Solar PV MPPT board for Hot Water heating

[TackyTeddy]

Originally Posted by Xringer

I'm currently testing out the 800w array connected directly to the lower
heating element in my new GE water heater w/ A7 on top.
(No MPPT being used yet).

Here’s my 3 panels that I plan to use for my Water Heater.

Looks like I’m going to have to use them Direct Feed. I had planned to try the Solar Hybrid Hot Water Solution - No Plumbing Mods Required - At TechLuck board, but he doesn’t sell direct anymore. His resellers are lacking!

My concern with direct DC feed is Arcing and Pitting on the (old style) water heater Contacts
If you have any suggestions for an Low Cost MPPT I could use, please advise.



I still have to workout some BTU’s for this setup

I have an GE water heater w/ A7 on top (early Dark Gray version) that I had planned to use the solar to heat the bottom element.
But it doesn’t have the thermostat (with contacts) for the bottom element like most water heaters had. So I might do a separate (old style) waterheater as a preheating tank feed into the (GE water heater w/ A7 on top)

Thanks for posting your water heating, testing info. If anyone see problems with my watts so far, Please advise.

P.S. my estimates are based on my older 1.654kW Solar feed info Prospective by TackyTed - Solar (bottom of that page, just above our Solar PV Google Map)

[Xringer]

If your heating element is 13 ohms (like mine) and you have 91.2 volts (vmp) from the PV,
91.2 / 13= 7 amps. That 7A gives you 637 watts. (P=I sq x R)
Which is about 2173.5 BTU per hour. (When the sun is perfect)!


I have been looking at things to control my tank's temperature..
Not much luck so far.. Also have been looking at MPPT stuff too.

Tigo Energy Dual Maximizer mm 2ES50 2 x 300W MC4 New | eBay

Two of these for my 4 panels = $170 and that seems a bit high.
Plus, I'm not sure how much extra power I really need..
I've already disconnected the 500W array..
So far it's not been overheating. Of course it's not Spring here yet..

[TackyTeddy]

Originally Posted by Xringer

If your heating element is 13 ohms (like mine) and you have 91.2 volts (vmp) from the PV,
91.2 / 13= 7 amps. That 7A gives you 637 watts. (P=I sq x R)
Which is about 2173.5 BTU per hour. (When the sun is perfect)!


I have been looking at things to control my tank's temperature..
Not much luck so far.. Also have been looking at MPPT stuff too.

Tigo Energy Dual Maximizer mm 2ES50 2 x 300W MC4 New | eBay

Two of these for my 4 panels = $170 and that seems a bit high.
Plus, I'm not sure how much extra power I really need..
I've already disconnected the 500W array..
So far it's not been overheating. Of course it's not Spring here yet..

First off thanks for your estimate of the BTU's :-)

Second I almost found the answer (well not)

- - - - - - - - -
Randy over at TN Solar Systems | PV Solar System Kits | Home Energy Monitor | Simple Energy Works sent me an email knowing that I'm in search of a MPPT for my water heater.

"Here is the solution you need"
CyboEnergy

So I gave it view and it looks like it just might fit my needs. So I ask Randy to see if he could find some pricing for me as I couldn't find a price anywhere on the web. Below you'll see why

Well he got price from them. Much to his (and my) wonder and astonishment. Remember Randy was just the messenger. Are you sitting down!!!!

$750

My comment was ....
💩💩💩 (if the three little graphics don't show up it's three little piles of pooh)

How much for the one that doesn't have the gold plated cover?

They must think they are Apple selling a gold plated Apple Watch!

As an end consumer, I think they'd sell at $150-$200 range.

I can run direct DC less the benefit of MPPT.
Or I can run two DC micro inverters for $200 total, for four panels.

Randy you can to forward my comment to them if you wish.

So I'm in still in search of ...................

[Xringer]

The way some people look at the cost of MPPT, is by power gain/BTUs per watt.

Once they have the cost, they compare that cost to buying one more PV panel.
Because normally, buying more PV watts is cheaper than buying MPPT stuff.


That's how people figure out 'tracking' mounts. If it costs more than 200 or 300 more
watts of additional PV panels. It's better to buy more watts up front..

[TackyTeddy]

Found this page with Spec sheets for Water Heaters along with Service manual & fault codes

GE heat pump manuals by date

Mine is the 2009 GE