# Inverters



## aldra (Jul 2, 2009)

We need to get an inverter fitted, 

The ? is how powerful For example we have two electric bikes so do we need to double the power required to charge one if they are put on charge together. If so do we need to add up all the bits and pieces Kindles ect to determine the power needed?

The Hymer has an 1800 inverter which we tended to use only when the van was travelling although we did have 1600 Solar panels

Our present van has a 1200 solar panel

I seem to think that inverters use a lot of power in relation to their output so would it be better to have two smaller inverters to use independently?

Aldra


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## DABurleigh (May 9, 2005)

To answer your questions, yes and maybe. Read the members' guide on Inverters.

Dave


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## TR5 (Jun 6, 2007)

I find it surprising the number of people who fit inverters just for charging phones, laptops, kindle's, camera batteries, etc., all items that can be charged from 12v sockets.
I have fitted a triple 12v c. l. socket in the hab area, and another in the cab. 12v chargers are smaller, easier to store, and no worry about inverter drain during use.
Also very handy if required in another vehicle.

I fully understand the principle of having a mains inverter, if no alternative is available and mains really is required, but not if it is only for charging items that have more compact 12v chargers!

Am I missing something?


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## peribro (Sep 6, 2009)

aldra said:


> If so do we need to add up all the bits and pieces Kindles ect to determine the power needed?


Effectively yes, taking into account how long you think you will be charging / running each appliance for. You also need to build in some headroom (at least 10%) due to inverter inefficiency. Also watch out if any appliances have initial high start up power consumptions. You also need to think about the size of the batteries. There's no point in going for a large inverter to run x,y,z appliances if the batteries are going to discharge down (to about 50%) before the running / recharging has been achieved.


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## jud (Aug 15, 2009)

aldra said:


> We need to get an inverter fitted,
> 
> The ? is how powerful For example we have two electric bikes so do we need to double the power required to charge one if they are put on charge together. If so do we need to add up all the bits and pieces Kindles ect to determine the power needed?
> 
> ...


hi aldra .we have 2 e-bikes 36volts and a 2000watt inverter which we run all sorts of things sky + h.d box -vacuum cleaner- t.v- microwave - (electric blanket only when on the move ) but i have never tried to charge things through the inverter i am no techno but i seem to remember some where that it could damage the chargers they can only be plug in to the mains . if i am wrong please tell me . i once damaged a cordless drill trying to charge it from a generator .jud


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## geraldandannie (Jun 4, 2006)

TR5 said:


> Am I missing something?


I think so. When I buy a piece of portable equipment, it comes with a mains charger. I don't need to buy separate 12V chargers for everything.

We do have a 12V iPod charger, which we use for the iPod which contains our audio books for when we're driving along.

When we go away in the van, I have a "techie bag" (i.e. a computer bag), which contains computer plus all the various chargers from home.

I think this might be a Marmite thing - you either can't stand the thought of charging stuff via an inverter, or you do. For us, the £40 investment in an inverter several years ago was definitely worth it. Laptop, iPods (several), shaver, camera batteries (2), phones (2), Kindles, and anything new which comes along in the future.

Gerald


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## jud (Aug 15, 2009)

aldra said:


> We need to get an inverter fitted,
> 
> The ? is how powerful For example we have two electric bikes so do we need to double the power required to charge one if they are put on charge together. If so do we need to add up all the bits and pieces Kindles ect to determine the power needed?
> 
> ...


hi aldra. i have been on to my e-bike supplier and he says normally the e-bike chargers are 500watt and to charge them from an inverter at least 1000watt its o/k .jud


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## tulsehillboys (Jul 22, 2010)

geraldandannie said:


> TR5 said:
> 
> 
> > Am I missing something?
> ...


Vast majority of devices will charge from a usb socket these days.

http://www.google.co.uk/products/ca...=X&ei=RBzVTv7oIs7bsgaXxunIBQ&ved=0CIUBEPMCMAA

£4 and will charge nearly anything (often with the usb cable supplied with the charger) and no wasted energy in the (inefficient) process of 12v->240v->9v


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## peribro (Sep 6, 2009)

tulsehillboys said:


> Vast majority of devices will charge from a usb socket these days.


