About to spend a lot of money tomorrow on this system (am I making a mistake?)

AlaskanNoob

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Planning on buying the bolded * items tomorrow for our completely off grid homestead. Big purchase for us! Just posting this in case somebody sees something glaring with our mix of components who might sound the alarm and prevent me from making a costly mistake. I'm showing the 22KW ground mounted PV array (which will be split into 8 x 6-or-7-panel strings going into the 8 trackers of the two charge controllers) will produce roughly 400 amps max (22KW divided by 48V) which the MPPTs can use to charge the 48V/800AH battery bank (it can accept 800amp charging).

Biggest draw will be a 230V GSHP at our cabin and otherwise the two structures will just be wired for regular 110V outlets. The Multi-Plus from what I understand can auto-start the Honda 7000 generator to charge the batteries and supply power to the structures in case of low SOC and lack of PV power as needed.

Any comments or warnings or recommendations are greatly appreciated before we spend money tomorrow!

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Location A:
* 50 x LG440N2T-E6 Bifacial Solar Panels
*
2 x Victron SmartSolar MPPT RS 450/200-Tr
* Victron Multi-Plus II 48/8000/110-100/100 230V
* Victron ITR000100101 Autotransformer 120/240V-100A
* Victron Cerbo GX
* 2 x
Victron Lynx Distributor
* 3 x Victron MEGA-fuse 125A/58V for 48V products
* 2 x Victron MEGA-fuse 250A/58V for 48V products
* Victron MEGA-fuse 300A/58V for 48V products
* 3 x Victron RJ45 UTP Cable 0,9 m
* Victron VE.Can to CAN-bus BMS type A Cable 1.8 m
* Victron Interface MK3-USB (VE.Bus to USB)
* 8 x Pylontech US5000 48V/100AH LifePo4 batteries (US5000 not shown on
Pylontech website for some reason)
- Honda EU7000is Generator to plug into the Multi-Plus for backup

Location B (Cabin 500 feet west of Location A connected with 1/0 trenched wire)
- ClimateMaster Trilogy 45 Q-Series 2-ton Ground Source Heat Pump
- Normal 110V loads

Location C (Structure 300 feet east of Location A connected with 1AWG trenched wire)
- Normal 110V loads
 
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MisterSandals

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will produce roughly 400 amps max (22KW divided by 48V) which the MPPTs can use to charge the 48V/800AH battery bank (it can accept 800amp charging).
This sounds like you are not understanding what MPPTs do.
You want to setup your array into strings that fit your Victron 450/200, so roughly 400V and not 400A.
I'd get this worked out before ordering to make sure your panels work with your SCCs.

Have you done the wire size calculations for your wire runs to location B and C? Those runs are mighty long... but i see you have 1/0 and 1AWG respectively so maybe is been worked out. Just checking because getting that wrong would be costly.

Looks like run from A to B could handle 25A at 120V AC (need to check wire ampacity of course too):
Screen Shot 2022-01-20 at 10.39.00 PM.png
 

MisterSandals

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I'm showing the 22KW ground mounted PV array (...) will produce roughly 400 amps max (...).
It looks like he will have TWO SCC (200A SCC) and that how OP comes up with 400A of charging current, each SCC are combined to charge the battery bank, that is my understanding.
Yea, not what he said, but rereading it with the rose glasses you provided, i am with you. Thanks!
 

AlaskanNoob

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Thank you both for taking the time to once over this proposed system. I really appreciate it.

Yes, two SCCs combined will give 400 amp battery charging. Apologies if I wasn't clear on that point.

The plan for wire sizing is to run 230V on the 500 foot direct buried wire to the cabin (Location B). I'm showing I could do it with 1AWG wire but I think I'm going to use 1/0 anyway just in case my demand at the cabin increases for some reason. I used this calculator for that wire sizing. While there will be some voltage drop, the ClimateMaster GSHP can accept as low as 208V (if I recall correctly) and has its own inverter (why it has an inverter I'm not sure, as I was under the impression an inverter took DC power and turned it to AC power and yet this GSHP takes AC power).

