Inverter

[Big Ted]

What is the best inverter for my autotrail apache 700

 

[Bessy765]

Rough rule of thumb, you need 28 amps @ 12 volt d.c. to produce 1 amp @ 240 a.c. Allowing for inverter inefficiencies and voltage drop. So 1000 watts @ 240 volt a.c will pull 112 amps d.c. but as battery voltage drops the load req changes.

 

[Raul]

Autorouter explained it very well. If you want to get the understanding of the lead batteries in depth, I recommend a good read of battery university website.
Personally I don’t care what ppl do with theirs, but I design and use mine with a C/10 rate continuous duty, and C/5 for peak loads. The lead grids warp and active material just falls of in the jar from discharging abuse, been there.

 

[82125]

I have a Prowatt 1500w inverter spare (and im in Ayrshire at the moment).
It was fitted to my boat when i got it but i swapped it out for a pure sine wave.
£50 if youre interested and ill even throw in a low power 1000w hair drier that was also on board!
Im just having a clear out ready to move to the MH).
(couldnt see any way to message you privately, sorry if inappropriate)

 

[Lenny HB]

we have the same inverter but 200ah of pure lead Carbon batteries, may i ask if you have a fuse/trip between the inverter and batteries and if so what size is it.

Using our new 1100w Kampa kettle it trips my 150a trip switch before boiling so i'm asking if i need to go higher with the trip current rating

Any help from anyone would be really appreciated

thanks Al

An 1100 watt kettle should even allowing for inverter efficiency only draw around 100 amps so the trip could be faulty. Depending on the type trip/MCB' normally need twice the rated current for 10 seconds to trip or much longer times at lower overloads the spec should have a graph showing trip time versus current.
One thing you need to is to at least double the size of your battery bank if you want your batteries to last.

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[Lenny HB]

I use the inverter in the main to run a 750w little coffee machine, charge Mac laptop (85w) and using a 1400 w Dyson hairdryer. Now on the inverter I have 200A fuse and 25mm cables. The hair dryer when operated is for around 10 minutes off and on in the morning only when the shunt shows the batteries at 100%. From the comments around C/5 ( a first for me on this info) is it said that I simply do not have enough battery bank power.

Correct, if the 1400 watt load is the max, ideally you need 600ah of batteries, if only used occasionally for short periods you could get away with 400ah.
If you want to use the full output of the inverter you need around 900ah, or for ocassional short period use 600ah.

 

[funflair]

Correct, if the 1400 watt load is the max, ideally you need 600ah of batteries, if only used occasionally for short periods you could get away with 400ah.
If you want to use the full output of the inverter you need around 900ah, or for ocassional short period use 600ah.

That’s certainly more than we ever had to run 1000/1200watts, 2x80ah gel for a good few years and then doubled it to 320ah but 10 years on the originals are still OK.

I do think it’s important to select the heaviest battery possible though.

 

[Lenny HB]

That’s certainly more than we ever had to run 1000/1200watts, 2x80ah gel for a good few years and then doubled it to 320ah but 10 years on the originals are still OK.

I do think it’s important to select the heaviest battery possible though.

If you want to be sure your batteries are going to last stick to the C5 rate. Many over crank their batteries and get away with it like you. I have a 1000 watt inverter with 3 x 78ah Gels and I do occasionally take 66 amps out of them for 3 or 4 min (small kettle on the tunnel).

But it would be wrong to advise people on a forum to over crank their batteries, I like to advise what is acceptable not what they might get away with.

 

[BillyKontiki]

Hi Al.
I had a 150 amp trip and like you it tripped quite often, swapped it out for a 150 amp
In-line fuse no problem since.
Hopefully you can get the same result.

 

[Insider]

Start with the power that is needed. For example 1000w divide by 12v operating system. That’s 83a needed to come out of the battery. A lead of any kind can discharge a max C/5 current. The C is your total battery capacity divided by 5. In our case we have 83a needed times 5 = 415ah battery bank to sustain a 1000w load. Any more is abuse on batteries. When you have a large load and small battery bank, you help it with direct solar production and engine alternator. If you want large power draw lithium is your friend.

