diy solar

diy solar

Efficient long distance transmission of power

Zil's link is not inconsistent with the voltages/currents/pulse rates of the links I found.
Snoobler's paste "1000 watts" is 3x the voltage/current product of the figures I saw for 1 pair of wire, could be larger gauge.

1000 watts, 1 ms would be 1 Joule, low enough to not be safety hazard for humans or ignition for combustibles (but not for an explosive atmosphere.)

Basically, pulses are sent for brief periods, about 1 ms. That is short enough to not be a human safety hazard, so long as they are stopped after detecting incorrect impedance. That provides ground-fault protection as well as if the human is across the leads, something GFCI can't detect.

If voltage and joules delivered were excessive, a 1 ms pulse would be long enough to blow something apart, but a few hundred volts is OK.

The voltage is too high for insulation in LAN cable, beyond what it is rated for. But, the repeated tests of impedance would detect breakdown so circuit could be shut off. It would provide some degree of arc-fault protection as well.

The key for this to work is a controlled impedance of the receiver, so any other loads can be distinguished. Having sloppy control there would allow larger faults to go undetected.

Where I've worked, any shock not due to normal static (shuffling feet over a carpet) was a reportable incident. If something like this gave a 1 ms 300V shock to a person handling RJ-45 plug with sweaty fingers, that would be unacceptable.

I once interviewed with a company bringing out dimmable lights powered by LAN cable. I pointed out that at allowed voltages/currents, it couldn't deliver the watts they planned for. Never heard back from them, eventually got an aerospace job instead. (2008/2009, it was a slow time for employment. 1000 applications, 6 interviews, 1 offer)
 
I have 3 separate systems here off grid. I have a situation where I am setting up a solar only system near our cabin and want to run supplemental power in winter a hydro based system about 800' away. I have a 10AWG UF wire run from the hydro system to the new solar only system. Looking for ideas to run maybe 1000-2000 watts (or more?) over that cable to the new system as efficiently as possible.
With 1600 Ft AWG you have about 1,7ohm resistance.
One should go for at least 300VDC, with that voltage you can run standard 240VAC power supply modules. They rectify 240V AC to ~300VDC internally.
What is your hydo-power gen providing? DC? AC? 3phase? voltage?
 
That looks like it would work. Now to find one...

Another option is getting some power supplies from big routers. I don't know the efficiency, but they definitely are cheap.

Just wire multiple in series so you can get the maximum voltage the MPPT accepts, and make sure the power supplies are rated higher than the MPPT can handle. The MPPT will act as current limiter, otherwise the power supply might shutdown due to overload.

https://www.amazon.com/Controller-Regulator-Backlight-Display-Lead-Acid/dp/B078W6SY8Y for example is $170 for a 60A controller and can handle up to 150V. So when using 3x 40-50V powersupplies in series you're within its limits (and the long wire will add some voltage drop as well)
This will charge at 60A (2880W @ 48V)

For the power supply: Have a look at some Cisco 6500 powersupplies
The Cisco 1300W for the 6500 series for example does 42V @ 27A (or 55A when using 240V). Hooking 3 in series will give you 126V @ 27A = 3400W of power. They cost <$30 on Ebay.

The biggest-ass powersupply (8700W) provides 200A @ 42V when connected to 3 220V circuits...
(94A when connected to 3 110V circuits)
Costs you a whopping $40 or so on Ebay ;)

Only thing of caution is you might to modify to get them floating, some powersupplies have their negative connected to ground, so you can't serie-connect them, but this is usually easily to fix.
Another potential point might be safety: High DC voltages are more lethal/dangerous than AC power. So you have to make sure the cable is properly secured from damage.


If the hydro side is able to provide 3-phase, a step-up transformer to 440V and a stepdown to 110V might be a better (more efficient) option.
 
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With 1600 Ft AWG you have about 1,7ohm resistance.
One should go for at least 300VDC, with that voltage you can run standard 240VAC power supply modules. They rectify 240V AC to ~300VDC internally.
What is your hydo-power gen providing? DC? AC? 3phase? voltage?
P.S. You just must care not to use standard AC switches, that are not designed to switch high voltage DC and have no arc suppressors. 300V DC can generate up to 20cm long sparks when some inductance (like your long power line) is present!
Use DC circuit breakers rated for 600V instead and be very careful: DC 300V is a weird dangerous voltage!
 
