# Help needed with inverter setup



## jiwawa (Jun 22, 2007)

I have a 300W modified sine wave inverter that plugs into the 12v cigarette-lighter-type socket. I haven’t used it in over a year, mainly cos it’s a nuisance to set up and it makes my netbook whine.

However, over the summer we bought a couple of electric bikes and we will need the capacity to charge the batteries (2 at 300W each, apparently taking c.3.5hrs to charge). We also bought a Dyson rechargeable but I’m not so worried about charging that! (350W 3-hr charge)

We have a 130W solar panel and 2 x 125Ah leisure batteries. Reading online it would seem that with batteries, more is better, but we don’t really have the weight or space capacity to install more.

I also read that it’s much better to hard-wire the inverter than to use the 12v socket.

We pretty much full-time, and pretty much off-grid, so I’d like to get this right.

Do I go for a set-up where I can use the kettle (750W) and toaster (800W)? – though not at the same time. Do I have the normal 230V sockets wired into the inverter or do I just use the single socket on the inverter? – I’ve read there are safety issues with integrating the inverter into the current 230v system. I’m thinking that to power the toaster means I’d need to have 800W which would be wasted the vast majority of the time. I’ve also read that there’s a permanent leak of power as it’s always on and can’t be turned off?

We would like to use a 450W oil-filled radiator on cold nights.

Our leisure batteries are about 3.5m behind the transit battery which is under the driver’s seat. Am I better to charge, say, the bike battery ‘on the move’? Tho, having said that, we don’t drive a lot of miles at a time, maybe an hour or so.

You’ll have guessed that I’m totally at sea over this, and I’d be interested to know what set-up folks out there have, and how it works for you.

Many thanks.


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## rosalan (Aug 24, 2009)

I too have electric bikes AS Electrobikes and would have loved to charge them with an inverter and saved myself hooking-up costs. I was not confident that the cigarette socket would cope with the load sodid not take that route. Does anyone know if it would have been practical with a 300w inverter?

Alan


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## inkey-2008 (May 24, 2008)

Jww 
I would say you are expecting to much for your system to cope with, for get kettles and toasters/electric heaters.

You will need more solar panels and possibly pure sine wave inverter.

Some transformers don;t like the basic inverters.

I have recharged my mobility scooter on a good sunny day but you need to have your leisure battery fully charged before plugging something else in or you may find you run out of power in the evening.

Andy


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## bognormike (May 10, 2005)

I have a 300w inverter in my Hymer, but it's fixed next to the bench seat and wired directly to the leisure battery. I use it to charge up my devices, but nothing more. I think my daughter in law tried to run her hair dryer on it when they borrowed the van, and had blown the fuse! I think if you want to run some of those things you're going to need a decent bank of batteries, and of course it would be draining them pretty quickly. Maybe a gennie is needed (wash my mouth out!) if you're off grid that much - especially in winter.


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## wakk44 (Jun 15, 2006)

I have a 1500 watt modified sine wave inverter hard wired right next to a 270A/H Elecsol leisure battery,the inverter 12v leads are very short and large diameter,this is very important to avoid volts drop.On the roof is 180watt of solar panels.

This set up charges both electric bike batteries simultaneously whilst they are in the garage.It also charges the Dyson battery,Karcher battery,hair dryer(important) and will power the toaster or kettle if required.

I have separate 240v sockets powered by the inverter(4)so the 2 mains systems run side by side.However I have fitted a 240v socket(spurred off the original m/home fitted sockets)near the inverter so if we are on hook up I can simply remove the inverter 240v supply plug and plug it into the spurred socket.This means that the 4 dedicated inverter sockets can be powered from the ehu when we have one.Finally there is a remote control for the inverter fitted in a convenient position so I don't have to remove the seat cushions and get under the seats to switch it on. 

Hope it all makes sense,it's not as complicated as it sounds and it works well.Even with this set up I still prefer a ehu in winter as the solar panels give little output from Nov-March,the rest of the year I have electrical independence.The anomaly is though in summer when we don't need as much solar power there is a surplus of the stuff.


