Fitted Inverter but it shuts off power to the van? (3 Viewers)

[MisterB]

Hi, we have an Adria 640 SLT and i have tried to fit a 1000W pure sine wave inverter.

when i connect the inverter direct to the leisure battery, it trips the electric supply into the van - even without the fuse/circuit breaker on the inverter set to 'on' -

it appears that the onboard Adria controller detects that something has been added, even though the inverter is fitted directly to the battery, and triggers into a 'safe mode' by shutting all the 12v amd 240v supplies off.

the two connections i have made to the inverter are crimped connections and i have an inline 100A circuit breaker on the + side fitted between battery and inverter.


can anyone suggest why this may be happening? i did think it might be a faulty inverter, but it isnt even receiving power as i have yet to 'set' the circuit breaker?


could it need a separate earth connection direct to the chassis or to the earth connection for the on board electrics??

i did think the negative wire would provide the earth, but if the on board system is looking for a balanced circuit, could that be the issue?

i will try that later when i get chance


as a safety precaution i have now removed the inverter and wiring from the system and all power is now back functioning correctly

 

[Raul]

Surge start up current flow through the negative, and the AC PE is bonded to this DC negative

 

[Reallyretired]

As I understand this, it doesn't seem to make sense. As the circuit breaker is open all you have connected on the + side of the battery is a short wire with effectively nothing connected to it. Are you sure the circuit breaker isn't faulty. The inverter itself is irrelevant as according to your description it isn't connected.

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[MisterB]

Welcome to confused dot com

 

[Hoovie]

Sounds very strange generally and makes little sense as described TBH.

I will add one comment ... the majority of DC Circuit Breakers on sale on places like eBay and Amazon trip way before their rated current. Once you suss out what the problem is and sort that, I will predict the Circuit breaker you have added will trip out when you don't expect it to.

PS. a 100A breaker or fuse is a bit undersized for a 1000W Inverter. If you did hit the 1000W figure you would almost certainly be pulling >100A once you factor in the combination of voltage drop under the high load and the inverter inefficiency overhead.

 

[Reallyretired]

Sounds very strange generally and makes little sense as described TBH.

I will add one comment ... the majority of DC Circuit Breakers on sale on places like eBay and Amazon trip way before their rated current. Once you suss out what the problem is and sort that, I will predict the Circuit breaker you have added will trip out when you don't expect it to.

PS. a 100A breaker or fuse is a bit undersized for a 1000W Inverter. If you did hit the 1000W figure you would almost certainly be pulling >100A once you factor in the combination of voltage drop under the high load and the inverter inefficiency overhead.

I have to agree with the above my inverter 1500w continuous, 3000w peak is fused at 350A. I use circuit breakers in the solar charging circuits at 30A not expecting more than 20A at best.

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[Raul]

The fuse has nothing to do with the inverter rating, it’s there to protect the feeding cable. And depending on type of fuse used, the fusible fuses blow at a much higher value than the nominal rating.
In this case, the op has a 1kw inverter and 100A fuse will be adequate, as long as no long overload, and the cable can take it. It’s best to undersize a fuse, rather than melt the wire before the fuse blows.
DC breakers are different, and the thermal ones are rely really pants. The electro magnetic ones are good, but at a price.
Look at Schneider or midnite solar genuine DC breakers, then compare them to chipchina thermals.

On topic, when you connect the inverter DC cables to the battery, there will be a very high inrush current (sometimes sparks), to the caps in the inverter. This despite the inverter is of. This can be picked up by over sensitive equipment.
What I understood, it trips the AC ehu feed breaker(rcd), ? Is that right?

 

[MisterB]

Raul

If i explain what it is that I am doing, it might you point/push me in the right direction?

I attach the inverter via a circuit breaker to the positive terminal connection, then connect that to the leisure battery. The circuit breaker is in the 'off' position.
I then connect the negative terminal to the leisure battery and almost immediately I hear a click in the main electric bix/gizmo that feeds everything 12v in the van and nothing works.