I suspect few of you have had a course in Thermodynamics. There are 2 Laws of Thermodynamics. 1) Energy can not be created of destroyed, only transferred from one form to another. 2) Any transfer of energy results in some loss.

Hydro converts the energy of falling water in to mechanical rotational energy and ultimately electrical energy. Solar takes the energy from the sun and converts into electrical energy. Hydro is continuous (unless the source dries up or freezes), but the output varies. Solar in not continuous. In both case, you will want to store some energy (convert electric to chemical through a battery charger and battery). When you have multiple sources of electrical energy at different potentials (voltage) and currents (AC? vs DC), you must convert to a common voltage even if that is AFTER two different chargers. Batteries are great "hold tanks" especially when being "filled" from more than one source.

The important thing that the OP did not say is what voltage and current type come out of his hydro. You want the voltage to be as high as is reasonable possible. Higher voltage (different gear/pulley ratio between the water wheel and the generator) will mean lower current. Lower current means less loss for the same size wire over a long distance or smaller wire. Copper wire has less losses than aluminum.

Cost is always an issue, so again, thinner wire (higher voltage, lower current) is best. It is difficult to find wire smaller than 12 gauge that is suitable for use outside (even a plastic conduit is not considered "waterproof"). Extension cord wire (electricians call it "cordage"; the best type for this application would be SJOOW) does come in sizes down to 18 gauge. 1000' of that would still cost over $250.

With the insufficient data we have been give, run power directly from the hydro to your battery storage area and convert it there. Run the solar to the same location and convert it there. Connect both to your battery bank. You still have to "conversions"; first from the incoming coltage to tha appropriate voltage for the batteries, second from electric to chemical.
 
I have 3 separate systems here off grid. I have a situation where I am setting up a solar only system near our cabin and want to run supplemental power in winter (when we only have rain...) to charge this system from a hydro based system about 800' away. I have a 10AWG UF wire run from the hydro system to the new solar only system. Looking for ideas to run maybe 1000-2000 watts (or more?) over that cable to the new system as efficiently as possible.

I am planning the new solar based system to be 48V nominal

My original idea was to run 120V ac from the remote inverter to a 48V battery charger on the new system. Having trouble finding an efficient 48V charger.
Next idea was to find a 56V AC to DC power supply and run the DC output to a cheap MPPT charge controller, but again, the power supplies seem to all be clustered around max 85% efficiency, added to the MPPT losses and wire losses and well, that leaves a lot to be desired...

Got to be a better way to do this.
Need some other ideas from you folks who are smarter than me.
 
Are we into the Westinghouse/Edison argument. If you Produce AC and rectify it at the delivery site, low transmission losses and smaller wire.
 
Does the hydro produce more power than you need?
In that case efficiency isn't so important; even if a percentage is lost, so long as enough reaches the battery you're fine.
High voltage 3-phase generator and 3 + ground UF cable or wire in conduit.
 
I agree that none of us have seen the property and don't really know what's going on, so we are all just guessing. While we are standing around the Cracker Barrel, I will throw in my two cents. I had a need to run power about a half-mile several years ago. I spent a few days looking for some surplus utility transformers, but since we were in the middle of nowhere, I didn't have any luck with that. So I took a couple of transformers out of scrap 2000 watt inverters. The windings are approximately 10 to 1. 120 volts in gives you 1200 out. That easily traveled the half-mile thru 2000v PV wire and came right back out of the other transformer at pretty close to 120. I know what you are going to say, don't bother, I know it was a harebrained scheme. But we were in the middle of nowhere working with what we had. And it worked great. Lasted all summer. We took it down and I'd forgotten all about it until I read this thread. I'm not even sure I would recommend that anyone try that. I guess it's just a reminder that sometimes you have to think out-of-the-box.
 
I agree that none of us have seen the property and don't really know what's going on, so we are all just guessing. While we are standing around the Cracker Barrel, I will throw in my two cents. I had a need to run power about a half-mile several years ago. I spent a few days looking for some surplus utility transformers, but since we were in the middle of nowhere, I didn't have any luck with that. So I took a couple of transformers out of scrap 2000 watt inverters. The windings are approximately 10 to 1. 120 volts in gives you 1200 out. That easily traveled the half-mile thru 2000v PV wire and came right back out of the other transformer at pretty close to 120. I know what you are going to say, don't bother, I know it was a harebrained scheme. But we were in the middle of nowhere working with what we had. And it worked great. Lasted all summer. We took it down and I'd forgotten all about it until I read this thread. I'm not even sure I would recommend that anyone try that. I guess it's just a reminder that sometimes you have to think out-of-the-box.
Pretty unlikely to find transformers that won't saturate with 5x normal voltage. 140% nominal voltage might just work.
 
