Advice on buying generator please

[ice man]

Hi

I am looking at purchasing and running a drinks cooling machine to run on no mains electric what so ever!



The company that sells the machine have advised the following

Frequency: 50Hz Rated current: 5.5A Rated input: 800W



This machine is a liquid to liquid based (water and anti freeze bath) heat exchange and only runs when liquid is passing though it. And will only operate when I open the tap and fill a glass up from it so it will not be running most of the time



The two option I am considering is buying a generator inverter and battery and charging the battery up as required. Or just running the generator when it is in operation. So what do you think?



Thanks

 

[pc1966]

Looking after a generator is a pain, but presumably you don't have the options for that much power otherwise.

If it is a drinks machine you probably want as little noise as possible, so look for that in any specification as it might pay for a slightly bigger model that has a better silencer, etc.

Leaving generators running on no/light load is not good for them, especially diesel type (search for "wet stacking") so if you have the budget, space and transport (if necessary) then running a generator for short periods at high load to charge a large car/lorry/boat battery and then running your kit off an inverter from that might be better overall, even if the initial cost is a bit higher.

 

[Rockingit]

Is this for events use?

 

[Lucien Nunes]

Does this use compressor refrigeration? Your description suggests not, but if it does, allow for a compressor starting load of 3-5 times the running load. This is quite critical especially if it is designed to start against remaining head pressure. With an undersized generator or inverter if the compressor stalls and trips its thermal protection, it might not then be able to restart for a further 5 minutes. Also, if the load on a small generator is mostly from an induction motor, a self-regulating alternator will tend to drop out of voltage regulation due to the low power factor. An inverter generator or one with a proper AVR is beneficial.

Can you post or link to the machine specs?

 

[ice man]

Is this for events use?

yes it is

 

[ice man]

Does this use compressor refrigeration?

Can you post or link to the machine specs?

I dont know. Since the company selling the drinks chiller do not give out any info on manufature or diagram of the iteam. I know very little about it

 

[Rockingit]

yes it is

OK, I thought as much. Be aware that for a variety of reasons most event sites expressly forbid 'private' generators and insist that if you need power then it's provided by the event electricians (aka 'hook-up'). So before you spend anything I'd strongly suggest doing your homework on that aspect first. I say this as an experienced events electrician!

 

[marconi]

Hi

I am looking at purchasing and running a drinks cooling machine to run on no mains electric what so ever!



The company that sells the machine have advised the following

Frequency: 50Hz Rated current: 5.5A Rated input: 800W



This machine is a liquid to liquid based (water and anti freeze bath) heat exchange and only runs when liquid is passing though it. And will only operate when I open the tap and fill a glass up from it so it will not be running most of the time



The two option I am considering is buying a generator inverter and battery and charging the battery up as required. Or just running the generator when it is in operation. So what do you think?



Thanks

May I ask you to amplify what ‘drinks’ you want to ‘cool’? What form do the drinks have before the need to cool? Could you also say something about a typical day’s business selling these cooled drinks: How many in total? What volumetric quantity is each drink? What rate of sale? How many days per week, per month, per year?

and do want to keep already cool drinks cool or to cool drinks which presale are at ambient temperature?

 

[ice man]

OK, I thought as much. Be aware that for a variety of reasons most event sites expressly forbid 'private' generators and insist that if you need power then it's provided by the event electricians (aka 'hook-up'). So before you spend anything I'd strongly suggest doing your homework on that aspect first. I say this as an experienced events electrician!

sorry there is no chance of mains, but I will need a fairly silent generator like a Honda due to noise to local residents

 

[ice man]

May I ask you to amplify what ‘drinks’ you want to ‘cool’? What form do the drinks have before the need to cool? Could you also say something about a typical day’s business selling these cooled drinks: How many in total? What volumetric quantity is each drink? What rate of sale? How many days per week, per month, per year?

and do want to keep already cool drinks cool or to cool drinks which presale are at ambient temperature?

They are 11 kegs of beer that a forced out of the keg (at room temrature) by C02 and into the drinks cooler

To be used all weekend

 

[PEG]

Hi,i have done a similar project for a pal,and on assessment,we worked out the following....

You will not want a geny running full time,for sporadic use,and you will not want to start a geny,string or buttton,on every need...

Add to that the extra issues of fuel,security and reliability,and we plumbed for bank of 4 deep cycle batteries paralleled up to an inverter.

These were mounted in a cradle underneath the trailer,and charged up at base,and i believe we had to over spec the inverter,but it worked ok.

You may need to find out some details regarding the start current,running load,and cycle pattern of your chiller,in order to plan an accurate choice of useable stored power,remembering minimum voltage requirements,standby losses,etc.


Just to cheer you up,if you opt for a small,quiet generator,in the scenario described,get two....

