In our van we have a102lt 12/240v fridge and a 41lt Dometic fridge
the 102lt fridge states 0.41a
just trying to work out our consumption
we have 2 x 200w solar panels 2000w inverter and two 120ah AGM batteries
running
24" 12v tv at the most 4hrs
nvidi player same
storage drive same
charge 3 mobiles
led lighs 4 hrs
400w microwave 10 mins
sirocco fan 8 hrs
any idea how all this will work
TIA
Possum3 said
06:14 PM Dec 18, 2022
You first need to determine Wattage of appliance plus time being used. Your cabling (length and wire gauge) and insulation effectiveness along with ambient temperature in van will also be a factor in power usage.
The 0.41Amps will be at 240v . Assuming you will be running from a 12v system, that converts to a tad over 9amps. Assuming that is the current it draws whilst running, & assuming the fridge is set at fridge (not freezer temperatures) it should run about 50% of the time over the course of a 24hour period. so 9 x 12 =108. That is 108Amp hours use every 24 hours. If it's very hot, or if the temperature of the fridge is turned down, or if the fridge is opened & shut more rather than less, it will use more. It's a big fridge & 108Amp hours (Ah) per day is a lot to sustain. Add all the other things you list & you do not have a sustainable set up at present. If anyone suggests different they will be leading down the flat battery warm beer path.
To put that into perspective your 2x 200w panels will at best provide an average of 150Ah a day. - maybe 210Ah a day in the longer sunny days of the north or as little as 90Ah in winter in the south. Those figures will reduce by almost 30% if your panels are roof mounted on your vehicle.
That's without anything else on your list plugged in.
Of course it all depends upon how you travel.If you are happy to go to a caravan park every 2nd or 3rd night night to top up your batteries (assuming you have a 240v battery charger fitted) & to use your microwave & watch your Tv, you'll probably get by, but if you want to free camp for more than a single night at a time, even if it's sunny you'll be in trouble.
Your choices are relying on driving to charge you batteries (dc to dc charger) & driving most days, or if you want to remain in places for longer periods without plugging into an external 240v each time, & without driving you will need a fair bit more solar and/or a smaller more economical fridge.
The smaller fridge you have will consume on average 40 to 50Ah per day (24 hours) with the same variations I mentioned in regard to the larger fridge.
I recommend Collyn Rivers books - easy to read & to understand & will get you up to speed with what you need to run what you have, as well as how to manage with less power hungry appliances.
This one should see you right. https://rvbooks.com.au/rv-solar-that-really-works/
-- Edited by Cuppa on Sunday 18th of December 2022 10:06:09 PM
Whenarewethere said
10:31 PM Dec 18, 2022
Prior to having a Victron controller which calculates the watts daily.
During extensive tests heating a room to 35°C in winter to test the fridge, I jotted down the volts & amps on a dozen pages. It was extremely tedious, but I now have a full understanding of the fridge's performance under different conditions, especially with different thicknesses of insulation.
Our fridge with it's current setup uses about 15AH per 24 hours. About 9.5AH per 24 hours in cool weather. Could get better with Aerogel insulation but that has a few of its own issues.
As we mostly sleep in a car we didn't have the luxury of inefficient setup. Getting insulation, wiring & components right was less weight & volume than larger batteries. 7 days off battery, quiet, but it took a lot of tedious work to get there.
Jaahn said
09:47 AM Dec 19, 2022
Hmm maids there is no easy answer. THE Fridges are the biggest users as they go 24/7. The rest is easy, probably similar to ours. If you want to run two fridges and one is a 240V then you should have some metering to watch so you will know if you are winning or loosing normally. WHAT DO YOU HAVE TO METER THE POWER USAGE.
But generally more solar is the answer to more 12V battery power. AND careful monitoring of your power use. but you need to know what you are using under most conditions, good, normal and poor sun. Using the motor to top up is what we do use for bad sun.
Victron make a power usage meter that measures the power being put into the battery and the power going out, continuously, so it can always give you what is left to use. There are several models and they must be set-up correctly to be effective but they are probably the gold standard. Some cheaper units are not as good.
-- Edited by Jaahn on Monday 19th of December 2022 09:55:40 AM
Whenarewethere said
11:22 AM Dec 19, 2022
The Victron controllers up to 20 amp like Victron MPPT 100/20 you can connect the load & it will tell you each days' load. I think about 40 days history.
Whenarewethere said
11:35 AM Dec 19, 2022
Calculating panel efficiency vs sun angle (angle to the panel).
For example if you have 150 watts of panels & the sun is 25° above the horizon. Type in the following on your smartphone calculator. You will only get 63.39 watts, assuming the panels are clean etc!
Bobdown said
03:31 PM Dec 20, 2022
Whenarewethere wrote:
Prior to having a Victron controller which calculates the watts daily.
During extensive tests heating a room to 35°C in winter to test the fridge, I jotted down the volts & amps on a dozen pages. It was extremely tedious, but I now have a full understanding of the fridge's performance under different conditions, especially with different thicknesses of insulation.
