Power needs for start up business

[SethElton]

Hello everyone,

I have posted before on here regarding a mobile startup i am pursuing, and got some very helpful replies. So please can i have a repeat of that!

So, i think i am running me head round in circles trying to work out how best to power my appliances.

At the moment, what i feel i will need is:

Fridge
Freezer
Ice Machine/Crusher
Juice Cooler (similar to slush puppy machine)
Lights (L.E.D.)
Sound System
And acouple of other little things...

I will be mostly using my setup in summer at festivals, so i would like to fit a solar panel on the roof. Maybe 2, to supply energy to the batteries.

I know power consumptions vary, but does anybody know if this kind of setup might be possible with 2 deep cycle AGM batteries? I would also get a generator to charge these batteries up when the sun is not so bright.

Is it ok to keep the chargers (generator or solar panel) plugged into the batteries whilst my appliances are drawing power?

What is the most efficient way of converting DC/AC? Obviously my generator produces AC, the batteries take DC, and most of my appliances will take AC. So i am trying to figure out a way of not having a converter and inverter in my setup. Maybe this is the only way? I've read that it draws alot of energy from the batteries to convert DC to AC?

I know theres afew questions here, and any response would be greatly appreciated!

Seth

 

[Marvo]

Hello everyone,

I have posted before on here regarding a mobile startup i am pursuing, and got some very helpful replies. So please can i have a repeat of that!

What was your other account name?

So, i think i am running me head round in circles trying to work out how best to power my appliances.

At the moment, what i feel i will need is:

Fridge
Freezer
Ice Machine/Crusher
Juice Cooler (similar to slush puppy machine)
Lights (L.E.D.)
Sound System
And acouple of other little things...

The power requirements of these items could be anything depending on the size of them, also they could be single or three phase. Each item should have a power consumption stated on it in KW or KVA or maybe a current requirement in Amps. You need to add these up to come to a total requirement but also diversity, start currents and power factor must be factored in so it's not as easy as it sounds.

I will be mostly using my setup in summer at festivals, so i would like to fit a solar panel on the roof. Maybe 2, to supply energy to the batteries.

I know power consumptions vary, but does anybody know if this kind of setup might be possible with 2 deep cycle AGM batteries? I would also get a generator to charge these batteries up when the sun is not so bright.

From your list I don't think you've got any chance whatsoever of running those items from 2 PV panels and 2 deep cycle batteries.

Is it ok to keep the chargers (generator or solar panel) plugged into the batteries whilst my appliances are drawing power?

Generally yes...

What is the most efficient way of converting DC/AC? Obviously my generator produces AC, the batteries take DC, and most of my appliances will take AC. So i am trying to figure out a way of not having a converter and inverter in my setup. Maybe this is the only way? I've read that it draws alot of energy from the batteries to convert DC to AC?

Your whole proposed setup doesn't make sense to me. Why would you want to use a 230v generator to charge batteries which in turn will be supplying an inverter that's supplying 230v to the appliances? Every time you convert from AC-DC or vice versa or change the voltage you have losses. If you're intending to use a generator why not just power everything direct from it?

 

[SethElton]

Hi Marvo,

Thanks for the reply.

What would be the easiest way to work out which appliances are single or three phase?

Lets take this bit of gear for example: KLARSTEIN RESTAURANT KITCHEN BAR ICE CUBE MACHINE 25KG FREE STANDING ICE MAKER | eBay

240watts, 240V= 1A? Running for 10 hours= 2.4KwH? Correct? If my calculations are right, this time of appliance would be able to run off a 240AH deep cycle battery for a very long time, no? I might have got this wrong because of the change between AC and DC.

I have also worked out (hopefully in the right way) that the fridges and freezers i would be using would only draw around 200w also (per unit), at around 2A... Does that sound right? New fridges have a power rating of about 172KwH per year: which equates to 19watts i believe. Not too much power being drawn there.

I suppose the reason i wanted to have the generator was to keep the batteries fully charged with a three stage charger. I suppose this dosn't really make too much sense when i say it out loud! I would like to if possible stay clear of a generator for noise, petrol and other reasons. If the festivals supply power, i could use there 240v for my appliances. I would need to keep my fridge and possibly freezer cold overnight, and i would prefer not to be doing this with a generator.

I don't just need the batteries to supply 230v. I also will be using 12v lights, speakers and maybe some other appliances. I am basically trying to figure out the cheapest way to run my setup. I have been looking at solar set ups that power deep cycle batteries in converted vans. They seem to be able to power fridges, tv's, speakers, fridges and water pumps, all without losing charge! I don't think solar is the way for me as i don't have constant sunshine, but if i was able to install some kind of setup that could keep my DC batteries charged, that would be great.

I am by no means an electrical expert, but i know i what i need in the end.

All the best,

Seth.

P.S. i didnt have another account, that was a mistake.

 

[Marvo]

The ice machine you've linked to is a 25kg machine, it will only produce 25kilos of ice in 24 hrs and often the manufacturers figures are wildly optimistic to say the least. Most 25 kilo ice machines are in the region of 400 watts energy requirement (here's the specs of the equivalent scotsman machine). It's a very small machine and I wouldn't see 25 kilos of ice going very far at a festival, for such small quantities of ice you might as well make it off site in advance and take it there in a couple of cooler boxes.

 

[SethElton]

Ok well scrap that. It was just an example really. I am going to need lots of ice so i also need to work out the best way to achieve that. What about the other issues i mentioned?