 That's probably fine if all you want to do is charge devices. In our case we use a number of devices that are not rechargeable and can only run off the "mains" - hairdryer, slow cooker, microwave etc etc. There are also some devices that are rechargeable but will draw too much current through a normal 12v socket, I believe.


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## Addie (Aug 5, 2008)

geraldandannie said:


> I think this might be a Marmite thing - you either can't stand the thought of charging stuff via an inverter, or you do. For us, the £40 investment in an inverter several years ago was definitely worth it. Laptop, iPods (several), shaver, camera batteries (2), phones (2), Kindles, and anything new which comes along in the future.
> 
> Gerald


I don't think it is a 'marmite' issue but rather one of economy / battery saving. You can upgrade your batteries / add solar etc or you can use the power you have more efficiently and reap the rewards.

Our 12v Laptop charger was £7, 12v camera battery charger £3 off eBay and a cig-lighter to USB adapter which charges everything else. 12v > 240v > 19v makes no sense in a lot of cases and too many people (not necessarily yourself) fall foul of seeing an inverter as a magic box to solve all power problems when there are better solutions to make the best of you available battery capacity.

Many laptop chargers buzz loudly and overheat on an modified sine inverter, we lost two before we switched to 12v chargers. The only thing we use an inverter for is a hairdryer (when the engine is running) - the majority of other devices can be charged directly from 12v and give you more hours of usage then inverters.

In answer to you question, Aldra, I would look at what devices you must use an inverter for and try and get one rated about 25%-50% higher then you maximum anticipated load. We have a 2100w unit to power a 1500w hair dryer.


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## tulsehillboys (Jul 22, 2010)

Slow cookers are available in 12 v
But a pressure cooker on the hob will do the same job in minutes.
Microwaves are sometimes handy but it you want to use one at will without EHU you need a big sine wave inverter. By all means if that is your bag - just not for me!


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## Antonia (Apr 27, 2008)

*Charging off invertors*

Hi folks

Many chargers these days are switched mode chargers as they tend to be smaller, lighter and cheaper than the old heavy duty transformer regulator types. Laptop, ipod/pad and TV ones are switched mode.

Techie stuff
(The way they work of to increase the mains opperating frequency electronically way above the normal 50Hz in order to utilise much smaller, cheaper and lighter ferrite ring transformers. The reduced voltage is then rectified, regulated and smoothed. )

If, you use a cheaper invertor these switched mode power supplies will receive a VERY dirty ac wave input which can make it very difficult for the switched mode adaptors to function correctly.

To use an invertor on these or any other hi tech electronic equipment you should use a good quality sine wave invertor, these are quite expensive however.
The previous posters are correct, run electronics from 12v.
Run fridges, hairdriers, straightners, tongs, drills, pumps and the like from cheaper modified invertors.

Regards

Antonia


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## aldra (Jul 2, 2009)

Well, that's given us plenty to think about

Thanks to all of you

MHF is certainly great to harness the power of advice from those in the know

Aldra


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## Yaxley (Jul 25, 2008)

Hello Aldra
I use a 200w Pure Sine Wave Inverter wired directly to the battery with an inline fuse. I have three 110AH leisure batteries and 80w solar panel.
I use it to power the TV and satellite decoder. Also the laptop, DVD drive and to charge the mobile phones, shaver, small batteries, kindle etc etc. We have also charged the batteries for 2 elec bikes(which we no longer have).
We do not have a microwave, hair dryer or elec blanket.
I believe that there are issues with modified sine wave inverters and some electrical items such as laptops.
Hope this is of some help.
Ian


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## HurricaneSmith (Jul 13, 2007)

We've just bought an electric bike from A.S. Bikes and they suggested a 300watt modified sine inverter, costing only £30.

I'll use it to charge the bike's battery whilst driving as I rarely stay longer than a couple of days at any one site.

Everything else needing charging will come out of the van's power outlet socket.


