I'm looking for the easiest way to switch which of three all in one solar units is powering a particular 110 appliance. This is a high draw item that could drain one of the three down to nothing so I want to either automatically or manually be able to flip a switch to change its power source. Plugging and unplugging it directly from the device doesn't work because of how these things fit in the space of my bus - hard to reach to keep plugging/unplugging. The units I'm using to power this can't be chained together. Is there any device that exists for this purpose? Thanks.
Switching Between All In One Units
- Thread starter Mary
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svetz
Works in theory! Practice? That's something else
If it's a lot of amps you'll probably need a contactor. But you might be able to get away with a multithrow multipole switch. Just make sure the poles match the voltage/current ratings and it's setup for AC.
Recommend staying far away from any switches that don't have a stamp from UL, CE, or similar - so not worth it.
Ask if you have questions and I hope that helps!
Recommend staying far away from any switches that don't have a stamp from UL, CE, or similar - so not worth it.
Ask if you have questions and I hope that helps!
Thanks, that's very helpful!
OffGridInTheCity
Solar Wizard
I bypass my all-in-one in the trailer by using this rotary. They go up to 63a - not sure what you need. https://www.amazon.com/gp/product/B07N119RY9/ref=ppx_yo_dt_b_search_asin_title
Not sure my brain is entirely wrapped around this but I will check it out. Thanks!
svetz
Works in theory! Practice? That's something else
ROFL, oh yeah... it's the type of thing that makes your eyes cross to be sure. Somewhere in the listing should be a diagram similar to the one on the right. Basically, that's a matrix showing what's hot and what's not for each of the switch positions. In the one to the right, in position 0, terminal 1 shorts to terminal 2, and terminal 3 shorts to terminal 4. Assuming you're in the U.S on a 120V or 240 you might wire it as: |  |
| Device | L1 | L2 |
|---|---|---|
| Inverter #1 | 1 | 3 |
| Inverter #2 | 5 | 7 |
| Inverter #3 | 9 | 11 |
| Appliance | 2, 6, 10 | 4, 8,12 |
So in position 0, inverter 1 would power the appliance. In position 2, Inverter 2, and in position 3 the third inverter.
Hope that helps!
It does, thanks a lot!
OffGridInTheCity
Solar Wizard
Yea - I wanted to be able to just bypass my MPP Solar for long winter storage but yet have shore power skip past it. Here's the circuit diagram I used and the rotary switch diagram - to give you the idea.
Awesome, thanks!
svetz
Works in theory! Practice? That's something else
This might be of interest to you: https://diysolarforum.com/threads/please-help-me-learn-why-this-happened-so-i-don’t-do-it-again.28086/#post-336197 as a cautionary tale.
It's why I recommended a UL, CE, or similar accreditation. There's a lot of cheap garbage out there. That said, there are good devices without accreditation too, it's separating the wheat from the chaff that makes it a gamble and why recommendations from members that have validated the device are invaluable. If you're ordering from Amazon, make sure there isn't a box on the page that says it's not returnable, then worse case you get your money back if it fails on the first go.
It's why I recommended a UL, CE, or similar accreditation. There's a lot of cheap garbage out there. That said, there are good devices without accreditation too, it's separating the wheat from the chaff that makes it a gamble and why recommendations from members that have validated the device are invaluable. If you're ordering from Amazon, make sure there isn't a box on the page that says it's not returnable, then worse case you get your money back if it fails on the first go.
svetz
Works in theory! Practice? That's something else
Should have mentioned early... nearly all of these switches break the existing contacts before establishing the new contacts. If you didn't, out-of-phase power could mingle with undesirable sparky/smokey results. Not surprisingly these switches are called Break-Before-Make. Make sure you don't accidentally buy one that isn't break-before-make.
Notice how in the matrix of OffGridInTheCity device Position 0 has no connections? It's not shown, but I'm pretty sure if you could see the face of the rotary selector it would be something like 1 - 0 - 2. That is to go from one to two you must go through 0.
That has a few uses. A lot of people like that 0 position with no contacts as it ensures a break before make. It also provides a "true" off-state useful for maintenance. The example in #6 has no such off-state. There are a few clever instances I've seen where folks use traversing through that state for different purposes.
Another thing to consider is the number of terminals, the example in #6 assumes L1 and L2 where the neutrals from all 3 inverters are bonded. If you wanted to keep the neutrals isolated you'd need more terminals. Or, if you were only using L1 you could isolate the neutrals by using the column marked as L2 in the example as the neutral.
Notice how in the matrix of OffGridInTheCity device Position 0 has no connections? It's not shown, but I'm pretty sure if you could see the face of the rotary selector it would be something like 1 - 0 - 2. That is to go from one to two you must go through 0.
That has a few uses. A lot of people like that 0 position with no contacts as it ensures a break before make. It also provides a "true" off-state useful for maintenance. The example in #6 has no such off-state. There are a few clever instances I've seen where folks use traversing through that state for different purposes.
Another thing to consider is the number of terminals, the example in #6 assumes L1 and L2 where the neutrals from all 3 inverters are bonded. If you wanted to keep the neutrals isolated you'd need more terminals. Or, if you were only using L1 you could isolate the neutrals by using the column marked as L2 in the example as the neutral.
I saw that as soon as I came to the site today - yeah that is scary.
I have decided to do this the low tech way - that is, unplugging from the device with waning power and plugging in to the freshly charged one. I had to rearrange some things to make that doable but it just feels so much simpler than all this.
svetz
Works in theory! Practice? That's something else
Possibly impractical, but if you could merge the 3 separate battery banks into one, that one battery bank could feed all three inverters.
See also Incrementally adding DC batteries for some things to think about if you think you might want to do that. You might post that as a new question to see if anyone has done that and if they had to do anything special if it sounds like it might have merit.
Best of luck!
Yeah, I have thought about this, too, but I don't think I'm ready for that right now. I'm not what you'd call a fast learner, and I like to understand things pretty thoroughly before trying to do them. I love to take on new things but not until I have a really clear picture of the function and end goal. I think it comes from being a firefighter's daughter! It was drummed into my head that if you don't understand what you're wiring and why, don't wire it. So I think I'll wait till I "get this" a little better before I do anything more sophisticated. Thanks so much for your help - I've learned a lot from what you've posted on this thread already.
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