# 600W inverter - installation and use



## timbop37 (Jun 28, 2006)

Hi everyone.

I know a lot of this is covered elsewhere but I have read through many posts (honest) and I am a little confused. I have 2 matching 85ah leisure batteries. I have a 600W inverter (from Maplin). Is it best to fit 1 terminal to 1 battery and the other to the 2nd battery (observing polarity of course!), or doesn't it matter? Further, is there a problem using the inverter when the leisure batteries are charging, either on hookup or via the engine running. I read a post that seemed to imply that there are conflicts to be aware of (Dave Burleigh). This has confused me somewhat. My small brain led me to believe that I could simply connect the inverter cables to the + and - terminals on one of the batteries and, hey presto, away we go.

Regards

Tim


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## deansquire (Jan 9, 2007)

*Invertor*

hello.

I connected our maplins 600W invertor to the car + and - terminals, through a 20amp fuse on the + cable side. The vehicle charges the invertor during driving, and it means we get to use the invertor to power laptops, or a small TV+DVD player, while driving, without affecting the leisure battery which powers lights, water pump etc. I added a plug on the invertor wires, and a plug on each battery, so if I really wanted to I could easily move the invertor over to the leisure battery at any time. Havent found a need to do that though.

;-)


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## timbop37 (Jun 28, 2006)

Thanks for the reply.

Was it just a case of cutting the + wire and putting in a standard fuse holder in between, with the 20amp fuse?

Tim


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## sallytrafic (Jan 17, 2006)

To get 600W out of an inverter you need at least 50A going in so 20A fuse and thin wires ain't going to do it.


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## timbop37 (Jun 28, 2006)

What do you suggest, Frank, and where do I get the leads? Can you get them without the crocodile clips ready made to fit permanently to the battery, with an inline fuse insitu? Do I need a 50a fuse?

Thanks

Tim


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## DABurleigh (May 9, 2005)

Tim,


timbop37 said:


> Is it best to fit 1 terminal to 1 battery and the other to the 2nd battery (observing polarity of course!), or doesn't it matter?


Yes, it is better in the general case. Whether it matters depends on the length and thickness of the interconnecting cables. This thread covers the same issue:
http://www.motorhomefacts.com/ftopicp-168474.html#168474



timbop37 said:


> Further, is there a problem using the inverter when the leisure batteries are charging, either on hookup or via the engine running. I read a post that seemed to imply that there are conflicts to be aware of (Dave Burleigh). This has confused me somewhat.


Every so often I have this feeling I confuse more than I help :-(
The answer is "no". To confirm this, you could look at the acceptable input voltage range spec for your inverter. If 14.4V up its spout is OK, it can't hurt. As you don't say which of my posts confused you, I can't attempt to correct/ resolve. I recall at one point wondering whether two simultaneous chargers would be a problem as together they might squirt more current into the batteries than desirable, but that's not your question at all.

I hope this is clearer 

Dave


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## pippin (Nov 15, 2007)

Do you need a 50A fuse?

Do you want a fire? 

Thought not, so 50A fuse it is!

You have to cater for the maximum current draw, even if you rarely, if ever use it to its full 600W capability.

You stated that you added a plug/socket arrangement.

I really hope that they are capable of handling 50A constantly otherwise they will melt, at best, or melt and burn and make a fire at worst.

Sorry to sound so doom and gloom but most people (including house-wiring type time-served electricians) do not appreciate the huge currents associated with low voltage wiring.

600W is nothing to a 240V ring main and 13A plugs and sockets.

Multiply that current draw by 20 for 12V and it takes serious cabling, fusing and plug/socketry to cope.

I would also add - why bother with the extra complications and inefficiency of an inverter when virtually all laptops, TVs, DVDs, and whatever will run from 12V with an adapter lead.


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## DABurleigh (May 9, 2005)

"why bother with the extra complications and inefficiency of an inverter"

How about these reasons?:

a) It's not complicated.
b) It's not inefficient (90-95% not good enough?)
c) One inverter does everything in one go.

Dave


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## pippin (Nov 15, 2007)

I have not changed my mind.

Gloves on at 20 paces then?!!


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## DABurleigh (May 9, 2005)

My wife's stubborn, too.

I just have to go away and read Mars and Venus again to the bit where it says "How DARE you deny me the right to feel the way I do?!!". And, though I always want to say "Um, because you're wrong?" I have learned to bite my lip.

At least you know Ohm's Law, though. Smack on with fuses 

Dave


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## Scotjimland (May 23, 2005)

pippin said:


> - why bother with the extra complications and inefficiency of an inverter when virtually all laptops, TVs, DVDs, and whatever will run from 12V with an adapter lead.


hi pippin .. 
No reason at all if you only have one or two bits of kit, but where it does get complicated when you have three laptops, three phones, two tvs, two digi boxes, two external hard drives, hair drier, .. etc etc

The point is that everyones needs are different and what is perfectly fine for one person is totally inadequate for another..

'one size does not fit all' :wink:


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## DABurleigh (May 9, 2005)

"when you have three laptops"

I suppose when one suffers from Mac delusions, such things are necessary ....

(cast, strike, reel in .....)


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## Scotjimland (May 23, 2005)

DABurleigh said:


> "when you have three laptops"
> 
> I suppose when one suffers from Mac delusions, such things are necessary ....
> 
> (cast, strike, reel in .....)


well, I didn't want to mention it for fear of ridicule, but it's actually four, I never boast about Jan owning a Dell 8O ..


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## timbop37 (Jun 28, 2006)

Ok. Thanks to everyone now that the fighting has stopped  

Dave, you said "when running the van off an inverter, automatically or manually, one way or another, you have to deconflict/switch hookup, genny, battery charger, fridge, electric water heater, electric space heater, etc." This is what confused me but I'm now thinking that you were referring to wiring it up properly to run everything off the inverter when not on 12v.

Also, then, just to clarify, what size cabling is required and where is best to get it, and the fuse holder, etc. I'm not a total muppet, I will be able to do the job, but just need pointing in the right direction. It's only difficult when you don't know. By the way, the inverter will be almost next to one of the batteries. If it easier and makes little difference then I will connect it up to this one only.

Regards, and thanks again,

Tim


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## timbop37 (Jun 28, 2006)

Got some cables today, 16mm x 24cm. Is a fuse required between the inverter and the 2nd leisure battery it is being connected to, when there is already an inline fuse between the 1st and 2nd leisure batteries?

Tim


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## DABurleigh (May 9, 2005)

Tim,

Not if the inverter is in the same compartment as the battery (ie. no bulkhead to short cabling) and the inverter has a built-in fuse.

As to the confusion post:
http://www.motorhomefacts.com/ftopicp-250301.html#250301
yes, that is when one wishes to run all the van's mains sockets switchable between mains/genny input and inverter off leisure batteries.

Dave


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## timbop37 (Jun 28, 2006)

Dave

The inverter has a built-in fuse of 25amps. The cabling is short and the inverter will be about 20cm away from the battery. All I will be running is a tv/portable DVD player with the occasional phone charger, etc, nothing too power-hungry.

Thanks again,

Tim


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## DABurleigh (May 9, 2005)

Don't understand how you are supposed to get 600W out if you only have a 25A 12V fuse :-(

Dave


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## timbop37 (Jun 28, 2006)

Actually, looking at the instructions with it, there appears to be 3 fuses.

It says, and I quote exactly: 25A*3PCS

Thanks

Tim


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