a) Looking at the schematic diagram (11/9/2002) shows that the current setup can accommodate solar panels, optional charging from the car and optional battery
b) I have a dual battery system in the 4x4 for the cooler box etc. While driving and using the dual battery system, can I still charge the caravan from the car?
I'm looking for installers in Joondalup, familiar with Jayco, that can tell me what needs to be installed to take off the grid?
What appliances can I use and for how long?
What performance can I get - how long can I stay off the grid?
Will do a separate post for Internet coverage
Thanks
Gerrard
-- Edited by ottg on Tuesday 19th of October 2021 06:08:45 PM
Whenarewethere said
06:10 PM Oct 19, 2021
How long do you want to stay off grid?
North or South or both?
If you are running a 2.5kW home split system air conditioning off batteries you will need a decent setup.
200L fridge bigger system.
Induction cooking bigger....
Your limiting factor won't be dollars but it will be your payload. Even with quality Victron lithium, solar panels & controllers weight adds up very quickly.
Look up the mass of each item & work back from there. Including wiring, solar panel pads & switch gear.
Draw up an accurate scale plan of the caravan roof to see what size panels you can fit. Watch out for self shadowing. Stuffing the roof too full will back fire if you have shadows. Far cheaper to make a mistake on a drawing.
PeterD said
07:21 PM Oct 19, 2021
Most of us do not consider camping as a relocation of home style living. We are prepared to so without things like cappuccino coffee and are content with a good instant coffee (or percolate it over the gas stove.) As soon as you start installing inverters and using 230 V appliances you need large battery systems. Those that insist on transferring their domestic living into the camping world spend $3,000 or considerably more on their battery systems. We also have all of our things running off 12 V and do not use inverters.
If you are like the majority of us and are content to only using the batteries for lighting, radio, TV and communications you can get away with a 100 Ah battery and a 150 to 200 W solar panel (I live comfortably off an 80 W pane.) [in the early days we just used stoplight globes for light and powered them from the tugs battery.] If you are prepared to live simply you can install a small system and be quite comfortable. If you wish for the comforts of home prepare to spend big bickies on your solar system and more money on upgrading the carrying capacity of your van to carry the batteries.
Don't be sucked into purchasing big inverters. Those who sell them at caravan shows tell you how you can power all sorts of things with big inverters. They neglect to inform you of the battery capacity need to drive them.
-- Edited by PeterD on Tuesday 19th of October 2021 07:24:27 PM
Jaahn said
07:38 PM Oct 19, 2021
Hi
I suggest that you spend a bit of time looking at the Solar sub forum at the top of the Techies Corner as well as here on the Techies Corner. Plenty of discussion.
To help you there is also a SEARCH function of this forum at the top of the page under the Adds. Do a bit of home work and see what you find.
I like to think a forum is a conversation between the members not just a question and answer for new members.
Jaahn
-- Edited by Jaahn on Tuesday 19th of October 2021 07:41:38 PM
Whenarewethere said
08:57 PM Oct 19, 2021
We stay off-grid as long as our water lasts. Our batteries will keep our fridge going for a week, but we pull out the solar panels after 4 days. So we have plenty of reserve for inclement weather.
We grind our beans by hand & have very nice coffee with filtered water heater with metho.
Everything that needs electricity runs off 12 volts. We have avoided 240 volts to make life easier. We have 2xAA rechargeable toothbrushes.
yobarr said
09:17 PM Oct 19, 2021
Do it once,do it well.You should have plenty of room on 15ft van as panels are (roughly) 1900 x 1000.The panels also keep the van a lot cooler,just as they do when on a house roof. Yesterday it was 41 degrees where I am travelling,and the AC was on all night,from batteries.This morning batteries were on 85.9% and 12.96 volts.Back up to 100% before 8.30am. There are no gas appliances in my van.nothing.Cheers
-- Edited by yobarr on Tuesday 19th of October 2021 09:26:18 PM
I have a couple of Daikin AC in a unit I let to tenants. One is a small 2.5kW model, brilliant at what it can do both high, low settings & also dehumidifying setting.
