# Inverter query



## Pudsey_Bear (Sep 25, 2008)

Has anyone got one of these, I'm not very up on the more powerful inverters, so would appreciate some advice on This one.

I have 2 x 110ah batteries, about one metre apart, linked by 16mm cable, the present plan is to fix it to the seat box, next to the batteries, but not sure if I should connect it to the battery which already is connected to the hab, or to the other one which only connects to the main hab battery.

It looks like a good piece of kit for the money, I know it's not the best out there, but from the info on the web page, can you tell if it's worth trying, also at the fan end there are what looks like 3 x long lumps, anybody know what they are? and as it only has one socket, would it be OK to use a multiple adapter to plug in two appliances, or would it be better to just connect it into the EHU box?

Kev.


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## camoyboy (May 9, 2005)

When 2 batteries are connected together, it is best to both charge and draw current equally from both. Therefore it is best to connect to the + on one battery and the - on the other.
If you connect the mains side of the inverter to the existing sockets in the MH you will need a switch to change over to the mains when on hookup, otherwise you will have a thermal incident.
Hopefully Clive Mott will see your post and explain better.
Colin


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## pippin (Nov 15, 2007)

I suspect those three black lumps are fuse covers for the 12V side.


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## teensvan (May 9, 2005)

Hi.

You can fit a 2 or 3 way adaptor to the 13a socket outlet but get one that has a fuse holder and fit it with a 5amp fuse. This in theory gives you a max output of about 1200 watt. We wired in separate sockets and put a label on them so anyone would know the difference between 240 volt or invertor 240volt. Make sure you use the correct cable on the 12 volt side keeping it as short as possible, with an isolator in the circuit. We also fitted a fuse holder in the 12 volt cable with a 60 amp fuse.

steve & ann. -------------- teensvan


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## WiltonShagpile (Apr 10, 2008)

Hi,

This looks about the best price for a 1000 or above I've seen. Been looking for a while so t'other 1/2 can use her hair dryer off MHU.

Any one tried one yet?

All the best Wilt


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## wakk44 (Jun 15, 2006)

Looks to be a very good price for a more powerful inverter.

Check out >>>HERE<<< on the FAQ section for useful information re. inverters.


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## Pudsey_Bear (Sep 25, 2008)

camoyboy said:


> When 2 batteries are connected together, it is best to both charge and draw current equally from both. Therefore it is best to connect to the + on one battery and the - on the other.


Thanks Colin, that's a useful bit of info re connecting to two instead of one, but as usual it brings another question, one cable will need to be longer than the other, (unless I put it in between the front seats and climb over it), would there be any benefit to either pole +/- being shorter than the other, also I'm aware that there is a running cost with the larger inverters, IE they take some power to run themselves, despite searching around I couldn't find the info, is there a rule of thumb, which tells us how much that cost is say per Kw.

Thanks Teenvan, cracking tip re 5amp fused 3 way, I would probably never even have thought of that, we're all better on here when we work together aren't we.

Thanks Pippin, my assumption as wel.

Kev.


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## Pudsey_Bear (Sep 25, 2008)

> camoyboy wrote: ‹ Select ›
> When 2 batteries are connected together, it is best to both charge and draw current equally from both. Therefore it is best to connect to the + on one battery and the - on the other.


I just re-read that from Camoyboy, and wondered if that was for a 24v system, mine is 12v and I have assumed but not asked how to connect the 2 x 110ah batteries, I was planning to go + to + and - to -, is that the correct way, still need to know if there is a need for one pole to favoured over the other distance wise as posted earlier, I can't continue until I've heard from you guys, so don't be shy.

Kev.

PS it would be really useful to hear from someone in the know re this particular inverter before I buy one.


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## gromett (May 9, 2005)

My only initial concern here is the size of the wires interconnecting the batteries. If you start pulling 1100 watts from the batteries that is aprox 90Amps. I don't have my notes to hand on cable sizes but 16mm seem a little small for 90amps? Having said that only half that will come from the battery you are not directly connected to so at 45Amp may just be ok. I seem to remember 50amps for 16mm?

Sorry I don't have my data sheets to hand.

Karl


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## Pudsey_Bear (Sep 25, 2008)

If you're concerned Grommett so am I, also does that mean then, that i need to be looking at similar sizes for the inverter to battery cables.

I think I need to contact the sellers to get more info.

Kev.