If you don't have theft or a breakdown in the first dozen outings....it'll be a first?

 

[ice man]

Hi,i have done a similar project for a pal,and on assessment,we worked out the following....

You will not want a geny running full time,for sporadic use,and you will not want to start a geny,string or buttton,on every need...

Add to that the extra issues of fuel,security and reliability,and we plumbed for bank of 4 deep cycle batteries paralleled up to an inverter.

Where you running a drinks chiller? What kind of drinks where you doing?
Can you recomend any batteries; As they all very in size. What size inverter did you have?
Thanks

 

[marconi]

I designed a system to power 20 odd catering vans, each with chest freezer, 2 tall larder fridges, lighting and payment system using solar power Mar-Oct - and on peak solar days in summer a 1kW hand hot water heater. Other times a Honda engined 3.4kVA LPG generator with automatic voltage regulator provides van power during opening hours and charges the batteries for overnight use.

This is the robust 3kW inverter which has a very high peak power capability (9kW), pure sinewave and 'sleep' mode when load drops below 75W and wake up when load rises above this figure which conserves battery power.

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine - https://www.photonicuniverse.com/en/catalog/full/164-3000W-24V-low-frequency-pure-sine-wave-off-grid-inverter-peak-power-9000W.html

Batteries are Advanced Gel Matrix by Victron:

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine - https://www.photonicuniverse.com/en/catalog/full/470-200Ah-12V-Gel-deep-cycle-battery-for-motorhomes-caravans-boats-and-off-grid-power-systems.html

Either 6 x 200Ah or 4 x 300Ah, wired in strings of 2 batteries in series to give 24V and these then connected in parallel. The theoretical power available from fully charged to batteries 'flat' is 12 x 1200 = 14.4kWh but this is not achieved nor relied upon. Instead the batteries are never discharged more than 50% to preserve their life; thus about 7kWh is the working amount of electrical energy available.

7kWh would run an 800W cooler constantly for 7000/800 = about 9 hours.

This system is static apart from when the catering van is driven to and from site for its annual maintenance and refurbishment - the electrical wiring and electronics is only shaken about for a few hours each year. Of 20 vans we have only had one inverter failure which was on arrival not when in use and the supplier replaced it.

Don't operate at 12V. Use 24V and the cabling must be multi-stranded with properly crimped on ring terminals tightly bolted. One needs to buy a hydraulic crimper tool.

The amount of energy stored in each battery and then as a bank is extraordinarily high and it is highly dangerous if a battery or the bank is short circuited or if there is a fault current. Circuit breakers are essential and the battery must be located in an lockable enclosure. Special precautions, insulated tools and personal protective equipment are required when connecting up the batteries and high current 24 V cabling: this is a job for a skilled person. I wrote a procedure to do this which is followed to the letter.

The flat roof of the catering vans has a 1.5kW array of solar voltaic panels to charge the batteries.

On the mains voltage side everything has to be done to meet the IET electrical installation regulations and my client (brother in law) has to have annual certificates for inspection and testing including PAT of the electrical items for him to operate. We include the 24V dc and the solar photovoltaic wiring in the inspection and testing since it too can kill or harm just as much as the 240V.

I will not say more because I do not want to design your working safe system. There are safety features and programming of the inverter to do for the intended application. I suggest you contact Tom at Photonics Universe for further advice and an electrician familiar with off-grid battery to mains installations. I strongly advise against doing it yourself because you are not competent and do not know how to deal with all the risks.

PS: I am not saying this set up will satisfy your requirement. I have not done the analysis which should include whether you would be wiser to just use a generator to meet the business and operational requirement as distinct from the technical requirement.

 

[marconi]

I should have said that there was a business requirement for constant availability of power 24/7/365 in the application I mentioned.

 

[pc1966]

Just to add for the OP that "you are not competent" has a specific meaning in terms of electrical regulations. They divide people in to electrically skilled and competent (i.e. trained electricians and the like) who can be expected to work safely on electrical systems, and the rest of the population.

It has nothing to do with your competence in any other aspect of life!

 

[ice man]

I designed a system to power 20 odd catering vans, each with chest freezer, 2 tall larder fridges, lighting and payment system using solar power Mar-Oct - and on peak solar days in summer a 1kW hand hot water heater. Other times a Honda engined 3.4kVA LPG generator with automatic voltage regulator provides van power during opening hours and charges the batteries for overnight use.

This is the robust 3kW inverter which has a very high peak power capability (9kW), pure sinewave and 'sleep' mode when load drops below 75W and wake up when load rises above this figure which conserves battery power.

