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smokedvw
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# Posted: 13 Apr 2021 09:22pm - Edited by: smokedvw
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Hi,
After reading various things online then trying to read through as much as I could find on here I have a few questions.
First the cabin setup. There are 3 main locations.
The water/pump/shower/bathroom building
I have our current water tank setup in the middle of the lot this is where the water pump and propane hot water heater are located. We are building a new bathroom with shower and toilet at this location as well. This location is a small shed with a slopped roof. The slop is from East (highest) to West (lowest). I figured I could setup a panel on this roof and make a contained solar/controller/battery setup here to power the waterpump for the hot and cold water along with the 2 lights.
Location needs:
2 16w LED lights
Pump is a 7.5 AMP 12 V RV pump. I expect this to be used for about 2-3 hours per day maximum.
The main cabin
We have our main cabin at a location where Solar can be mounted on the ground in 2 different locations. One location puts the solar within 20’ of the cabin and we could put a charge controller there with the batteries. This would be directly under the cabin in an open area but I can build a battery box to house them if needed. I can then run an inverter inside the cabin which would be about 10-15’ from the battery box.
Location needs:
6 x 11-16w and ideally charge our phones.
Outdoor eating area and wall tent
I would also love to be able to have a wire going out to our tent platform and outdoor eating area to run another set of lights. This location would be about 40’ from that battery housing.
Location needs:
6 x 16w lights used at night
If I was going to run a wire from the batteries to the water/pump/shower/bathroom building it would be around 60-70’.
All the lights in here can DC (RV lights) or AC lights.
My questions are as follows
Since everything can be run in DC should I just leave the system in a DC setup and run wire to all those locations with a wire bar to split when it gets to the cabin, bathroom and outdoor eating areas then run individual wires to each of those lights?
Should I just put everything in AC and run an inverter and then extension cords to the bathroom/outdoor eating area? For the shower I would have to change that AC into DC for the water pump.
Should I just buy 2 setups, 1 setup that I can mount on top of the bathroom (probably a single panel and PWM charger and 100ah AGM battery)
leave that in DC which will power the pump and lights and then put the rest in AC at the cabin?
I really have no idea around the wiring between the areas and how to setup the battery/inverter controller in proximity which will make the most sense. I have read various things that DC is not exactly as safe for overheating and has larger voltage drops but I’m trying to understand what the best setups would be for this situation.
I could also run 3 totally independent systems but batteries seem to make that probably not a smart idea and seems like a waste.
I am really hoping to get some inputs on if I should setup an entire AC system and run the lines to those 2 out locations or if I should do 2 solar setups or if I can do the entire thing in DC? What would be the best. In the future the location of the cabin may require more power to it as we decide to do more at the lake but for now its pretty bare bones.
Thank you very much
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gcrank1
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# Posted: 14 Apr 2021 12:09am - Edited by: gcrank1
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Id do a stand alone 12v system at the shower house. You can make a tidy little system right there for not a lot; trying to run 12v there from the cabin will kill you on properly gauged heavy wiring. If you switch it to AC from the cabin you have to buy new stuff for 120vac.
You could run 120vac from the cabin but it would have to be overhead on poles or underground, Not just a contractors extension cord!
Your est time of use seems high, lots of people?
The main cabin and platform I would feed with AC.
If you go with 24v or more from an array 20ish feet to the cabin the proper wire gauge wont be too heavy/expensive (there are online calc's for line losses but iirc about 8ga would do that run at 24v to the mppt charge controller inside the cabin.
From the cc you want a short, and heavy gauge, fused wire set to the battery bank.
The bat-bank (size and chemistry) and its voltage becomes a whole discussion in itself.....we have some threads on such in the recent past.
The inverter size will be based upon bat-bank, what your power needs are vs 'wants', but what you have stated is not demanding (not unlike my system); you may want to add a fan or two?
Were I buying new stuff Id likely go 24v bat-bank and inverter to 120vac. As is, I 'inherited' a 12v system, it has limitations as demands increase (which they always do).
