12v & 240v for Coffee Trailer, advice needed.

[Wilber]

Hi all,

After a bit of technical knowledge when it comes to 240 and 12v electrics for a vehicle. I am starting a mobile coffee business from a converted T3 that I've made into a trailer and here is the schematic showing how the devices will/should work. Now, I'm no electrical engineer so all advice welcome.

http://bit.ly/dNeuYp

My main concerns are the battery charger and 12v - 240v inverter as these will be hard wired into the van and worried about passing 12v current the wrong way through the battery charger whilst driving and the alternator is working.

The other concern is if I use the 240v hookup is passing current the wrong way through the inverter.

If someone knows of an automated way to stop these issues I'd love to know........

Many thanks, Will

[Oldiebut goodie]

I would have thought that as you are describing a commercial undertaking all the ramifications of health and safety, insurance/public liability etc. would come into force and you would be best advised to have all the work carried out by a proper accredited electrician, plumber etc. For this reason I doubt that many people on here will advise you.
Thankfully us DIYers have a degree of control over how we carry out this type of work.

[AdrianC]

My main concerns are the battery charger and 12v - 240v inverter

Umm, this might be a daft question, but are you seriously thinking of powering a 240v coffee machine & grinder from a 12v inverter? Are you planning on having anything other than 12v batteries in the van?

If your coffee machine pulls 1500w @ 240v, that'll be closing on 130A at 12v - before the inefficiencies in the inverter. I'd give a typical battery about 10min before it's not got enough juice to actually power the inverter up.

[jamesc76]

get it wired for 240, and buy a honda suitcase genny, never gonna work off batterys!

[Red Westie]

I agree, the most reliable solution would be to have a standard 230volt 'hookup' going to a consumer unit and off into 2 or 3 conveniently mounted double sockets. Ideally powered by a good 3KW generator for reliable power.
You could add a simple 12 volt circuit for instant lighting and hand washing water pump/sink (one leisure battery and charger) if you felt that was needed, no need to split charge as the small charger would keep this topped up when the genny is going.

PS: I say 3KW as you might want to boil a kettle occasionally?

Martin

[Wilber]

Hi All,

Might not of explained everything in enough detail, my bag...

The coffee machine is both electric and gas powered so when using the batteries the main heat source for the boiler will be from the gas. Also I will need to run the coffee grinder through the inverter when no 240v is available. I have bench tested this system and each bank of batteries lasts well over 1.5 days each so should be fine for a weekend event.

When 240v power is available I would prefer to use it but am concerned as the inverter will be hard wired and the current will be flowing the wrong way into it. Will this be an issue?

Regarding the health and safety aspect of it all, thank you for the concerns, but by law this will need to be certified by an authorised electrician and ratified by the local authority. Trust me its a lot of paper work to fill in!

Hope this info helps.......

Will

[billy739]

love to see some pics of your project!

[jamesc76]

ahhhhh the mist clears a bit! Reet, if there on gas then the set up you have should be ok! As fot the invertor, put a heavy duty switch in the line between the invertor and the incoming mains should solve it a decent sparks should sort it!

[Wilber]

Hi Billy,

http://www.camper-cafe.co.uk

If you click on the Facebook there are some photos of the progress.

The trailer is booked in to be sprayed next week then decals and fit out shortly after.

Should be live on 14th May at Dubs at the Pub, fingers crossed!

Will.

[jamesc76]

just looked at your pics! thats gonna have a very high nose weight! have you tried to counter balance it ????

[AdrianC]

just looked at your pics! thats gonna have a very high nose weight! have you tried to counter balance it ????

Bejaysus!


Even if the water tanks and batteries are at the very back, that is going to be immensely nose-heavy. What's maximum noseweight for a T25? 50-75kg's usual.

I wonder if it'd be possible to get a hidden front axle under there to take some of the weight - and make it freestanding?

[jamesc76]

Just got off the phone with Will, nice bloke! sounds like he's got his head screwed on correctly and from the sounds of it the nose weight is actually ok!!!

[AdrianC]

Just got off the phone with Will, nice bloke! sounds like he's got his head screwed on correctly and from the sounds of it the nose weight is actually ok!!!

Good news - but wow...

[Wilber]

Think I may have found a way to 'switch' between the hook up and inverter:

Quote from interweb

"Connect the output of this circuit breaker to the coil and the normally open contacts of a chunky 16 amp or 30 amp AC rated mains two pole relay. Connect the normally closed contacts to the output of your inverter. Connect the common contacts to the fuse box that feeds the rest of the vans mains system. This relay will then default to INVERTER unless the real mains is present. "

So just need to draw it up then test..........?

Cheers, Will.

[jamesc76]

Think I may have found a way to 'switch' between the hook up and inverter:

Quote from interweb

"Connect the output of this circuit breaker to the coil and the normally open contacts of a chunky 16 amp or 30 amp AC rated mains two pole relay. Connect the normally closed contacts to the output of your inverter. Connect the common contacts to the fuse box that feeds the rest of the vans mains system. This relay will then default to INVERTER unless the real mains is present. "

So just need to draw it up then test..........?

Cheers, Will.