Cannot understand this Chinese solar charge controller

[corporal_Canada]

Hello I am a french canadian living in the philippines plenty ofsun here got a solar panel 300 watts connected to a chinese very small wallet sized charge controller and that is also connected to a 12v 100 amp hour car battery also connected to a 1,000 w chinese sine wave inverter, i'm not sure how to set it correctly because there's only three buttons there's power going to the charge controller was tested at 12 something volts and 12 or 14 volts going to the battery but to the load side not even one volt.
..... I would demonstrate a photo of what everything is connected but if I show you, you would all panic and freak out at the amount of cable going all over the place, did I do something wrong ??

 

[upnorthandpersonal]

Load side? You mean the charge controller has a load output and the inverter is there? If so, don't use that for the inverter. The inverter has to be connected to the battery directly, same as the charge controller.
Picture (and diagram) would help, and the make/model of all the equipment.

 

[corporal_Canada]

Yes load side... It has a + and -... And a lightbulb symbol

 

[upnorthandpersonal]

Yeah, don't use that - it's only intended for things like a small light or something, not an inverter. Connect the inverter at the battery (or use a bus bar).

Your load (inverter), battery and solar charge controller all connect to the same points (bus bar preferably).

 

[corporal_Canada]

Yeah, don't use that - it's only intended for things like a small light or something, not an inverter. Connect the inverter at the battery (or use a bus bar).

Your load (inverter), battery and solar charge controller all connect to the same points (bus bar preferably).

Oh, I thought the controller would have a diod to direct the direction of electrons, I'm not really fond of tapping into the battery while it is being charged

 

[upnorthandpersonal]

Oh, I thought the controller would have a diod to direct the direction of electrons, I'm not really fond of tapping into the battery while it is being charged

If you generate more power than you need, the battery charges. If you generate less than you need, the battery discharges. You can't charge and discharge at the same time.

 

[corporal_Canada]

If you generate more power than you need, the battery charges. If you generate less than you need, the battery discharges. You can't charge and discharge at the same time.

Exactly i thought the charge controller would allow you or the inverter to pull power from the solar panels directly instead of going to the battery

 

[42OhmsPA]

.

 

[upnorthandpersonal]

Exactly i thought the charge controller would allow you or the inverter to pull power from the solar panels directly instead of going to the battery

No, the solar panels are not regulated (voltage is higher than the battery, often times much more so) and a solar panel isn't a voltage source. You're still getting the power from the panels directly through the charge controller though (as long as your load is less than what the panels can provide) - it's not going 'through' the battery, since the battery is still charging when the solar panels can provide more power than your inverter needs.

 

[corporal_Canada]

No, the solar panels are not regulated (voltage is higher than the battery, often times much more so) and a solar panel isn't a voltage source. You're still getting the power from the panels directly through the charge controller though (as long as your load is less than what the panels can provide) - it's not going 'through' the battery, since the battery is still charging when the solar panels can provide more power than your inverter needs.

So if you cannot charge a 12v battery and pull watts/electrons at the same time, then I'm doing the exact thing that goes against this......at this point, I think the charge controller has zero purpose in all this, I might as well just use clamps straight to the battery

 

[sunshine_eggo]

So if you cannot charge a 12v battery and pull watts/electrons at the same time, then I'm doing the exact thing that goes against this......at this point, I think the charge controller has zero purpose in all this, I might as well just use clamps straight to the battery

I think you're missing something.

You can't have electrons flowing in both directions at the same time. Yes, you can have a charger going and loads going at a the same time, but there's only flow in one direction.

If you are producing 10A of charge and have 8A of loads, the battery charges at 2A.

If you are producing 8A of charge and have 10A of loads, the battery discharges at 2A.

 

[upnorthandpersonal]

I think you're confused a little. Let me make sure we're on the same page.

A solar panel is not a voltage source, it more akin to a current source. You have to find the maximum power point: by just connecting a load to a panel that is not matched to the resistance of the panel, you'll probably just pull the voltage down, or you'll have only a fraction of the power it can deliver actually going to your load. The easiest way to see this is looking at the MPPT curve:



To get the maximum power out, one has to find a combination of optimal current and voltage - these are the Vmp and Imp parameters you can find on your solar panel. You can get these with a true MPPT charge controller, or using a PWM method, but I digress. Point being: you can't hook up a load directly to a solar panel and expect it to work.

Thus, we need a charge controller. This charge controller will then turn whatever voltage of the panel Vmp is (and note, with any recent and decent size panel this is way more than 12V!) and at max power point to a steady 12V (or whatever your battery and load needs) at whatever current is needed and can be supplied (remember: Watts in = Watts out).

If you now hook the output of the charge controller to a battery, and the battery is full - there will be no current flowing, because there is no load. If you hook up the inverter at this point to the same place as the battery (the output of the charge controller), a load is introduced and power will flow from your panels, conditioned through the controller, to your inverter to power it and whatever loads are attached to it. No power is coming from the battery: it's still full.

Now the sun sets. Your battery takes over powering the loads all night. Next morning, the panels start producing again. If you have 100W of panels, and your inverter needs 50W to power the loads, the other 50W will go to the battery to charge it, until it is full again. All the time your loads are powered from the panels, not the battery - since that one is charging.

 

[corporal_Canada]

Thank you professor I think I learned all this in automobile mechanics school but if the charge control is sending wattage to the battery and i'm trying to pull from the battery at the same time wouldn't that just not work at all ??

 

[sunshine_eggo]

Thank you professor I think I learned all this in automobile mechanics school but if the charge control is sending wattage to the battery and i'm trying to pull from the battery at the same time wouldn't that just not work at all ??

