Cool find on those panels, perfect voltage for 120v or 240v. You should look into an inline dc breaker for the wiring. 240v dc may arch flash when the panels are connected using those mc4 connectors. I’ve had a few of those burn out as have others. 15 or 20 amp fuses?
I will look into that. Thank you for that information. Yes I found those panels and the first thing I did was wire two up at 120-volts and was able to solder with a small 100-watt soldering iron. So I bought all I could afford at the time not really knowing what I was going to do with them.
Thanks for making these videos, I've watched the others as well. I have a few questions as it will relate to my potential build. 1: why not use a thicker ga wire with the insulation stripped off for inside the sand battery? Due to copper melting at about 2k this will get more power to your elements? 2: Would compressing or tamping the sand down make it more efficient? 3: what is the maximum amount of heat output you are expecting to output from this (from the outside)? Thanks and keep the vids coming. Great stuff
As far as the wire thickness I don't really know the answer. And I really don't know the exact capacity of these crazy prototypes but I am making some progress I believe. I will calculate the heat potential as best as I can figure. One number I have just now come up with that will change everything is. 5-watts per pound of sand. That is the ratio they are at in the Finland giant 100-ton sand battery project. So at that ratio I need approximately 3,500 watts to charge this 55-gallon heater. I am already building a 27-gallon one as of now.
You can get better efficiency if you match the resistance if the heating element to the resistance of the solar panels. See video and spread sheet by David Poz.
Nicely done! Great to see these DIY projects, so inspiring! If you got a clamp meter, you could take a current measurement, so we can estimate the actual power. (I know you won't be able to measure the voltage while it's running, with those connectors nicely sealed up. That would be ideal. But it's dangerous anyway, if you're not familiar with it.)
I am capable of measuring the voltage from a couple exposed copper bus bars I have that are totally unsafe lol. These techniques were fine with the lower voltages I normally work with so I need to change a few things soon. I did read approximately 60 volts under load if that tells you anything. I may have an clamp meter I can try also.
That is a reasonable question. Even in the summer the sand will cool down at night in the desert. It will all depend on insulation and balancing the correct amount of mass or sand to the wattage required. I can't really answer any technical questions but I can say there are commercial industries who are using this thermal energy storage technology. Thank you for the question and for watching the video.
@off-gridsurvivalmike8120 so let me help a bit... sand has much worse heat capacity than water at 800 J/kgK vs 4000 for water... So 100c water will have the same energy stored as sand at 500c?
Sand is an insulator. Heat doesn't easily spread down from the top layer into the depths, so the sun can only heat the surface layer so deeply, then the open skies of the desert night quickly radiate the heat out of the top. These systems put the heat near the bottom/center
Cool find on those panels, perfect voltage for 120v or 240v.
You should look into an inline dc breaker for the wiring. 240v dc may arch flash when the panels are connected using those mc4 connectors. I’ve had a few of those burn out as have others. 15 or 20 amp fuses?
I will look into that. Thank you for that information. Yes I found those panels and the first thing I did was wire two up at 120-volts and was able to solder with a small 100-watt soldering iron. So I bought all I could afford at the time not really knowing what I was going to do with them.
@ that’s cool, right off the bat you had a plan. I’ve been toying with using 30v panels in a similar way to heat water.
Thanks for making these videos, I've watched the others as well. I have a few questions as it will relate to my potential build.
1: why not use a thicker ga wire with the insulation stripped off for inside the sand battery? Due to copper melting at about 2k this will get more power to your elements?
2: Would compressing or tamping the sand down make it more efficient?
3: what is the maximum amount of heat output you are expecting to output from this (from the outside)?
Thanks and keep the vids coming. Great stuff
As far as the wire thickness I don't really know the answer. And I really don't know the exact capacity of these crazy prototypes but I am making some progress I believe. I will calculate the heat potential as best as I can figure. One number I have just now come up with that will change everything is. 5-watts per pound of sand. That is the ratio they are at in the Finland giant 100-ton sand battery project. So at that ratio I need approximately 3,500 watts to charge this 55-gallon heater. I am already building a 27-gallon one as of now.
@@off-gridsurvivalmike8120 thats good info on the 5 watts per lbs of sand. thanks
You can get better efficiency if you match the resistance if the heating element to the resistance of the solar panels. See video and spread sheet by David Poz.
@@Mrmicpolock barrel 200liter = 300kg sand>500°c/or400K=.....KW. THATS THE QUESTION no.?there must be atleast addet 50kw to the mass i think
Sand battery has so much potential. Just imagine an ibc full of sand and insulation.
Imagine an insulated _basement_ filled with sand and a heating system
yeahhhh finaly!!!
I know lol.
Nicely done!
Great to see these DIY projects, so inspiring!
If you got a clamp meter, you could take a current measurement, so we can estimate the actual power.
(I know you won't be able to measure the voltage while it's running, with those connectors nicely sealed up. That would be ideal. But it's dangerous anyway, if you're not familiar with it.)
I am capable of measuring the voltage from a couple exposed copper bus bars I have that are totally unsafe lol. These techniques were fine with the lower voltages I normally work with so I need to change a few things soon. I did read approximately 60 volts under load if that tells you anything. I may have an clamp meter I can try also.
The medieval torture device is complete!
How did you guess? The spikes must have given it away. Crazy projects for sure.
If the sand battery is great why are the nights in the desert cold?
That is a reasonable question. Even in the summer the sand will cool down at night in the desert. It will all depend on insulation and balancing the correct amount of mass or sand to the wattage required. I can't really answer any technical questions but I can say there are commercial industries who are using this thermal energy storage technology. Thank you for the question and for watching the video.
@off-gridsurvivalmike8120 so let me help a bit... sand has much worse heat capacity than water at 800 J/kgK vs 4000 for water... So 100c water will have the same energy stored as sand at 500c?
Sand is an insulator. Heat doesn't easily spread down from the top layer into the depths, so the sun can only heat the surface layer so deeply, then the open skies of the desert night quickly radiate the heat out of the top.
These systems put the heat near the bottom/center
Protect from hail? They must be at a good price for a reason. Slip down mesh covers on rollers?
Marvellous simply Marvellous we have heat lol
How about a parabolic reflector to add to the mix.
❤I am in full,,(at)tension,,😮