Once the dc is inverted to the higher voltage ac you can run pretty long standard wiring using a small service panel.
I think what you propose is affordably doable. I know LED lighting was a game changer for us (we are happily using several 9w Edison base bulbs and only one 13w) as was going to 120vac asap at the bat-bank with the inverter.
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Brettny
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# Posted: 14 Apr 2021 06:06am
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I would run everything in 120ac. They sell those small water pumps in 120v and that's really the only thing keeping you from going fully 120v. Running this all in DC and even a separate system will cost more. People dont like to run things through an inverter because it has some loss. Add another pannel and battery. Ease of use is also something else to keep in mind and theres almost no one I know that cant plug a plug in an outlet.
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smokedvw
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# Posted: 14 Apr 2021 09:23am - Edited by: smokedvw
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Yes just to be clear I can change that water pump to 120v for sure. $150 loss but can be done. I'm wondering then what kind of wiring do I need between the inverter and the 40' to the eating area and 70' to the bathroom?
I will be having a small excavator in there soon so this is why if I want to run cables to both I can underground in a conduit.
Thank you
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Nobadays
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# Posted: 14 Apr 2021 09:45am
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I would second Gcrank on this one. It takes very little solar/battery to run an RV pump and a couple of LED lights. Our cabin originally had just a marine deep cycle battery and the pump in a movable box (drain and take it in during the winter) and a 20w solar panel to keep it charged. Worked well really. I would definitely use a bigger panel, 80 - 100w. Likely you won't use the power all day so it will have all day to charge... you might want to mount the panel so it faces a bit more south to better catch daytime sun.
You could feed 120v to the shower/bath as Brettny indicates but there are a couple of reasons that wouldn't be my choice. You would need a minimum of 10awg direct burial wire and even with 10awg you are looking at ~2% line loss, which is ok but only for the current planned needs (I calculated that on a 15amp draw.) If you have 120v out there, someone, sometime is going to plug something else in! In addition, though I couldn't find the thread, I know folks on here who have used both 12v and 120v RV pumps ultimately stick with the 12v, even if a transformer is needed. The reasons being 120v have been said to be noisier and the big reason is they fail more often.
Again what gcrank said for the cabin, 24v gives you future options, 12v system is money thrown away if you ever want more electrical devices... microwave, fan, etc.
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smokedvw
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# Posted: 14 Apr 2021 10:20am - Edited by: smokedvw
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I had read about 12v pumps running better as well but seems 120 is hot or miss but shurflo has some.
I could do a marine battery plus a cheap 100w kit for $150 battery and $250 panel, controller kit but the location of the panel on that roof has some direct sun but also a fair amount of trees during the morning to noon then it would get sun noon to about 5 with possibly partial shading vs the other location can get sun unblocked all day beside the cabin.
Regarding someone else plugging something in I don't plan to out any plugs there for people.
I think running 10g wire in the buried conduit and replacing the pump would be cheaper than a separate system and get a lot more power on the panel if moved to the other location.
Then again I see that 10g / 2wg costs $100 for a 50' roll or $350 for a 150' roll here in canada. I might have to call some electrical supply shops to see if I can find a better deal.
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Nobadays
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# Posted: 14 Apr 2021 10:34am
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Quoting: smokedvw I think running 10g wire in the buried conduit and replacing the pump would be cheaper than a separate system
Very likely.... if you run conduit I do believe you need to run THWN wire, not romex. Would be simpler and cheaper to just use direct bury cable. You do need conduit on each end where it comes out of the ground.
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NorthRick
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# Posted: 14 Apr 2021 04:38pm
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Quoting: smokedvw I will be having a small excavator in there soon so this is why if I want to run cables to both I can underground in a conduit.
Then I would do a single system at the cabin and run buried lines to the bath house and the tent. You could get a transformer to drop the 120 AC to 12 DC at the bath house and keep your existing equipment.