What needs to be done with the power at the cabin, to feed the GSHP the 230V and to create a normal breaker box and AC outlets in the cabin, is something I haven't yet explored. The system will need an auto transformer apparently and I have a quote for one of those as well. I think that will be installed with the other components at Location A but I'm not certain.

I definitely need to make a wiring diagram so that I can understand exactly what will be plugged into what. My plan is to wire everything up myself (having zero experience wiring things up makes me feel like I'm totally qualified for this) with all the power off to all the components and then have an electrician come up and check/adjust everything before we flip any power switch to ON. I'd like to save money but I don't trust myself to play with this kind of power in the middle of a forest that will go up like a tinderbox if I get something wrong. But I have a lot more research to do before I lay any wires or connect anything to anything. At this juncture I just want to make sure I'm getting the right stuff that will be able to do what I need so I can put the order in and hopefully supply chain issues don't prevent me getting this stuff by spring after the thaw, so I can get to work.
 

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Thank you both for taking the time to once over this proposed system. I really appreciate it.

Yes, two SCCs combined will give 400 amp battery charging. Apologies if I wasn't clear on that point.

The plan for wire sizing is to run 230V on the 500 foot direct buried wire to the cabin (Location B). I'm showing I could do it with 1AWG wire but I think I'm going to use 1/0 anyway just in case my demand at the cabin increases for some reason. I used this calculator for that wire sizing. While there will be some voltage drop, the ClimateMaster GSHP can accept as low as 208V (if I recall correctly) and has its own inverter (why it has an inverter I'm not sure, as I was under the impression an inverter took DC power and turned it to AC power and yet this GSHP takes AC power).

What needs to be done with the power at the cabin, to feed the GSHP the 230V and to create a normal breaker box and AC outlets in the cabin, is something I haven't yet explored. The system will need an auto transformer apparently and I have a quote for one of those as well.

I definitely need to make a wiring diagram so that I can understand exactly what will be plugged into what. My plan is to wire everything up myself (having zero experience wiring things up makes me feel like I'm totally qualified for this) with all the power off to all the components and then have an electrician come up and check/adjust everything before we flip any power switch to ON. I'd like to save money but I don't trust myself to play with this kind of power in the middle of a forest that will go up like a tinderbox if I get something wrong. But I have a lot more research to do before I lay any wires or connect anything to anything.
How much difference in price to run 1/0 awg for both runs?
Are we talking copper or Aluminum?
 

AlaskanNoob

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How much difference in price to run 1/0 awg for both runs?
Are we talking copper or Aluminum?
Planning on copper wire. Not sure the difference in price between those two wires. I just know it's WAY less expensive than 4/0 wire which I can't afford. What little I think I know about wire sizing I learned from this thread:

 

sunshine_eggo

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Biggest draw will be a 230V GSHP at our cabin and otherwise the two structures will just be wired for regular 110V outlets.

How are you converting the MP 230VAC output to 110V?

The Multi-Plus from what I understand can auto-start the Honda 7000 generator to charge the batteries and supply power to the structures in case of low SOC and lack of PV power as needed.

You will need to confirm explicitly that the generator is compatible.

Location B (Cabin 500 feet west of Location A connected with 1/0 trenched wire)
- ClimateMaster Trilogy 45 Q-Series 2-ton Ground Source Heat Pump
- Normal 110V loads

WTF 1/0? Have you priced that? I calculate 2awg is fine (< 3% drop):


Location C (Structure 300 feet east of Location A connected with 1AWG trenched wire)
- Normal 110V loads

4 awg looks good to me:

 
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Planning on copper wire. Not sure the difference in price between those two wires. I just know it's WAY less expensive than 4/0 wire which I can't afford. What little I think I know about wire sizing I learned from this thread:

I urge you to check the price differential between copper and equivalent ampacity aluminum.
I have a vague recollection that we discussed urd cable.
 