Yobarr, I am assuming you maybe running your AC at some level of low output overnight. It would be interesting some power input numbers as the manufacturers only seem to state power input at rated output which is not a lot of help if one wants to run it at a low power level for people who maybe a touch under capacity with batteries.
Obviously running the AC on a low setting it won't cool as much & will be a bit less efficient, but it may get one through the night if one has X amount of AH.
It is surprising how well these things cool even if they are on the dehumidify setting.
yobarr said
10:29 PM Oct 19, 2021
Whenarewethere wrote:
I have a couple of Daikin AC in a unit I let to tenants. One is a small 2.5kW model, brilliant at what it can do both high, low settings & also dehumidifying setting.
Yobarr, I am assuming you maybe running your AC at some level of low output overnight. It would be interesting some power input numbers as the manufacturers only seem to state power input at rated output which is not a lot of help if one wants to run it at a low power level for people who maybe a touch under capacity with batteries.
Obviously running the AC on a low setting it won't cool as much & will be a bit less efficient, but it may get one through the night if one has X amount of AH.
It is surprising how well these things cool even if they are on the dehumidify setting.
Hi Jonathan.Don't know anything about electricitynothingbut I set my 2.5kw Mitsubishi Heavy Industries AC on 25C after the van has been cooled, and I wish to retire,when generally temps have come down a bit.Because I don't sleep well,I can keep an eye on it overnight,and sometimes it says 19 watts,and others it says 220 watts,up to maybe 250 watts? One mistake I made when I installed it was to put the console (?) on a side wall instead of rear wall,so getting cool air into the bedroom,which has its own door and dividing wall,is difficult.But it is what it is,and performs well for my needs.If it is of any interest to you,I can post a photo of the unit's spec sheet,which means nothing to me! Cheers
Whenarewethere said
11:04 PM Oct 19, 2021
Thanks, but I have looked at the specs. Basically a quality 2.5kW AC is about 500% efficient so at rated output you would have an input of 500 watts.
But if the environment reaches the set temperature the AC will cycle so use less power. You said you have set it at 25°C so obviously not going to use truck loads of power to cryogenically freeze yourself!
Re AC in less than idea spot. Can you add some baffles to deflect air to some degree.
& or,
a fan somewhere into the room to either push or pull air in or out of the room so air will then be drawn in or out through the door.
Another idea:
In a previous unit we had an AC in the lounge & it wouldn't reach the bedroom to cool. I know with cold air you should point it up. But we put the AC on the lowest fan speed, pointed it down to the floor & the cold air drifted into the bedroom. Often we had to turn it off as it ended up too cold.
peatop said
02:16 AM Oct 20, 2021
Hi Gerrard, I think you need to look at what you need then what you want, then add up the running (not starting) usage and work from there, for example fridge 24Ah, lights 3Ah microwave 5 Ah these figures are over 24 hours not 1 hour so we have 24+3+5=32Ah used every 24 hours, so you need to be capable of producing 32Ah of power everyday, rain, hail or shine so to minimize any issues you add battery capacity this is your buffer, if you have 100Ah of usable capacity (not battery capacity) then you have 3 days of storage if you can charge your battery/batteries back up 32 Ah somewhere in those 3 days your good for another day.
This is just a hypothetical example as there are so may variables to add or remove but this gives you a how to workout your power needs, then you need to do some reading on how best to produce your required power, store your power (type of batteries) storage capacity (this includes buffer) the rated capacity of all batteries is not the usable capacity lead batteries are best kept on float and for best performance only 50% discharged, while lithium's have upto 100% discharge but most only use 80% of the rated capacity and they prefer to be left at around a 50% charge rather than float. charging you have several options, dc to dc but not recommended unless your driving, solar, wind and generator.
As the others have said you can live like you do at home but most don't as it's not really practical. And it is probably best to read the other threads on solar systems and battery choices, you will see that everyone is different with how they have setup their system (capacity) but they all seem to use the same theory behind it all. get to know as much as you can about every part of the system from panels, batteries, fuses, wire and even the switches. I've been doing my setup since April and all the information you need to do it is available on this site if you search the part example "solar", "batteries", "controller" and so on. hope this gives you a good start and doesn't confuse you too much.
ottg said
12:59 PM Oct 20, 2021
Thank you everyone for your feedback. You prompt me with the correct questions.
