Can I connect a 7pin tow bar to a 32A trailer socket to run a 2850kw machine?

[xpresso]

I have a 2850kw coffee machine and I need to keep it running whilst I am on the move. It is in a trailer that is set up at 32A so the inlet is a three pin 32A socket. Can I connect it to the 7 pin connector on my tow bar and if so will this produce enough juice to keep it running?

 

[Avo Mk8]

Presumably your coffee machine is 2850 watts, not 2850 kilowatts!
And presumably it runs on 240 volts, whereas the 7 pin socket on your vehicle is 12V?
Apart from not sounding a very safe thing to do, I think the answer is "no" !

 

[brianmoooore]

Changing 12 volts DC to 230 volts AC is not an insurmountable problem, but 2850W at 12 volts is 240 amps, before taking conversion losses into account.
The 7 pin socket is good for about 15 amps max, so totally inadequate.
The average vehicle alternator can produce 100A or so, if you could overcome other problems, you'd need another vehicle alongside you to share the load.

 

[xpresso]

Presumably your coffee machine is 2850 watts, not 2850 kilowatts!
And presumably it runs on 240 volts, whereas the 7 pin socket on your vehicle is 12V?
Apart from not sounding a very safe thing to do, I think the answer is "no" !

Yes to the watts v kw sorry. So can I ask an alternative question. I have two 110ah leisure batteries on-board and a 10,000w inverter. When the machine is fully warmed up these batteries will last all day running the machine and a grinder. However, if the machine is cold, the machine draws too much power and the inverter freaks out and turns off. The machine is dual fuel so I could warm it up using the gas but I'm not sure it would be safe or legal to have that running whilst towing. Is there a way round this? Do I need another battery or something to help the inverter cope with the peak demand? My problem is that I often attend events where no power is available and the trailer is too small to warrant a generator. So I either need to arrive with the machine ready warmed so the inverter can cope, or I need to find a way of generating enough power to get the thing started off grid.

 

[xpresso]

Changing 12 volts DC to 230 volts AC is not an insurmountable problem, but 2850W at 12 volts is 240 amps, before taking conversion losses into account.
The 7 pin socket is good for about 15 amps max, so totally inadequate.
The average vehicle alternator can produce 100A or so, if you could overcome other problems, you'd need another vehicle alongside you to share the load.

Thanks that's what I suspected but I was clutching at straws. Do you think it is the amps that is making my inverter freak out?

 

[Avo Mk8]

Yes to the watts v kw sorry. So can I ask an alternative question. I have two 110ah leisure batteries on-board and a 10,000w inverter. When the machine is fully warmed up these batteries will last all day running the machine and a grinder. However, if the machine is cold, the machine draws too much power and the inverter freaks out and turns off. The machine is dual fuel so I could warm it up using the gas but I'm not sure it would be safe or legal to have that running whilst towing. Is there a way round this? Do I need another battery or something to help the inverter cope with the peak demand? My problem is that I often attend events where no power is available and the trailer is too small to warrant a generator. So I either need to arrive with the machine ready warmed so the inverter can cope, or I need to find a way of generating enough power to get the thing started off grid.

Could I ask exactly the model of inverter you have? The headline wattage figure is sometimes 'optimistic'! Also do you know if it is a 'pure sine wave' inverter?
The current into the inverter when you start the coffee machine cold will be in the order of 250 Amps, if not more. This requires really substantial wiring with well made, probably crimped, connections, and batteries in good condition. Do you think the supply side of your inverter meets these critria?

 

[UNG]

I think you need to speak to Home | powerall - https://www.powerall.co.uk/ they might have a solution to meet your 230v power needs

 

[Avo Mk8]

You say that once warmed up, the machine runs ok for the rest of the day.
That rather infers there's only a problem with a sustained heavy load on the inverter.

Does the inverter 'freak out', as you put it, immediately you switch it on from cold, does it run for a bit and then give up, or does it do peculiar things like stopping and starting continuously?
Monitoring what's happening to the dc input voltage while it's freaking out might be useful?

 

[Lucien Nunes]

To suggest a strategy, it would be very helpful to know the voltage at the inverter DC input, and at the battery terminals themselves, when the machine is heating. Although a load of nearly 3kW is easy to supply at 230V and within the scope of a 13A plug, it's not a trivial task at 12V and as Avo says requires good batteries and very short, very thick, well engineered cables.

It also represents an extreme rate of discharge for the batteries.. The 110Ah rating is for discharge over a period of 20 hours. Instead, the heating load is trying to discharge them in less than an hour, which pushes their ability to release the stored energy to its limit, drags the terminal voltage down and reduces the effective usable capacity.

Are the two batteries connected in parallel to make 220Ah at 12V? As at the moment the inverter seems to be independent of the towing vehicle and its voltage, there would have been sense in connecting the batteries in series to operate a 24V inverter, as this dramatically reduces wiring voltage drop issues although not the battery rate-of-discharge.