Raul - If I could be a bit cheeky and pick your brains. I have 2xlead acids with 190Ahr(VartaLFD90s) in total. Using the C/5 approach this means I shouldn't go over 36A. So lets say I want to run a microwave every 2nd day for 2mins. Roughly speaking I'm going to need to supply 90A. Up my sleeve I have a 60A Sterling B2B. If I start the van and wait the 2 mins for the B2B to kick in, can I then assume that my B2B will throw in the 50Amps and the batteries take up the remainder. You can assume that wiring and fuses would be appropriately sized. TIA

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[funflair]

If you want to be sure your batteries are going to last stick to the C5 rate. Many over crank their batteries and get away with it like you. I have a 1000 watt inverter with 3 x 78ah Gels and I do occasionally take 66 amps out of them for 3 or 4 min (small kettle on the tunnel).

But it would be wrong to advise people on a forum to over crank their batteries, I like advise what is acceptable not what they might get away with.

I am very reluctant to offer advice, especially for free so instead I offer my experience and people can then make up their own minds play safe vs take a gamble

 

[Lenny HB]

Raul - If I could be a bit cheeky and pick your brains. I have 2xlead acids with 190Ahr(VartaLFD90s) in total. Using the C/5 approach this means I shouldn't go over 36A. So lets say I want to run a microwave every 2nd day for 2mins. Roughly speaking I'm going to need to supply 90A. Up my sleeve I have a 60A Sterling B2B. If I start the van and wait the 2 mins for the B2B to kick in, can I then assume that my B2B will throw in the 50Amps and the batteries take up the remainder. You can assume that wiring and fuses would be appropriately sized. TIA

In theory yes it would work but you only really want to do it when driving. Modern diesels should not be started and run on tickover they should be driven off straight away.

 

[Raul]

Raul - If I could be a bit cheeky and pick your brains. I have 2xlead acids with 190Ahr(VartaLFD90s) in total. Using the C/5 approach this means I shouldn't go over 36A. So lets say I want to run a microwave every 2nd day for 2mins. Roughly speaking I'm going to need to supply 90A. Up my sleeve I have a 60A Sterling B2B. If I start the van and wait the 2 mins for the B2B to kick in, can I then assume that my B2B will throw in the 50Amps and the batteries take up the remainder. You can assume that wiring and fuses would be appropriately sized. TIA

I would do the same if I was in your position, as a temporary solution, just add 2mins running the engine after the microwave off. That will level off the starter battery. The power has to come from somewhere, the B2B will deliver its rates output.

 

[Al n Val]

An 1100 watt kettle should even allowing for inverter efficiency only draw around 100 amps so the trip could be faulty. Depending on the type trip/MCB' normally need twice the rated current for 10 seconds to trip or much longer times at lower overloads the spec should have a graph showing trip time versus current.
One thing you need to is to at least double the size of your battery bank if you want your batteries to last.

Hi Lenny

its this one or at least very similar

<Broken link removed>

I had actually thought it may be faulty tbh, would you advise me to up the rating and if so what to?

I'm only on non ehu occasionally, would you still advise me to double up my batteries to 400ah or go down the lithium route, bearing in mind I’ve a Victron MPPT controller 75-15 with a 140w panel separate to a 100ah panel via the Sargent EC700, also I’ve a Victron 12-30 DC to DC charger

Al

 

[Lenny HB]

Hi Lenny

its this one or at least very similar

<Broken link removed>

I had actually thought it may be faulty tbh, would you advise me to up the rating and if so what to?