Pretty unlikely to find transformers that won't saturate with 5x normal voltage. 140% nominal voltage might just work.
Yeah, I don't remember any specifics about the transformers. And we weren't running an entire house, we just needed a few tools and some shop lights in the evening for a couple hours each day. It beat hauling batteries up the side of the mountain. "Pole pigs" used to be easy to find, I guess with PCBs, they're little more careful about where they leave those laying around these days.
 
I have 3 separate systems here off grid. I have a situation where I am setting up a solar only system near our cabin and want to run supplemental power in winter (when we only have rain...) to charge this system from a hydro based system about 800' away. I have a 10AWG UF wire run from the hydro system to the new solar only system. Looking for ideas to run maybe 1000-2000 watts (or more?) over that cable to the new system as efficiently as possible.

I am planning the new solar based system to be 48V nominal

My original idea was to run 120V ac from the remote inverter to a 48V battery charger on the new system. Having trouble finding an efficient 48V charger.
Next idea was to find a 56V AC to DC power supply and run the DC output to a cheap MPPT charge controller, but again, the power supplies seem to all be clustered around max 85% efficiency, added to the MPPT losses and wire losses and well, that leaves a lot to be desired...

Got to be a better way to do this.
Need some other ideas from you folks who are smarter than me.
All the microhydros I'm aware of are three phase AC that gets rectified. Only two workable options that I can see:

- Two 3 phase transformers, one end a step up and one end a step down then rectify and feed to mppt controller. 2000w 3 phase transformers are REALLY expensive.
- Choose your microhydro windings so it outputs ~200V AC, rectify to 230ish volts DC at production end and feed 230-240DC back to high voltage MPPT controller like a Midnite Classic 250, they're expensive too ~$725 each.

The higher the voltage you can get for transmission the better but I'm not aware of any MPPT charge controllers that can handle higher than 250V and are specifically compatible with microhydro.

Edit: Outback has a Flexmax that'll go up to 300VDC, $875 There's no inexpensive way I can think of that doesnt have huge losses.

Edit to the Edit: Option 3: DIY your own 3 phase transformers https://www.electronics-tutorials.ws/transformer/three-phase-transformer.html out of three 120-to-240v single phase transformers, you'd need 6 of them. Step down and rectify at battery bank end. Still going to need a microhydro compatible MPPT controller though.
 
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- Two 3 phase transformers, one end a step up and one end a step down then rectify and feed to mppt controller. 2000w 3 phase transformers are REALLY expensive.

Not cheap by any means, but $190 gets single phase 500 VA, 120V to 480V.
3 of these at the generator side, 3 at the charger side, for 1500W total.

 
Not cheap by any means, but $190 gets single phase 500 VA, 120V to 480V.
3 of these at the generator side, 3 at the charger side, for 1500W total.
I was actually thinking of these 1500w 2:1 up/down for $60 each. Rip out the guts and wire them up as above.

Microhydro 3 phase windings to 200V, step it up to 400v and then back down to 200, rectify to 240v DC and feed to a Midnite 250

Edit, my math was wrong, you'd get 280V DC out of rectifying 200v, you'd need 170v 3 phase out of the microhydro head to get to 240v rectified DC. He can use a stack of paralleled microwave oven capacitors as the filter, electrolytics of decent size at that voltage are expensive.

Also, just found a 11000uF 300v aluminum electrolytic on Mouser for $55 which is a pretty good price, you'd need two.
 
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This sounds more and more like a lot of work. I would be inclined to move my living room over by where the hydro unit is, and hang a hammock there...
 
I think a step up AC transformer (120v to 240v or 480v) by the panels, and a step down (back to 120v) would be the best option. No matter how you slice it, its going to be expensive (and somewhat lossy) to throw 2kw that far.
 
I saw a thread a long time ago about some guy that used a pair of microwave oven transformers with the shunt gap removed.
He ran a single steel wire on high wooden poles at around 1.5 to 2Kv ac with earth return.
It was only a low power system, but for simplicity and low cost it would be hard to beat.
Very easy to fix too if the wire ever came down.
 
I keep thinking to build the solar in full series to hopefully come close to 600 volts and use an MPPT at the destination.
I would bury the cable. Might need more solar ;)
 
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