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine - https://www.photonicuniverse.com/en/catalog/full/164-3000W-24V-low-frequency-pure-sine-wave-off-grid-inverter-peak-power-9000W.html

Batteries are Advanced Gel Matrix by Victron:

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine - https://www.photonicuniverse.com/en/catalog/full/470-200Ah-12V-Gel-deep-cycle-battery-for-motorhomes-caravans-boats-and-off-grid-power-systems.html

Either 6 x 200Ah or 4 x 300Ah, wired in strings of 2 batteries in series to give 24V and these then connected in parallel. The theoretical power available from fully charged to batteries 'flat' is 12 x 1200 = 14.4kWh but this is not achieved nor relied upon. Instead the batteries are never discharged more than 50% to preserve their life; thus about 7kWh is the working amount of electrical energy available.

7kWh would run an 800W cooler constantly for 7000/800 = about 9 hours.

Did you use all of that set up to power all of the vans at once?

 

[marconi]

No, poor writing. Each van had an installation since the fleet of them is dispersed around England. I tried to persuade my client/BIL to use Honda inverter generators but he continued with the conventional Honda GX engined frame generators because he and his team knew them so well and had a maintenance and repair set-up for them already. It is the engine which fails not the alternator. My BIL changes engines and sets them up to start and run correctly.

Generators are attractive items to 'certain' folk and are easily stolen unless solidly chained to something immovable or built in to the structure. Overnight or when unattended, if not built in to the structure behind a very strong locked door (obviously when shut down) or if left chained up outside they will soon disappear.

 

[ice man]

No, poor writing. Each van had an installation since the fleet of them is dispersed around England.

Surly you are not tell me each van had 6X £350 vorth of batteries and a £500 invertor to run a couple of houes hold fridges?

 

[ice man]

The company that sells the machine have advised the following

Frequency: 50Hz Rated current: 5.5A Rated input: 800W

This is the robust 3kW inverter which has a very high peak power capability (9kW), pure sinewave and 'sleep' mode when load drops below 75W and wake up when load rises above this figure which conserves battery power.

Surly not in my case is it not?

 

[ice man]

...........error post

 

[marconi]

Yes. If food is kept in a fridge or freezer to be sold to the general public then those fridges and freezers must always have electricity to maintain their correct temperature. It is not satisfactory to rely on their insulation. This applies to my clients business and is a condition of his licence to operate on the sites he trades at.

We tried electric-start Honda frame generators triggered to start by a separate thermostat inside the fridges and freezers but they did not start reliably and had to be exposed to the possibility of theft in order to run. The modifications to do this to the van were unacceptable we decided after doing one van.

When I did the analysis, it is more economic too because the generators consume less gas, break down less frequently and have a longer life. Two other benefits are the van is quieter more of the time and produces less CO2. The staff, mainly women, also like not having to start and stop and regularly checking the gennie.

As I finished with in one of my earlier posts I am not suggesting this is your solution but rather something similar and at a smaller scale. For example you said it only operates at the weekend whereas my solution is every hour, every day all year.

 

[marconi]

The first vans used a 2kW (6kW peak) inverter without problem. We upped the power to 3kW because we wanted to have the spare capacity to run other equipment which so far has not happened. The marginal increase in cost was small.

I have most likely taken you down a rabbit hole and your solution will be much simpler and cheaper. I did suggest you contact Tom and an electrician who does off-grid installations. Or you can just buy a generator after seeking advice on kVA from the supplier. It is difficult to advise you on kVA without knowing more about the beer cooler refrigeration system so we tend to say anywhere between 5-10 times the running power for generator kVA and buy one with an automatic voltage regulator AVR. It becomes a little more complicated if you have several motors supplied by the same generator but you indicate you only have one to start.

 

[pc1966]

Surly you are not tell me each van had 6X £350 vorth of batteries and a £500 invertor to run a couple of houes hold fridges?

It really is a design aspect. You and whoever is doing the electrical design side have to work out what the load is:

• Peak demand as fridge(s) kick in as that sets the inverter size)
• Average between charging based on the insulation quality, throughput of drinks bring cooled, and any other loads (e.g. LED lights, payment system, etc) as that sets the battery size.

If you can charge from mains overnight then it might be worth spending more on batteries and not on a generator.

If you simply have to have a generator (e.g. parked in the middle of nowhere for days on end, etc) then you might decide on smaller and cheaper batteries and a charge pattern of running the genny a couple of times per day (ideally electronically controlled starting so staff don't need to worry about it). But then you have the issues of safe ventilation for CO poisoning risk, fire hazards if near dry long grass or similar, any permits/permission or restrictions for handling/storing fuel (near arable land, rivers, etc), the risk of theft, ongoing maintenance costs for the generator's engine, etc.

 

[marconi]

It really is a design aspect. You and whoever is doing the electrical design side have to work out what the load is:

• Peak demand as fridge(s) kick in as that sets the inverter size)
• Average between charging based on the insulation quality, throughput of drinks bring cooled, and any other loads (e.g. LED lights, payment system, etc) as that sets the battery size.

