diy solar

diy solar

Can I use my Manual Transfer Switch Home Backup Setup for Solar Backup as well?

What is the make and model of the ATS shown in your setup?
I use Progressive - 240v@50a. Have both the surge and non-surge options in operation. They have several models - the same basic relays but with bells/whistles - e.g. some have surge, some have little lights to show you the state. I bought surge thinking that their might be surge on AC compressor... or refrigerators... or furnace fan motor... (e.g. motors) as the sine-wave mismatch syncs up - but not sure it's worth $500 for surge - doesn't seem to matter.

Surge.... (Wow the price has gone up - almost double what I paid)

Non-Surge... / no lights.
- I used these 110v LEDs (drilled hole in lid) for my own visuals on which side (grid or inverter) is live - just wired them into the output of the relays https://www.amazon.com/gp/product/B07FXCGDDX/ref=ppx_yo_dt_b_search_asin_title

Note: For 120v @ 30a I use Go-Power - https://www.amazon.com/gp/product/B00153EYTO/ref=ppx_yo_dt_b_search_asin_title. Have 3 of these and they work OK.
 
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Hello all,

I am trying to find out whether I can utilize (all, or most of) my existing transfer switch setup by swapping out the gas generator with a solar generator. The setup was installed by an electrician for the purpose of using it with a gas generator.

I have a power inlet box and transfer switch already in place for home backup which I'm currently using for my gas powered generator during power failures. The generator is attached to the inlet box via a 30-Amp 250-Volt Generator Power Cord (L14-30P to L14-30R)

Inlet box:
Amazon.com : Reliance Controls Generators Up to 7,500 Running Watts PB30 30-Amp NEMA 3R Power Inlet Box, Gray : Generator Cord Sets And Plugs : Patio, Lawn & Garden

Power cord:
Amazon.com: Champion 25-Foot 30-Amp 250-Volt Generator Power Cord for Manual Transfer Switch (L14-30P to L14-30R) : Everything Else

My hope is to utilize this setup with solar.

I believe this is a standard Manual-Transfer-Switch setup. This works by turning off Main and enabling the generator breaker in the main panel, and then enabling/disabling the breakers independently as needed. Note that the generator breaker is in the main panel box. There are no sub panels. This gives me full utilization of the main box as long as I stay within the constraints of the 30 Amp inlet box (to my understanding).

So is it possible to utilize the existing manual transfer switch by simply replacing the gas generator with solar? Could it be so simple as to find a cord that fits one end into the inlet box above, and the other into a solar generator, and add some panels? Or am I thinking too optimistically?

Do you have any recommendations for how you would go about this?

Thanks in advance for anyones time on this!
When I purchased my manual transfer switch, I got the same two parts with the transfer box. And yes I used it for solar instead of the generator. This is the manual transfer switch that I installed. Actually I have two installed now.

https://www.amazon.com/gp/product/B005FQJD7K/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&th=1
 
When I purchased my manual transfer switch, I got the same two parts with the transfer box. And yes I used it for solar instead of the generator. This is the manual transfer switch that I installed. Actually I have two installed now.

https://www.amazon.com/gp/product/B005FQJD7K/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&th=1
This is basically how my system is set up. I have two transfer switches set up with generator cords running from the inverter to the switches. I can unplug either one and hook the genny up to it if need be. Also this setup allows choosing between grid or generator(solar) power without disconnecting the house from the grid.
 
This is basically how my system is set up. I have two transfer switches set up with generator cords running from the inverter to the switches. I can unplug either one and hook the genny up to it if need be. Also this setup allows choosing between grid or generator(solar) power without disconnecting the house from the grid.
I did not use the plug or cord. I wired directly from the inverters to my house panel through my manual transfer switch.
 
Here's a link to a SunGoldPower 18kw setup :

I tried to join your forum and it won't let me It says rejected and I was just trying to join? let me know thnx
 
Hello all,

I am trying to find out whether I can utilize (all, or most of) my existing transfer switch setup by swapping out the gas generator with a solar generator. The setup was installed by an electrician for the purpose of using it with a gas generator.

