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diy solar

The upgradable system problem

Begginer7

Location: Cyprus EU
Joined
Feb 15, 2022
Messages
97
It seems that there is a wise advise going around, try to get a big enough setup in the beggining so that it will be cheaper in the long run. I agree with it but I am finding a difficulty, the AIO systems that I can get so far, increate the size of the charge controler as they increase the voltage requirment, e.g.
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So lets say I want to get an inverter and solar controler that will cover me for the future when I will buy 3 panels of 410W and 2 Lithium 12ah 12 V, but I want to start with just one panel and one battery.

So 3 * 410W = 1230W /12V= 102.5 a charge controler, rounded up to 110a or 120a. But I cannot find an AIO with 12 V batt. and 110 charge controler. Should I do it with a separted inverter and charge controler?

Another solution 1230W/24V=51.25 a charge controler, ok this is the MPP 3024MSXE 3000W with 60a charge controler at about 700 Eur., not bad but there is a catch it needs 24 V batteries, I need either to get 2 12V batteries of 100ah (SOK 630 x2 = 1260 EUR) each and put them in series or one 24 V of 100 ah (SOK 1300 EUR). But this is not a solution as it doesnt make sense to have one panel of 410W with a 3k Inverter and batteries of total 2400W.

Maybe is possible to get an AIO that can manage both 12V for the first phase with one battery and then 24V for the additnal battery and panels.

Any thoughts on the subject?
 
Choice 1: go with 12V for now and scrap the 12V AiO when your needs exceed it. There are few standalone MPPT that are > 100A for 12V and no AiO. Very likely that your SOK 12V battery won't accept more than 50A of charging.

Choice 2: spend more now so that you're not completely replacing major components. Furthermore, adding a second 12V in series LATER is generally not recommended as the two batteries need to be as close as possible in every way when in series.

Have you actually designed your final system, i.e., outlined your needs and goals and designed it accordingly? If not, you're likely wasting time and money.

Keep in mind that most AiO of the MPP Solar and Growatt variety (and all other chinese made inverters) tend to have very high idle consumption. That 3024 likely burns 40-50W all the time. That's 50W * 24h = 1200Wh, i.e., just having the inverter on would consume 50% of your battery capacity.
 
Keep in mind that most AiO of the MPP Solar and Growatt variety (and all other chinese made inverters) tend to have very high idle consumption. That 3024 likely burns 40-50W all the time. That's 50W * 24h = 1200Wh, i.e., just having the inverter on would consume 50% of your battery capacity.
This is a big factor especially on smaller systems. When going from a 12v system to a 24v system you usually need to toss the inverter, so if you can make the choice now it saves you hassle in the long run. If you roll a component system you gain MUCH more expandability in the future.

Rolling your own system lets you put multiple SCC's in parallel to add more panel to a smaller system, you can keep the SCC's and just replace the inverter if you decide to upgrade. Since the SCC's will 99.9% of the time do at least 12v/24v you don't need to replace them later if you jump to a 24v system. Paralleling battery banks in is very easy as well.

Yes, having the single unit is handy and convenient and has nifty things like generator/grid feed and auto changeover, but they're really designed for a Set-It-And-Forget-It setup. You're trading modularity, efficiency and expandability for convenience.

The reason you see so many 24v and 48v systems at the 3Kw mark is because of the amperage. If you did a 3Kw inverter on 48v that's a 75a fuse and wire. Doing it on 24v? That's 150a fuse and thicker wire. If you tried to do 3Kw on a 12v system you're looking at a 325a fuse and AWGHonkinHuge wire!
But this is not a solution as it doesnt make sense to have one panel of 410W with a 3k Inverter and batteries of total 2400W.
Correct, 1 panel would be undersized and take 6 hours of perfect light to completely fill your battery. However 3 panels would do it in 2 hours ASSUMING that you completely drained your battery each day. If that's the case you've seriously undersized your system. Since the SCC's are limited by amperage, the only way to get more Watts is to give it more Volts at the same Amps.

There's a reason everyone tells you to do a power audit before anything else. The power audit will tell you 3 very important things, 1: How big your inverter needs to be, 2: how much battery capacity you need to feed the load for $Time, and 3 how much solar panel to refill those batteries in a reasonable amount of time.
 
