2000W solar with 12V

I used to have three different voltage strings. On cloudy days, one would take over and the other two would add nothing. I have a dozen charge controllers for testing other electronics with. I get defective solar electronics like women buy shoes. They all did the same thing. Mine is a unique small system and not like anyone else's here. It is an ultra efficient system and it shows a lot of strange things controllers can do as a result of much smaller than normal battery. As I said, a heavily used large system remains mainly in bulk. The OP's idea of using five charge controllers would not wok as well as just one. My ending solution was to just eliminate a dozen panels from my system. And look at this site, see any panels. I could have a more normal system. Manufacturers send me totally free charge controllers, inverters, batteries, breakers, wire, etc. Being ultra efficient is my challenge.

Based on everything above it seems it would be best for me to purchase the Victron 250/100. A comment above mentioned I need to get a matching battery. It looks like I need 100A battery. Looks like the 200Ah Litime has some 200A batteries here. Does this seem suitable?

https://www.litime.com/products/12v-200ah-plus-lifepo4-battery

heimlich said:

Based on everything above it seems it would be best for me to purchase the Victron 250/100. A comment above mentioned I need to get a matching battery. It looks like I need 100A battery. Looks like the 200Ah Litime has some 200A batteries here. Does this seem suitable?

https://www.litime.com/products/12v-200ah-plus-lifepo4-battery

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You can adjust the victron output .
So from 100 to 25 if you need it
So its more flex than you think
A 200Ah battery can do c1 charge of 200ampere max .
On c0.5 it do 100ampere means its go good fit for that mppt.

See picture that you can adjust the settings.

Is it better to buy a larger battery? I am thinking of getting the 460Ah one here: https://www.litime.com/products/12v-460ah-lithium-battery
I calculate I have maybe 5 hours of daylight total. The Victron MPPT can do 1450W from the panels.

I have 2k panels. I figure 5 hours of daylight. That gives me 10k. I found some calculations that say take 75% of that which gives me 7.5k.

I like redundancy. so, would get 2 of the 200ah batteries.

heimlich said:

Is it better to buy a larger battery? I am thinking of getting the 460Ah one here: https://www.litime.com/products/12v-460ah-lithium-battery
I calculate I have maybe 5 hours of daylight total. The Victron MPPT can do 1450W from the panels.

I have 2k panels. I figure 5 hours of daylight. That gives me 10k. I found some calculations that say take 75% of that which gives me 7.5k.

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I'd suggest two 12V 280Ah from ecoworthy, $950 after $50 coupon. Current price per watt champion. And gives you some redundancy if one should fail.

Brucey said:

I'd suggest two 12V 280Ah from ecoworthy, $950 after $50 coupon. Current price per watt champion. And gives you some redundancy if one should fail.

https://www.amazon.com/ECO-WORTHY-12V-280Ah-2Pack-Phosphate/dp/B0CKT2J3M9/

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Wow. That's a good price.

I keep seeing sites saying you can only put 4 in parallel. That is one reason I thought about going with the larger battery. Would two of the 460Ah be too much for me? I am limited on my solar panels so there will never be anymore than the 5. The only thing I could do is run a generator at the same time.

Am I doing my solar battery calculation correct?

heimlich said:

Wow. That's a good price.

I keep seeing sites saying you can only put 4 in parallel. That is one reason I thought about going with the larger battery. Would two of the 460Ah be too much for me? I am limited on my solar panels so there will never be anymore than the 5. The only thing I could do is run a generator at the same time.

Am I doing my solar battery calculation correct?

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You just missed out ebay had a coupon for 20% off but it ended on the 16th. There's really no limit to the number of batteries you can run in parallel assuming they have same characteristics (16 cells, lfp etc). But usually the 12s can be seried up to 48V, and they'll often have a diagram showing four in parallel as well.

I would just buy three or four of the 280s if you need more storage.

You went about this backwards.

1) Calculate loads
2) Calculate battery size based on those loads
3) Calcualte amount of solar needed to recharge the battery.

BUT, the advantage to LiFePO4 is they don't need to recharged fully every day, so you can do it wrong and still be OK.

heimlich said:

Wow. That's a good price.

I keep seeing sites saying you can only put 4 in parallel. That is one reason I thought about going with the larger battery. Would two of the 460Ah be too much for me? I am limited on my solar panels so there will never be anymore than the 5. The only thing I could do is run a generator at the same time.

Am I doing my solar battery calculation correct?

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2x 460 Ah is about minimum for 2000w solar in my opinion. Two is actually easier to balance the wiring so I think you are on the right track with this.
I have 1200 Ah total with just 675w solar (12v). I like more battery for when solar is not viable.

Q-Dog said:

You went about this backwards.

1) Calculate loads
2) Calculate battery size based on those loads
3) Calcualte amount of solar needed to recharge the battery.

BUT, the advantage to LiFePO4 is they don't need to recharged fully every day, so you can do it wrong and still be OK.