I have a power inlet box and transfer switch already in place for home backup which I'm currently using for my gas powered generator during power failures. The generator is attached to the inlet box via a 30-Amp 250-Volt Generator Power Cord (L14-30P to L14-30R)

Inlet box:
Amazon.com : Reliance Controls Generators Up to 7,500 Running Watts PB30 30-Amp NEMA 3R Power Inlet Box, Gray : Generator Cord Sets And Plugs : Patio, Lawn & Garden

Power cord:
Amazon.com: Champion 25-Foot 30-Amp 250-Volt Generator Power Cord for Manual Transfer Switch (L14-30P to L14-30R) : Everything Else

My hope is to utilize this setup with solar.

I believe this is a standard Manual-Transfer-Switch setup. This works by turning off Main and enabling the generator breaker in the main panel, and then enabling/disabling the breakers independently as needed. Note that the generator breaker is in the main panel box. There are no sub panels. This gives me full utilization of the main box as long as I stay within the constraints of the 30 Amp inlet box (to my understanding).

So is it possible to utilize the existing manual transfer switch by simply replacing the gas generator with solar? Could it be so simple as to find a cord that fits one end into the inlet box above, and the other into a solar generator, and add some panels? Or am I thinking too optimistically?

Do you have any recommendations for how you would go about this?

Thanks in advance for anyones time on this!
I'm not sure what your reasons for installing solar are, your goals.
In your first post I though you simply wanted to have solar as backup power for when the grid does down. Is that correct?
Are you looking to lower your electricity costs? Partially or entirely?
Are you looking to "go green"?
Do you want to be self-sustaining when the grid goes out? for how long?

I think when designing a system that you have to start with your objectives. Then you need to size your system according to your load study and other factors. Then choose equipment.
 
I'm not sure what your reasons for installing solar are, your goals.
In your first post I though you simply wanted to have solar as backup power for when the grid does down. Is that correct?
Are you looking to lower your electricity costs? Partially or entirely?
Are you looking to "go green"?
Do you want to be self-sustaining when the grid goes out? for how long?

I think when designing a system that you have to start with your objectives. Then you need to size your system according to your load study and other factors. Then choose equipment.
That makes sense. My thinking was… Since I already have this existing setup for a generator, where I’m able to hand pick the loads by selecting breakers, why not also have a secondary use for it by possibly employing an inverter, some batteries and solar panels (or simply an all-in-one solar generator).

My goals are to:
  1. Find a backup option that doesn’t require fuel to run a few core things in a longer term grid down scenario.
  2. Find secondary method of utilizing the existing inlet box setup (opposed to a costly full blown solar setup) that I can manually swap to when the grid is out.
I would like to be able to run household barebones essentials (including 1 or 2 240v appliances) like:

water pump,
water softener,
sump pump (or at least recharge a 12V backup sump pump battery),
septic pump
A few lights, recharge small electronics, etc.
So all in all, I’m not looking for enough juice to run everything in a house 24/7 (like the generator can, provided I always have gas). I just want enough to keep the barebones functioning in a manner that doesn’t exclusively rely on gasoline.

I also considered if an all-in-one solar generator may be suitable here if connected to the inlet box, although I tried to avoid these due to their limitations (like powering 240v).
 
That makes sense. My thinking was… Since I already have this existing setup for a generator, where I’m able to hand pick the loads by selecting breakers, why not also have a secondary use for it by possibly employing an inverter, some batteries and solar panels (or simply an all-in-one solar generator).

My goals are to:
  1. Find a backup option that doesn’t require fuel to run a few core things in a longer term grid down scenario.
  2. Find secondary method of utilizing the existing inlet box setup (opposed to a costly full blown solar setup) that I can manually swap to when the grid is out.
I would like to be able to run household barebones essentials (including 1 or 2 240v appliances) like:

water pump,
water softener,
sump pump (or at least recharge a 12V backup sump pump battery),
septic pump
A few lights, recharge small electronics, etc.
So all in all, I’m not looking for enough juice to run everything in a house 24/7 (like the generator can, provided I always have gas). I just want enough to keep the barebones functioning in a manner that doesn’t exclusively rely on gasoline.