Choice 1: go with 12V for now and scrap the 12V AiO when your needs exceed it. There are few standalone MPPT that are > 100A for 12V and no AiO. Very likely that your SOK 12V battery won't accept more than 50A of charging.

Choice 2: spend more now so that you're not completely replacing major components. Furthermore, adding a second 12V in series LATER is generally not recommended as the two batteries need to be as close as possible in every way when in series.

Have you actually designed your final system, i.e., outlined your needs and goals and designed it accordingly? If not, you're likely wasting time and money.

Keep in mind that most AiO of the MPP Solar and Growatt variety (and all other chinese made inverters) tend to have very high idle consumption. That 3024 likely burns 40-50W all the time. That's 50W * 24h = 1200Wh, i.e., just having the inverter on would consume 50% of your battery capacity.

Could you please let me know any good options for the 100A for 12V MPPT standalone? And if possible a 1500W inverter that accepts generator?

I agree I prefer to spend more now.

No I have not finished with the design.

Do you think the 3024 spends 40-50W allthough in their manual it specifies minor to 25W?
 
Also, there are many, MANY battery options that will save you more than enough to justify more batteries for longer uptime, unless there's a specific need to run SOK's.
No special reason for SOKs, could you suggest any other Lithium batteries?
 
As long as they're not going to get below freezing, the Chins/Ampertime/Zooms are a great bang for the buck. They save money by going with a plastic case instead of steel and not having as fancy a BMS with low temp cutoff, which seems to be about a $300 feature for some reason. :rolleyes:
 
Thanks, thing is I am in Cyprus EU, Chins web site appears to be non secure, I sent them email, Zoom and Ampertime dont have shipping to Cyprus in their sites but I email them.

Any options that have delivery to Europe?
 
As long as they're not going to get below freezing, the Chins/Ampertime/Zooms are a great bang for the buck. They save money by going with a plastic case instead of steel and not having as fancy a BMS with low temp cutoff, which seems to be about a $300 feature for some reason. :rolleyes:
Ampertime replied it seems they have good customer support, hopefully they will give me a quote, is the low temp cut off important ? this is the temperature while charging so its day time maybe 6am not the lowest night time temp. right?
 
Very likely that your SOK 12V battery won't accept more than 50A of charging.
But the OP's 2 SOK 12V batteries in parallel will accept 100A of charging.

Edit: I missed the OP maybe starting with one and adding a second later.
 
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Ampertime replied it seems they have good customer support, hopefully they will give me a quote, is the low temp cut off important ? this is the temperature while charging so its day time maybe 6am not the lowest night time temp. right?
Welcome to the forum Begginer7

Let folks know where you are by putting information below your Avitar. Go to your account details and scroll down to CUSTOM TITLE.
 
Can I ask what is the importance of this? Does it relate to the battery charger of the inverter?
You are asking about a charge controller that can put out 120A of charge current. But the 2 SOK batteries can only accept up to a max of 100A of charge current. This roughly means you can't make use of any more than 1200W of solar with those two batteries. Your proposed 1230W will be fine. Just be sure you setup any charge source to provide no more than 100A of charge current to those two batteries.
 
Choice 2: spend more now so that you're not completely replacing major components. Furthermore, adding a second 12V in series LATER is generally not recommended as the two batteries need to be as close as possible in every way when in series.
But lets say I want to buy just one 12V battery now and one later, if they need to be as close as possible then I cannot do it in series ot I could but I will lose the diff. Of the used to the new one. So maybe I do that in parallel?
 
I missed the part where you will only have one SOK battery now and maybe a 2nd one later. If you start with one battery then that is a max of 50A charge current. That's only 600W of solar roughly. You can't go to 1200W until you add a second battery.
 
As long as they're not going to get below freezing, the Chins/Ampertime/Zooms are a great bang for the buck. They save money by going with a plastic case instead of steel and not having as fancy a BMS with low temp cutoff, which seems to be about a $300 feature for some reason. :rolleyes:
And not to mention the Amperetime cells rated for 1500 cycles only, so an additional 2500+ cycles is a huge $300 feature
 
And not to mention the Amperetime cells rated for 1500 cycles only, so an additional 2500+ cycles is a huge $300 feature
So does that mean that if we discharge and charge once a day then Ampertime will last 1500/365= 4.1 years while sok 2500/365= 6.8 years,? maybe this is the reason for the guarantee difference?
 
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