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## macone48 (Mar 14, 2006)

Kev_n_Liz said:


> If you're concerned Grommett so am I, also does that mean then, that i need to be looking at similar sizes for the inverter to battery cables.
> 
> I think I need to contact the sellers to get more info.
> 
> Kev.


Kev,

The spec of the invertor also states it can support surges up to 2.2Kw. Your 60A wiring could be seriously under rated.

As Grommit says you will need to have something that can support 90 A. During surges you could potentially draw twice that 180A. So 60A is a little too small.

If you DO run smaller rated cables, you'll get voltage drops and the under-voltage protection will kick-in meaning you may never take the 1100 watts that you think is available.

Finally, try and keep you wires as short as possible.

Can I please ask, what plans do you have to re-charge the batteries on-site afterwards ?? Solar, if the panel is large enough will work - you don't mention that ??

Good luck and always ask yourself if you "really, really" need to invert battery voltage to mains ??? It is such a hassle at times !!!

Trev


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## gromett (May 9, 2005)

I based my initial comments on the fact he was going to put a 5 amp fuse in the plug so no need to go for the 180Amp cable.

I have just done some googling.
http://www.solar-wind.co.uk/cable-sizing-DC-cables.html

For a short high power run I wouldn't recommend anything more than a 1% drop.

The results are 15mm2 for 45amps. For the full 90 amps you would need 30mm2. Now I am taking this calculator on trust as I don't have my proper tables with me. But based on this I would say your battery interlink is ok but you would need 30mm2 for the main invertor cabling.

Frank may be able to offer more advice cause he probably can do this stuff in his head :lol:

Karl


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## Pudsey_Bear (Sep 25, 2008)

I've sent them an email, outlining points raised on here and also what I want and where I'm going to mount it etc, so I await the reply if any, as I've not dealt with them before, but looking around the site, they don't seem to sell junk gear, so hopefully the inverter is a quality item at good money.

To answer the queries raised


Trev said:


> Can I please ask, what plans do you have to re-charge the batteries on-site afterwards ?? Solar, if the panel is large enough will work - you don't mention that ??


I do have a solar panel but only 40 watts, not yet fitted, the inverter will probably never get used to its full capacity, but a microwave oven has been considered, as has a coffee maker, blender etc, however at the price of this unit I'd rather go for the bigger over capacity one than mess around with the little ones again. and yes the inverter is the way to go coz we is those nasty Wild campers, the scourge of the planet (according to some anyway) We do have a Honda genny 700 watts, but have yet to use it, it came with the MH, and it's comforting to know that should we flatten all the batteries, we can at least re-charge them, and yes we carry a charger just in case the EHU charger doesn't work for some reason, I was a cub once you know :lol: :lol: :lol: .

I had a look at the Power Inverter Connection Leads section of the site also to get a bit more info, but not revealing anything really. power Inverter Leads and Connections Page I don't get why they don't say what cables you need for which inverter over a given length, or why on the leads page they don't suggest which inverter the may suit :? :? :?

Gromett, the 5amp fuse was just to go into the 3 way adapter (suggested by Teensvan earlier in this thread)so as not to overload the inverter, not got as far as fusing between the inverter and the batteries yet, and there are still some unanswered questions re length of cables to the batteries.

To sum up these are things I'm not sure of yet.

Size of cable between batteries, currently have 1 x 16mm cable and 1 x 20mm cable (that's all they had in the caravan shop) not yet mounted, waiting for decent soldering gun to sweat ends on with. got ends,

Size of cable to inverter (mounted on to the side of Fiat Ducato front seat base 1 x 110ah battery under each front seat, 2 x pos + 2 x neg (I assume the info to connect pos on one and neg on other battery is correct as no one has said any different) and it seems sensible, just wondered if, as I'm forced to have the inverter nearer one battery than the other if there was a benefit to one cable +/- being shorter, as one of them will have to be anyway.

What size fuses for inverter/battery, and should I have one for each pole, or just one the positive side.

I've kept the cable runs as short as possible, longest is about 1.5 metres battery to battery.

Thanks for the information so far.

Kev.


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## Pudsey_Bear (Sep 25, 2008)

I just got an email from the people selling The Inverter, they are talking to the manufacturers, before advising me further, I will of course post the information when I know more.

Kev.


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## Pudsey_Bear (Sep 25, 2008)

Just went to the manufacturers website Here

Kev.