Spend a bit of time on the Internet and find a useful spreadsheet. After a discussion with my wife, I had a better idea of what essential appliances is needed.
Attached is my power consumption calculations
As a 1000W inverter system, batteries at 50% drainage, I'll require a 100Ah battery, to be safe a 2000W will do the trick
Now for the system design integrated into the Jaco existing electronics.
Not to forget drawing 1200 watts from one battery is 120amps will drop its effective capacity 50% so you really only have a 50AH battery, & then you do not want to regularly you more than 50% of that.
So in reality you can only boil water for 12 minutes & you have nothing left to power anything else.
& the battery will have a very short life with this daily demand.
Jaahn said
02:31 PM Oct 20, 2021
Hi Gerrard
Glad that you took the suggestions and looked at your potential needs. Always a good starting point. However out on the road we find that we vary our use depending on the conditions. We have solar and the car alternator for charging and a 140Ah battery and a small 350W inverter now. The fridge is a compressor type. We have mostly 12V chargers.
So when we drive and power is unlimited we charge the laptops and the phones. When parked and the sun is shining we use anything that we like as we know the power is being replaced. If the sun is not out then we refrain from wasting power. If I had twice as much battery storage I would be happier to be less frugal sometimes but so far we manage well off the grid for as long as we want.
But we carry a toaster and jug for when we stay at a powered site which we do when we want the amenities. Works for us !!
I believe your estimates of Ah use on the spread sheet are probably a bit tight. For the inverter I would not allow too much over your need for the inverter size as the losses add up ! My old one goes to sleep and wakes up automatically when loaded so standby loss is minimal.
Jaahn
ottg said
05:38 PM Oct 20, 2021
Hope I have done it correctly. This kettle takes 1 litre.
Power consumption is 1200W; the current 1200/220/efficiency = 6.4A
It takes approx 5 minutes to boil, thus for 30 minutes we can boil 6 times a day
Total current: 3.2 A/h for the day
ottg said
05:48 PM Oct 20, 2021
Thanks, everyone. Jhaan I see what you say - be flexible and plan ahead.
I think it will take some time but after the 1st cold cup of cuppa we are going to learn fast
As long as I have a power management board/meter and can see the available battery energy - we will be planning. Obviously, on partly cloudy days things are going to change.
I like the comment elsewhere - stay off the grid as long as your water last - makes sense as we never used the water tanks. Will get it checked!
1. Does anyone know how long will I be able to run a small Dometic gas fridge off a 9kg bottle?
Whenarewethere said
05:52 PM Oct 20, 2021
ottg wrote:
Hope I have done it correctly. This kettle takes 1 litre.
Power consumption is 1200W; the current 1200/220/efficiency = 6.4A
It takes approx 5 minutes to boil, thus for 30 minutes we can boil 6 times a day
Total current: 3.2 A/h for the day
No.
1200/10 = 120AH running the kettle for 60 minutes.
120AH/60min x 5min = 10AH
10AH x 6 timesa day = 60AH
Whenarewethere said
05:53 PM Oct 20, 2021
Found a reachable carving knife about $100 so you have one less thing on 240 volts.
Kenwood Rechargeable Electric Knife KN500
Whenarewethere said
05:59 PM Oct 20, 2021
ottg wrote:
ower consumption is 1200W; the current 1200/220/efficiency = 6.4A
The red text is stuffing up your calculations.
You need to divide the wattage by 12 volts plus inefficiencies.
ottg said
09:03 PM Oct 20, 2021
Thank you for the feedback.
I should have calculated the current drawn on the 12V side of the invertor (attached)
As the 220V appliances are only used a few times per week - I calculate the average daily current, using the weeks total.
Thus 1312/5 = 187A pd
With 2x 300Ah batteries it will last up to 1.6 days. I read somewhere to make provision for at least 3 days without recharge to compensate for cloudy days.
