Solar panel

btemplet

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Nov 7, 2020
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Need help what is the max number of solar panel wattage I can put on a 200 amp hour battery bank
 

rmaddy

Full-time Solar-powered Trailer Life
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The max wattage is not related to the battery capacity. The max wattage is related to the battery voltage. The wattage divided by the battery voltage gives you the charge current. You need to make sure that current is less than the max charge current supported by the battery. All of this is also affected by the choice of charge controller.

In the end, battery capacity will determine how long it will take to charge the battery based on the amount and duration of the charge you get out of the system and how depleted the battery is.
 

circus

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There is no maximum that I know of, within reason. Too much solar would just be wasted.
 

OffGridInTheCity

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Need help what is the max number of solar panel wattage I can put on a 200 amp hour battery bank
To help guide this it helps to answer a couple of questions....
1) Are you thinking an off-grid system? - e.g. cannot sell excess to the grid. In this case, you typically do not put up more than you can consume. If you plan a battery bank big enough to support consumption thru the night, then this can be coordinated. For example - my 13kw PV array (45 panels) can produce 80kwh/day in spring/summer - and with a large enough battery, this will support my entire home for 24hrs.

2) If you're thinking grid-tie (sell excess to the grid) or hybrid (grid-tie + battery) - then there's not so much of a limit as you can divert excess to the grid.

Perhaps you could explain your goals a bit more - and you'd get better discussion/info.
 

btemplet

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Nov 7, 2020
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I’m building a off grid system in mini Winnie in stages I have 200 watt of cells 200 amp hour lithium batteries I’m gonna get more batteries or panels which way should go
 

12VoltInstalls

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Depending on region 200-400W of solar matches 200Ah of usable storage as a wild hat guess generalization. 200W panels is about the minimum for 100Ah at my latitude

What is the time period you wish to grow in? And how many Ah are needed for your end goals?
 

OffGridInTheCity

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Extrapolating my larger system downward, and assuming similar consumption (mine is hefty), weather/sunlight available - I get 800w of panel -> 200ah@12v for 80% DOD.

My best advice is to start with 400w suggested by @12VoltInstalls but leave room to double it as you see how the system performs.
 

btemplet

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Depending on region 200-400W of solar matches 200Ah of usable storage as a wild hat guess generalization. 200W panels is about the minimum for 100Ah at my latitude

What is the time period you wish to grow in? And how many Ah are needed for your end goals?
My goal is to have 800 amp hour battery bank and 1000 to 1200 watts of panels I live in south Louisiana. I want to do by alternating buying batteries and panels, without getting out of balance I don’t have a lot of space so I’m thinking of 300w panels. I’m a 80 year hvac tech I don’t have trouble with wiring and putting the system together but I don’t have a lot time to size and match components any help and advice will be appreciated

Thanks
 

OffGridInTheCity

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My goal is to have 800 amp hour battery bank and 1000 to 1200 watts of panels I live in south Louisiana. I want to do by alternating buying batteries and panels, without getting out of balance I don’t have a lot of space so I’m thinking of 300w panels. I’m a 80 year hvac tech I don’t have trouble with wiring and putting the system together but I don’t have a lot time to size and match components any help and advice will be appreciated

Thanks
If I may gently suggest - it helps to pin things down. Just to confirm, when you say 200ah and 800ah you mean 12v? (as apposed to 24v or 48v)

There's nothing wrong with 300w panel and 200ah @ 12v battery - won't hurt anything to get started. In fact, its really good (in my experience) to just get started but leave room to grow. Things will make so much more sense after you have a working system! Don't worry about 'out of balance' to get started at this smaller level :)
 

btemplet

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Nov 7, 2020
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Extrapolating my larger system downward, and assuming similar consumption (mine is hefty), weather/sunlight available - I get 800w of panel -> 200ah@12v for 80% DOD.

My best advice is to start with 400w suggested by @12VoltInstalls but leave room to double it as you see how the system performs.
Thanks if I would put a 300 W panel extra on my 200 W panels on my two Amp hour battery would heard anything
 

btemplet

New Member
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Nov 7, 2020
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If I may gently suggest - it helps to pin things down. Just to confirm, when you say 200ah and 800ah you mean 12v? (as apposed to 24v or 48v)

There's nothing wrong with 300w panel and 200ah @ 12v battery - won't hurt anything to get started. In fact, its really good (in my experience) to just get started but leave room to grow. Things will make so much more sense after you have a working system! Don't worry about 'out of balance' to get started at this smaller level :)
I am staying with 12 hours everything in the camper is 12 V and all the runs will be real short so the wiring size wouldn’t be any problem
 

OffGridInTheCity

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Thanks if I would put a 300 W panel extra on my 200 W panels on my two Amp hour battery would heard anything
You should have a "Charge Controller" between the panels and the battery. Its Panels -> Charge Controller -> Battery.

So no, there's no trouble adding 300w to 200w but you need to make sure the "Charge Controller" will allow this (or get a new one that will). The Charge Controller's job is to deal with panels and convert them to suitable charging current for the battery :)
 

GLC

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The amount of solar panels, watts or volts will be limited by which solar controller you will be using.
 

btemplet

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Thanks I will make sure that I don’t overload the amps or volts But can I add another charge controller if needed
 

12VoltInstalls

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Thanks if I would put a 300 W panel extra on my 200 W panels on my two Amp hour battery would heard anything
Two 100W with a 300W could limit your net nominal input to 400W or less due to electrical functions.
If the voltages and amps would/were matched better you get more out of them. Like three 100W panels in series parallel to the 300W panel- but that’s just guessing because we don’t know the voltage - VOC- and amps of any of the panels. Panel output sums are linear or stepped- depends on how they’re made

Can you post the labels from the back of each panel?
 
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