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## LazyRover (Apr 13, 2008)

There is some excellent information HERE


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## Pudsey_Bear (Sep 25, 2008)

You might have warned me that there was a lot of worms, I struggle when there's a lot of worms.

I'll have to read it later when my brain has cooled down.

Kev.


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## MikeyB (Jun 20, 2005)

Kev, Sterling Products, I think, make and sell a host of gear that you might be interested in, incl. inverters. Their website has some very useful info about this topic. Might be worth a "Google". Mike.


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## Pudsey_Bear (Sep 25, 2008)

They've just got back to me with the following advice,



Power Bright in USA said:


> We have heard back from Power Bright:
> 
> ***********
> For a permanent installation I would recommend wires with ring type
> ...


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## teemyob (Nov 22, 2005)

*Inverter*

Hello,

We have a Ring Branded 2kW inverter linked to the leisure batteries in our MH. When I first installed it via a changeover switch it was a pain in the backide.

When you drove away from hook-up you had to switch inverter on and put changeover switch in correct position. Trouble was the only place I could locate said swicthes and inverter was under seats. Coupled with the fact that I seemed the only one whoe could remember position of switches things soon became a bloody nightmare. I would press switches to correct position. Then someone from cabin crew would come along and thinking I had'nt done the switches would press/switch them again. This would only be discovered when say on on the motorway for example when one of the crew wanted to charge a phone or use laptop

"there is no Power" would come a voice from the cabin. 
"but I switched them all over before we left" would be my reply. 
"no I did it just before you drove off" would come my Co-Pilocks response.

The whole saga and arguments would then begin because gaining access to swicthes under seats when driving was not possible. It got realy bad one week when total confusion caused chaos.

I would recomend you fit an auto changover system. I fitted a contacter so that if we plug the van into hook-up the system is automticaly swiched to shore power. When unplugged it instantly reverts back to on-board inverter power (Provided the now easy to reach inverter switch is in the ON position.)

I think Clive on here had something to do with the MMMagazine How To article on how to install the contacter. Of wich I have a copy somewhere if you ever need it.

Regards,
Trev.


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## Pudsey_Bear (Sep 25, 2008)

Thanks Trev,

I've no intention of running it as anything other than a stand alone inverter, I'm a strong believer in the K.I.S.S. principle.

Kev.


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## teemyob (Nov 22, 2005)

*KISS*



Kev_n_Liz said:


> Thanks Trev,
> 
> I've no intention of running it as anything other than a stand alone inverter, I'm a strong believer in the K.I.S.S. principle.
> 
> Kev.


Keep It Simple......s?

Trev


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## gromett (May 9, 2005)

Stupid :lol: 


If the output sockets are separate from the shore supply that is a nice simple solution.

I fuse each battery independently on my system right at the battery. 

Karl


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## Pudsey_Bear (Sep 25, 2008)

I don't see the point in running cables here, there, and everywhere, life in a MH is complicated enough, without having two different banks of sockets, Although I do seem to remember the previous owner saying his previous owner wired a couple up to his inverter, and there are a couple that don't look original, I'll have to look into it sometime, I assume just standard domestic cables will do for that, it's just the 21mm cable up to the Inverter, then it's situation normal?

Kev.


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## gromett (May 9, 2005)

Kev, If you are plugging stuff directly into the inverter then you are ok and don't need to worry about complicated switches.

If however you are routing the output of the invertor to the same sockets that are already installed in the van you will need some switch gear which can be either automatic or manual.

If you just wire the inverter output directly to the existing sockets in your van you will get problems. Should you connect shore supply at the same time as the inverter is providing output they will not be in phase and will fight with each other. Your battery powered inverter will lose the battle with the national grid everytime and the magic smoke that makes your inverter work will escape 

Karl


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## Pudsey_Bear (Sep 25, 2008)

Absoflippinlutely Gromett, never the twain shall meet.

The sockets I reffered to are just two, and wired directly to the battery, (he used 12v via 3 pin 13amp plugs, not a good idea) so I think I just need to move them onto to a std 13amp plug, and plug into the inverter when needed, and either run stuff from these 2 sockets, or directly from the inverter, which saves me using an extension lead, I will label them up as inverter only, and as we only use EHU at home, to top up, and cool the fridge, we should be Ok.

I'm just a bit concerned re the battery connecting cables being a bit light at 16mm.

Kev.


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