so even with the inverter's power switch in the off position it is still drawing power?

Siimplyloco
24-12-2013, 18:28
so even with the inverter's power switch in the off position it is still drawing power?

I think you'll find that the inverter draws a little power when it is switched on but not being used. IIRC this is called its quiescent current. It shouldn't use any when switched off.
John

markland
24-12-2013, 18:33
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
24-12-2013, 18:38
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
24-12-2013, 20:55
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
24-12-2013, 23:58
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
25-12-2013, 07:24
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
26-12-2013, 19:50
Excuse me for popping in. The piece of kit Francophile1947 posted Ė

90w LAPTOP MAINS & CAR POWER SUPPLY 5000ma 5A 12-24v with 12v cig lead & 240v | eBay (http://www.ebay.co.uk/itm/90w-LAPTOP-MAINS-CAR-POWER-SUPPLY-5000ma-5A-12-24v-with-12v-cig-lead-240v-/231049087456?pt=UK_Computing_LaptopAccessories_Pow erSupplies&hash=item35cb9949e0)

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 donít really understand them and this looks as though itís a bargain

vespalien
27-12-2013, 09:47
Excuse me for popping in. The piece of kit Francophile1947 posted Ė

90w LAPTOP MAINS & CAR POWER SUPPLY 5000ma 5A 12-24v with 12v cig lead & 240v | eBay (http://www.ebay.co.uk/itm/90w-LAPTOP-MAINS-CAR-POWER-SUPPLY-5000ma-5A-12-24v-with-12v-cig-lead-240v-/231049087456?pt=UK_Computing_LaptopAccessories_Pow erSupplies&hash=item35cb9949e0)

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 donít really understand them and this looks as though itís 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
27-12-2013, 15:10
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
27-12-2013, 15:23
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
27-12-2013, 15:50
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
27-12-2013, 17:32
I wouldn't buy one that wasn't 12v, not had a problem finding them so far.

Why?

vespalien
27-12-2013, 19:38
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
27-12-2013, 21:21
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
01-01-2014, 21:16
??? 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
01-01-2014, 22:11
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).


CLICK HERE TO REMOVE THESE ADVERTS