I'm only on non ehu occasionally, would you still advise me to double up my batteries to 400ah or go down the lithium route, bearing in mind I’ve a Victron MPPT controller 75-15 with a 140w panel separate to a 100ah panel via the Sargent EC700, also I’ve a Victron 12-30 DC to DC charger

Al

At that price I wouldn't hold out much hope for it why not just fit a midi or maxi fuse

Pardon our interruption...

www.ebay.co.uk

As for the batteries if you are only using high power from them occasionally you could see how they go then make a decision if & when they fail.
Lithium is a big expense but if keeping the van a good few years or you could even transfer them to the next van it would make sense.
I would love Lithium but my Gels at 5 years old are still performing like new.

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[royw]

that kettle should be using a shade under 100 amp at 90% efficiency thats only 110 amps , i wonder why tripping a 150?

we have the same inverter but 200ah of pure lead Carbon batteries, may i ask if you have a fuse/trip between the inverter and batteries and if so what size is it.

Using our new 1100w Kampa kettle it trips my 150a trip switch before boiling so i'm asking if i need to go higher with the trip current rating

Any help from anyone would be really appreciated

thanks Al

 

[Al n Val]

that kettle should be using a shade under 100 amp at 90% efficiency thats only 110 amps , i wonder why tripping a 150?

that’s what i’m wondering tbh, unless it is a faulty breaker

 

[BillyKontiki]

we have the same inverter but 200ah of pure lead Carbon batteries, may i ask if you have a fuse/trip between the inverter and batteries and if so what size is it.

Using our new 1100w Kampa kettle it trips my 150a trip switch before boiling so i'm asking if i need to go higher with the trip current rating

Any help from anyone would be really appreciated

thanks Al.

that’s what i’m wondering tbh, unless it is a faulty breaker

I thought that but replaced breaker same problem think breakers are a bit sensitive.

 

[Googlebot]

that kettle should be using a shade under 100 amp at 90% efficiency thats only 110 amps , i wonder wh

I thought that but replaced breaker same problem think breakers are a bit sensitive.

I have seen those trip switches and wouldn’t trust them.

A mega fuse and holder will be the exact rating you put in with no messing.

 

[Raul]

Those type of breakers have no type of approval and are pants.
Fit a well known manufacturer fuse that actually tested and accredited for the intended use.

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[Al n Val]

I’ll certainly fit a proper fuse but wanting to know what rating is correct, is a 150a fuse the correct size does anyone know

Al

 

[Googlebot]

150amp will only give you half the inverter capacity but I would size for the cabling and not the inverter if it’s smaller.

I am fairly sure you need 50mm cable and a 300amp fuse but that’s a rough guess.

 

[Raul]

I’ll certainly fit a proper fuse but wanting to know what rating is correct, is a 150a fuse the correct size does anyone know

Al

The way to find out is to test it. Someone already did it and posted on YouTube. Did a proper tear down and testing under different currents with inconsistent results. It’s a bi metal thermal expansion contractor with a spring loaded trip. Very poor. Fuse or midnite proper electromagnetic breakers. Schneider does dc breakers to, for a price.

 

[Al n Val]

The way to find out is to test it. Someone already did it and posted on YouTube. Did a proper tear down and testing under different currents with inconsistent results. It’s a bi metal thermal expansion contractor with a spring loaded trip. Very poor. Fuse or midnite proper electromagnetic breakers. Schneider does dc breakers to, for a price.

Well i’ve ordered a couple of fuses care of Lenny’s link so let’s hope that cures the issue.
Meanwhile a new low wattage toaster appeared yesterday and tested today and it’s as good a toaster we’ve ever used

Argos and a tenner so not bad

 

[Raul]

I run my multiplus 2000kva on a 150a maxi fuse, largest load I had 1480w displayed on victron console. Fuse should hold 1,5-1,6 of the rated current for few good seconds. I will never draw max power continuously as I don’t have a need, and would have to overload the inverter to do that.

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[Al n Val]

just an update to my dilemma

so I removed the 150a breaker and replaced with a 150a fuse and bingo, all works now as it should

cheers and looking forward to many inverter powered cuppa’s in the future