Looking to build a system to replace generator setup

Hi everyone, I own an offgrid cabin which I currently run off a generator. My cabin is wired to a breaker box and I have a power cord from the breaker box to the generator. Can I build a system in which the power cord can go directly to the inverter or will I have to wire differently? I appreciate any help. I've been reading and reading and watching video after video but can't find exactly what I'm looking for.

hunter2093 said:

Hi everyone, I own an offgrid cabin which I currently run off a generator. My cabin is wired to a breaker box and I have a power cord from the breaker box to the generator. Can I build a system in which the power cord can go directly to the inverter or will I have to wire differently? I appreciate any help. I've been reading and reading and watching video after video but can't find exactly what I'm looking for.

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It really depends on how much power you're pulling. Many small inverters include standard 110VAC GFCI outlets into which you can simply plug a standard power cord.

You definitely CAN, but it's best to start with system requirements. Is your cabin all 110V equipment, or do you have split phase? You have to have an idea of how much energy you're using on the daily, what the peak loads are, how much space you have for solar panels...

There's a lot more to consider with solar compared to just buying a gas generator.

Yes, you can generally just replace the generator with a solar system. You just need to make sure the wire is big enough to handle the full output of the inverter.

What size plug are you plugging into the generator? A regular house hold u ground plug or Is it a larger 3 pin or 4 pin?

Sizing the system is tricky. My family cabin is in Doyles(Codroy Valley) and we went too small with our solar system. It was fine for the summers but my retired parents are now spending most of the winter at the cabin. In January there is about 1/6th the average daily solar power as in June.

First time around I went with 1200watts of panels, 4x S550 6v flooded lead acid batteries wired for 12v and a 3000watt inverter/charger.

That system has already paid for itself since 2020 in gas and propane saved during the summers with my parents being there pretty much full time. Now we are ready to reinvest and get the generator usage down in the winter and leave us with excess power to burn in the summer.

So now I'm in the process of upgrading. I've ordered 2 server rack batteries from AOLithum (Great deal right now, free shipping from within canada, no duty or even taxes charged, extra 5% off if you fill out a cart with your email attached, you will get a code in your email within 24 hours). I've gone with a EG4 3000EHV-48 inverter as it supports high voltage from the panels so the panels can be away from the cabin without requiring big wire. That wasn't maybe the cheapest option after the exchange rate, shipping, taxes and UPS brokerage charge. For panels I'm getting 8x545watt Longi bifacial for $2332 taxes included pick up in Dartmouth.

For summer only use you can get away with a smaller system. I'd still go with the same EG4 inverter and a server rack battery. I would never consider using lead batteries ever again. They just don't have the useable capacity or lifespan and are expensive.

Edit: Just seen a nice Growatt 3500watt split phase inverter on amazon for less than what I paid for the EG4.

Pictures would help ... take a picture of the circuit-breaker box where the gen cord plugs in, and try to get the manufacturer nameplate in some of the pics. Take a pic of the generator, or give us the exact model. Take a pic of the cord coming out of the gen, and another where it plugs into the panel. I think you have something like a Reliance Controls panel with a gen plug and extra circuits for house wiring, but the pics would help identify things.

So, what I think you want is possible, if not a clean, done-right-from-the-start electical approach ... the GEN is your current power source, and the HOUSE PANEL takes a feed from some power source (currently the GEN).

If it is indeed a reliance-like box, you could unplug the GEN from that panel's SOCKET (hereafter called AC POWER IN), and plug in an INVERTER's AC OUT power cord (custom cord) into the panel's now empty AC power in socket.

Carefully choose and install your solar gear, as your inverter would need to have an AC-out wiring block connection, and you'd need a custom cord to go from that wiring block to the reliance-like box's (the HOUSE PANEL) gen plug. Whatever power was put out by the inverter (let's say 15-amp or 20-amp) thru that wiring block, that's all the power you would have to the panel, and any electrical devices beyond in your house), whereas the gen might be putting out more power.

In this fashion, you'd only have EITHER the GEN plugged into the panel (power source #2), or the INVERTER (power source #1), but never both at the same time. You'd be in the business of plugging/unplugging, depending on which thing is your power source.

Once your solar gear is in place, and feeding the HOUSE WIRING system thru the PANEL, you can still make use of the gen as a separate backup power source:
- assuming the gen is not an inverter-gen (low-THD), but is an open-frame (higher-THD) model? Put a battery-bank battery charger in place, fed by the GEN, and tied to your battery-bank. If solar panels are blocked, or battery-bank running low, then switch on gen and battery charger. There's other options if your GEN is an inverter-gen.
- leave in place the option of unplugging the INVERTER cord, and plugging back in the GEN cord, as this gives you more fallback capability, if anything goes wrong with solar gear.

