Solar Mini Split or ... Solar and a Mini Split

[jorby]

Well, I think you are correct the batteries now are fine...it's just the cost to produce them...but that will change

I have a lot of gassers but can't wait to get an electric!

And yes, it's all the gizmos that cause the problems. Although I have been disappointed to hear about tesla replacing multiple motors on high mileage cars. I mean it's an electric motor we have been making those for a long time and they should last almost forever...at least WAY longer than a gas engine but it appears they aren't there yet. Maybe "they" is just Tesla ... maybe the car makers with more experience will do better...or it will just take a while for the manufacturers to get it together. But really the motor should never need to be replaced.

Any idea how those motors fail? Is it mechanical or the windings? Are there any gears in the "motor" assembly? I am just curious because I agree that the 3 phase motor itself should last forever.

 

[jorby]

On the water heating issue, I am running my old school heater from the inverter. I run the top element full time at 120f. We get by fine with that much hot water. The lower element is used as a dump load for when the batteries get full. The bottom thermostat is driven separately and is set to 150f. It usually raises the whole tank to150 on a sunny day like today, unless the dryer (6kw) is being used. I considered a hpwh, and could get a 50% utility co rebate, but the other $800 I would have to pay, and the failures i have read about, made me just go this route. I have been running my 22kw rated system for about 3 months now. In the summer, I am going to need an EV to charge but I probably don't drive enough to keep it empty enough. We heat with a wood stove already (for 23 years).

 

[jorby]

The impedance match problem for resistance heating is addressed several different ways here: https://diysolarforum.com/threads/simple-home-made-analog-mppt-contoller.47057/page-1


It is a work-in-progress for me, but I have had success so far.

 

[Solar1]

Yeah, not sure how they failed I have just seen a couple of articles about high mileage Teslas that reported multiple motor failures during the cars lifespan. But it is really inexcusable. I mean how many parts are there that could go wrong vs a gas engine. What have they got a couple of bearings? Anyway, electric cars, if not already, will be great and will eventually dominate the market...and I say that as a gas car collector/lover!

I mean if batteries had been great at the turn of the century we would all be driving electric. I cannot even imagine a scenario where the electrics won but then we needed to switch to gas. I can hear it now....I will have to go to a station and fill my car?!? ...and then I have to change the oil (and back in the day points/plugs/etc..), and they will only last 2-300K, and you want me to drive around in a car with 20 gals of highly flammable liquid and even park it in my garage?!?!, What if I get in a wreck, it will explode! And how will we get all this gas? It's not like we can drill for it in Saudi Arabia ship it around the world, process it, and then ship it to my local "gas station" that's crazy!!! I could go on and on ...people would be freaking out,

 

[Solar1]

On the water heating issue, I am running my old school heater from the inverter. I run the top element full time at 120f. We get by fine with that much hot water. The lower element is used as a dump load for when the batteries get full. The bottom thermostat is driven separately and is set to 150f. It usually raises the whole tank to150 on a sunny day like today, unless the dryer (6kw) is being used. I considered a hpwh, and could get a 50% utility co rebate, but the other $800 I would have to pay, and the failures i have read about, made me just go this route. I have been running my 22kw rated system for about 3 months now. In the summer, I am going to need an EV to charge but I probably don't drive enough to keep it empty enough. We heat with a wood stove already (for 23 years).

Oh, and don't get a heat pump dryer...what a disaster. A friend had one in a rental, after going over to fix it a couple of times I told him to take it out as it was just never gonna work. While a GREAT idea the implementation was sub par. Blowing the warm moist air over the cold coils to dry it out is a great idea...unless there is lint in that air, which even with 2 filters it was still getting through. That in turn leads to a clogged coil and no drying. The tenants were getting fed up with that.

That design just needs to spend a little more time in the oven... I'm sure it can and will be functional eventually...

 

[usherben]

Yeah, not sure how they failed I have just seen a couple of articles about high mileage Teslas that reported multiple motor failures during the cars lifespan. But it is really inexcusable. I mean how many parts are there that could go wrong vs a gas engine. What have they got a couple of bearings? Anyway, electric cars, if not already, will be great and will eventually dominate the market...and I say that as a gas car collector/lover!

I mean if batteries had been great at the turn of the century we would all be driving electric. I cannot even imagine a scenario where the electrics won but then we needed to switch to gas. I can hear it now....I will have to go to a station and fill my car?!? ...and then I have to change the oil (and back in the day points/plugs/etc..), and they will only last 2-300K, and you want me to drive around in a car with 20 gals of highly flammable liquid and even park it in my garage?!?!, What if I get in a wreck, it will explode! And how will we get all this gas? It's not like we can drill for it in Saudi Arabia ship it around the world, process it, and then ship it to my local "gas station" that's crazy!!! I could go on and on ...people would be freaking out,

These would be drive units. I believe they have the fixed gear reduction inside, as well as the differential.
If I recall some of the earlier ones were traced to current leaking from the motor going through the bearings causing failures from micro arcing.

 

[jorby]

These would be drive units. I believe they have the fixed gear reduction inside, as well as the differential.
If I recall some of the earlier ones were traced to current leaking from the motor going through the bearings causing failures from micro arcing.

That seems to be an insulation failure as root cause. Replacing the "drive unit" vs "just the motor" is what I was thinking about with my questions.

 

[PVGeezer]

The impedance match problem for resistance heating is addressed several different ways here: https://diysolarforum.com/threads/simple-home-made-analog-mppt-contoller.47057/page-1


It is a work-in-progress for me, but I have had success so far.

Very cool thread Jorby. Not surprised there are folks on here working on this. I only understand about half of what you're doing there but I think it's a good track.

We used to have simple fixed input voltage buck converters back in the 80s. They were used for impedance matching between PV arrays and DC permanent magnet water pump motors. They took advantage of the motor inductance to eliminate the additional inductor. They worked very well and the losses from not doing perturb and observe optimization were quite small, around 5-10% IIRC.

Then of course the variable frequency 3 phase motor drives came out and that was the end for most of that. I think Aquatec still makes one, not sure what MPPT strategy they use.

 

[PVGeezer]

Anyway, electric cars, if not already, will be great and will eventually dominate the market...and I say that as a gas car collector/lover!

What flipped me over the fence to electric was when I overhauled my airplane engine (with the help of my A&P of course). I'd rebuilt plenty of auto engines before, didnt think anything of it. But putting together all those reciprocating parts I started thinking about the forces on them, knowing that if anything went wrong with pretty much any of them it could mean I wound up impacting a tree at 60 knots in what amounts to a big aluminum can. Pistons experience something over 1000 g's.

So I started replacing every ICE I could with electric. Now there's only two left to go: my tractor and, you guessed it, the airplane. Go figure.