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Brettny
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# Posted: 15 Apr 2021 05:53am
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Quoting: smokedvw Yes just to be clear I can change that water pump to 120v for sure. $150 loss but can be done. I'm wondering then what kind of wiring do I need between the inverter and the 40' to the eating area and 70' to the bathroom? I will be having a small excavator in there soon so this is why if I want to run cables to both I can underground in a conduit. Thank you
12/2 UF-B will be good for 20a. It's also direct burial rated. You can do 14/2 if u want 15a
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Nobadays
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# Posted: 15 Apr 2021 07:57am
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Here is a Voltage Loss calculator for future reference: HERE
Code requires no more than a 5% voltage loss, that said the target is usually set at no more than a 3% loss.
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gcrank1
Member
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# Posted: 15 Apr 2021 09:37am
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I always look at the costs of upgrading, say if 12ga. is ok at x cost how much more for 10ga.
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smokedvw
Member
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# Posted: 16 Apr 2021 01:18pm
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Hi guys,
I think after all of this going with 10/2 UF-B would be the way to go. That will allow me to support higher loads later on and the difference is $120 12/2 250' or $250 for 10/2.
The main reason I am leading towards putting the panels at the cabin is that I can have them facing south into full sun all day on a ground mount. If I mount at the pump house then it will only get 4-5 hours a day.
I figured even if running a inverter to go from DC -> AC -> 10/2 wire 70' to the pump house then AC -> DC I will still gain more juice from the panel with full days sun vs restricted sun.
Even if I left it in DC and had a 30% line loss but gain 100% more sun I assume that would make up for that loss. This is why I'm leading more towards the cabin setup as the main and send out to the other locations.
Now if I could only find cheap 10/2 wire in Canada. It looks like ill have to order from the US and bring it up.
Just wondering if I'm missing anything else in this calculation? Next ill create a different post on the actual solar/battery setup to make sure I'm not making any mistakes there.
Thanks!
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Nobadays
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# Posted: 16 Apr 2021 02:57pm - Edited by: Nobadays
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Quoting: smokedvw Even if I left it in DC and had a 30% line loss but gain 100% more sun I assume that would make up for that loss.
No. To run 12vdc 70 feet even with 10 guage wire you will be left with less than 10vdc at the pump house. This might run the pump but I'm sure it would lead to premature failing. If you turned on a light with the pump running, forget it.
Better to stick with 120v going to the pump house and either use a 120v RV pump or a transformer and 12vdc RV pump.
Diysolarforum.com is a great place to look around in for solar stuff. There are even small solar "blueprints" for several sizes of systems. All the recommended equipment listed in those are tried and true and mostly on the lower cost end.
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Brettny
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# Posted: 16 Apr 2021 03:31pm
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I wouldnt bother with any thing over 12/2 at 120v. Your LED lights and small pump prob pull less than 8a at 120v
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gcrank1
Member
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# Posted: 16 Apr 2021 08:25pm
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Brett, what if that load increased by 50% to 12a @ 120vac.
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ICC
Member
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# Posted: 16 Apr 2021 09:26pm
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I am a believer in 120 VAC for almost everything.
I also believe in maximizing sunshine.
I would likely go for 10 AWG wire if it did not break the bank. I usually manage to find new uses for electrical power a year or two after the fact.
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gcrank1
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# Posted: 16 Apr 2021 09:49pm - Edited by: gcrank1
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I know my life with solar got easier when I stopped trying to split uses from 12v and 120vac to just the 120.
The only time I use 12vdc now it for low load short term with mostly a portable power pack.
Something that hasnt been mentioned on this thread regarding inverting asap to 120 is that you can use standard house wiring, fixtures and switches; way cheaper than good quality (expensive) 12vdc stuff and heavy ga. stranded wiring. The circuit breakers in the service panel can be standard, with additional dc you should have a dedicated service panel (if more than only a couple of circuits which you can fuse individually) with high quality dc fuses or breakers.
Well, thats the practical side, your local requirements may specify differently but it has often been said they dont typically know how to handle solar and/or dc.
