12 Volt geyser element and PV system

[Pineapple Smurf]

The only way to risk water leaks in the roof is to remove geyser from the roof cavity.
It makes no sense to exchange one risk (water leaks) and replace it with another (fire risk from overheated DC cables) in a badly designed PV system used for water heating.

My geyser sits in my scullery.
I have zero water pipes in my ceiling nor anywhere around there and wont have such a thing installed ever. It's just my fear.
DC cables will never ever overheat if installed properely

 

[Geoff.D]

Unfortunately, for many, the geyser is just about always located somewhere close to the bathrooms in the ceiling cavity, in the middle of the house.
I am painfully aware of these problems because I am busy helping my daughter renovate her bathroom/s and at the same time ensuring that should she ever move to solar beater heating, that gradually but sure of the water risks will move to a less vulnerable part of her home.
We have been really careful about pipe replacements material used etc to ensure a phased sensible transition.

 

[ekkekan]

900 watt element at what voltage?
900 W @ 12V = 75A.
@ 48V = 19A.
Both scenarios equal lots of panels regardless of the amount of sunlight available.

Somehow a point is missed. The system only uses PV to heat and does not use 12V or 48V battery power.
I still rate the kit very expensive as a on grid via grid tied to use the panel power based on the sun that is available to power the whole dwelling is a far better option.
Off grid you need deep pockets - refer to the 10 days of cloud we had in Feb. Genny's running all over due to flat batteries.
In over 45 years I have only had leaks due to burst geysers and with the compulsary pan below them no further water damage risk.

 

[Thor]

Does not matter. If the element is 2 000 Watt, then the current drawn is going to increase drastically for a drop in voltage. Personally, this is a fire waiting to happen.

This is what I am trying to wrap my head around.

I want to install an inverter for my house with solar, but thinking I might as well install a "dumb" inverter and do just the critical load with batteries and then do a separate circuit for solar, that only warms the geyser.

Since the geyser is my biggest cost, 2kW is 2kW so can either feed that into the house ( will need an expensive hybrid inverter to blend my electricity usage ) or I can just shove that straight into a geyser using a smaller inverter.

Unsure.

 

[leon.davibe]

Does not matter. If the element is 2 000 Watt, then the current drawn is going to increase drastically for a drop in voltage. Personally, this is a fire waiting to happen.

They work with 3 panels in series to keep the amps lower

Edit :so i was mistaken i thought it goes direct to element ie up to 120v

The element is a 900w 48-72v and it uses an mppt on the 3 panels in series that then adapts to the element voltage

 

[leon.davibe]

That is if you go solar via photovoltaics

You can also go collector that heats the water via convection

Takes up less roof space
If you have limited space

ie the water gets pumped through heat exchanger/evacuated pipes or panel that is heated by sun, no electrics involved
Except for the pump if tank is lower than collector