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## jiwawa (Jun 22, 2007)

Thanks for the input folks - I shall mull over the info. 

Yes, I'm inclined to think the kettle n toaster are wishful thinking tho Wakk44 gives hope!


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## coppo (May 27, 2009)

If you fulltime and don't drive far as you say then maybe a Sterling B2B is a good idea.

Paul.


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## jiwawa (Jun 22, 2007)

Wakk, it sounds as if you turn your inverter off when not in use. I'd that a special feature? I seem to remember reading that most couldn't be turned off n would always be in standby mode, pulling amps from the battery. 

Are your 4 inverter sockets spread round the van or is it like a 4-gang extension? 

When you plug the inverter sockets into the EHU do you then have the original sockets plus the 4 inverter sockets available? 

Do you charge your bikes on the move or in situ? 

Sorry for so many questions! I'm just trying to get my head round the problem.


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## Mrplodd (Mar 4, 2008)

Like any other appliance you can turn an inverter off so it draws NO power.

Mine is permanently wired to the leisure batteries (the 12v cigarette lighter supply isnt really up to driving an inverter with any half decent output) . just make sure you use hefty cables to prevent voltage drop between the battery bank and the inverter)

I have an inverter and 2 'leccy bikes. I usually turn the inverter on and charge the bike batteries whilst driving along!! the alternator provides more than enough output and it doesnt drain my leisure batteries (I also charge the bike batteries when parked up and there is bright sunshine,)

I would forget a toaster and electric kettle (thats what your gas cooker/hob are for) you will need a very high output inverter AND it will drain your leisure batteries very quickly.


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## jiwawa (Jun 22, 2007)

What size inverter do you use MrPlodd?


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## inkey-2008 (May 24, 2008)

jww 

If you want to charge both the bikes and the Dyson together then you will need a 1000 watt at least. but you could get away with a 400 watt if you do 1 at a time.

Andy


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## jiwawa (Jun 22, 2007)

Thanks inkey - I finally got round to trying the 300w with 1 bike battery on a beautiful sunny afternoon here in Donaghadee. 

It didn't like it and whined. It did manage tanking up a new hair trimmer. 

I'd probably want the capability of charging both bike batteries together - we'd been told we'd need a 600w for that. Not bothered about the Dyson - housework can wait! Our batteries are 36v 300w I believe.


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## kevanna1959 (Apr 5, 2010)

*dyson charging*

you can buy a 12v adapter to charge the dyson direct from the ciggy lighter to the dyson it cost £15.00 on ebay someone on here recommended it when we had problems.


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## inkey-2008 (May 24, 2008)

If I was you I would look for a pure sine wave 1000 watt unit wired direct to the battery, you will then have spare capacity. 

Andy


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## rod_vw (May 10, 2005)

A reply sort of half on and half off the topic.

I run a 300w inverter permanently wired but via a relay and fuse. The output is connected to a fixed CBE 13A socket via a short cable. The socket looks discreet and part of the fittings except for a sticker indicating a max load of 300w.

The CBE socket is modified with a microswitch embedded below the guard slide so that when a plug is inserted the switch makes. This in turn operates the relay so switching on the inverter.
This enables the inverter location to be near the battery thus keeping 12v cables short and volt drop down but not needing accessibility for switching on and off. It works well with a single socket outlet as all we have to do is remember to pull the plug when not using the supply.
The inverter could of course be larger with just the 12v cabling, relay and fuse capacity uprated as necessary.

Rod


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## jiwawa (Jun 22, 2007)

Thanks kevanna - I might do that. I believe the direct 12v chargers are usually more power-efficient than using an inverter to convert. 

Inkey, I did originally think higher would be better but I believe if you're using a 1000 inverter to charge something of 300w, then there's going to be a fair bit of waste? 

Rod, I like the sound of your setup. Our batteries are under the wardrobe at the foot of the bed so could be wired through the hidden wall to the cupboard under the bed. 

Another question - how much space is needed round the inverter when it's in such a location? My cupboards tend to be pretty stuffed!


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