So it seems if 2x 400Ah won't give me 3 days (only 2.13 days)
For me - Better planning and less 220V appliance usage
-- Edited by ottg on Thursday 21st of October 2021 06:26:08 AM
Hi Gerrard, You are confusing the amps produced at 220V with the MUCH MUCH GREATER amps needed at 12V(x 10)by the inverter, as already said another way. This electricity is hard to get your head around when working in 220V AC and 12V DC. Stay with it it is not rocket science but is tricky if you have not done it before. Jaahn
Hmm you answered while I was writing but yes the 220V appliances burn up the battery power fast.
-- Edited by Jaahn on Wednesday 20th of October 2021 09:12:55 PM
Jaahn said
09:19 PM Oct 20, 2021
Gerrard
If you want to use power then you must plan to MAKE power every day or you will soon run out. The sun shines most days so use solar panels. The engine alternator is the best charger you have available so use that too particularly for bad weather days. There is a lot of discussion on both those ways to keep the batteries charged.
Read up on charging before deciding on how to use the power, is my advice !
Jaahn
Whenarewethere said
10:12 PM Oct 20, 2021
It takes some time to get your head around it. I only started a couple of years ago. One can avoid making expensive mistakes by doing the homework thoroughly.
We cook with metho due to our very limited space & everything else off 12volts.
So, look at doing your cooking with gas (or metho), that will take the heavy loads off the batteries.
If you can, chuck out the 3 way fridge & get a compressor fridge. They are really efficient these days, then you have more gas for cooking.
Get a lower power microwave.
Curler is not going to use 1500 watts, or continuously, unless you are creating steel wool.
Our Kambrook toaster is 850 watts. Go without toast on overcast days when solar input is limited. On sunny days you could run the toaster while you also have solar input to take load off the batteries. A slightly later breakfast! Your batteries will be thankful.
Same with a 750 watt kettle, use gas when there is no solar input. Chuck out the 1200 watt kettle!
It is about cutting back high wattage & extended loads.
If you have say 1000 watts of solar & say around mid morning they are producing 500 watts due to the angle of the sun. When you fire up the toaster that's going to take about half the load off the batteries. Same with the kettle.
With all your appliances under 1000 watts, your wiring doesn't heat up!
With careful design a 1200VA inverter may be enough. 1000 watts at 25°C/850 watts at 40°C.
If you want to use power then you must plan to MAKE power every day or you will soon run out. The sun shines most days so use solar panels. The engine alternator is the best charger you have available so use that too particularly for bad weather days. There is a lot of discussion on both those ways to keep the batteries charged.
Read up on charging before deciding on how to use the power, is my advice !
Jaahn
Agree.
Like knowing fuel range before running out.
ottg said
10:42 PM Oct 20, 2021
Thank you for all the feedback and ideas
Indeed "plan to MAKE power every day or you will soon run out" Will do!
Regards
Gerrard
kesa32 said
09:37 AM Oct 21, 2021
Re your gas fridge , they run for ages on gas , that's if you are happy with its performance etc , one less thing to replace and can be changed out later on if needed
Peter_n_Margaret said
10:23 AM Oct 21, 2021
ottg wrote:
1. Does anyone know how long will I be able to run a small Dometic gas fridge off a 9kg bottle?
Your gas fridge will be the largest consumer of gas that you have.
Our fridge is a 12V compressor, our hot water is diesel or engine waste heat.
We use gas for all cooking.
On a recent trip, a 4kg gas bottle lasted 3 months while free camping.
Next motorhome will have more solar and an induction cook top and no gas.
Cheers,
Peter
ottg said
11:40 AM Oct 21, 2021
Thanks Peter, that is good to know.
Aus-Kiwi said
02:37 PM Oct 22, 2021
When we had 200l gas fridge . Gas lasted approximately 3 weeks . Switched to 12v 220l compressor, use inbuilt insulated geni sparingly to boil jug . Inopriate time we use gas stove . The inverter uses too much battery to boil jug .We have a 50 amp battery charger so charges in no time !! 5 min at most !!
peatop said
12:12 AM Oct 23, 2021
Hi Gerrard, sorry that I didn't explain it better, I forget the specific law but someone might put it out there but the formulae is P=A x V where P is power in watts, A is amps and V is volts or something like that, but anyway what this all means is watts if being 1200 and to get the amps we need to divide it by the voltage for the supply, for example: if running and inverter at 240v using 1200w we use P=AxV, 1200=5x240 next transpose the formulae P/V=A which gives you 1200/240=5A now since you real power supply is 12v not 240 you have to turn that 240v into 12v P/V=A, 1200/12=100A. I hope I'm explaining this correctly with so many experts here anyway it give you the right information to work out your needs correctly.