 

[Marvo]

If it were me I'd make the ice off-site or more likely I'd just purchase it ready made unless I was doing at least 1 or 2 festivals each month. I'd use large domestic chest freezers for storing and transporting the ice as well as keeping it cold at the festival so I'd suggest probably 2 x chest freezers and just use cooler boxes with some ice instead of a separate fridge. Because the ice is already made I'd look at 'absorption' freezers which run from a small LPG bottle, they don't have the raw refrigeration 'umph' of a compressor type freezer but they're great for maintaining product that's already at low temperature, no noise, polution-free (almost) and simplicity at it's best.

There are lots of pre-packaged solar/battery powered LED lighting kits available so in the interests of simplicity I'd find one of those that was suitable.

That just leaves your juice cooler and sound system which is a far more sensible load that you could run from a couple of PV panels and batteries with an inverter if necessary or just plug it in if they supply you with power. The absorption freezers also have the option to run from mains electricity if it's available.

 

[SethElton]

Hi Marvo,

Thanks, that info is very helpful.

So, i have bought an old milk float that i am renovating. The reason i have asked all this i because i am trying to figure the best way to kit it out. I am taking the batteries out and towing the vehicle.

I am selling one type of cocktail, with a dairy ingredient. So i know that i am going to need a fridge on board to hold the alcohol and dairy. My thinking at the moment is that when trading has finished for the day, i can stock the fridge again for overnight. My only concern is that i am going to have to keep the dairy cool for the entire weekend. And alot of it, at that!

The absorption freezer sounds like a good idea for the ice.

Once again, thanks for the help.

Seth

 

[SethElton]

On second thought absorption freezers seem to pretty large. Way to big for my humble little float

 

[PEG]

Hi Marvo,

Thanks, that info is very helpful.

So, i have bought an old milk float that i am renovating. The reason i have asked all this i because i am trying to figure the best way to kit it out. I am taking the batteries out and towing the vehicle.

I am selling one type of cocktail, with a dairy ingredient. So i know that i am going to need a fridge on board to hold the alcohol and dairy. My thinking at the moment is that when trading has finished for the day, i can stock the fridge again for overnight. My only concern is that i am going to have to keep the dairy cool for the entire weekend. And alot of it, at that!

The absorption freezer sounds like a good idea for the ice.

Once again, thanks for the help.

Seth

...Well there's your DC power pack,right there...although you will need 20 strong hippies,to push you off every field you visit...

The LPG fridges i have fitted,are normally tri-fuel,that is 240v/12 or 24v and LPG. they murder your 12/24v,and are mainly powered by this means,whilst driving,switching to one of the other methods,on parking up.

With a bit of planning,you could achieve operation of the kit you need,using a standard site 16A hook-up.

The feasibility of powering your float,using alternative means,will very much depend on what permissions you have,whilst on site,regarding things such as fuel storage,noise,duration of operation,cost,myther and patience.

I have had a bit of experience,with setting up spur-of-the -moment dragons' den this-time-next-year-rodney ideas...and it is usually better to come at it from the other angle.

Work out what you will be allowed to have/use. Calculate the power available from this,both in amplitude and duration.

Select your equipment according to this.

Good luck,dude.....my favourite character in "Cuckoo",is the yank with the tiny jacket potato van :wink5:

 

[SethElton]

Hippies are meant to be strong, no? Haha

I wish i could keep the batteries in but at this stage its not feasible. Maybe i can keep acouple in for DC power? Would you know if these could be charged with a standard 3 stage charger?

Sorry, so your saying that when driving and being parked up you would run the fridges on LPG?

Have you done the festival circuit?

I hope to be needing to much power in total. My main power consumption is keeping the alcohol, diary and ice cool. (I may even be able to keep the ice cold in a cooler) The other fly in the ointment is the amount of product that i will need. This is where things get difficult and a bit more expensivo.

Thanks for your help, but im afraid i dont know what 'Cuckoo' is!

 

[Lucien Nunes]

240watts, 240V= 1A? Running for 10 hours= 2.4KwH? Correct?

Correct

If my calculations are right, this time of appliance would be able to run off a 240AH deep cycle battery for a very long time, no?

Hmm. Energy capacity of 240Ah battery approx 240x12/1000 = 2.8kWh, allowing complete discharge in not less than 20 hours when new. Used cyclically at 5-10 hour discharge rate, as battery ages, don't expect more than 2kWh. Icemaker consumption 240W / 90% inverter efficiency = 270W. Run time = 2000/270 = 7.4 hours. Is that what you meant by a long time?

When looking at refrigeration energy usage in kWh/year, that is averaged over summer and winter for a specific amount of door-opening and product chilling. For a domestic fridge, opened ten times a day with 2kg of produce chilled, the consumption might be low as you suggest. But in peak summer, with commercial usage, you might have the compressor running all the time. Nothing is actually 19W, that's just an average. If the compressor is running it's whatever the compressor power is, a few hundred watts for a larger unit as you suggest. If you had four refrigeration units and a total of 1kW running load, your 240Ah battery would be caned by the 100A discharge rate and probably run you for a couple of hours max. unless everything was in your favour (new batt, cool weather, all produce cool when loaded etc.)

Also take heed of Marvo's point about optimistic figures. I was surprised by the 240W rating too, they probably aren't lying but everything needs to be just right to achieve the quoted performance. Feed it warm water or stop it overnight or whatever and it probably won't stay in spec.