Our fridge with it's current setup uses about 15AH per 24 hours. About 9.5AH per 24 hours in cool weather. Could get better with Aerogel insulation but that has a few of its own issues.
As we mostly sleep in a car we didn't have the luxury of inefficient setup. Getting insulation, wiring & components right was less weight & volume than larger batteries. 7 days off battery, quiet, but it took a lot of tedious work to get there.
Fridge on, fridge off.......hope you had a good holiday Homer.
In our van we have a102lt 12/240v fridge and a 41lt Dometic fridge
the 102lt fridge states 0.41a
just trying to work out our consumption
we have 2 x 200w solar panels 2000w inverter and two 120ah AGM batteries
running
24" 12v tv at the most 4hrs
nvidi player same
storage drive same
charge 3 mobiles
led lighs 4 hrs
400w microwave 10 mins
sirocco fan 8 hrs
any idea how all this will work
TIA
See; www.batterystuff.com/kb/tools/calculator-sizing-a-battery-to-a-load.html
The 0.41Amps will be at 240v . Assuming you will be running from a 12v system, that converts to a tad over 9amps. Assuming that is the current it draws whilst running, & assuming the fridge is set at fridge (not freezer temperatures) it should run about 50% of the time over the course of a 24hour period. so 9 x 12 =108. That is 108Amp hours use every 24 hours. If it's very hot, or if the temperature of the fridge is turned down, or if the fridge is opened & shut more rather than less, it will use more. It's a big fridge & 108Amp hours (Ah) per day is a lot to sustain. Add all the other things you list & you do not have a sustainable set up at present. If anyone suggests different they will be leading down the flat battery warm beer path.
To put that into perspective your 2x 200w panels will at best provide an average of 150Ah a day. - maybe 210Ah a day in the longer sunny days of the north or as little as 90Ah in winter in the south. Those figures will reduce by almost 30% if your panels are roof mounted on your vehicle.
That's without anything else on your list plugged in.
Of course it all depends upon how you travel.If you are happy to go to a caravan park every 2nd or 3rd night night to top up your batteries (assuming you have a 240v battery charger fitted) & to use your microwave & watch your Tv, you'll probably get by, but if you want to free camp for more than a single night at a time, even if it's sunny you'll be in trouble.
Your choices are relying on driving to charge you batteries (dc to dc charger) & driving most days, or if you want to remain in places for longer periods without plugging into an external 240v each time, & without driving you will need a fair bit more solar and/or a smaller more economical fridge.
The smaller fridge you have will consume on average 40 to 50Ah per day (24 hours) with the same variations I mentioned in regard to the larger fridge.
I recommend Collyn Rivers books - easy to read & to understand & will get you up to speed with what you need to run what you have, as well as how to manage with less power hungry appliances.
This one should see you right. https://rvbooks.com.au/rv-solar-that-really-works/
-- Edited by Cuppa on Sunday 18th of December 2022 10:06:09 PM
Prior to having a Victron controller which calculates the watts daily.
During extensive tests heating a room to 35°C in winter to test the fridge, I jotted down the volts & amps on a dozen pages. It was extremely tedious, but I now have a full understanding of the fridge's performance under different conditions, especially with different thicknesses of insulation.
Our fridge with it's current setup uses about 15AH per 24 hours. About 9.5AH per 24 hours in cool weather. Could get better with Aerogel insulation but that has a few of its own issues.
As we mostly sleep in a car we didn't have the luxury of inefficient setup. Getting insulation, wiring & components right was less weight & volume than larger batteries. 7 days off battery, quiet, but it took a lot of tedious work to get there.
Hmm maids there is no easy answer.
THE Fridges are the biggest users as they go 24/7. The rest is easy, probably similar to ours. If you want to run two fridges and one is a 240V then you should have some metering to watch so you will know if you are winning or loosing normally. WHAT DO YOU HAVE TO METER THE POWER USAGE.
But generally more solar is the answer to more 12V battery power. AND careful monitoring of your power use. but you need to know what you are using under most conditions, good, normal and poor sun. Using the motor to top up is what we do use for bad sun.
Victron make a power usage meter that measures the power being put into the battery and the power going out, continuously, so it can always give you what is left to use. There are several models and they must be set-up correctly to be effective but they are probably the gold standard. Some cheaper units are not as good.
https://www.victronenergy.com/battery-monitors/bmv-700
Jaahn
-- Edited by Jaahn on Monday 19th of December 2022 09:55:40 AM
The Victron controllers up to 20 amp like Victron MPPT 100/20 you can connect the load & it will tell you each days' load. I think about 40 days history.
Calculating panel efficiency vs sun angle (angle to the panel).
For example if you have 150 watts of panels & the sun is 25° above the horizon. Type in the following on your smartphone calculator. You will only get 63.39 watts, assuming the panels are clean etc!
Fridge on, fridge off.......hope you had a good holiday Homer.