I also considered if an all-in-one solar generator may be suitable here if connected to the inlet box, although I tried to avoid these due to their limitations (like powering 240v).

What is the longest outage time that you would design to sustain? My concern here is that the cost/benefit ratio not may work. You need to determine how much battery capacity you would need to sustain your max outage period. Then work the umbers from there.

You may find out that in order to see the cost benefit that you need to install a full blown solar system, with net-metering and solar tax credits and incentives.
 
I too have a 50A L14-50P inlet connected with an interlock to my single circuit breaker panel and an ICE generator to power it for backup during power outages.

My grid power prices are low enough, around $0.10 per kWh that solar to replace grid power has a very long payback time, over 10 years by my calculations and much more with battery backed solar, but I would like to have options in case of extended power outages. Over the last 10 years, I've twice had power outages that lasted 1-2 weeks. Even that frequency makes the high fixed cost of solar problematic unless I can take advantage of it daily.

To avoid the costs of grid-tied systems and since my POCO does not support TOU or net metering, I'm not interested in feeding back to the grid. My main options are something like an MPP feeding a subpanel and using it daily or something smaller just for emergency use with the interlock inlet but am undecided.
So here we are years later. This thread originally made me decide to do nothing at all. Have you ever come up with a solution? It seems we are in the same boat with the inlet setup, and cheap electricity. That pesky 240v situation really throws a wrench into things.

I believe my water pump is really the only 240v I’d want backed up through solar anyways. I’ve even considered something like RPS Solar Pumps who sells solar systems specifically for water pumps + a backing up a few extras if needed. It’s been awhile since I’ve looked into that option though. Just curious if you ever figured out another solution to utilize that interlock!
 
What is the longest outage time that you would design to sustain? My concern here is that the cost/benefit ratio not may work. You need to determine how much battery capacity you would need to sustain your max outage period. Then work the umbers from there.

You may find out that in order to see the cost benefit that you need to install a full blown solar system, with net-metering and solar tax credits and incentives.
Based on some of the initial replies here and the issue of providing power at 240v through an interlock, I assumed this idea was dead in the water.. But I’ll add some details nonetheless—

If I could make this happen (utilize the interlock with solar/batteries, that is), I would like to treat this as an off-grid scenario, so the plan would be to be able to sustain it forever (barring equipment failures).

I’m definitely not looking to go “all in” on a complete solar build or anything that competes with that price range.

I feel like what I’m looking for is quite simple in features and low in price in comparison to a complete system.

I am talking about connecting a budget inverter, simple performance monitoring, a battery and a few panels (or, an all-in-one unit + panels). Nothing fancy. Just needs to be compatibility with the inlet box I have listed in the first post.

The goal would be, when I manually switch back to grid power, the batteries would have no load and would continue to recharge via solar.

This is an extremely low power requirement to cover “critical needs only”. By my estimate it’s around 5k Wh/Day (150 Kwh/Month) on the low end, and 10 Wh/Day (300 Kwh/Month) on the high end.

For comparison, a Goal Zero Yeti 3000X has a standard battery capacity of 3032Wh which may be sufficient to meet my low end once solar charging is factored in. Or I would think a few standard 100 Ah 12v LiFePO4 batteries would be sufficient.

So what I’m looking for is an all-in-one unit or a DIY build that can handle 120v loads and one 240v load (water pump), and does not break the bank.

If I could power the 240v without having to buy multiple all-in-one units, or adding a sub panel, or other costly methods, etc, I would have done that already. I am trying to avoid that.

I feel like what I’m asking for is achievable with low effort and low cost, and I also feel that one of Will’s budget options that fit the specs could work here. BUT, the issue from what I’ve gathered in this thread, is properly and safely powering both 120v & 240v via the interlock. Everything else that is ‘critical needs only’ is 120v.
 
Pumps take a lot of power to start. You should check the specs to make sure the Yeti can provide the required power.
If so, you can use an autotransformer to get 240V from the Yeti.
 
Pumps take a lot of power to start. You should check the specs to make sure the Yeti can provide the required power.
If so, you can use an autotransformer to get 240V from the Yeti.
Thanks, do you have a link to this product? I tried to search but I’m not able to find it.
 
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