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## aldra (Jul 2, 2009)

I don't use haidryers, microwave or heavy draining elec equip

I do carry a small pressure cooker- fantastic quick and economical

Its mainly the bikes that I would want to keep charged, need power assistance these days  Those and the kindles, must have my books. Only use the TV on hookup

I have a remoska when on hookup and also a slow cook pot

Ill look into the 300w inverter but we need to charge two bikes so does that mean two inverters? or one larger one

Aldra


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## DABurleigh (May 9, 2005)

The answer is to read and understand the MHF inverter guide to which I referred you much earlier in the thread 

Dave


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## aldra (Jul 2, 2009)

Aldra


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## aldra (Jul 2, 2009)

Please Sir

I cant find the guide

Aldra


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## aldra (Jul 2, 2009)

No wait, Eureka 

I've found it so now Ill try to understand it 8O

Aldra


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## Yaxley (Jul 25, 2008)

Aldra
Now that you have found the guide maybe you would tell me where it is as I cant find it.
Ian


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## alphadee (May 10, 2009)

Neither can I


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## aldra (Jul 2, 2009)

Go to Resources (top right)
Click on articles -
thenMembers guides

Scroll down

Daves article on inverters is listed

Aldra


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## cronkle (May 1, 2005)

A link to the guide

http://www.motorhomefacts.com/ftoptitle-65101-inverters.html


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## jud (Aug 15, 2009)

aldra said:


> I don't use haidryers, microwave or heavy draining elec equip
> 
> I do carry a small pressure cooker- fantastic quick and economical
> 
> ...


hi . it depends on your bike batteries 24v or 36v ours are 36v and they say just under 500watts is needed to charge them .if you look at it this way buying small sooner or later its not big enough its the same with most things domes-sat dishes - solar panels -batterys and inverters even m/h's . get a 1000watt at least and don't get those small 1000watt ones on e-bay they are crap use maplins or similar .we charge our bikes en-route so when we arrive our batteries are full .jud


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## Yaxley (Jul 25, 2008)

Thank you Aldra and Cronkle
The reason that it is difficult to find is that the drop down box from 'Resources' is now so long that it is going off the bottom of my laptop screen. I cannot see the links at the bottom of the list. 
Ian


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## grizzlyj (Oct 14, 2008)

I wonder if you could get a TOAD?

ie a trailer with the front bikes wheel fixed and towed, the back wheels on the ground therefore charging the bike while driving the motorhome? 

Or a donkey and cart?


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## aldra (Jul 2, 2009)

Hi Grizzlyj,

My bike does not recharge from a running back wheel   

In Israel I had a donkey, used to take it into the Old City to carry back provisions-no cart, the streets are very narrow

Those were the days my friend

Aldra


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## jud (Aug 15, 2009)

aldra said:


> Hi Grizzlyj,
> 
> My bike does not recharge from a running back wheel
> 
> ...


hi aldra. i have been on that market many a time for them black puddings . these a guj in hyde that sells them now .jud


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## jud (Aug 15, 2009)

grizzlyj said:


> I wonder if you could get a TOAD?
> 
> ie a trailer with the front bikes wheel fixed and towed, the back wheels on the ground therefore charging the bike while driving the motorhome?
> 
> Or a donkey and cart?


 hi grizzlyj. you only charge the battery not the bike .jud


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## aldra (Jul 2, 2009)

Jud,

bury market is second to none

Well (whisper) maybe Bolton, depending on what you want

I hope those black puddings are the genuine ones, whole., plump and juicy, steamed or simmered to heat up

But I really meant the market in the old city of Jerusalem when I lived there nearly 40 yrs ago

Aldra


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## jhelm (Feb 9, 2008)

We have a non-sinewave 600watt inverter. I have an extension chord with 5 outlets that I shortened the chord on so it is attached to the wall just above the inverter which is connected directly to the leisure batteries - two 100 amps. We mostly use it to charge all our little devices, laptop, phones, razor, etc. and have never had a problem with any of these things. We also have a dvd player plugged into it which is pretty much the only 230 device we run off of it other than the chargers. 

As far as I understand it there is only a very small power loss within the inverter. We could use 12v chargers, but the cost of the one for the laptop is close to the cost of the inverter and then there would be the need to get 12v chargers for all the other stuff, so it's just easier. And any new device we get just plugs in.

Our tv is a 230v tv that uses a 12v converter/transformer so it is just hooked up directly to the camper 12v system. 

Maybe my point is that you don't necessarily have to spend a bunch of money on pure sine wave inverters, tv's specially designed for 12v, or a bunch of 12 chargers, etc.


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