Need help choosing components

Paperlanterns98

New Member
Joined
May 7, 2022
Messages
5
I have a battery bank. Bus bars not currently connected.
New to solar. Need help choosing components.
Eventually want to build cabin but currently for 35' travel trailer.
Alcad LSe 1400 (x14)
Am I correct that 11 in series is 24.75 volts?

Recommendations on exact make and model components greatly appreciated in advance!
 

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Rednecktek

Photon Sorcerer
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On a boat usually.
2.25v per cell? That pack looks like it weighs more than the trailer. :)

Well, I'll start the default answer to these questions and we can work from there. Here's you To-Do list:

1: Power audit! This will give you some important information on how big your inverter needs to be as well as how much battery capacity you'll need. There is a link in the FAQ section (I think, or someone here will post it shortly) so fill in the blanks and see what it comes up with. You'll probably need some sort of Kill-A-Watt to get accurate measurements. Are you going to be running a 12v system? 24v system? 48v system? What are the specs on your solar panels? VoC? Vmp? Being as this is a new build, throw together a wish list of what you want and estimate on the high side.

1a: Where do you live? Speccing out a system for Scotland is a LOT different numbers than Arizona due to the amount of light you actually get. Someone here can post the link to the PVwatts.com or JCR Solar Uber-Sun-Hours calculator sites to help figure out how much you'll have to work with. That will be a box in the Power Audit form.

2: Parts list: You don't need a make & model list, just a parts list to start from for reference. You'll need an inverter, a MPPT charge controller, fuses, shunt, buck converter, batteries, wire, etc. Once you have a basic list it can be fine tuned to make & models after that. If you're looking at the All-In-Ones check for correct voltage outputs (120v or 240v Split Phase for North America, 220v Single Phase for European type areas) and make sure it has enough capacity for a little bit of growth and fudge factor.

3: Budget!: Steak is great but doesn't mean anything if your wallet says hamburger. :) Figure out what you're able to spend now vs what you'll have to cheap out on now and upgrade later.

4: Tape measure! Figure out where you're going to stick all the stuff you'll need. A dozen 3000AH batteries sounds great until you're sleeping on the floor because there's no room left for a bed. Is there a compartment that can house all this stuff? Will the server rack batteries fit? Are you going to have to make space? Physics can be pretty unforgiving.

5: Pencil out what you think you need and throw it at us so we can tell you what you've missed (because we ALL miss stuff the first go-round :) ) and help figure out which parts and pieces you're going to want to get.
 

Paperlanterns98

New Member
Joined
May 7, 2022
Messages
5
2.25v per cell? That pack looks like it weighs more than the trailer. :)

Well, I'll start the default answer to these questions and we can work from there. Here's you To-Do list:

1: Power audit! This will give you some important information on how big your inverter needs to be as well as how much battery capacity you'll need. There is a link in the FAQ section (I think, or someone here will post it shortly) so fill in the blanks and see what it comes up with. You'll probably need some sort of Kill-A-Watt to get accurate measurements. Are you going to be running a 12v system? 24v system? 48v system? What are the specs on your solar panels? VoC? Vmp? Being as this is a new build, throw together a wish list of what you want and estimate on the high side.

1a: Where do you live? Speccing out a system for Scotland is a LOT different numbers than Arizona due to the amount of light you actually get. Someone here can post the link to the PVwatts.com or JCR Solar Uber-Sun-Hours calculator sites to help figure out how much you'll have to work with. That will be a box in the Power Audit form.

2: Parts list: You don't need a make & model list, just a parts list to start from for reference. You'll need an inverter, a MPPT charge controller, fuses, shunt, buck converter, batteries, wire, etc. Once you have a basic list it can be fine tuned to make & models after that. If you're looking at the All-In-Ones check for correct voltage outputs (120v or 240v Split Phase for North America, 220v Single Phase for European type areas) and make sure it has enough capacity for a little bit of growth and fudge factor.

3: Budget!: Steak is great but doesn't mean anything if your wallet says hamburger. :) Figure out what you're able to spend now vs what you'll have to cheap out on now and upgrade later.

4: Tape measure! Figure out where you're going to stick all the stuff you'll need. A dozen 3000AH batteries sounds great until you're sleeping on the floor because there's no room left for a bed. Is there a compartment that can house all this stuff? Will the server rack batteries fit? Are you going to have to make space? Physics can be pretty unforgiving.

5: Pencil out what you think you need and throw it at us so we can tell you what you've missed (because we ALL miss stuff the first go-round :) ) and help figure out which parts and pieces you're going to want to get.
Shed build

1) Kentucky USA
2) wanting all in one if possible. I understand what you're saying but guess there's brands to stay away from. Wanting pure sine.
3) Don't have a set budget. Not looking to splurge but wanting to do it right the first time.
4) room should not be an issue. Dedicated shes build
5) I know my specs are vague. Again hoping to do a small home eventually but for now... need it to do a 30 Amp 120volt travel-trailer camper.
At 2.25v per batt... I have 14... so I could do 24v inverter but I'm under the impression I don't have enough for (in series) a 48v system.

If I do a 24v inverter... the all-in-ones that are quoting AC output @208 or 220v... how do I step that down to 120v 30A ?
 

Paperlanterns98

New Member
Joined
May 7, 2022
Messages
5
Lets look at it from a battery capacity perspective. How many watt hours are your cells or overall battery?
I have 14 of these. But for 24v inverter I believe I would use only 11.

 

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MisterSandals

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1400Ah @ 2.25V (?) = 3150Wh
3150Wh x 11 cells = 34650Wh
50% dischargeable? = 17325WH

To fully charge from empty in 5 hr solar day:
17325Wh / 5h = 3465W solar array

3465W / 28V charging voltage = 124A (that's a LOT)
 

Paperlanterns98

New Member
Joined
May 7, 2022
Messages
5
1400Ah @ 2.25V (?) = 3150Wh
3150Wh x 11 cells = 34650Wh
50% dischargeable? = 17325WH

To fully charge from empty in 5 hr solar day:
17325Wh / 5h = 3465W solar array

3465W / 28V charging voltage = 124A (that's a LOT)
I believe I'm mostly tracking what you're saying, but to make sure... how many (spec?) panels am I looking at?
Also trying to choice an inverter
 

MisterSandals

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how many (spec?) panels am I looking at?
3465W solar array
That would be 14x 250W panels, ... or 9x 400W panels

Have you looked for big cheap panels on craigslist or local online markets?

If you reveal your city or zip, maybe someone can point you to good deals in your area.

Depending on the specs of the panels, something like a pair of Victron 150/70 SCCs would work. I think there are bigger ones that can handle 124A in one unit but i am not familiar with them.
 

MisterSandals

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But this was backing into the numbers based on your battery bank. You REALLY should figure out how much power you need/want to produce each day. That should drive how big your array should be (how much power you need to harvest).
 

Paperlanterns98

New Member
Joined
May 7, 2022
Messages
5
But this was backing into the numbers based on your battery bank. You REALLY should figure out how much power you need/want to produce each day. That should drive how big your array should be (how much power you need to harvest).
Right. At a minimum, I need it to power a 120v 30A camper every other weekend. Seems like I wouldn't be running bank down to 50% every day.
 
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