If you can charge from mains overnight then it might be worth spending more on batteries and not on a generator.

If you simply have to have a generator (e.g. parked in the middle of nowhere for days on end, etc) then you might decide on smaller and cheaper batteries and a charge pattern of running the genny a couple of times per day (ideally electronically controlled starting so staff don't need to worry about it). But then you have the issues of safe ventilation for CO poisoning risk, fire hazards if near dry long grass or similar, any permits/permission or restrictions for handling/storing fuel (near arable land, rivers, etc), the risk of theft, ongoing maintenance costs for the generator's engine, etc.

Nicely put.

 

[ice man]

Yes. If food is kept in a fridge or freezer to be sold to the general public then those fridges and freezers must always have electricity to maintain their correct temperature. It is not satisfactory to rely on their insulation. This applies to my clients business and is a condition of his licence to operate on the sites he trades at.

Did you or him ever consider consider cooling down with ice every day?

We tried electric-start Honda frame generators triggered to start by a separate thermostat inside the fridges and freezers but they did not start reliably and had to be exposed to the possibility of theft in order to run. The modifications to do this to the van were unacceptable we decided after doing one van.

When I did the analysis, it is more economic too because the generators consume less gas, break down less frequently and have a longer life. Two other benefits are the van is quieter more of the time and produces less CO2. The staff, mainly women, also like not having to start and stop and regularly checking the gennie.

So did you not bother with generators for the rest of the fleet in the end; where by you charged the batteries up from mains from a building?

I have most likely taken you down a rabbit hole and your solution will be much simpler and cheaper. I did suggest you contact Tom and an electrician who does off-grid installations. Or you can just buy a generator after seeking advice on kVA from the supplier. It is difficult to advise you on kVA without knowing more about the beer cooler refrigeration system so we tend to say anywhere between 5-10 times the running power for generator kVA and buy one with an automatic voltage regulator AVR. It becomes a little more complicated if you have several motors supplied by the same generator but you indicate you only have one to start.

I have looked online again for other beer chiller as I was not happy with the tecnical speck I was given for the chiller I was quoted for. Have a look at this one
BRW36H Series Water Cooled Range Base - https://www.booth-dispensers.co.uk/Catalogue/Products/Brewery-Equipment/Beer-Coolers/BRW36H-Series-Water-Cooled-Range-Base-2
Its about the closest I could find to my needs. there is the option on that page to download a manual but you have to email the company to get it (so have done so)

You said on this project for you customer you installed fridges for him. Are these domestic type fridges? The reason I ask is I was adviced not to use fridges as they do not oporate well when in transit. The gases need to settle first and can take up to 24hrs. I was also told that they only consume a lot of power when they start up from warm and cool the contence of the fridge down. But once cool they use very little power keeping them cool at all

 

[ice man]

Either 6 x 200Ah or 4 x 300Ah, wired in strings of 2 batteries in series to give 24V and these then connected in parallel. The theoretical power available from fully charged to batteries 'flat' is 12 x 1200 = 14.4kWh but this is not achieved nor relied upon. Instead the batteries are never discharged more than 50% to preserve their life; thus about 7kWh is the working amount of electrical energy available.

I was always on the idea that batteries should by fully charged and then fully discharged to flat and fully charge again to increase there life spam. Is this then wrong? or dose it depend on the type of battery?
Thanks

 

[marconi]

Taking your questions in order:

1. My client has 20 or so vans at 20 or so locations. He would have to build 20 ice making systems and then transport the ice blocks each day of the year. It is however a very good idea to keep the freezers filled up with frozen goods and if they cannot be done with produce then frozen blocks can fill in the gaps. He keeps his freezers over half full.

2. I was not clear enough. Each van still has a generator to cover the winter months and some prolonged periods during the year when sunshine alone is not enough to keep the the batteries sufficiently charged. The batteries must have by the end of working day enough power to maintain the refrigeration overnight and on some sites from close of play Saturday to opening up Monday morning. All his fridges and freezers have max and min thermometers inside them to check the food has been kept safely frozen or chilled. Before going on site the fridges and freezers are brought to the required temperatire either from solar of mains. It depends on the time of year they first arrive on site after refurbishment or from start up.

3. He was not allowed access to the site‘s power supply, not even from lamp standards nearby. He had to be completely off grid.

4. I repeat, in order for him to obtain a licence to operate and liability insurance The fridges and freezers have to have power available constantly for them to run as demanded by their thermostats. He previously operated using gennies running during the day and reliant upon the freezer or fridge insulation keeping contents cold enough when the van was closed for business. Alas, another licence holder, using the same scheme sold some burgers which had been defrosted while the gennie was shut down overnight in hot summer period and then refrozen when the genie was running again next day, and then cooked. the punter who ate them was very poorly afterwards.

