Imaginative Regulator Dump load? 240v immersion?

[VicS]

It takes 4200 Joules of energy to raise the temperature of 1 litre of water by 1 degree C.

Half a battery would give you 55 Amps for an hour, or 3600 seconds

55 A for 3600 seconds is 198000 joules

198000/4200 gives you a temperature rise of 47 degrees Centigrade for 1 litre of water.

So if you took 10 litres of water at 20C and heated it with 55A for an hour, it would be heated to 24.7C.

Heating water is expensive!

You have missed out the voltage. You calcs are out by a factor of 12 if we are talking about a 12 volt system

55A at 12volts = 660 watts

1 watt = 1 joule per second Therefore 660 watts for 1 hour = 660 x 3600 = 2376000 joules

...

The final result is that 55A at 12 volts for 1 hour will heat 10 litres through 56. 6 degrees, i.e. from 20C to 76.6C

 

[elton]

You have missed out the voltage. You calcs are out by a factor of 12 if we are talking about a 12 volt system

55A at 12volts = 660 watts

1 watt = 1 joule per second Therefore 660 watts for 1 hour = 660 x 3600 = 2376000 joules

...

The final result is that 55A at 12 volts for 1 hour will heat 10 litres through 56. 6 degrees, i.e. from 20C to 76.6C

You're correct of course. I thought my result looked too low, but I couldn't be bothered and knew someone would eventually correct me. Thanks.

 

[Heckler]

You have missed out the voltage. You calcs are out by a factor of 12 if we are talking about a 12 volt system

55A at 12volts = 660 watts

1 watt = 1 joule per second Therefore 660 watts for 1 hour = 660 x 3600 = 2376000 joules

...

The final result is that 55A at 12 volts for 1 hour will heat 10 litres through 56. 6 degrees, i.e. from 20C to 76.6C

Aha, now we are cooking with gas! So, a nice dedicated tank with plenty of insulation, the dump part of my regulator feeding it, with a bypass switch for a quick warm up if necessary and water for swmbo shower he we come! Plus a nice write up for PBO!
S

 

[VicS]

Aha, now we are cooking with gas! So, a nice dedicated tank with plenty of insulation, the dump part of my regulator feeding it, with a bypass switch for a quick warm up if necessary and water for swmbo shower he we come! Plus a nice write up for PBO!
S

well yes if have that much surplus solar power. The example is 660 watts for an hour but of course could be a fraction of that for several hours . 660/n watts for n hours.

I've not previously come across a regulator the behaves exactly as you describe. More usually the load terminals just provide power from the system but protect the battery from being discharged below some specified level by disconnecting the load when the volts fall below a certain value and reconnecting when they rise again to some higher level. This is useful for controlling the operation of a fridge, for example, but operates independently of the solar input, giving the same control whatever energy input there may be; engine, genset, windgen, shorepower charger etc as well as the solar panels.

 

[PetiteFleur]

Just googled 12v water heater and lots of info turns up from various sources, someone on ebay who makes and supplies them and he is quite informative.