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Help with mobile power for a Synesso

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  • Help with mobile power for a Synesso

    Hey guys!

    I have the exciting but challenging task of working out a mobile power supply for a 2 group Synesso

    I'm wondering if there are any battery or coffee cart experts in here that could help me out. (Powerman where are you? :-))

    One thing to note is one of the steam elements will be disengaged bringing the total draw of the machine to around 3800watts.

    The breakdown is:

    Steam element 2000 watts
    Each group head 700 watts
    Water pump 400 watts

    Firstly, I've worked out that a petrol inverter like the Honda EU65is will likely do the trick. It can take continuous output of 5500 watts and peak 6500 watts.

    Only thing is they make a little noise, and while it's probably tolerable, I'd like to explore any other options before taking the plunge.

    So I'm wondering if anyone has experience and could recommend an inverter system powered by batteries?

    I've seen a few inverters that look like they'd do the trick, but am quite unsure about the batteries.

    My other question is, is there a way to work out how many amps the machine would draw in an hour, or for a certain number of coffees made?

    For example, for 100 shots does the machine draw 700watts for the total of around 50minutes (at 30 seconds a shot)

    And for the steam is it just when the steam is engaged that it draws the 2000watts (so for 100 coffees, 2000watts for 17minutes at around 10 seconds each milk heated)

    I assume there is probably a fair amount of power draw in the warmup as well, and maybe a little in between shots and steaming. But is this an ok way of working it out, or is it way off?

    Any tips would be great!

    Finally, I'm wondering if anyone knows everything needed in a battery/inverter setup?

    My guess was the inverter, enough batteries to supply the power, and a battery charger. Is this it or is there more?

    I'm slowing bettering to understand I think, but I clearly need an expert to show me the way!

    Any tips, advice or recommendations would be greatly appreciated!

    Thanks so much,

  • #2
    My advice is to get a decent generator and a dual power gas/electric coffee machine. The number of very costly deep cycle batteries you will need for the amperage required is mind boggling, not to mention both bulky and heavy as well. And... don't forget the additional power requirements for the grinder(s), the refrigerator and the hot water supply.


    • #3
      For that kind of draw you will literally end up with a van full of batteries (in my experience around 20 @ say $450 dollars each), the kind of deep cycle batteries you require are large and heavy and exie. That will cost you dearly in the fuel consumption of the van. Also the cost of the inverter system will drain you of valuable working capital and will cost (upfront) a small fortune if you are having it done professionally (as you should)......far far more than a generator. The fiscal benefit in using an inverter system comes over time when there is no fuel or maintenance cost (except if you dont treat the system properly and end up replacing failing batteries over time. Batteries that fail will bring down the others, so the expense of replacing battereries can be considerable due to replacing groups of them rather than single failed bateries.

      You initially bring the machine to temp BEFORE leaving home while it is still plugged in to the mains.

      You could consider that selecting a more suitable machine (smaller draw) will save you considerable money in terms of the cost of having to spec up a larger power supply whether it be inverter or genie.

      + 1 for the genie. The honda generators are the quiestest around....but that of course is up to the individual. Also of course you dont need to go that large on the gen spec, you can use a good quality large fishing cooler for milk rather than a fridge, and go easy on the addition of other possibly unnecessary (in the scheme of things) electrical appliances.

      Also you are asking a very specialised electrical plant question in a coffee forum. My advice is to seek out a professional in the field of electrical (portable) inverter systems. They are around.
      Last edited by TOK; 1 July 2014, 07:40 AM.


      • #4
        I run an inverter system with 4 deep cycle batteries for my coffee van and it's fine for 2 hour running at moderate pace without mains power. generator would be the way to go if you dont intend to run where 15 amp power is readily available


        • #5
          A 1 group machine? The whole thing depends on what an individual wants to do with his van, part time or full time, type of events, etc.

          My family ran a coffee van for 2 years with a double inverter set up and it started out with 12 large deep cycle batteries. The van would go out early morning and come back in at lunchtime for a top up charge, during which time we would take care of paperwork, pick up supplies (other vehicle) or go surfing for 2 or 3 hours...

          Then out again mid afternoon until the evening.

          That was running only a 10-12 amp maximum load, and the electrical set up was done professionally and was certified (no back yard stuff).

          If you run for longer periods and don't want to have to carry a generator around as a "top up" charger, you need a sheet load of batteries.

