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Nemos Dad
04-11-2013, 20:37
We had a scary episode yesterday in our MH. We were on a site using EHU and the 2500W inverter was accidentally left on. After several hours it suddenly started spewing out clouds of acrid smoke. Fortunately it didn't actually catch fire but it seemed pretty close due to how hot it got. We got the kids out straight away and isolated both 12v and 240 volt electrics.
I was just wondering if this may have been caused because the inverter was switched on whilst we were using EHU - ie. on hook up, you would not normally use the inverter? This is a fairly new (to us) van and I have not had an inverter before so was this just one of those things or is there a vital lesson to be learnt here?
I have no instructions for the unit - it is a Mercury 2500W with an on/off switch and two UK sockets at the top. It is wired from 2x 110ah batteries (new) directly behind it.
Thanks for any advice......

Firefox
04-11-2013, 21:42
The inverter should have thermal cut outs and fuses. It should be fine to use on hookup or off.

By the way 2500W is far too big off 2 batteries, you will ruin your batteries in no time with that kind of draw. 500 to 1000W is as high as you should go.

maxi77
04-11-2013, 21:47
If the inverter and the hook up were paralleled the op is lucky to have got away with as little as he has. If you are paralleling AC it has to be correctly phase matched or nasty things happen

wineciccio
04-11-2013, 22:06
I totally agree, but where was the inverter made?? China perhaps, my mate Alan thought he bought a bargain with his 500 watts one, and guess what yeah you guessed right, it burned itself out, and luck would have it he was actually disconnecting an item rated at 120 watts from it, if he hadn't been there anyone can guess what the outcome would have been, this is an advice I was given many many moons ago by an electrical engineer that served aboard one of the british submarine, he told me that camping is fine as long some rules are obeyed, to cut it short he advised to install everything in the camper/motorhome that would work on a 12 volts fused power. To this day I have never needed an inverter to power tv. or hair driers for the wife or whatever, I have been camping in small campervans and massive motorhomes since 1974 and to this day I can look back at having no accidents or mishaps of any kind. Why do converters fit chargers instead of inverters, ask yourself that and the answer is in front of your eyes.

Firefox
04-11-2013, 22:13
There is no way an inverter should ever be paralleled with incoming AC. The inverter should be wired off the battery. The AC can be connected to the battery but only via a step down 12v DC trickle charger.

shortcircuit
05-11-2013, 07:57
From the description give of 2X13A socket outlets from the inverter its difficult to see how it was paralleled with EHU unless with some modified wiring. Was there anything plunged into the inverter at the time it overheated?

My 3000w inverter is connected to 2X110A batteries and I have had no problems, admittedly it is only used in short burst to run the hair drier.

Wooie1958
05-11-2013, 08:11
I presume it`s this one :- SOFT START INVERTER 12V 2500W - 651.671UK - MERCURY (http://cpc.farnell.com/1/1/77159-soft-start-inverter-12v-2500w-651-671uk-mercury.html)

maxi77
05-11-2013, 08:20
There is no way an inverter should ever be paralleled with incoming AC. The inverter should be wired off the battery. The AC can be connected to the battery but only via a step down 12v DC trickle charger.

but some people use the inverter to power the same sockets as the ehu. Silly unless you have proper auto changeover stuff but thats life

gagie
05-11-2013, 11:00
I see from the spec that it indicates a minimum load of 1.5amps so it could be that due to having no load for such a long period has cooked something inside it. I suppose the main lesson for all of us is don't leave them on with no load. If you where local id open it up and have a look inside to see if anything obvious and repairable. A harsh lesson but hopefully we can all benifit from it.

shortcircuit
05-11-2013, 11:33
I see from the spec that it indicates a minimum load of 1.5amps so it could be that due to having no load for such a long period has cooked something inside it. I suppose the main lesson for all of us is don't leave them on with no load. If you where local id open it up and have a look inside to see if anything obvious and repairable. A harsh lesson but hopefully we can all benifit from it.

I do not think that is correct. I would think the inverter does not switch on until it has a load in excess of 1.5A so no use for phone charging

Nemos Dad
07-11-2013, 20:07
Hi Guys
Thanks for the replies. Yes, it is the Mercury model detailed in the link - no idea how old it is as we have only had the van for a month. It was not connected in any way to the EHU - just directly through to the batteries but I wondered if being on hook up MAY have affected it in some way? The theory of it being switched on but not actually powering anything sounds more plausible. We had a DVD lead plugged into it but not into the player so I guess this could be a reason. Thanks for the offer to have a look at it - I will maybe get an auto-electrician to diagnose it before probably replacing with a smaller one or getting rid altogether.
THANKS AGAIN


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