Horsefly

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A couple of thoughts:
  1. Although direct burial wire can be used just that way, it may be worth it to consider PVC conduit. Where our cabin is there are critters (marmots) that dig and love to eat through wires.
  2. It sounds like location B is the main living space. If you are putting the inverter and batteries in location A, you'll need to keep in mind that they cannot be charged below 32°F without irreparable harm to the batteries. It's a problem that many folks here have addressed.
  3. If you are running single phase 230V from B to both A and C, you will need an autotransformer at both A and C. I have no experience here with autotransformers. My preference would be to run split phase 240V, but I'm not aware of a split phase from Victron, which may be a deal breaker for you. Just be aware that the 230V boxes from Victron are really intended for places outside North America.
 

sunshine_eggo

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While there will be some voltage drop, the ClimateMaster GSHP can accept as low as 208V (if I recall correctly) and has its own inverter (why it has an inverter I'm not sure, as I was under the impression an inverter took DC power and turned it to AC power and yet this GSHP takes AC power).

Inverter type motors are variable speed and eliminate surge currents typical of standard AC motors. A standard 2 ton compressor motor has a massive surge that might bring the MP to its knees.

From: https://files.climatemaster.com/97b...ng-and-cooling-system-installation-manual.pdf

RLA 32A vs. the MP max continuous output of 8000W/230V = 34.78A. The heat pump has the potential to use 32/34.78 = 92% of your available power.
 

Hedges

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Ground-Source Heat Pump
Alaska (if that is where this is going)
Solar
Honda Generator

I suppose you have warmth available for the heat pump, either well or trench of pipe below the frost line (how deep is that in Alaska?)

Solar - have you worked out how much it produces each month? Obviously less sun that those of us in balmy locations enjoy.

Generator - I guess that will be sole source of power some seasons.
Powering heat pump, you get more heat than from resistive heating. How does that compare to straight fossil fuel heating?
A generator dumps around 2/3 of energy in fuel as waste heat, either to water cooling or air cooling, and to exhaust. "CHP", combined heat and power, means harvesting that waste heat.

400A charging into 800 Ah battery (accepts 800A)
Most batteries spec'd for 1C charging, most for 0.5C, guess yours take the larger rate.
Horsefly mentioned no charging below freezing.
But allowed charge current is not uniform 0.5C or 1.0C at all temperatures above freezing, it curves down.
If your battery is relatively cold, need to limit charge rate to something much lower, maybe 0.05C or 0.1C. Victron supports use of a battery shunt to measure and regulate charge current (allowing more current from SCC if consumed by inverter) although I'm not away of it implementing a current vs. temperature adjustment.
 

AlaskanNoob

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How are you converting the MP 230VAC output to 110V?



You will need to confirm explicitly that the generator is compatible.

I don't know how we're going to convert 230VAC to 110V. I would assume the line that goes to the cabin (Location B) will feed into the GSHP and then *something* (perhaps a step down transformer) that feeds to a 110V circuit breaker box. Haven't gotten this far. I have just assumed I can take 230V and wire up normal wall plugs from it.

Thanks for the tip on the generator. I know the EU7000 can deliver 230V but I'll need to get into the nuts and bolts to ensure it's compatible.
 

AlaskanNoob

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I urge you to check the price differential between copper and equivalent ampacity aluminum.
I have a vague recollection that we discussed urd cable.

I'll take a look at it. I don't know much about the difference between aluminum and copper. I was under the impression aluminum was more brittle, more of a fire hazard, and maybe would be less ideal for the temp changes or if we have a freak winter where the frost goes down ten feet. But I will look into it. Thanks!
 
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I don't know how we're going to convert 230VAC to 110V. I would assume the line that goes to the cabin (Location B) will feed into the GSHP and then *something* (perhaps a step down transformer) that feeds to a 110V circuit breaker box. Haven't gotten this far. I have just assumed I can take 230V and wire up normal wall plugs from it.