Read this again. Hopefully, it will click:

You can't have electrons flowing in both directions at the same time. Yes, you can have a charger going and loads going at a the same time, but there's only flow in one direction.

If you are producing 10A of charge and have 8A of loads, the battery charges at 2A.

If you are producing 8A of charge and have 10A of loads, the battery discharges at 2A.

and going back to mechanics school...

The alternator produces 70A, but the car has 30A of 12V loads... so the battery charges at 40A.

 

[upnorthandpersonal]

but if the charge control is sending wattage to the battery and i'm trying to pull from the battery at the same time wouldn't that just not work at all ?

1: read @sunshine_eggo comment again

2: Think of it this way: your battery is a buffer. As long as your buffer is full, and there are no loads, no power is taken from it. You introduce your solar panels in full sun though your charge controller to this buffer. What happens? Nothing. Your buffer is full. Nothing else needs power. There is no current.

Now, you introduce a load (your inverter) which is connected at the same location where your charge controller and battery are. This load is less than what your panels in full sun can provide. What happens: your panels will provide exactly what your introduced load needs through your charge controller. No more, no less. Even if the panels could provide double: they won't, because nothing is drawing this power. Your buffer (battery) is still full and nothing happens.

Sun goes down. Now your buffer kicks in, providing the power your loads (inverter) needs.

Sun comes back up: your panels will provide whatever the load now is. What is the load in this case? The inverter of course, but also the battery (buffer) since it's not full anymore. Power now goes from your solar panels, through the charge controller, to both your battery and your inverter. How much to each? That depends. If your inverter load is small, more will go to your battery. If your inverter loads are high, it might be that the battery still needs to help out because the sun isn't shining fully on the panels just yet.

Point being, you don't 'send wattage' anywhere. A load will pull whatever it needs, no more, no less.

 

[corporal_Canada]

1: read @sunshine_eggo comment again

2: Think of it this way: your battery is a buffer. As long as your buffer is full, and there are no loads, no power is taken from it. You introduce your solar panels in full sun though your charge controller to this buffer. What happens? Nothing. Your buffer is full. Nothing else needs power. There is no current.

Now, you introduce a load (your inverter) which is connected at the same location where your charge controller and battery are. This load is less than what your panels in full sun can provide. What happens: your panels will provide exactly what your introduced load needs through your charge controller. No more, no less. Even if the panels could provide double: they won't, because nothing is drawing this power. Your buffer (battery) is still full and nothing happens.

Sun goes down. Now your buffer kicks in, providing the power your loads (inverter) needs.

Sun comes back up: your panels will provide whatever the load now is. What is the load in this case? The inverter of course, but also the battery (buffer) since it's not full anymore. Power now goes from your solar panels, through the charge controller, to both your battery and your inverter. How much to each? That depends. If your inverter load is small, more will go to your battery. If your inverter loads are high, it might be that the battery still needs to help out because the sun isn't shining fully on the panels just yet.

Point being, you don't 'send wattage' anywhere. A load will pull whatever it needs, no more, no less.

Okay, I think I somewhat understand, I was hoping to run my desktop PC 24/7 on the battery and solar panels alone and at some point upgrade to more batteries and power a 680 watt AC...at least during daytime hours

 

[OffGridForGood]

Say you have a hose running water into a bucket (incoming PV), and a tap in the side of the bucket letting water out (inverter running loads) the bucket is the battery:

if the hose runs faster than the tap, the bucket (battery) is filling.
if the hose runs slower than the tap, the bucket (battery) is emptying.

 

[corporal_Canada]

1: read @sunshine_eggo comment again

2: Think of it this way: your battery is a buffer. As long as your buffer is full, and there are no loads, no power is taken from it. You introduce your solar panels in full sun though your charge controller to this buffer. What happens? Nothing. Your buffer is full. Nothing else needs power. There is no current.

Now, you introduce a load (your inverter) which is connected at the same location where your charge controller and battery are. This load is less than what your panels in full sun can provide. What happens: your panels will provide exactly what your introduced load needs through your charge controller. No more, no less. Even if the panels could provide double: they won't, because nothing is drawing this power. Your buffer (battery) is still full and nothing happens.

Sun goes down. Now your buffer kicks in, providing the power your loads (inverter) needs.

Sun comes back up: your panels will provide whatever the load now is. What is the load in this case? The inverter of course, but also the battery (buffer) since it's not full anymore. Power now goes from your solar panels, through the charge controller, to both your battery and your inverter. How much to each? That depends. If your inverter load is small, more will go to your battery. If your inverter loads are high, it might be that the battery still needs to help out because the sun isn't shining fully on the panels just yet.

Point being, you don't 'send wattage' anywhere. A load will pull whatever it needs, no more, no less.

 

[corporal_Canada]

Okay, hopefully I fully get you now, the battery should be at full capacity before I attempt to use the inverter, I currently have 2x 300 watts panels and 1x100 watt panel all going into the input portion of the Chinese charge controller, the controller claims to be 20a.. I believe that means it can handle up to 2000 watt input

 

[sunshine_eggo]

Okay, hopefully I fully get you now,

Not quite.

the battery should be at full capacity before I attempt to use the inverter

Nope. You can use both at the same time. If you provide more charge than the inverter uses, the battery will charge. If you use more loads than the charger provides, the battery will discharge.

I currently have 2x 300 watts panels and 2x100 watt panel all going into the input portion of the Chinese charge controller, the controller claims to be 20a.. I believe that means it can handle up to 2000 watt input

Not even remotely close. 20A is OUTPUT. 14.4V charging * 20A = 288W MAX.

That's it. Never more. If it's a cheap PWM controller, you do not want to overpanel it.

Your 300W panels are likely crippled to ~150W each because they are unable to maintain their Vmp, but are forced to operate at battery voltage.