I then remove the inverter connections from the battery terminals and connect it all back up again and everything 12v works

As the positive connection isn't being made, it must be something to do with the only connection that is made, that being the negative between the inverter and the battery.

Tomorrow I will fit the earth connection from the inverter direct to the earthing connection for the van wiring. I assumed it would be earthed via the negative cable but perhaps that isn't the case. Not sure why that would matter but I will do it anyway.

Reallyretired
Hoovie

 

[Raul]

The inverter may have a fault, or incorrectly grounded as you touch dc negative?
Is the inverter working ok of a separate battery? Some double insulated centre tap can’t be grounded.

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[Hoovie]

The fuse has nothing to do with the inverter rating, it’s there to protect the feeding cable. And depending on type of fuse used, the fusible fuses blow at a much higher value than the nominal rating.
In this case, the op has a 1kw inverter and 100A fuse will be adequate, as long as no long overload, and the cable can take it. It’s best to undersize a fuse, rather than melt the wire before the fuse blows.
DC breakers are different, and the thermal ones are rely really pants. The electro magnetic ones are good, but at a price.
Look at Schneider or midnite solar genuine DC breakers, then compare them to chipchina thermals.

On topic, when you connect the inverter DC cables to the battery, there will be a very high inrush current (sometimes sparks), to the caps in the inverter. This despite the inverter is of. This can be picked up by over sensitive equipment.
What I understood, it trips the AC ehu feed breaker(rcd), ? Is that right?

"nothing to do with ..."? fit a 10A one then

I get what you are talking about, but "nothing to do" is a stupid thing to say.
You need to fit a Fuse that is within the ampacity of the cable, and above the current draw of the device. it is that simple.
Is 100A adequate? guess we will have to disagree on that one. You don't undersize a fuse to avoid the cable melting - you use the right cable to start with.
Saying it is "best to undersize rather than melt the wire" is just promoting the idea of poor cabling and a dreadful example to set.

 

[MisterB]

Easy guys, you're both trying to help ....

 

[Hoovie]

Easy guys, you're both trying to help ....

sorry, but when some information or advice is poor and potentially harmful it has to be pointed out.

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[Raul]

sorry, but when some information or advice is poor and potentially harmful it has to be pointed out.

What bit of info or advise is potentially dangerous? The one you suggest to up the fuse without knowing the cable size? You know only bits of info, but willing to dish the full menu, guess if things go wrong nothing to do with you. You know nothing about me, and please don’t attribute me the promoting of pore cabling. I always advocated Cable calculation for intended purpose, and always suggested, to chose under 3% voltage drop. Funsters know I have always suggested cable sizes more that others expected, you really got this really wrong. I’m the overkill type, not undersize.
Like I said, you don’t know me, keep it clean and civilised.

 

[Hoovie]

I did not advise increasing the size of the fuse in that installation (it does not actually have a fuse fitted even, it is a breaker). I said a 100a fuse is not sufficient for a 1000W inverter. A very different thing and a general comment for anyone fitting a 1000W inverter.

Given your previous posts and advice which has always been pretty decent, I was very surprised at the comments you made on the specific installation (lower the fuse rating below what is required for the device to save the cable?) that clearly implies it is ok to for the cable to be undersized for the job. If you didn't mean that - and I am sure you didn't, them you should not have written it that way, and should go back and reword it). I determined those to be bad and potentially dangerous should someone follow them.
"The fuse size has nothing to do with the inverter rating"? Rediculous

Calling your advice stupid on this occasion is what is was. Your previous postings and advice don't come into it.


Finally .... "Keep it clean and civilised" says the man who posts the classic argumentative "popcorn" like on a post. Hah!

 

[JockandRita]

MisterB. Dave, I'm betting you wished you hadn't asked.

Jock.

P.S. I'm sorry I can't be of help, but I am interested in the cause, and the solution.

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[funflair]

Raul

If i explain what it is that I am doing, it might you point/push me in the right direction?

I attach the inverter via a circuit breaker to the positive terminal connection, then connect that to the leisure battery. The circuit breaker is in the 'off' position.
I then connect the negative terminal to the leisure battery and almost immediately I hear a click in the main electric bix/gizmo that feeds everything 12v in the van and nothing works.