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I understand what you are saying. I started out doing that and realized it doesn't matter what loads I have. What matters is what power I can produce. I only have room for 5 panels on top of the camper. So I need to size the batteries according to those panels. That will dictate what loads I can attach to it. For anything else I need a load for such as AC I will wire directly to a generator.

heimlich said:

Each panel is 38Amps. I attached the document for it here in message.

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Says 13.78

2x victron 150/60s would probably be my preference

pollenface said:

Says 13.78

2x victron 150/60s would probably be my preference

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I can see how that would be good to add some redundancy.

heimlich said:

I can see how that would be good to add some redundancy.

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Also could add some shade tolerance depending on how the panels are grouped. Shaded panels would not affect the full sun panels

What you are running into is exactly why I am a big fan of 24 volt systems for DIYers.

( I mostly build 24 and 48 but am in fact building a 12 volt one now and it is a pain )

Especially if you have not purchased the inverter yet, it will solve a lot of issues vs 12 volt. ( as long as there are not very large 12 volt loads ). A fridge is not a large load. You can check your fridge - some are dual 12 / 24 volt, but if not, good quality DC - DC converters in that power range are reasonably priced.

The same components that are commonly used by people to build 12 volt systems are compatible with 24 volt systems - you just get double the power carrying capacity. It also makes it easier to build.

The risk in building a power system is not really 12 vs 24 volt, it is pumping the amps through the connection points. That is what gets hot, and making reliable, consistent connections that can carry 200 - 300 amps and stay that way while bouncing down the road, large temperature changes, etc, is not completely trivial.

I haven't bought anything except the solar panels. I too am struggling with the 12/24/48v. I was thinking I'd change to 48V but the 24V looks very promising. The only 120V load I have would be an air conditioner for the summer or a water heater for the winter. I think they both each pull under 1000W. I thought I was kind of stuck between the 24V and 48V decision. I'm really leaning towards 48V. Can anyone offer any advice as to why I wouldn't want to do 48V?

heimlich said:

I haven't bought anything except the solar panels. I too am struggling with the 12/24/48v. I was thinking I'd change to 48V but the 24V looks very promising. The only 120V load I have would be an air conditioner for the summer or a water heater for the winter. I think they both each pull under 1000W. I thought I was kind of stuck between the 24V and 48V decision. I'm really leaning towards 48V. Can anyone offer any advice as to why I wouldn't want to do 48V?

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48volt is more future proof if you go for higher inverter in the future
So if you have nothing and just start .

Imagine for a moment that you already had 24 volt inverter, 12 24 volt refrigerator, and 24 volt led strip lights, in a trailer / RV / Camper.

Pretty much everything is powered by 24 volt and you built it up from off the shelf parts from Bluesea and the usual charger / inverter offerings.

The USB ports are intelligent ones, so they will auto adjust the charge voltage to match what your phone can do, and will charge faster than they would from 12 volt because of how modern USB charging works.
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Now starting from this position, you decided to build another RV.

Would it ever make sense to do that one in 12 volt ? Probably not. It would feel like going back to the stone age.

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Would there be a big gain in trying to do the same thing with 48 volt?

Some, perhaps 20 % better, but now:
- Absolutely nothing that you are using for fuse blocks, breakers, etc from the bluesea catalog can be used, so you will be starting from scratch on your research.
- Good luck finding a 48 volt fridge. There are a couple but not many.

Don't get me wrong - I like and build all three types ( mostly 24 and 48 ) but there is also the reality that for "today", there just are not as many 48 volt directly run items out there.

A 24 volt system, a person can research and build faster than this thread has run.

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Here is a simple example of a dual 24 / 12 volt system. Post 3 of this thread. Very easy. Just copy what is there and adapt to your space constraints.

I figured I would get a 48V to 12V 30A converter. That should power every 12V item I have. I can run that into my 12V fuse box. Any reason I can not do it that way?

heimlich said:

I figured I would get a 48V to 12V 30A converter. That should power every 12V item I have. I can run that into my 12V fuse box. Any reason I can not do it that way?

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You can do that .
We use this on the boat what have 24 volt on board.
And are rebeult to 48 volt for hybride engine (my next project)
And than people like to use that 48volt systeem.
The new Hybrid engine can be use to charge the battery to.
But no fridge and other stuff that run on 48 volt.

Link you see a 48volt hybrid engine (2035 in the EU have to be full electric cars , house , boat and trucks) (old junk can stay running)


And


So yes you can use a dc to dc stapdown model and fix that problem.
Only one thing always thake a spare unit with you.

heimlich said:

I figured I would get a 48V to 12V 30A converter. That should power every 12V item I have. I can run that into my 12V fuse box. Any reason I can not do it that way?

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It might make sense to do a small test build of the 48 volt portion of the system on a piece of plywood in the garage or in your hobby area and see how it goes. Don't buy the inverter, just the wire, fuses, breakers and similar inexpensive parts to see how you like it.

That way it is inexpensive to change if needed. Paper is not the same as actually building and it will help you make the decision on your own.

I bought the EG4 3000W all in one along with their 100ah 48V battery.