5. I will read the product spec you provided tomorrow.

6. My client buys domestic fridges and they are changed for new every couple of years. He buys LEC and the ones capable of being placed in a warm environment - fridges and freezers have environmental classes to suit where they are used in the world. This should be taken into account also for one placed in a warm garage or conservatory.

7. Yes, one should allow some time for the gas to settle before powering up after significant motion of them. My client allows a few hours not 24 hours.

8. Yes, Fs and Fs need time and energy to cool their contents to the point that they are thermostatically regulated in temperature. Opening the door or lid of course will demand some energy during normal operation and placing products inside which need cooling. Every time the motor starts to run the compressor there is a brief surge in power/current drawn to quickly accelerate the mechanical components to running speed. When running the power/current is that necessary to run the refrigeration. Think about you having to quickly run up to speed a children’s roundabout and the compare that to with what is required from you to keep it at that speed. The same physics applies.

9. Batteries- a vast subject. You get what you pay for and their life and degradation of capacity t9 store energy over time depends much on how they are charged over time and depth of discharg and what temperature they operate in and what temperature the heating effect of the current which flows in them causes. Too much to cover right now. I specified top end victron brand batteries. Two years on the first few vans are still performing well on their original batteries.

 

[ice man]

4. I repeat, in order for him to obtain a licence to operate and liability insurance The fridges and freezers have to have power available constantly for them to run as demanded by their thermostats. He previously operated using gennies running during the day and reliant upon the freezer or fridge insulation keeping contents cold enough when the van was closed for business. Alas, another licence holder, using the same scheme sold some burgers which had been defrosted while the gennie was shut down overnight in hot summer period and then refrozen when the genie was running again next day, and then cooked. the punter who ate them was very poorly afterwards.

You are only supposed to freeze raw meet once you see

6. My client buys domestic fridges and they are changed for new every couple of years. He buys LEC and the ones capable of being placed in a warm environment - fridges and freezers have environmental classes to suit where they are used in the world. This should be taken into account also for one placed in a warm garage or conservatory.

Domestic fridges are availbe and as cheep as chips second hand on ebay. And this is why I first considered using them as kegorators as they would do bough the work of the cellar cooler and the beer chiller. But I was concerned about over all power that they would use being to much.

So being an electrion man and since you have worked with domestic fridges. Can I ask you what the typical draw of an typical domestic under the counter fridge would use. And by that I dont mean warm start where it has to chill the contence of the fridge. I just mean its typical power consumtion keeping it all ready cool!

8. Yes, Fs and Fs need time and energy to cool their contents to the point that they are thermostatically regulated in temperature. Opening the door or lid of course will demand some energy during normal operation and placing products inside which need cooling. Every time the motor starts to run the compressor there is a brief surge in power/current drawn to quickly accelerate the mechanical components to running speed. When running the power/current is that necessary to run the refrigeration. Think about you having to quickly run up to speed a children’s roundabout and the compare that to with what is required from you to keep it at that speed. The same physics applies.

Yes I know what you mean! I pedal my bike up to speed then to keep it up to speed is nothing compared to getting it there. But if I let go I free fall all that energy I used to get it up to speed. So in the same way it takes a lot of energy and time to get the fridges to cool the contence. If you switch them off it will take a long time to heat back up again
Thanks

 

[ice man]

9. Batteries- a vast subject. You get what you pay for and their life and degradation of capacity t9 store energy over time depends much on how they are charged over time and depth of discharg and what temperature they operate in and what temperature the heating effect of the current which flows in them causes. Too much to cover right now. I specified top end victron brand batteries. Two years on the first few vans are still performing well on their original batteries.

Ow I hope you dont mind me bringing this question up; but briefly; what make those batteries you buy better then the typical Leisure batteries for caravan found at places like this

Leisure Batteries | Free Delivery | Leisure Battery

Leisure Batteries for Caravan, Motorhome, Motor Mover, Boat and Marine. Cheap Leisure Battery with Free next day delivery in the UK. Best Leisure Battery Range.

advancedbatterysupplies.co.uk

Is it the life span or power out put?
Thanks

PS is it some kind of fleet of tea wagons your client runs or something?

 

[marconi]

Fridge or freezer energy consumption: I would look up the specification of the appliance or a number of similar ones and then take the average. So for a typical fridge and freezer whose data sheets are attached the figures are 128kWh per annum and a freezer 209kWh per annum. Divide by 365 to obtain daily consumption. Then consider the difference between the domestic setting these figures refer to and your intended one eg: will the door or lid be opened more or less often.

