Mobile Barista at wits end!

[Seb217]

All I want to do is sell coffee!!! ... yet I have found myself stressing about power supply!

I have a mobile coffee van. I'm done with using generators and so are many event/festival organisers who are now banning petrol/diesel from their sites. In an ideal world I would like a battery fed inverter to power all the equipment that I can't run on LPG.

I would like to achieve 1.5kW of power - I actually currently need 1.2kW of power (not all continuous) but want the extra to future proof against any further equipment that I may want to put on the van in the future.

I need to be able to have power for approx. 10hrs per day. I have sufficient space (but not endless amounts of) to house the batteries and inverter.

As all the equipment that requires power is plugged in to sockets on the walls of the van, can I plug the ‘hook up’ plug into the inverter?

I understand everything there is to know about coffee (and it's more of a science than many people may think) but I know nothing about power. Is there anyone that can please please help.

 

[James]

All I want to do is sell coffee!!! ... yet I have found myself stressing about power supply!

I have a mobile coffee van. I'm done with using generators and so are many event/festival organisers who are now banning petrol/diesel from their sites. In an ideal world I would like a battery fed inverter to power all the equipment that I can't run on LPG.

I would like to achieve 1.5kW of power - I actually currently need 1.2kW of power (not all continuous) but want the extra to future proof against any further equipment that I may want to put on the van in the future.

I need to be able to have power for approx. 10hrs per day. I have sufficient space (but not endless amounts of) to house the batteries and inverter.

As all the equipment that requires power is plugged in to sockets on the walls of the van, can I plug the ‘hook up’ plug into the inverter?

I understand everything there is to know about coffee (and it's more of a science than many people may think) but I know nothing about power. Is there anyone that can please please help.

 

[James]

I will do some calculations for you.
hang fire.

 

[Seb217]

I will do some calculations for you.
hang fire.

THANK YOU!!!!!

 

[James]

so 1.5kw for 10 hours is 15Kwh
at 12v that works out to be 1250Ah capacity required
add in 20% for losses and battery degradation over time gives around 1500Ah
or 15 leisure batteries at 100Ah each.

at 20Kg each, that is a total weight of 300Kg

 

[James]

I it will be drawing around 130A from the batteries at 1.5Kw load so you will need some big cables (starter motor size) from battery bank to the inverter.

 

[Seb217]

That's all reading as though it is not going to be feasible - where is the sad face emoji on this website.

I asked a friend of mine and they said that 4 x 224Ah 6V batteries (weighing 30kg each), would give me 2.7kW per hour for 10hrs. Could they have been so wrong?!!

 

[James]

so around £1200 for the batteries, £250 for the inverter, £150 for all the other bits like cable and battery connectors etc.
its not cheep at around £1600 parts.

 

[Seb217]

so around £1200 for the batteries, £250 for the inverter, £150 for all the other bits like cable and battery connectors etc.
its not cheep at around £1600 parts.

More expensive than a Honda EU22i!!

These are the batteries that the friend of mine reckons I only need 4 of - Powerline T105 AGM

 

[James]

at 12v 1.5kw draws 125A
so for 1 hour you will need 125Ah of battery
for 10 hours you will need 1250Ah of battery.

at 6v the current draw will be 250A, you can do the maths yourself on that one!
but you have also got to remember that these things are not 100% efficient so you will need a bit more to cover it.
however, you are probably not using anything like 1.5Kw continually, so that would reduce the storage requirement

 

[James]

anyone fancy checking my maths?
I don't think I have got it wrong but I have had a beer so its always possible!!

 

[Seb217]

at 12v 1.5kw draws 125A
so for 1 hour you will need 125Ah of battery
for 10 hours you will need 1250Ah of battery.

at 6v the current draw will be 250A, you can do the maths yourself on that one!
but you have also got to remember that these things are not 100% efficient so you will need a bit more to cover it.
however, you are probably not using anything like 1.5Kw continually, so that would reduce the storage requirement

My exact requirements are:

APPLIANCE​	kW​	USAGE​
Coffee machine pump	0.350​	Constant​
Coffee grinder	0.350​	15min/hour​
Flo-Jet (water pump)	0.046​	10min/hour​
Fridge	0.300​	Constant but fluctuating​
Till	0.002​	Constant'ish​
Main strip light	0.072​	Constant​
LED blue lights	0.075​	Constant​
TOTAL	1.195​

 

[The Ghost]

How about gas or coal or wood.

 

[Seb217]

anyone fancy checking my maths?
I don't think I have got it wrong but I have had a beer so its always possible!!

I'm mathematically brain dead and don't understand even the basics of electricity - so as far as I'm concerned you could be right and my friend could be wrong. All I know is that I am having some construction work done on my van and need to whether or not to allow space for batteries or not.

 

[Seb217]

How about gas or coal or wood.

I'm having gas installed on the van to power the coffee machine and water boiler. I'm not sure that the EHO would approve of me using coal or wood