The other thing as already stated by others you must take losses into consideration these come from many sources, however inverters can account for some pretty high end losses but also be quite efficient depending on how they are matched to there intended use.
Gas V Electricity? horses for courses I use a flywire style toast cooker on my gas cooker on a very very low heat and it does 1 slice by the time I've buttered the last slice, I boil water on the gas stove, I would never entertain the idea of using an electric kettle while camping or any mainstream 240v appliance for that matter unless it was the only way I could do it without gas, with the exception of the fridge which I recently purchased a 12/24v compressor fridge.
Some good points were raised and I think your getting the idea, so stick with it and soon you should be well on the way to working out what the hell E=mc^2 means lol joke, Like Jaahn said it's not rocket science but can be tricky to understand at first I had been through all this many many years ago and it has taken a while to remember just some of it over the last few months, but these guys have been doing it fora while so your in good hands
I have a Jayco Freedom 15 feet
a) Looking at the schematic diagram (11/9/2002) shows that the current setup can accommodate solar panels, optional charging from the car and optional battery
b) I have a dual battery system in the 4x4 for the cooler box etc. While driving and using the dual battery system, can I still charge the caravan from the car?
I'm looking for installers in Joondalup, familiar with Jayco, that can tell me what needs to be installed to take off the grid?
What appliances can I use and for how long?
What performance can I get - how long can I stay off the grid?
Will do a separate post for Internet coverage
Thanks
Gerrard
-- Edited by ottg on Tuesday 19th of October 2021 06:08:45 PM
How long do you want to stay off grid?
North or South or both?
If you are running a 2.5kW home split system air conditioning off batteries you will need a decent setup.
200L fridge bigger system.
Induction cooking bigger....
Your limiting factor won't be dollars but it will be your payload. Even with quality Victron lithium, solar panels & controllers weight adds up very quickly.
Look up the mass of each item & work back from there. Including wiring, solar panel pads & switch gear.
Draw up an accurate scale plan of the caravan roof to see what size panels you can fit. Watch out for self shadowing. Stuffing the roof too full will back fire if you have shadows. Far cheaper to make a mistake on a drawing.
Most of us do not consider camping as a relocation of home style living. We are prepared to so without things like cappuccino coffee and are content with a good instant coffee (or percolate it over the gas stove.) As soon as you start installing inverters and using 230 V appliances you need large battery systems. Those that insist on transferring their domestic living into the camping world spend $3,000 or considerably more on their battery systems. We also have all of our things running off 12 V and do not use inverters.
If you are like the majority of us and are content to only using the batteries for lighting, radio, TV and communications you can get away with a 100 Ah battery and a 150 to 200 W solar panel (I live comfortably off an 80 W pane.) [in the early days we just used stoplight globes for light and powered them from the tugs battery.] If you are prepared to live simply you can install a small system and be quite comfortable. If you wish for the comforts of home prepare to spend big bickies on your solar system and more money on upgrading the carrying capacity of your van to carry the batteries.
Don't be sucked into purchasing big inverters. Those who sell them at caravan shows tell you how you can power all sorts of things with big inverters. They neglect to inform you of the battery capacity need to drive them.
-- Edited by PeterD on Tuesday 19th of October 2021 07:24:27 PM
Hi
I suggest that you spend a bit of time looking at the Solar sub forum at the top of the Techies Corner as well as here on the Techies Corner.
Plenty of discussion.
To help you there is also a SEARCH function of this forum at the top of the page under the Adds. Do a bit of home work and see what you find.
I like to think a forum is a conversation between the members not just a question and answer for new members.
Jaahn
-- Edited by Jaahn on Tuesday 19th of October 2021 07:41:38 PM
We stay off-grid as long as our water lasts. Our batteries will keep our fridge going for a week, but we pull out the solar panels after 4 days. So we have plenty of reserve for inclement weather.