I then remove the inverter connections from the battery terminals and connect it all back up again and everything 12v works

As the positive connection isn't being made, it must be something to do with the only connection that is made, that being the negative between the inverter and the battery.

Tomorrow I will fit the earth connection from the inverter direct to the earthing connection for the van wiring. I assumed it would be earthed via the negative cable but perhaps that isn't the case. Not sure why that would matter but I will do it anyway.

Reallyretired
Hoovie

You could fit the -ve first and if it still trips there is a big problem somewhere, more than likely nothing will trip which suggests that your +ve circuit breaker is not "broken"

 

[MichaelT]

May sound stupid but have you isolated(turned off) the main 12v feed so nothing is on before fitting the inverter in?

 

[MisterB]

Thanks everyone for your help.

i got it all working by simply connecting the negative side first as a couple of you suggested, so thanks for that !

i checked the circuit breaker and it works correctly (assuming it cuts out at 100a of course) but the reset switch worked and isolates the supply when operated.

HOWEVER, the inverter is underpowered for the 700w microwave as many people suggested it would be - BUT it did work at a low power setting - so i am not too dissapointed as all i need is more powerful inverter (something similar to JockandRita suggested - thanks)

So i am now looking for a 3000w inverter (also going to collect 2 x 130AH batteries this evening) - its a long slog this improvement lark !!!

but i will get there - still got more additions when i finish this 'little project' .....

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[Hoovie]

Thanks everyone for your help.

i got it all working by simply connecting the negative side first as a couple of you suggested, so thanks for that !

i checked the circuit breaker and it works correctly (assuming it cuts out at 100a of course) but the reset switch worked and isolates the supply when operated.

HOWEVER, the inverter is underpowered for the 700w microwave as many people suggested it would be - BUT it did work at a low power setting - so i am not too dissapointed as all i need is more powerful inverter (something similar to JockandRita suggested - thanks)

So i am now looking for a 3000w inverter (also going to collect 2 x 130AH batteries this evening) - its a long slog this improvement lark !!!

but i will get there - still got more additions when i finish this 'little project' .....

Good to get it operational

Ref the Microwave ... most Microwaves operate in a similar way to the majority of Induction hobs. i.e. When you select a lower power, they just alterate between full power and off in a on/off cycle to average the selected power, so the inverters need to support the maximum power even if there is no intention to ever run the device on max power.

As may have been pointed out previously (?), the quoted power of a Microwave is the 'cooking' or output power. The Input power will be on a label on the back and is typically around 1.5x the Cooking power. So even if it appears to be ok at a lower power setting, the inverter could well be hitting peak power or higher every few seconds which could be a little unhealthy in the longer term.
I run my 800W Microwave off my 1300W Inverter (part of the Victron 1600 EasyPlus) and that is close to the limit of that (and pulls around 130A from the battery), but the Victron inverters will take an significant overload by design for 30 second periods so not overly worried.

 

[MisterB]

Good to get it operational

Ref the Microwave ... most Microwaves operate in a similar way to the majority of Induction hobs. i.e. When you select a lower power, they just alterate between full power and off in a on/off cycle to average the selected power, so the inverters need to support the maximum power even if there is no intention to ever run the device on max power.

As may have been pointed out previously (?), the quoted power of a Microwave is the 'cooking' or output power. The Input power will be on a label on the back and is typically around 1.5x the Cooking power. So even if it appears to be ok at a lower power setting, the inverter could well be hitting peak power or higher every few seconds which could be a little unhealthy in the longer term.
I run my 800W Microwave off my 1300W Inverter (part of the Victron 1600 EasyPlus) and that is close to the limit of that (and pulls around 130A from the battery), but the Victron inverters will take an significant overload by design for 30 second periods so not overly worried.

thanks for the practical example - i am looking at getting a 2000w inverter (4000w peak power) pure sine wave with the ability to remotely turn the inverter off when not in use.

also just about to upgrade my batteries to 260Ah in total. hopefully that will get close to where we want to be.

next will be a 260w solar panel followed by battery master and decent B2B

learning lots - thanks everyone

 

[Lenny HB]

So i am now looking for a 3000w inverter (also going to collect 2 x 130AH batteries this evening) - its a long slog this improvement lark !!!

