12V heating element recommendations

[jaybee]

Hello,

I'm trying to look for 12V water heating elements for dumping excess charge into a hot water tank.

Would like to compare prices for various makes but have only found the one so far.

Any help would be appreciated.

[Shadow]

Are these the ones you found? http://www.survivalunlimited.com/diversionloads.htm

[jaybee]

Thanks for that list. More to chose and they're cheaper.

Useful additional info as well.

[Drives]

http://www.meci.com/Catalog/Category/351a1e14-68ea-4bf1-b992-9029fc6b6669

I have never purchased from these people, so I do not endorse them.  I just noticed that the prices looked good.  

Remember the following formulas  Power (watts) = Volts X Amps  (in a DC circuit)

                                       Volts divided by Amps = Ohms (resistance)

For example, the first heating element rated 4500 watts at 208Vac can handle only 21.6 amps flowing through it.  It has a resistance of 9.6 ohms, and at 12 Vdc it will only draw 1.3 amps for a total wattage of 15 watts when used with a 12Vdc system.

Therefore, these immersion heaters would not work, but if you could generate high voltage DC with a Industrial PM motor, these would work well.

[ghurd]

I have purchased items from them a time or 2. Seemed fine.

The 6000 watt should do a little better than the 4500 watt at lower voltage.

I wondered about the 12V 120w coffe cup heaters, like you see at flea markets for $3.  They look just like this expensive one.

http://www.3rivers.net/~cmac/k10.htm

G-

[Laylow]

Here is the cheapest place that I could find DC heating elements.  They are called SJH elements if you want to search for them but this was the only place I could find to buy them.  Their server was down just now but I bought one last week so I would imagine they are still there.

http://www.hydrogenappliances.com/hotwater.html

They had 12V, 24V, and 48V DC elements.  You could get 300 watts for $30 or 600 watts for $40.  I definately recommend the 600W.

Does anyone have any idea what happens if you use an AC element with DC or vice versa?  Or what about mixing voltages?

[Laylow]

The site is back up.