# 800w Pure Sine Inverter- Cables/Fuse/Switch?



## Addie (Aug 5, 2008)

Hello,

Recently picked up a 800w (1600w peak) Pure Sine Inverter off eBay, it will only be used to power my girlfriends hair dryer for circa 5 minutes every other morning (we've tryed every 12v method going, no good!). We move on every couple of days so no worry about it draining the battery.

I'd like some recommendations of guage of cable, size of fuse and holder and seperate 12v switch (is it best to connect via relay?).

Thanks in advance 

Adam


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## Jezport (Jun 19, 2008)

It will need to be fitted next to the battery with as thick cable that will fit into the terminals on the inverter. The inverter will have internal fuses and no relay is required. Also make sure you have a good heavy duty battery.

BTW you could have uses a modified sinewave inverter to run a hair dryer, my wifes runs fine on one.


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## clive1821 (Mar 27, 2010)

UUmm yes, the curent it would take will be around 80 amps at max, (the rated value of the inverter) so you'll need cables of around 20mm at least, and mounted next to the battery, and a means to switch the inverter on and off, I my view....


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## Addie (Aug 5, 2008)

Jezport said:


> It will need to be fitted next to the battery with as thick cable that will fit into the terminals on the inverter. The inverter will have internal fuses and no relay is required. Also make sure you have a good heavy duty battery.
> 
> BTW you could have uses a modified sinewave inverter to run a hair dryer, my wifes runs fine on one.


Seemed to be a bit hit and miss with hair dryers and hair straightners and modified sine units. I haven't managed to get either to run on the units I have at present.

I only paid £40 for this unit (it was wrongly described).

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=140474195385

Something like that - just need a decent switch as they can sometimes draw current even when turned 'off'.


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## Jezport (Jun 19, 2008)

Yes with straightners you can have problems. Are you sure it is pure sinewave as at £40 i would place an order for a few.


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## clive1821 (Mar 27, 2010)

Yes 35mm cables will be fine.... ebay might help you as well for the switch, just think on the battery you have, it must be fully charged and when the unit is running say with your hair dryer make sure the battery volts don't go below 12.3 volts at that level the battery is not able to supply the current required, you'll need at least 150AR battery to drive it... I hope that helps


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## Addie (Aug 5, 2008)

Jezport said:


> Yes with straightners you can have problems. Are you sure it is pure sinewave as at £40 i would place an order for a few.


http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=220686236684

Arrived in 4 days after purchase by Fedex, was pretty impressed to be honest.


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## captmike (Sep 30, 2008)

Just one extra point. If you have more than one domestic battery feeding the inverter as many MHs do, make sure the cable joining the batteries is the same size as the inverter feed cable.

Cheers,

Mike


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## peribro (Sep 6, 2009)

captmike said:


> If you have more than one domestic battery feeding the inverter as many MHs do, make sure the cable joining the batteries is the same size as the inverter feed cable.


That's an interesting tip and something that hadn't occurred to me. I have two 110A batteries connected to each either through a relatively thin wiring loom and each protected by a 20A fuse close to the terminals. I have a 1000w inverter connected directly to one of the batteries with a much thicker cable and protected by a 200A fuse. The inverter is generally used for only small loads when not on hook up but once a day it will supply 700watts for 10 minutes or so. Obviously it will be draining the batteries unevenly but I imagine that the charge between the two batteries will then balance itself. Is it likely that any damage will be caused by the batteries discharging at an uneven rate? I appreciate that there is a danger of draining one battery down to say 50% of its remaining charge without that being apparent from the control panel that is presumably giving the combined charge status.

ps - I'm not trying to hijack the OP's thread as I think that this question could be relevant to his original question


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## sallytrafic (Jan 17, 2006)

peribro said:


> captmike said:
> 
> 
> > If you have more than one domestic battery feeding the inverter as many MHs do, make sure the cable joining the batteries is the same size as the inverter feed cable.
> ...


I think you have answered your own question. When you have batteries in parallel its always best if they are treated the same. Some even go so far as to take the positive feed from one battery and the negative from th eother to improve matters still further.

If the OP wants a switch a 100A battery isolator (around £20) would do the job


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## CliveMott (Mar 10, 2008)

CaptMike is perfectly correct. Also you should put a visible indicator in the van to warn you that the inverter is switched ON as even without any load on it the quiescent current will discharge a battery in not too many hours. Suggest a built in extension lead to put a dedicated socket in a convienient place and use one of those sockets with a built in neon indicator.

C.


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## pippin (Nov 15, 2007)

Adam - the one piece of info that you have not given is the wattage of the hairdrier.

PS

It might be cheaper/easier to get a new girlfriend.


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## Addie (Aug 5, 2008)

Just a quick bump to this thread in case anyone can help me.

I'm wiring the inverter up to my cab battery (fitted under passenger seat) and found decent cable quite expensive.

Is there anything wrong with buying a pair of jump leads and cutting the end off and using the cable gripped and heat shrunk into 50mm cable lugs?

I was going to install an isolation switch in the form of a 12v isolation key switch just to turn it totally off so it won't draw any power.

It won't be used very often, just for Sophie's hair dryer when the engine is running!

Cheers


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## scottie (May 11, 2005)

Addie said:


> Just a quick bump to this thread in case anyone can help me.
> 
> I'm wiring the inverter up to my cab battery (fitted under passenger seat) and found decent cable quite expensive.
> 
> ...


Hi Again

I went to Maplins and bought my wire from there,good quailty,plastic coated,very flexible,not the cheapest wire on the market ,but far better quality than jump leads ,to get the same or near same you would need to buy very good quality commercial jump leads.
that is what I bought for the inverter you sold me.I bought a roll end bit about 1.5m red and 1 m brown,no black if, i remember it cost around 12.00 
scottie


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## Addie (Aug 5, 2008)

Hi Scottie,

Hope all is well. That's good to know, I've been leaving this job until last!

Cheers,

Adam


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