Thus a larder fridge with auto defrost is 128/365 = 0.35kWh a day (I would assume a figure of 0.5kWh for clients use.)
For chest freezer 209/365 = 0.57kWh (I would assume a figure of 0.7kWh)

Batteries: I am not a battery expect so had to do some research on brands and specifications. I looked at Leisure and Boating forums and googled 'which is the best leisure battery?' or 'is victron a good make of lesiure battery?' There are other good makes no doubt but I settled on Victron which was also stocked by the equipment supplier we used who happens to be close to my client's offices. If I could not obtain a comprehensive specification on the brand and battery I did not consider them.

Victron Advanced Gel Matrix are good because they are safe (don't spill acid), well made, sealed, fully specified and certified, have high charge/discharge cycles, age slowly and provided charged up carefully and discharged to no more than 50% will only slowly fall in storage capacity. Victron is a Dutch company which appealed to my client and me. You will often find Victron equipment in smart motor yachts. We discounted Li ion as too expensive.

Yes teas, coffees, sandwiches, griddle cooked food, chilled soft drinks.

Sir.....spend some time writing down a requirement (what you want and don't want) and then contact a few local off grid supplier for a proposal and price. Or 'do it yourself' noting my earlier remarks well though and you may or may not be successful. My solution had to work and be safe and reliable because it was essential to the bottom line of my client. Your requirement is much different - 2 days a week for how many weeks? One off. You are the operator.......

 

[ice man]

Fridge or freezer energy consumption: I would look up the specification of the appliance or a number of similar ones and then take the average. So for a typical fridge and freezer whose data sheets are attached the figures are 128kWh per annum and a freezer 209kWh per annum. Divide by 365 to obtain daily consumption. Then consider the difference between the domestic setting these figures refer to and your intended one eg: will the door or lid be opened more or less often.

Thus a larder fridge with auto defrost is 128/365 = 0.35kWh a day (I would assume a figure of 0.5kWh for clients use.)
For chest freezer 209/365 = 0.57kWh (I would assume a figure of 0.7kWh)

I looked at web sites like curry's and argos, going though some of there fridges and they listed nothing about power consumtion! But good google search you found there

Batteries: I am not a battery expect so had to do some research on brands and specifications. I looked at Leisure and Boating forums and googled 'which is the best leisure battery?' or 'is victron a good make of lesiure battery?' There are other good makes no doubt but I settled on Victron which was also stocked by the equipment supplier we used who happens to be close to my client's offices. If I could not obtain a comprehensive specification on the brand and battery I did not consider them.

Victron Advanced Gel Matrix are good because they are safe (don't spill acid), well made, sealed, fully specified and certified, have high charge/discharge cycles, age slowly and provided charged up carefully and discharged to no more than 50% will only slowly fall in storage capacity. Victron is a Dutch company which appealed to my client and me. You will often find Victron equipment in smart motor yachts. We discounted Li ion as too expensive.

I would always go for the Platium brand myself as I know they have a good name in the motor factor biz

Leisure Batteries | Free Delivery | Leisure Battery

Leisure Batteries for Caravan, Motorhome, Motor Mover, Boat and Marine. Cheap Leisure Battery with Free next day delivery in the UK. Best Leisure Battery Range.

advancedbatterysupplies.co.uk

But there again car batteries rang in life spam waranty from 1 year to 4 (or maybe 5 at best)
My mum and dad live in the out back with no mains electric and rely on a generator. When generator man showed up to fix it, I could not belive at fist what he was saying that the batteries they use last for 18 years

Sir.....spend some time writing down a requirement (what you want and don't want) and then contact a few local off grid supplier for a proposal and price. Or 'do it yourself' noting my earlier remarks well though and you may or may not be successful. My solution had to work and be safe and reliable because it was essential to the bottom line of my client. Your requirement is much different - 2 days a week for how many weeks? One off. You are the operator.......

So the 2 plans I have is to either use a cooler room with room cooled to 10C that will run all the time, then into drinks chiller that will only run when the tap is open and beer is being served
Or just to run apox 8 domestic fridges all the time to do the work of bough (commonly know as a kegorator)

So if I went with the later one then I would have 8 domestic fridges. Based upon the numbers you supplied above.
0.5kWh X 8 fridges = 4kWh
I am unable to do the maths hear as I just dont understand the discharge (%) rates listed for batteries
But if I wanted to run 8 fridges off of a battery inverter and generator and I was prepered to run the generator twice a day to charge the batteries up. How many of those photonic batteries you listed before would I need?

