Advice on buying generator please

[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?

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

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?

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

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

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

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

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

 

[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

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

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