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Brettny
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# Posted: 17 Apr 2021 09:50am
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Quoting: gcrank1 Brett, what if that load increased by 50% to 12a @ 120vac
Actualy a 120v 3.3gpm pump draws 1.4a max. You would have to add a hell of alot of LED lights to even come close to 15a. For instance you could run a water pump and a 1,000w microwave and still be under 15a. Theres almost no current reason to use 12/2 or bigger wire.
I also invert everything. I currently dont have a single load that is 12v. I may add a 12v fan for night use but it is something I alreaty have. I also have a 120v box fan.
We also have 2 strings of these bistro lights. 50ft each and they use about 2w each.
https://www.amazon.com/addlon-Outdoor-Dimmable-Commercial-Weatherproof/dp/B07QMKZWQF/ ref=sr_1_1_sspa?dchild=1&keywords=Bistro+lights+led&qid=1618667278&sr=8-1-spons&psc=1 &spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyR0FZUzdLNFVLREZGJmVuY3J5cHRlZElkPUEwODUwMzQzM0ZPVTN DVlpYMEtIQSZlbmNyeXB0ZWRBZElkPUEwMTExMDE4MlRQQU9WTTZEVlc0QSZ3aWRnZXROYW1lPXNwX2F0ZiZh Y3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
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smokedvw
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# Posted: 12 Jul 2021 09:28pm
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So I just installed 12/2 115' and I'm running dc to my shurflo pump and it's running fine.
Why should I convert to ac then back to DC when it seems to be fine with that line loss.
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gcrank1
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# Posted: 12 Jul 2021 10:14pm
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It 'seems to be fine' is the anecdotal conclusion based on 'it's running'.
The line losses are real and the results of running equipment on low (lower than designed for) voltage is well known.
Will it matter and how much? The pump may not run as efficiently, and being water cooled the negative of increased heat effects may be nullified, so in real life you might not notice. And what do you have to compare it to? At some point it will fail; stuff does. At that point only you can decide if the lifespan was acceptable.
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Nobadays
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# Posted: 12 Jul 2021 10:26pm
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Here is a voltage drop calculation. You might want to check your voltage at the pump. If it is indeed 7.37vdc at the pump, that pump won't last long. You are really aiming for no more than 3% drop. 120vac with 12/2 will drop about 3.33% which is borderline but probably doable.
Voltage drop: 4.63
Voltage drop percentage: 38.56%
Voltage at the end: 7.37
NEC data Estimated resistance Other
Wire material Copper
Wire size
12 AWG
Power factor (PF)0.85
Voltage 12 DC
single set of conductors
Distance (one-way) 115 feet
Load current 10 Amps
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ICC
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# Posted: 12 Jul 2021 10:29pm - Edited by: ICC
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Quoting: smokedvw So I just installed 12/2 115' and I'm running dc to my shurflo pump and it's running fine. Why should I convert to ac then back to DC when it seems to be fine with that line loss.
Let me try to explain why this may be a bad idea. I have no idea what you may know about electricity so some of this may seem very elementary to those who do know.
Long wires can cause a voltage drop when powering a device.
Motors are made to operate at a particular voltage. Most Shurflo are made to operate on 12 volts DC.
Shurflo has had several different pumps over the years. The amount of current, measured in amps, varies with the pump model, the GPM flow, and the pressure it is operating at. The pump in my RV averages about 5 amps, so I will use that in my example.
At 12 volts that 5 amps means that 60 watts is being used. ( Volts X Amps = Watts.... 12 volts X 5 amps = 60 watts.)
My calculator shows that using 12 gauge wires , 115 feet between power source and pump, at 12 VDC and 5 amps will produce a voltage drop of 18.5% or 2.22 volts. The 12 volts will be reduced to 9.78 volts
The pump will still want the full 60 watts of energy to operate properly. Using that formula we can use the 60 watts needed at the lower voltage to calculate how the voltage drop affects the amperage. (Watts ÷ Volts = Amps, so 60 ÷ 9.78 = 6.13 amps.) ^.13 amps may not seem like much more than 5, but it is actually 18.5% more.