          If the batteries are run down below the "recommended" level, some of them will fail and when that happens that puts extra load on other batteries in the set. You cant then replace "odd" batteries because the new ones will be pulled down by the older ones through the extra load. This starts a cycle of you chasing your tail replacing odd batteries in the set, and having to dive in for top up charges more frequently than you thought. Then you replace the whole lot....and you are dead in the water because you thought that after the initial set up cost, it was going to be maintenance cost free over a period of years.....

          Run the batteries down below half at your peril, and this is the reason for having a larger number of batteries rather than a minimum. No one wants to leave a busy site to go looking for a top up despite that the charge level still looks the tendency is to stay on and get a bit more out of the batteries....its called psychology! Management is critical.

          Our set up was upped from 12 to 16 batteries. And that still required a top up at lunchtime (or a standby genie for day events where power is not supplied by the organisers).

          My advice is to buy a more suitable 2 group machine (smaller load, a compact is ideal, or a full size 15 amp with 3 part element where 1/3 of the element can be isolated out) and use a suitable good quality generator straight up....but that's just my experience.


          • #6
            the total draw of the machine to around 3800watts.
            Well, that is a maximum draw ( but only for the m/c, as others have said..not for the full kit )
            ..... but even allowing a 50% duty cycle ( dont know how busy you may get) , it still means at least a 2kW average demand.
            Assuming you intend to operate for say an 8 hr period, that means you wil need about 16kWhrs of power
            With good deep cycle cells, that would dictate a pack size of roughly 22kWhrs ( allowing for peukert effect and cell life protection) of lead cells.
            Those batteries are about $200 /kWhr and 40kg/kWhr, so you could expect $8500 and 900kg of weight...just for the batteries
            And yes, you will also need a healthy (2+ kW, reliable) battery charger to recharge overnight. ..~$500+
            I assume you know the price of inverters.
            Obviously you could survive with less batteries if you plan on shorter "shifts" or a slow trade rate.
            You could also save a lot of weight (50%) and space by choosing LifePo4 batteries,..but that would require some technical expertise to manage.

            Have you considered trading your machine for a gas powered version ?


            • #7
              And yes, you will also need a healthy (2+ kW, reliable) battery charger to recharge overnight. ..~$500+

              The most effective / cheapest / most silent form of daily recharge is to plug into an ordinary household electrical supply, which is what happens whenever such a van is not out working. Genies are only for topping up when you are on the job or cant get home.

              The one thing you absolutely shouldn't do is go the same route as one big name coffee van franchise which in order to keep the cost of the electrical inverter/battery system to a "more manageable cost", uses full size coffee machines with element power reduced by half. This results in the equipment being unable to recover properly, the coffee is under extracted and the steam delivery poor. This kind of works if you have a daily run where you only make a small number of coffees in a row, pull up stumps and drive to the next stop (allowing some recovery between stops) but is hopeless for more lengthy events.

              ....but it also gives you an insight into what paying clients will accept.

              Again, only my experience.


              • #8
                Yes, that $500 for a charger was a estimate for a decent 240v mains powered unit.

                Estimating "actual" power usage for your particular machine is very tricky.
                better to seek data from the manufacturer, or better still to buy a power meter and do a test run back at base.
                remember though, a machine working in the open a van.... Is likely to use much more than the same machine in a shop....depending on the ambient conditions.


                • #9
                  Originally posted by GCWilliams View Post
                  I have the exciting but challenging task of working out a mobile power supply
                  G'day Geoff...

                  Just to give you an idea of what you would be looking at for power supply sizing, irrespective of what form this may take, here is a link to the SAA Wiring Rules Maximum Demand Calculator (free to use) which you can use to give you a close approximation of what quantum of power supply would be required for a range of loads. Although it is primarily aimed at calculating cable sizings, the end result can also indicate the type of power supply requirements needed.

                  By way of an example, I've just completed a "quickie" for you to get an idea, and attached it below. Hope it's helpful...

                  By far the best advice offered so far though, is what TOK suggested in his first post, commission the services of a professional to work all this out for you, and provide options from which to choose, that best serves your preferred modus operandi...

                  Attached Files


                  • #10
                    Wow some amazing advice and experience here. Thanks so much guys. What a great forum!

                    I'm getting the theme that going with batteries would be expensive and heavy. I'll still as (someone wisely mentioned) get a quote from a pro in this area to see what can be done. But it seems that a generator or sticking to events with power may be the way to go.

                    Thanks again for all the tips and advice. I really appreciate it :-)