Thanks for the tip on the generator. I know the EU7000 can deliver 230V but I'll need to get into the nuts and bolts to ensure it's compatible.
Don't spend money until you have this bit figured.
 

AlaskanNoob

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A couple of thoughts:
  1. Although direct burial wire can be used just that way, it may be worth it to consider PVC conduit. Where our cabin is there are critters (marmots) that dig and love to eat through wires.
  2. It sounds like location B is the main living space. If you are putting the inverter and batteries in location A, you'll need to keep in mind that they cannot be charged below 32°F without irreparable harm to the batteries. It's a problem that many folks here have addressed.
  3. If you are running single phase 230V from B to both A and C, you will need an autotransformer at both A and C. I have no experience here with autotransformers. My preference would be to run split phase 240V, but I'm not aware of a split phase from Victron, which may be a deal breaker for you. Just be aware that the 230V boxes from Victron are really intended for places outside North America.
Thanks, the PVC conduit sounds like a great idea plus I have these squirrels tamed and they think they run the place. They actually come into the cabin for breakfast, crawl up on my lap and even let me pull ticks off of them with tweezers (yeah, little known fact, we do have ticks in Alaska). I'm trying to buy them off in hopes they won't chew my place up but in case that fails, some conduit would be a good idea.

Good point on the cold and its effects. The batteries, inverter, and SCCs will be eight feet underground in a 12' diameter culvert with an insulated roof over top and a wood shed over top of that. Essentially a root cellar. Should keep them from freezing even in the dead of winter and I'll have a heater in there just in case to prevent anything from freezing.

I don't know much about it, but I am under the impression I will need an auto transformer and that is part of the order I"ll be placing today.
 

Horsefly

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Good point on the cold and its effects. The batteries, inverter, and SCCs will be eight feet underground in a 12' diameter culvert with an insulated roof over top and a wood shed over top of that. Essentially a root cellar. Should keep them from freezing even in the dead of winter and I'll have a heater in there just in case to prevent anything from freezing.
Good plan. Using the surrounding earth to keep things above freezing is always more dependable than any electrical thermostat-driven method.
 

Horsefly

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I don't know much about it, but I am under the impression I will need an auto transformer and that is part of the order I"ll be placing today.
Personal opinion, but "I don't know much about it" should not ever be in the same sentence with "is part of the order I'll be placing today." Best to understand it.

The multiplus puts out 230V, but does it bond one of the two wires carrying 230V to ground? If so you have a bit of a problem. The autotransformer would normally use the two wires of the 230V as two 115V legs, and the center tap of the autotransformer is the neutral. You would normally bond that neutral to ground in your 115V distribution / breaker panel. If one of the two 230V lines is already bonded to ground, you have a problem.
 

AlaskanNoob

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Inverter type motors are variable speed and eliminate surge currents typical of standard AC motors. A standard 2 ton compressor motor has a massive surge that might bring the MP to its knees.

From: https://files.climatemaster.com/97b...ng-and-cooling-system-installation-manual.pdf

RLA 32A vs. the MP max continuous output of 8000W/230V = 34.78A. The heat pump has the potential to use 32/34.78 = 92% of your available power.
Thanks for bringing this up. What do you mean by "92% of your available power?" Do you mean 92% of the power the MultiPlus can supply?
 

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AlaskanNoob

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Don't spend money until you have this bit figured.
Thanks!

That might take awhile. I don't have anything figured out... But from what I'm gathering the 230V supplied by the Multiplus isn't optimum. Any idea what I would need to do? Step down transformer?

Or perhaps I should go from the Multiplus II to the Quattro II since it apparently can deliver split phase 230V power?

I have no idea what split phase and three phase means. But the Quattro II apparently has "hybrid PowerAssist technology plus multiple system integration features such as three or split phase operation and parallel operation." I would assume split phase would mean I wouldn't need an auto transformer. Whether it makes it easier to split the power into the 110V (which I think it does because it's split phase) or not, I don't know.
 
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