We grind our beans by hand & have very nice coffee with filtered water heater with metho.
Everything that needs electricity runs off 12 volts. We have avoided 240 volts to make life easier. We have 2xAA rechargeable toothbrushes.
Do it once,do it well.You should have plenty of room on 15ft van as panels are (roughly) 1900 x 1000.The panels also keep the van a lot cooler,just as they do when on a house roof. Yesterday it was 41 degrees where I am travelling,and the AC was on all night,from batteries.This morning batteries were on 85.9% and 12.96 volts.Back up to 100% before 8.30am. There are no gas appliances in my van.nothing.Cheers
-- Edited by yobarr on Tuesday 19th of October 2021 09:26:18 PM
I have a couple of Daikin AC in a unit I let to tenants. One is a small 2.5kW model, brilliant at what it can do both high, low settings & also dehumidifying setting.
Yobarr, I am assuming you maybe running your AC at some level of low output overnight. It would be interesting some power input numbers as the manufacturers only seem to state power input at rated output which is not a lot of help if one wants to run it at a low power level for people who maybe a touch under capacity with batteries.
Obviously running the AC on a low setting it won't cool as much & will be a bit less efficient, but it may get one through the night if one has X amount of AH.
It is surprising how well these things cool even if they are on the dehumidify setting.
Hi Jonathan.Don't know anything about electricitynothingbut I set my 2.5kw Mitsubishi Heavy Industries AC on 25C after the van has been cooled, and I wish to retire,when generally temps have come down a bit.Because I don't sleep well,I can keep an eye on it overnight,and sometimes it says 19 watts,and others it says 220 watts,up to maybe 250 watts? One mistake I made when I installed it was to put the console (?) on a side wall instead of rear wall,so getting cool air into the bedroom,which has its own door and dividing wall,is difficult.But it is what it is,and performs well for my needs.If it is of any interest to you,I can post a photo of the unit's spec sheet,which means nothing to me! Cheers
Thanks, but I have looked at the specs. Basically a quality 2.5kW AC is about 500% efficient so at rated output you would have an input of 500 watts.
But if the environment reaches the set temperature the AC will cycle so use less power. You said you have set it at 25°C so obviously not going to use truck loads of power to cryogenically freeze yourself!
Re AC in less than idea spot. Can you add some baffles to deflect air to some degree.
& or,
a fan somewhere into the room to either push or pull air in or out of the room so air will then be drawn in or out through the door.
Another idea:
In a previous unit we had an AC in the lounge & it wouldn't reach the bedroom to cool. I know with cold air you should point it up. But we put the AC on the lowest fan speed, pointed it down to the floor & the cold air drifted into the bedroom. Often we had to turn it off as it ended up too cold.
Hi Gerrard, I think you need to look at what you need then what you want, then add up the running (not starting) usage and work from there, for example fridge 24Ah, lights 3Ah microwave 5 Ah these figures are over 24 hours not 1 hour so we have 24+3+5=32Ah used every 24 hours, so you need to be capable of producing 32Ah of power everyday, rain, hail or shine so to minimize any issues you add battery capacity this is your buffer, if you have 100Ah of usable capacity (not battery capacity) then you have 3 days of storage if you can charge your battery/batteries back up 32 Ah somewhere in those 3 days your good for another day.
This is just a hypothetical example as there are so may variables to add or remove but this gives you a how to workout your power needs, then you need to do some reading on how best to produce your required power, store your power (type of batteries) storage capacity (this includes buffer) the rated capacity of all batteries is not the usable capacity lead batteries are best kept on float and for best performance only 50% discharged, while lithium's have upto 100% discharge but most only use 80% of the rated capacity and they prefer to be left at around a 50% charge rather than float. charging you have several options, dc to dc but not recommended unless your driving, solar, wind and generator.
