How to control excess pv power production

[HighTechLab]

but since he isn't grid tie the system.... how will it scale back production with all the loads attached? it can't provide less power with our loaf shedding loads and that gets complicated

@GSXR1000 OP is grid tie, see this quote:

I don't want my system to send power to the grid . But take power from the grid when pv is not producing the house requirements.

_____________________________________________

Get a hybrid solar inverters with zero export device .

Kun, the Sol-Ark 12k inverter that I mentioned has "limited to home" mode that uses CT's to measure the demand of the home. It is a hybrid solar inverter and does have this zero export mode/device.

 

[Kun]

@GSXR1000 OP is grid tie, see this quote:

_____________________________________________



Kun, the Sol-Ark 12k inverter that I mentioned has "limited to home" mode that uses CT's to measure the demand of the home. It is a hybrid solar inverter and does have this zero export mode/device.

Sol-Ark is expensive and they don't have any sales and support network in India . Hence will have to depend on the company that are present there and have after sales support as well.

 

[Kun]

Sol-Ark is expensive and they don't have any sales and support network in India . Hence will have to depend on the company that are present there and have after sales support as well.

Two most widely used inverter brands are Godwe and growatt and they both have zero export meter .

 

[chrisski]

I have received another suggestion please advise

Get a hybrid solar inverters with zero export device .

Add backup as and when whish to and as much possible

I think this is the most practical solution to what you want. Seems like you want solar production without expensive battery storage, and don’t want to export back into the grid.

Went to Agra,India a long time ago, 1995. The power grid was pretty primitive. I remember sitting on a hill at night and seeing a bright light off in the distance, like an explosion, which I think was a transformer, and then power would go out to a section of town. Happened more than once. If that has not changed, I can see why you would not want to backfeed into the grid. Probably not built to absorb the excess production.

When I started my solar build, I thought solar was like wind power and needed a “Dump Load,” but turns out it does not. Solar Is on demand production, but unfortunately not so on demand as a battery, so there will always need to be something like a battery to cover the “lag.” Lot more to it than just lag, but that’s how I explain in it to myself.

 

[Jamsolar876]

simple answer, not used a ups but as buffer for the 14 without sun..
View attachment 47974View attachment 47975View attachment 47976

Nice ..where did you source these cells and how long did it take to be shipped?

 

[Jamsolar876]

They won't ever produce more than required. The solar inverter won't allow them to.

A solar inverter only draws from the panels the required power, up to the limit the panels are able to supply.

e.g. Say an array of panels in the middle of a sunny day are capable of producing 2000W while the loads only require 500W. The inverter's MPPT controller throttles the production from the panels such that the panels only supply 500W. If you then add an extra load and began to use 1000W, the inverter's MPPT controller will adjust its settings to draw more power from the panels. Modern inverters can adjust the power drawn anywhere between zero and the maximal output the array is capable of supplying.

Using the example about what if load demands 3000w and inverter maximum input power is 2000w will it damage the inverter?

 

[chrisski]

Using the example about what if load demands 3000w and inverter maximum input power is 2000w will it damage the inverter?

If the panels supply 2000 watts of power, the battery will make up.

If you’re saying the max the panels and batteries can supply together is 2000 watts, that voltage will start to drop, and amps will start to rise, which going from 14.6 to 10.5 can by about a 30% increase in amps for these same power which can be wire overheating or ampacity in wires. My inverter has a fixed 10.5 VDC low voltage cutoff, so that would be tested. I would say taxing the inverter like that on a constant basis would be bad.

I don’t want to test my inverter at its limits after watching one of many YouTube videos of inverters bursting into flames when ran at their published limits. Those videos made me buy a UL458 rated inverter.

 

[GSXR1000]

Nice ..where did you source these cells and how long did it take to be shipped?

about 2.5 months

Post in thread 'Just ordered Lifepo4 prismatic cell 3.2V 280Ah lithium lifepo4' https://diysolarforum.com/threads/j...-3-2v-280ah-lithium-lifepo4.14955/post-167697

 

[Jamsolar876]

If the panels supply 2000 watts of power, the battery will make up.

If you’re saying the max the panels and batteries can supply together is 2000 watts, that voltage will start to drop, and amps will start to rise, which going from 14.6 to 10.5 can by about a 30% increase in amps for these same power which can be wire overheating or ampacity in wires. My inverter has a fixed 10.5 VDC low voltage cutoff, so that would be tested. I would say taxing the inverter like that on a constant basis would be bad.

I don’t want to test my inverter at its limits after watching one of many YouTube videos of inverters bursting into flames when ran at their published limits. Those videos made me buy a UL458 rated inverter.

No actually I was referring to the same example he gave in that if your array can provide a max 5000W and your inverter is rated for 2000w max solar input but inverter output is great let's say 3000w output max , what if your load is demanding 2600 or even 3000w ? Will the inverter look to take the 2600 or 3000w from the panels or will it now only take it's rated 2000w and then the difference from the battery?

 

[12VoltInstalls]

The simplest answer I have is to use a big enough true-sine inverter that provides the 120V or 240V power required - connected to a small group 37 lead acid or self-bms lifepo battery to act as a capacitor or buffer. You should have like around 125%+ solar panel capacity as it takes to run all the intended appliances. And spending the money for a good mppt charge controller is important. Cheap stuff works but not very well and cheap doesn’t always last long enough to be a good value.

The charge controller will only output the solar power the load/battery state of charge requires- it will not ‘force’ electricity into devices or batteries and burn them out or whatever. Solar panels produce electricity potential but if there is no load the electricity does not ‘flow’ nor does it “build up.”

That would be my solution- other solutions here will work, you just need to learn enough info to make the right decision for your situation.

If you have a power grid, you can use an automatic switching solar transfer switch. It will use the solar and/or battery up until the point that the sun is not providing enough power and then will automatically switch to grid and then back to solar the following morning when the sun comes out.

in the end, panel-to-load can be done, but you can probably use lots of panel and a smallish (group 27 lead) battery for less money up front.

 

[Cheap 4-life]

I use SunG grid tie inverters with limiter that also use batteries. One model uses 22-65v battery. The other uses 45-90v battery. If the load demands more than the inverters can supply the grid supplies the remaining amount needed. If a person has grid power available the inverters I mention are great

 

[Cheap 4-life]

Two most widely used inverter brands are Godwe and growatt and they both have zero export meter .

Do both of those inverters use a battery and have zero export? Do they use CTs to control the limiting?