I should also mention that you always need to make sure that copper cables gauge and length are capable of handling the DC amps as well as any switches etc. you will be running the DC amps through.
I have a Stiebel Eltron 29kw whole house, tankless, electric, water heater that is about the size of a briefcase and hang on the wall and it works fantastic. I want to use two lower power electric tankless water heaters in an overlanding expedition vehicle(one for hot potable hot water and the other for hydronic under floor radiant heat), but that would mean I would need two very large inverters, could these water heater be converted to 24v or 48v DC?
the u type 12v element the are impossible to find on the web your help for some reference to where to purchase is very important to complete this project.
You can get them super cheap on Aliexpress: www.aliexpress.com/af/300w-12v-element.html?d=y&origin=n&SearchText=300w+12v+element&catId=0&initiative_id=SB_20211019070530 That's where i got mine.
Do you have a link to the high-temp epoxy (was it a special metal formula?) that you used after drilling the holes? Where did you use the silicon vs where (and when) the epoxy? did you consider just cutting away any of the original element?
Hi, I used JB Weld, despite some misinformation on the internet, All JB weld products are food safe once cured. They even say so themselves. I used JB weld on the back side (dry side ) mainly and then put some high temp silicone under the washers - on threads etc on wet side. To be honest if i was doing it again, i wouldn't bother with the JB weld. Just cover everything with high temp silicone. Definitely food safe and should last forever
You can absolutely cut away original element if you want. I just left it there because it wasn't in the way. Plus with it still there i can easily convert it back to 240v if i want. In fact i will be setting up a switch so that i can switch it between 12v and 240v - which would be handy when i'm on a 240v hookup. - hot water in 15mins!
@@thewanderingwarner5403 Thank you! Did you cut out a full ~1.25" diameter hole (for a 1" NPT male heating element) or did you drill out a small pattern of 2 or 4 smaller holes, just for the electrical ends to stub up through?
1 - would the red JB Weld silicone sealant be similar to what you used, or a good product in your view? 2 - Assuming you just drilled 4 holes through the metal plate of the water heater - what did you use to make sure that none of these 3 metal rods would contact the plate? (since the rods get electrified). Thanks!
I've ever used JB weld silicone. Probably fine, just check its data sheet that it works in 75c+. I used epoxy and silicon to insulate the connections from the plate
Its more about the current....it is significantly harder to break a high dc amp load vs a high ac amp load. The concern for me would be the life of the thermostat. Breaking the 25 amps (300 watts/12 volts) has got to be harder on then thermostat vs the 6 amps (1500/220). Besides the fact that is a very high amp load....its dc vs ac. In the US the current changes dirction 60 times a second...Europe at 50 times a second. It is why solid state relays do not work well in dc applications. Amperage never crosses zero in direct current like it does in ac making the thermostat have to break the full load. What happens? It will either fail on (contacts will weld close) or...as the contacts wear (because they wear faster on dc) he will burn up on one of the breaks and not make contact the next time....the second is the preferred....the first will have the water tank run away. A better bet would be to use the thermostat i the unit to fire a much larger dc rates relay made to break high dc currents. Just my two cents.
Awesome work mate, great info! really like that your going to have the ability to switch between 240 and 12v. Very cool. Is the 12v side still fused? im going to go 24v element on mine, my AC 1500w element is 110v so I just need to work out what I can run 24v element wise, I know my bms around 400a at 24v output so ive got loads of room to move. 1730w on the roof too
I should also mention that you always need to make sure that copper cables gauge and length are capable of handling the DC amps as well as any switches etc. you will be running the DC amps through.
It will be nice to add the link or suppliers after searching for 3 days the only u type found are 220v or more.
I just use a twin voltage heater... My 240v is 700w and my 12v is 300w, payed about £80 for it
I have a Stiebel Eltron 29kw whole house, tankless, electric, water heater that is about the size of a briefcase and hang on the wall and it works fantastic. I want to use two lower power electric tankless water heaters in an overlanding expedition vehicle(one for hot potable hot water and the other for hydronic under floor radiant heat), but that would mean I would need two very large inverters, could these water heater be converted to 24v or 48v DC?
Could you run a small inverter off mppt aux loads?
Great information, could you provide more details on the heated element from amazon I do not find your models
the u type 12v element the are impossible to find on the web your help for some reference to where to purchase is very important to complete this project.
Hi, just type 12v element into AliExpress, you'll find lots
Hi great video, this is definitely something I want to try in my camper, do you have a link to where you got the 12v 300w element from? thanks
You can get them super cheap on Aliexpress: www.aliexpress.com/af/300w-12v-element.html?d=y&origin=n&SearchText=300w+12v+element&catId=0&initiative_id=SB_20211019070530
That's where i got mine.
Do you have a link to the high-temp epoxy (was it a special metal formula?) that you used after drilling the holes? Where did you use the silicon vs where (and when) the epoxy? did you consider just cutting away any of the original element?
Hi, I used JB Weld, despite some misinformation on the internet, All JB weld products are food safe once cured. They even say so themselves. I used JB weld on the back side (dry side ) mainly and then put some high temp silicone under the washers - on threads etc on wet side.
To be honest if i was doing it again, i wouldn't bother with the JB weld. Just cover everything with high temp silicone. Definitely food safe and should last forever
You can absolutely cut away original element if you want. I just left it there because it wasn't in the way. Plus with it still there i can easily convert it back to 240v if i want. In fact i will be setting up a switch so that i can switch it between 12v and 240v - which would be handy when i'm on a 240v hookup. - hot water in 15mins!
@@thewanderingwarner5403 Thank you! Did you cut out a full ~1.25" diameter hole (for a 1" NPT male heating element) or did you drill out a small pattern of 2 or 4 smaller holes, just for the electrical ends to stub up through?
Nice 👍
Thanks!
1 - would the red JB Weld silicone sealant be similar to what you used, or a good product in your view?
2 - Assuming you just drilled 4 holes through the metal plate of the water heater - what did you use to make sure that none of these 3 metal rods would contact the plate? (since the rods get electrified).
Thanks!
I've ever used JB weld silicone. Probably fine, just check its data sheet that it works in 75c+.
I used epoxy and silicon to insulate the connections from the plate
Its more about the current....it is significantly harder to break a high dc amp load vs a high ac amp load. The concern for me would be the life of the thermostat. Breaking the 25 amps (300 watts/12 volts) has got to be harder on then thermostat vs the 6 amps (1500/220). Besides the fact that is a very high amp load....its dc vs ac. In the US the current changes dirction 60 times a second...Europe at 50 times a second. It is why solid state relays do not work well in dc applications. Amperage never crosses zero in direct current like it does in ac making the thermostat have to break the full load.
What happens? It will either fail on (contacts will weld close) or...as the contacts wear (because they wear faster on dc) he will burn up on one of the breaks and not make contact the next time....the second is the preferred....the first will have the water tank run away.
A better bet would be to use the thermostat i the unit to fire a much larger dc rates relay made to break high dc currents.
Just my two cents.
Awesome work mate, great info! really like that your going to have the ability to switch between 240 and 12v. Very cool. Is the 12v side still fused? im going to go 24v element on mine, my AC 1500w element is 110v so I just need to work out what I can run 24v element wise, I know my bms around 400a at 24v output so ive got loads of room to move. 1730w on the roof too
Sorry just got to the fuse part! nice