As the others have said you can live like you do at home but most don't as it's not really practical. And it is probably best to read the other threads on solar systems and battery choices, you will see that everyone is different with how they have setup their system (capacity) but they all seem to use the same theory behind it all. get to know as much as you can about every part of the system from panels, batteries, fuses, wire and even the switches. I've been doing my setup since April and all the information you need to do it is available on this site if you search the part example "solar", "batteries", "controller" and so on. hope this gives you a good start and doesn't confuse you too much.
Thank you everyone for your feedback. You prompt me with the correct questions.
Spend a bit of time on the Internet and find a useful spreadsheet. After a discussion with my wife, I had a better idea of what essential appliances is needed.
Attached is my power consumption calculations
As a 1000W inverter system, batteries at 50% drainage, I'll require a 100Ah battery, to be safe a 2000W will do the trick
Now for the system design integrated into the Jaco existing electronics.
A 100AH battery suggestion did not add up so I then looked at your spreadsheet.
Just looking at the 1200watt kettle at 3.2AH usage. So I take it you are only boiling 256ml of water per 24 hours.
My 750 watt kettle, 200ml water, water temperature 21°C, 120 seconds to boil. (10 instead of 12v for inefficiencies)
750/30/10 = 2.5AH
-- Edited by Whenarewethere on Wednesday 20th of October 2021 01:55:27 PM
If you are running your kettle 30 minutes a day.
1200x0.5 = 600 watts
600/10 = 60AH
Not to forget drawing 1200 watts from one battery is 120amps will drop its effective capacity 50% so you really only have a 50AH battery, & then you do not want to regularly you more than 50% of that.
So in reality you can only boil water for 12 minutes & you have nothing left to power anything else.
& the battery will have a very short life with this daily demand.
Hi Gerrard
Glad that you took the suggestions and looked at your potential needs. Always a good starting point. However out on the road we find that we vary our use depending on the conditions. We have solar and the car alternator for charging and a 140Ah battery and a small 350W inverter now. The fridge is a compressor type. We have mostly 12V chargers.
So when we drive and power is unlimited we charge the laptops and the phones. When parked and the sun is shining we use anything that we like as we know the power is being replaced. If the sun is not out then we refrain from wasting power. If I had twice as much battery storage I would be happier to be less frugal sometimes but so far we manage well off the grid for as long as we want
.
But we carry a toaster and jug for when we stay at a powered site which we do when we want the amenities. Works for us !!
I believe your estimates of Ah use on the spread sheet are probably a bit tight. For the inverter I would not allow too much over your need for the inverter size as the losses add up ! My old one goes to sleep and wakes up automatically when loaded so standby loss is minimal.
Jaahn
Hope I have done it correctly. This kettle takes 1 litre.
Power consumption is 1200W; the current 1200/220/efficiency = 6.4A
It takes approx 5 minutes to boil, thus for 30 minutes we can boil 6 times a day
Total current: 3.2 A/h for the day
Thanks, everyone. Jhaan I see what you say - be flexible and plan ahead.
I think it will take some time but after the 1st cold cup of cuppa we are going to learn fast
As long as I have a power management board/meter and can see the available battery energy - we will be planning. Obviously, on partly cloudy days things are going to change.
I like the comment elsewhere - stay off the grid as long as your water last - makes sense as we never used the water tanks. Will get it checked!
1. Does anyone know how long will I be able to run a small Dometic gas fridge off a 9kg bottle?
No.
1200/10 = 120AH running the kettle for 60 minutes.
120AH/60min x 5min = 10AH
10AH x 6 timesa day = 60AH
Found a reachable carving knife about $100 so you have one less thing on 240 volts.
Kenwood Rechargeable Electric Knife KN500
Thank you for the feedback.
I should have calculated the current drawn on the 12V side of the invertor (attached)
As the 220V appliances are only used a few times per week - I calculate the average daily current, using the weeks total.
Thus 1312/5 = 187A pd
With 2x 300Ah batteries it will last up to 1.6 days. I read somewhere to make provision for at least 3 days without recharge to compensate for cloudy days.
So it seems if 2x 400Ah won't give me 3 days (only 2.13 days)
For me - Better planning and less 220V appliance usage
-- Edited by ottg on Thursday 21st of October 2021 06:26:08 AM
Hi Gerrard,
You are confusing the amps produced at 220V with the MUCH MUCH GREATER amps needed at 12V(x 10)by the inverter, as already said another way.