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I know it states 200AH, But again I dont understand how this equates into discharge proportions.
Because I have experenced before that an inverter will automaticaly switch its self off when power from the battery is low

 

[ice man]

So if I went with the later one then I would have 8 domestic fridges. Based upon the numbers you supplied above.
0.5kWh X 8 fridges = 4kWh
I am unable to do the maths hear as I just dont understand the discharge (%) rates listed for batteries
But if I wanted to run 8 fridges off of a battery inverter and generator and I was prepered to run the generator twice a day to charge the batteries up. How many of those photonic batteries you listed before would I need?

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I know it states 200AH, But again I dont understand how this equates into discharge proportions.
Because I have experenced before that an inverter will automaticaly switch its self off when power from the battery is low

OK I have ad a brief go at the maths on how long that 200 amps/hr battery should last on 8 fridhes

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I am sure that this will be completely wrong! So please correct me

Fridges
0.5kWh a day x 8 fridges = 4kWh a day = 4000Wh /24hr = 166.6Wh

Battery
200Ah x 12V = 2400Wh

2400Wh/ 166.6Wh = 14.4hrs of battery life

 

[marconi]

I admire folk who persist and don’t give up. I will look at your sums tomorrow . But at the moment Maud, the recorded semis of the snooker and then line of duty have greater attraction ?

 

[marconi]

As I said I am no expert in batteries and brands of but I reckon there will be a difference between the battery life and guarantees/specifications of performance when it is used primarily for a few seconds to crank an engine and when used regularly for prolonged discharge to a deeper depth of discharge. Hence the rather odd phrase 'leisure battery'. I know nothing about the Platinum make.

To do the analysis of battery and generator charging I need to know how long the battery alone must provide power and remain above 50% discharge. In my clients case from shut up shop 7pm Saturday evening to opening up 7am Monday morning.

 

[pc1966]

I would agree with @marconi that you definitely want some over-provision of capacity to cover changes in load pattern, the battery capacity dropping over a couple of year's life, and losses in the conversion process from low voltage DC to 230V AC.

Also as already mentioned you don't want to be using 12V as then the current is huge, so your 5-10A for one or two fridge motors kicking in at 230V becomes 96A-192A at 12V. So if you and some PV specialist decide that, say 300Ah capacity is enough for your daily use-pattern it would still be far better to have that as 24V or 48V and consisting of a 2 * 150Ah or 4 * 75Ah 12V batteries in series coupled with appropriate protection and matching voltage of inverter/charger.

Also they will be a lot easier to wrangle as lead-acid batteries main disadvantage is high weight!

 

[Lucien Nunes]

Just to fill in this point:

I was always on the idea that batteries should by fully charged and then fully discharged to flat and fully charge again to increase there life spam. Is this then wrong? or dose it depend on the type of battery?

Yes it depends on the type of battery. Lead-acid batteries such as we are considering here do not like to be deeply discharged. Every deep discharge shortens their life; the deeper you go, the more they degrade. After using the battery, no matter how much or little charge has been taken out, the best thing for a lead-acid is to be fully recharged as soon as possible. For any ideal application there is a correct size battery that will give most bang for the buck, by not being over-large and expensive and not discharged very much per cycle, but also not being too small and having to go into deep discharge and losing lifespan as a result.

The idea of always discharging a battery fully related to NiCads in the 1980s and 90s, which would develop a 'memory' of how deeply they were discharged last time and deliver a reduced voltage on the next cycle if discharged more deeply. But since the ban on cadmium that chemistry is no longer used.

 

[ice man]

To do the analysis of battery and generator charging I need to know how long the battery alone must provide power and remain above 50% discharge. In my clients case from shut up shop 7pm Saturday evening to opening up 7am Monday morning.

I dont really understand this 50% discharge and how it relates to the 200AH quoted in the description

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[ice man]

Also as already mentioned you don't want to be using 12V as then the current is huge, so your 5-10A for one or two fridge motors kicking in at 230V becomes 96A-192A at 12V. So if you and some PV specialist decide that, say 300Ah capacity is enough for your daily use-pattern it would still be far better to have that as 24V or 48V and consisting of a 2 * 150Ah or 4 * 75Ah 12V batteries in series coupled with appropriate protection and matching voltage of inverter/charger.

But the overall power consumption (W) is still the same right!
If this was an advantage then all cars and bikes would be 48V

 

[ice man]

BTW I got this data sheet from the manufature of the drinks cooler

 

[ice man]

OK I have ad a brief go at the maths on how long that 200 amps/hr battery should last on 8 fridhes

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I am sure that this will be completely wrong! So please correct me

Fridges
0.5kWh a day x 8 fridges = 4kWh a day = 4000Wh /24hr = 166.6Wh

Battery
200Ah x 12V = 2400Wh

2400Wh/ 166.6Wh = 14.4hrs of battery life

I have just rang the above company about there batteries and asked him how the maths on 200AH work. And he states that that figure will be for 100% discharge which he strongly dose not recommend!
He said to aim between 30-50% of discharge to prolong the life of the battery. So meaning if I worked at 50% then 200AH would now only be 100AH