You are going to need a lot bigger battery bank than that if you want your batteries to last. You want to try and keep the battery draw to the C5 rate.

C5 for a 130 ah battery is 26 amps so for your 2 batteries 52 amp is the ideal max current.

For each 1000 watts of output from the inverter and allowing for inverter efficiency is 90 amps. So you need a battery bank of 450 ah.

So 2000 watts would be 180 amps. So a battery bank of 900ah
And 3000 watts would be 270 amps. So a battery bank of 1350ah.

That is the ideal but generally you can draw 50% more than that out of the battery without shortening their life too much so you can reduce the battery bank size by a ⅓.
So 1000 watts 300ah of batteries.
2000 watts 600ah of batteries
3000 watts 900ah of batteries.

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[autorouter]

i am looking at getting a 2000w inverter (4000w peak power) pure sine wave with the ability to remotely turn the inverter off when not in use.

That sounds like a good call. I was going to say that a 3kW inverter is probably too much for a couple of batteries, Also make sure it's pure sine wave. I had a 2kW modified sine wave inverter, and the microwave was very inefficient, taking twice as long to heat anything up, but still drawing lots of power from the battery. The remote on/off is very useful if you are mounting the inverter close to the batteries in an inaccessible space.

 

[Hoovie]

thanks for the practical example - i am looking at getting a 2000w inverter (4000w peak power) pure sine wave with the ability to remotely turn the inverter off when not in use.

also just about to upgrade my batteries to 260Ah in total. hopefully that will get close to where we want to be.

next will be a 260w solar panel followed by battery master and decent B2B

learning lots - thanks everyone

I would say Inverters are possibly the most variable products around in the Motorhome world in terms of capacity, price and quality.
It is incredibly easy to get total rubbish, and it is incredibly easy to get a brilliant one but at a very high price. Finding the sweetspot is the tricky task.
I personally like the Victron units as they are very capable, have a good warranty, but they are also expensive and for an occasional blast of a Microwave maybe a bit OTT. I run a Victron unit as not only do I have random uses for 240V AC, I also run a 240V Compressor Fridge 24/7 so need a reliable and safe device which I can leave powered up all the time (albeit most of the time in AES mode).
For a Microwave, I like the 2000W Inverter in this listing https://www.wildebus.com/product/12v-psw-inverter/
PS. this is my own shop, but doesn't influence my recommendation. The same unit is also available from Photonic Universe. These are very competitively priced for a PSW 2000W unit and also have a wireless remote control to turn on and off. I fitted one of these to a friends Burstner as his wife wanted to use a hairdryer off-grid occasionally (probably same amount of use and power as a microwave I would think?).

 

[MisterB]

You are going to need a lot bigger battery bank than that if you want your batteries to last. You want to try and keep the battery draw to the C5 rate.

C5 for a 130 ah battery is 26 amps so for your 2 batteries 52 amp is the ideal max current.

For each 1000 watts of output from the inverter and allowing for inverter efficiency is 90 amps. So you need a battery bank of 450 ah.

So 2000 watts would be 180 amps. So a battery bank of 900ah
And 3000 watts would be 270 amps. So a battery bank of 1350ah.