If you can't picture all of this in your head, or I lost you with some or all of the above, it could be time to call an electrician type of person ...

Again, pics would be a good start in getting help from us as to your options and possible directions, but it will still take someone like an electrician to get it done right, and safely, for you!

Hope this helps ...

Thanks for the great advice. You guys are quite helpful. I'll attatch a picture of the type of plug that I'm plugged into on the generator. I can't quite get to my cabin yet as it's in between snowmobile and driving season so will get pics as soon as I can get in. I use my cabin mostly in the summer. For the occasional times I go in the winter, I don't mind using the generator. In the summer I run a full size fridge, tv, modems for internet and a jet pump that pumps water from the pond as needed. It just kicks in basically when the pressure drops. I plan on building the system hopefully more than I need so as to not go too small.

This is a picture I found of my panel. It may not be wired correctly in the puc because it's one I sent to an electrician when I was trying to figure out how to wire for the generator. But just an idea.

Plugging into the 30A twist connector would likely require you to create your own plug. On my first inverter to connect to my RV, I installed a 30A RV dongle onto the L N and G connector on my inverter:



I then used the blue-ish adapter for my 50A RV umbilical.

You could do the same with a similar setup, or you would wire it directly to the panel.

Your panel appears to be wired for 100A split phase, but it's possible the other end of the cord shorts L1 and L2 giving you 120V to both legs with no 240V.

That generator plug is an L5-30 which means Locking 120v 30A. So you don't need a split phase inverter. A 3000 or better yet a 3500watt inverter will run everything that generator can. The panel is capable of split phase and much bigger inverters if you wanted.

The main concern would be the startup surge of the water pump. Depending on the size inverter you go with and the size of the motor on the pump you may need a soft starter. Some pumps are not bad, some are just trouble. Might not be an issue at all.

Are you getting internet from Bell wireless or Starlink? Starlink is a bit heavier on the power draw end of things. It's not a lot in watts, but it adds up when running 24/7. Typically uses like a 1kWh a day.

The fridge is the other big power user as it consumes power 24/7. You want to make sure you have enough reserve battery capacity to get you through a grey rainy weekend. A typical fridge might use 1.5kWh a day if not a bit more. I'd budget for maybe 3 days so that 4.5kWh of useable battery capacity to start with. That would be one server rack battery (~$1500CND from AOLithium). I would think you might want two. That said on a grey day you can simply start up the generator and charge the batteries in a few hours.

Panels these days are cheap, go with as many as you have room for.

Are you on the west coast? I grew up in Stephenville, but live in NS currently. I get over to the island as often as I can to spend time at the cabin and give the kids time with the grandparents.

LordGarak said:

That generator plug is an L5-30 which means Locking 120v 30A. So you don't need a split phase inverter. A 3000 or better yet a 3500watt inverter will run everything that generator can. The panel is capable of split phase and much bigger inverters if you wanted.

The main concern would be the startup surge of the water pump. Depending on the size inverter you go with and the size of the motor on the pump you may need a soft starter. Some pumps are not bad, some are just trouble. Might not be an issue at all.

Are you getting internet from Bell wireless or Starlink? Starlink is a bit heavier on the power draw end of things. It's not a lot in watts, but it adds up when running 24/7. Typically uses like a 1kWh a day.

The fridge is the other big power user as it consumes power 24/7. You want to make sure you have enough reserve battery capacity to get you through a grey rainy weekend. A typical fridge might use 1.5kWh a day if not a bit more. I'd budget for maybe 3 days so that 4.5kWh of useable battery capacity to start with. That would be one server rack battery (~$1500CND from AOLithium). I would think you might want two. That said on a grey day you can simply start up the generator and charge the batteries in a few hours.

Panels these days are cheap, go with as many as you have room for.

Are you on the west coast? I grew up in Stephenville, but live in NS currently. I get over to the island as often as I can to spend time at the cabin and give the kids time with the grandparents.

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Hey, yes I'm just outside corner brook in Meadows. My wife is from St.Georges. I was looking at going with a 48v system. Watching some videos it seems this is a wise choice. There is an electrical store here in CB that I can get panels for a dollar a watt which seems pretty good

Im doing almost exactly this right now for a friend's cabin.