The pump may run slower at the reduced voltage. That can result in having to run longer. So, the pump may use more total power to do the same work as if the voltage was higher.
When more amps are drawn through a wire, or a motor winding, more heat is produced. In this example that would equate to about 18.5% more heat. When electrical devices run hotter their lifespan is usually shortened. There may be some safety factor in the design of the motor but we have no real idea of how much.
Now, the good thing is that these pumps normally run in spurts, cycling on and off. So the pump may have time to cool between cycles.
It is not an "end of the world" scenario. It is simply not the best practice.
That was using a 5 amp figure for the load. Some of the Shurflo pumps can run up 10 amps for normal service. That 10 amps would drastically change things in the bad direction.
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Nobadays
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# Posted: 12 Jul 2021 10:31pm
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Different calculators but a definite drop in power...
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ICC
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# Posted: 12 Jul 2021 10:34pm
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Quoting: Nobadays Different calculators but a definite drop in power...
Actually very similar when I ran 10 amp load I get 36.99% drop in voltage. Not using any power factor adjustment.
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Brettny
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# Posted: 13 Jul 2021 05:58am
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I could tell when the sun got on my small solar systems battery by how the pump sounded. That was with 15ft of 12g copper stranded wire. The float voltage was about 14.5v and usualy sat at 12.5 with no sun in the morning. It sounded healthy at 14v, at 12.5 it worked but sounded sluggish
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gcrank1
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# Posted: 13 Jul 2021 09:00am
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To me, the real-world effect of running something on too low a voltage is like me pedaling a bicycle in too high a gear uphill. Wears me out way too soon.
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smokedvw
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# Posted: 14 Jul 2021 01:16pm
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Quoting: Brettny at 12.5 it worked but sounded sluggish
Yeah I don't know what normal sounds like since I was running it off a generator right beside it, my plan is to convert to AC via the inverter after going through a surge protector then wire up a outdoor electrical junction box, then the 115' to another outdoor junction box and run a AC to DC converter there.
I just wanted to ask since it seemed to be running. I will verify the actual voltage on the line this week when I'm back just out of curiosity.
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ICC
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# Posted: 14 Jul 2021 02:18pm
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Quoting: smokedvw I will verify the actual voltage on the line this week when I'm back just out of curiosity.
Measure the voltage under load and at the load. You could measure the voltage at the end of a mile of wire and still get the source voltage if there is no load. The higher the load (amps being drawn right then), the greater the voltage drop will be.
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smokedvw
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# Posted: 14 Jul 2021 02:23pm
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Quoting: ICC Measure the voltage under load and at the load.
Will do thank you.
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Daaaaaaaan
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# Posted: 15 Jul 2021 09:28pm - Edited by: Daaaaaaaan
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0. 6x 16w for an LED seems like a lot. They're equivalent to 100w each in light output.
1. If we're running off lead-acid batteries, we'll be running closer to 13V when fully charged. Maybe a bit higher when solar is on. You'll only see 12V when deeply discharged.
2. Running DC-->AC-->DC conversions might cause more power loss than a long DC run. If each conversion is 90% efficient, you're losing 19% converting back and forth. And more equipment/stuff to go buy/wrong/boom.
3. Running a ***DC*** motor at reduced voltages will not result in shorter lifespans *if it runs*. A 12V motor should work as low as 5 or 6V.
The nice thing about water pipes is that there will be some movement as soon as you open the faucet and that will help the pump start (instead of a standing start, even if flow is backwards).
It will not draw more current, but simply spin at lower RPM and do less work per minute, if it runs.
It will take longer to pump a given volume. If anything, it will warm up slower and its peak temperature will be lower which will prolong lifespan.
This will mean reduced gpm, but you can be the judge of that as a problem.
If it does not start when power is applied, then it might get hot. The pump might have cutoff protection for this.
(AC motors on the other hand.... their rpm won't change with changing voltages, they'll draw more/less current until they overheat/stall. This is why car alternators are AC and then rectify their output to DC. It would be a disaster if they were DC alternators: their voltage output would keep changing as you stepped on/off the gas!)
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