That is the ideal but generally you can draw 50% more than that out of the battery without shortening their life too much so you can reduce the battery bank size by a ⅓.
So 1000 watts 300ah of batteries.
2000 watts 600ah of batteries
3000 watts 900ah of batteries.

thanks for the info

obviously its something i need to be aware of - what ive based my thoughts on is that a 700w microwave ar 12v power for 1 hour uses @60Amps (1 amp per minute) - so a quick burst of 15/20 mins maximum, will use 15/20 Amps - of course my figures could be well out so any assistance or clarification of the correct figures would be helpful.

i used this calculator

Watts to Amps Conversion Calculator

Use our calculator and handy reference charts to convert electrical power (watts) to electrical current (amps)

www.thecalculatorsite.com

using your guidance of staying above 50% discharge rate would give me 260amps/50%= 130 amps - or 130 minutes use of the microwave at full power or 260 minutes at half power. our intent is only to defrost when necessary or heat some stuff up (beans, peas, sweetcorn etc and the odd microwave fries for the grandchildren)

i certainly dont think our plans are anything like cost effective and that isnt the intent, its just to make life a bit simpler for us simple folk !!

if anyone can see any holes in my thoughts/calculations - PLEASE tell me so i can review and ammend (as i have done throughout this project)

for those of you with microwaves in their vans that they use when not on EHU - when you are on EHU do you still run the microwave through the inverter (and the batteries being topped up by the ehu) or do you plug the microwave into the standard ehu supplied circuit? i am setting my circuit design so that the individual circuit that feeds only the microwave, can be plugged into the inverter or a feed from the ehu (via the consumer unit)

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[Lenny HB]

700 watt microwave will use a lot more than 700 Watts, that is the cooking power not the power consumed. More like 800 to 900watts and the startup power will be a lot higher. Also you haven't allowed for inverter inefficency normally 85 to 92% efficient.

Also my figures weren't referring to battery capacity but the actual load on the battery. i.e. If you were drawing 900 Watts that would be a load of around 82 amps taking into account Inverter efficency. That would be the absolute maximum I would want to take out or 260ah of batteries.

 

[MisterB]

700 watt microwave will use a lot more than 700 Watts, that is the cooking power not the power consumed. More like 800 to 900watts and the startup power will be a lot higher. Also you haven't allowed for inverter inefficency normally 85 to 92% efficient.

Also my figures weren't referring to battery capacity but the actual load on the battery. i.e. If you were drawing 900 Watts that would be a load of around 82 amps taking into account Inverter efficency. That would be the absolute maximum I would want to take out or 260ah of batteries.

thanks, i think i understand ....... and thanks for the gentle reminder about power being consumed and the inefficiency of inverters !

from what your saying its 'possibly' ok .... LOL though its borderline as to whether its sustainable long term (without increasing battery bank or going lithium)? on that basis, i think plugging the microwave direct to a 240v supply when it is available is by far the best option - so ive learned something ( i think LOL) - thanks again!

 

[Lenny HB]

Basicly overloading the batteries will reduce their life but loads of people do it and get away with it it just better if you don't.

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[BillandHelen]

We have an NDS 2000w pure sine wave invertor (with a remote on/off controller) running off 200amp NDS lithium, each with 150amp max draw.
Our 700w microwave works a treat, pulling 100+ amps, for the short times required to heat food or do the veg.
Just have to remember not to run anything else at same time!

 

[JockandRita]

for those of you with microwaves in their vans that they use when not on EHU - when you are on EHU do you still run the microwave through the inverter (and the batteries being topped up by the ehu) or do you plug the microwave into the standard ehu supplied circuit? i am setting my circuit design so that the individual circuit that feeds only the microwave, can be plugged into the inverter or a feed from the ehu (via the consumer unit)

No Dave, if on EHU, we run ours off that supply. Our setup (as funflair Martin will hopefully confirm), senses which power supply is available, and defaults to EHU where available. All our sockets are powered by either/or.

Cheers,

Jock.

 

[MisterB]

No Dave, if on EHU, we run ours of that supply. Our setup (as funflair Martin will hopefully confirm), senses which power supply is available, and defaults to EHU where available. All our sockets are powered by either/or.

Cheers,

Jock.

Cheers mate - perhaps that might be a future 'improvement' ...... as the only 240v appliances we have are the microwave (added), kettle, toaster and air fryer - it might be worth us looking down that route .... just because we have the ability to use a 240v appliance via an inverter, it doesnt mean we wouldnt use the kettle and grill utilising gas as the energy source thus saving 'battery life/power' when not on EHU.

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