The Square D load center could easily be replaced by a L5-30 plug box being the cabin is already ran off the gen cord.

I already have an L5-30 inlet plug for generator input/charging.

sunshine_eggo said:

Plugging into the 30A twist connector would likely require you to create your own plug. On my first inverter to connect to my RV, I installed a 30A RV dongle onto the L N and G connector on my inverter:

View attachment 205863

I then used the blue-ish adapter for my 50A RV umbilical.

You could do the same with a similar setup, or you would wire it directly to the panel.

Your panel appears to be wired for 100A split phase, but it's possible the other end of the cord shorts L1 and L2 giving you 120V to both legs with no 240V.

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Thank you for the info

hunter2093 said:

Hey, yes I'm just outside corner brook in Meadows. My wife is from St.Georges. I was looking at going with a 48v system. Watching some videos it seems this is a wise choice. There is an electrical store here in CB that I can get panels for a dollar a watt which seems pretty good

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I'm able to get them for around 50 cents a watt here in Dartmouth now and they will ship via freight. I just got a quote for ~$400 to ship 8 panels to our property in Doyles. I was going to bring them over on the roof of my minivan but they are a bit on the heavy side so I'd only be able to take 2 at a time. Shipping might be quite a bit less to the depot in CB.

I know most folks don't like lead acids but for northern climate cabins these Trojan SPRE-06-415 are a solid choice. I have a set at my own camp going on 7 years old now.

These are what im pairing with that victron panel above as they will stay in the cabin all winter.

seneysolar said:

I know most folks don't like lead acids but for northern climate cabins these Trojan SPRE-06-415 are a solid choice. I have a set at my own camp going on 7 years old now.

These are what im pairing with that victron panel above as they will stay in the cabin all winter.
View attachment 205976

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I strongly disagree. It's not hard to keep Lithium Iron batteries above freezing. But caring for flooded cells is a PITA and the just the power loss of charging lead batteries is enough reason not to use them. These days the Lithium Iron batteries are significantly cheaper per useable kWh. I just picked up 10kWh for $3000 Canadian delivered, to get the same useable capacity in flooded lead acid would be over $4000+shipping. Then you need charge controller with temperature compensation, to properly charge flooded cells in cold weather the voltage need to go way up. I can't wait to be rid of our lead acid bank. No more topping up with distilled water or acid spills. No more need to be vented outside. Then there is the weight of the bloody things.

At our cabin we simply put the batteries in the crawl space which doesn't drop below freezing. We don't get deep frost anymore, the shallow basement in the cabin stays above freezing all winter. That said our cabin isn't left cold for more than a few days at a time as my parents pretty much live there full time.

Even if the cabin drops below freezing, if you don't have any load on the batteries they will hold their charge. Once the cabin warms up with a fire the batteries can then take a charge no problem. Discharging from cold batteries is fine, it's the charging that degrades their life and thus why most have a low temperature cut off.

If one really needed the batteries to keep running all winter unattended, it wouldn't take much power to keep a small heater going inside a insulated box with the batteries.

LordGarak said:

I strongly disagree. It's not hard to keep Lithium Iron batteries above freezing. But caring for flooded cells is a PITA and the just the power loss of charging lead batteries is enough reason not to use them. These days the Lithium Iron batteries are significantly cheaper per useable kWh. I just picked up 10kWh for $3000 Canadian delivered, to get the same useable capacity in flooded lead acid would be over $4000+shipping. Then you need charge controller with temperature compensation, to properly charge flooded cells in cold weather the voltage need to go way up. I can't wait to be rid of our lead acid bank. No more topping up with distilled water or acid spills. No more need to be vented outside. Then there is the weight of the bloody things.

At our cabin we simply put the batteries in the crawl space which doesn't drop below freezing. We don't get deep frost anymore, the shallow basement in the cabin stays above freezing all winter. That said our cabin isn't left cold for more than a few days at a time as my parents pretty much live there full time.

Even if the cabin drops below freezing, if you don't have any load on the batteries they will hold their charge. Once the cabin warms up with a fire the batteries can then take a charge no problem. Discharging from cold batteries is fine, it's the charging that degrades their life and thus why most have a low temperature cut off.

If one really needed the batteries to keep running all winter unattended, it wouldn't take much power to keep a small heater going inside a insulated box with the batteries.

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Yeah... most dont like lead acids, but when the application involves being unattended in freezing temps i would never install something that turns off in the cold and/or consumes its own energy to stay warm. Its just asking for trouble.