This electricity is hard to get your head around when working in 220V AC and 12V DC. Stay with it it is not rocket science but is tricky if you have not done it before.
Jaahn
Hmm you answered while I was writing
but yes the 220V appliances burn up the battery power fast.
-- Edited by Jaahn on Wednesday 20th of October 2021 09:12:55 PM
Gerrard
If you want to use power then you must plan to MAKE power every day or you will soon run out. The sun shines most days so use solar panels. The engine alternator is the best charger you have available so use that too particularly for bad weather days. There is a lot of discussion on both those ways to keep the batteries charged.
Read up on charging before deciding on how to use the power, is my advice !
Jaahn
It takes some time to get your head around it. I only started a couple of years ago. One can avoid making expensive mistakes by doing the homework thoroughly.
We cook with metho due to our very limited space & everything else off 12volts.
So, look at doing your cooking with gas (or metho), that will take the heavy loads off the batteries.
If you can, chuck out the 3 way fridge & get a compressor fridge. They are really efficient these days, then you have more gas for cooking.
Get a lower power microwave.
Curler is not going to use 1500 watts, or continuously, unless you are creating steel wool.
Our Kambrook toaster is 850 watts. Go without toast on overcast days when solar input is limited. On sunny days you could run the toaster while you also have solar input to take load off the batteries. A slightly later breakfast! Your batteries will be thankful.
Same with a 750 watt kettle, use gas when there is no solar input. Chuck out the 1200 watt kettle!
It is about cutting back high wattage & extended loads.
If you have say 1000 watts of solar & say around mid morning they are producing 500 watts due to the angle of the sun. When you fire up the toaster that's going to take about half the load off the batteries. Same with the kettle.
With all your appliances under 1000 watts, your wiring doesn't heat up!
With careful design a 1200VA inverter may be enough. 1000 watts at 25°C/850 watts at 40°C.
https://www.victronenergy.com.au/upload/documents/Datasheet-Phoenix-Inverter-VE.Direct-250VA-1200VA-EN.pdf
Anyway, at least a starting point goal!
Agree.
Like knowing fuel range before running out.
Indeed "plan to MAKE power every day or you will soon run out" Will do!
Regards
Gerrard
Your gas fridge will be the largest consumer of gas that you have.
Our fridge is a 12V compressor, our hot water is diesel or engine waste heat.
We use gas for all cooking.
On a recent trip, a 4kg gas bottle lasted 3 months while free camping.
Next motorhome will have more solar and an induction cook top and no gas.
Cheers,
Peter
Thanks Peter, that is good to know.
Hi Gerrard, sorry that I didn't explain it better, I forget the specific law but someone might put it out there but the formulae is P=A x V where P is power in watts, A is amps and V is volts or something like that, but anyway what this all means is watts if being 1200 and to get the amps we need to divide it by the voltage for the supply, for example: if running and inverter at 240v using 1200w we use P=AxV, 1200=5x240 next transpose the formulae P/V=A which gives you 1200/240=5A now since you real power supply is 12v not 240 you have to turn that 240v into 12v P/V=A, 1200/12=100A. I hope I'm explaining this correctly with so many experts here
anyway it give you the right information to work out your needs correctly.
The other thing as already stated by others you must take losses into consideration these come from many sources, however inverters can account for some pretty high end losses but also be quite efficient depending on how they are matched to there intended use.
Gas V Electricity? horses for courses I use a flywire style toast cooker on my gas cooker on a very very low heat and it does 1 slice by the time I've buttered the last slice, I boil water on the gas stove, I would never entertain the idea of using an electric kettle while camping or any mainstream 240v appliance for that matter unless it was the only way I could do it without gas, with the exception of the fridge which I recently purchased a 12/24v compressor fridge.
Some good points were raised and I think your getting the idea, so stick with it and soon you should be well on the way to working out what the hell E=mc^2 means lol joke, Like Jaahn said it's not rocket science but can be tricky to understand at first
I had been through all this many many years ago and it has taken a while to remember just some of it over the last few months, but these guys have been doing it fora while so your in good hands 