I also asked him when he though the inverter would trip and he said it depends on the inverter but its normerly about 11amps. He said it was hard to equate into amprage but reconed it would be about 70-80% of discharge. Again he stated going to such low level of low voltage is bed battery health

He also stated that the life spam of a battery is done on cycles and not over time (like a manufatures warranty) He said if it never got used and remained fully charged all the time then it would last forever, but he said they do discharge over a period of time even when not in use

 

[ice man]

OK I have ad a brief go at the maths on how long that 200 amps/hr battery should last on 8 fridhes

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I am sure that this will be completely wrong! So please correct me

Fridges
0.5kWh a day x 8 fridges = 4kWh a day = 4000Wh /24hr = 166.6Wh

Battery
200Ah x 12V = 2400Wh

2400Wh/ 166.6Wh = 14.4hrs of battery life

I have just rang the above company about there batteries and asked him how the maths on 200AH work. And he states that that figure will be for 100% discharge which he strongly dose not recommend!
He said to aim between 30-50% of discharge to prolong the life of the battery. So meaning if I worked at 50% then 200AH would now only be 100AH

So if I have gotten all of this right then. If I am aiming at charging my batteries twice a day at a 30-50% discharge then I am going to need 2 of the above battaries for this equation to work?

 

[pc1966]

But the overall power consumption (W) is still the same right!
If this was an advantage then all cars and bikes would be 48V

Electric cars often are 48V

Larger vehicles, boats, etc, often are 24V.

You need to look at the peak demands, what sort of inverts are available (i.e. are they 12V, 24V, etc) and then how they can be hooked up and protected. Cables rated to carry 200A for any length of time are pretty large and difficult to work with, and you (or the designer) need to consider aspects such as a breaker for fault/overload protection and to allow the supply to be isolated for maintenance work.

 

[ice man]

Electric cars often are 48V

Larger vehicles, boats, etc, often are 24V.

Well the last time I looked inside my engine bay it was a 12V battery.
The reason large vehicles are 24V and boats 36V. Is because they are longer then cars and the brake lights would flicker on a lorry at 50 feet at 12V

 

[ice man]

BTW I got this data sheet from the manufature of the drinks cooler

The data sheet for this beer chiller says it power consumption is 627W. The beer chiller will only work when beer is being drawn off of the beer tap.

So if we said I was to sell 100 pints a day at 30 seconds a pour would mean 50 minutes of use per day.
Which is (50mins/ 60 mins) 0.83 of an hour. X 627W = 522.5W total power consumption for this machine for one day.

So the battery in question is rated at 200AH x 12V = 2400Wh total battery life. But at a 50% discharge equates to 1200Wh battery power

1200W/ 522.5 = 2.30 days before the battery needs charging.

With out doing the maths or anything. Dose this sound about right for a load of this kind on a battery of this size?
Thanks

 

[ice man]

Now I am going to move on to the generator that I would need to charge my batteries up
Again based on my maths. But no one has commented yes as to if they are spot on or far out!

for the 200AH battery in question
200AH x 12V = 2400Wa @ 50% discharge = 1200Wh

if I want the generator to run for say half an hour to charge the battery then I am going to want a 2400W generator right? (1200Wh x 1/2hr)

So for charging 2 batteries in half an hour dose this mean a 4800W generator?
Thanks

 

[marconi]

My #34 second paragraph- you have not provided the information.

 

[ice man]

My #34 second paragraph- you have not provided the information.

Im not quite so sure what you are asking hear but......

As I said I am no expert in batteries and brands of but I reckon there will be a difference between the battery life and guarantees/specifications of performance when it is used primarily for a few seconds to crank an engine and when used regularly for prolonged discharge to a deeper depth of discharge. Hence the rather odd phrase 'leisure battery'. I know nothing about the Platinum make.

To do the analysis of battery and generator charging I need to know how long the battery alone must provide power and remain above 50% discharge. In my clients case from shut up shop 7pm Saturday evening to opening up 7am Monday morning.

Leisure battery or better term deep cycle batteries are not what you find on a car! car batteries use a different type. Commonly refered to as CCA (cold cranking amps). A deep cycle battery will simplely not start an engine and a CCA battery will not last as long as deep cycle.

Anyone in the motor trade will know all about Platinum batteries. They are one of the best!

But again I am not quite so sure what you are asking hear. Because if I had the 200AH battery in question that I would discharge it to 50%. Then what size generator would you recomend if I wanted to charge it up for say 30 minuts?
Thanks

 

[marconi]

I’m out of this. Over to others.

 

[ice man]

???????????????????

 

[ice man]

right well I think we are not going to get a stright answer hear so best pack it all up and close down my account