Walking into the cabin when its wayyy below freezing, flipping the switch on the inverter and have everything work like normal -priceless.

In a cabin/part time scenario, they maybe need water twice a year, i dont mind. In my experience, they have just been simply reliable.

seneysolar said:

Yeah... most dont like lead acids, but when the application involves being unattended in freezing temps i would never install something that turns off in the cold and/or consumes its own energy to stay warm. Its just asking for trouble.

Walking into the cabin when its wayyy below freezing, flipping the switch on the inverter and have everything work like normal -priceless.

In a cabin/part time scenario, they maybe need water twice a year, i dont mind. In my experience, they have just been simply reliable.

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Lithium Iron batteries are fine to discharge when cold, it's only charging that needs to be done warm. So if you turn your batteries off when you leave they will be nearly at the same state of charge as when you left. They don't self discharge quickly like lead batteries. You will only have problems if you leave the batteries on and the BMS and/or inverter is drawing power.

Climate is a big variable too. Here in Atlantic Canada we don't get the big deep freezes anymore. We don't see sustained cold for very long. So if you have a decent amount of insulation the batteries will stay above freezing even without active heating.

I'm also not sure if the batteries with built in heaters try and stay warm all the time or only heat when there is power coming in attempting to charge. It would make sense to only burn power to heat when the sun is hitting the panels and providing that energy to heat.

If it's way below freezing for a significant amount of time, chances are the panels are covered in snow and the system will have self discharged to the point of damaging the batteries. Also if the lead batteries go dead, they will freeze and split the housing. Not only destroying the batteries but also leaking battery acid everywhere when they thaw.

LordGarak said:

If it's way below freezing for a significant amount of time, chances are the panels are covered in snow and the system will have self discharged to the point of damaging the batteries. Also if the lead batteries go dead, they will freeze and split the housing. Not only destroying the batteries but also leaking battery acid everywhere when they thaw.

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Wow. You are an alarmist.

You can't have it both ways. Lead acid will only freeze when the specific gravity is low. When the specific gravity is low, the acid is not as concentrated. Of course it varies by actual temperature, but if lead acid can freeze, the concentration of of the sulfuric acid is far lower than when fully charged.

A FLA at 25% SoC is good down to about -16°C.

It's not foolish to fall back on a technology that is centuries old and is still in widespread use today. Your reasons are your own, but you have no valid reason to shit on other people's choices when they are as valid as yours.

Looks like you have some 'splaining to do as well:

LordGarak said:

Lithium Iron batteries are fine to discharge when cold, it's only charging that needs to be done warm. So if you turn your batteries off when you leave they will be nearly at the same state of charge as when you left. They don't self discharge quickly like lead batteries. You will only have problems if you leave the batteries on and the BMS and/or inverter is drawing power.

Climate is a big variable too. Here in Atlantic Canada we don't get the big deep freezes anymore. We don't see sustained cold for very long. So if you have a decent amount of insulation the batteries will stay above freezing even without active heating.

I'm also not sure if the batteries with built in heaters try and stay warm all the time or only heat when there is power coming in attempting to charge. It would make sense to only burn power to heat when the sun is hitting the panels and providing that energy to heat.

If it's way below freezing for a significant amount of time, chances are the panels are covered in snow and the system will have self discharged to the point of damaging the batteries. Also if the lead batteries go dead, they will freeze and split the housing. Not only destroying the batteries but also leaking battery acid everywhere when they thaw.

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Yes, im aware. It just doesn't fit the profile for the cabin scenario.
For instance, showing up at camp and its 5 degrees F. This is a normal scenario for jan-feb. FLA- works, LFP- nope.

Panels covered in snow. Also normal scenario upon arrival. Lead acid self discharge is actually best at low temps, less than 5% in most brands. So they would have to sit 6 months or more before id be concerned. Solar is always on so they get topped off occasionally as well, lets say once ever 2 weeks in the winter the panelswill shed snow on their own. EG4 has a published heater wattage of 224W, thats insane for off grid winter use. That would kill itself in just a few days trying to stay warm.
FLA -works, LFP- nope.

One thing ill say about Lithium is that it has forced everyone to pay attention as to not upset the BMS. Or at least wrap their mind around power in/power out and depth of discharge

Lead acids will drain far into an unhealthy SOC without notice and most folks just thought "its still working, must be ok". In the old days, the only notification was the beeping inverter for low battery cutoff. Driving blind generally. This gets them the bad reputation of short life, high maintenance.