diy solar

diy solar

Cannot understand this Chinese solar charge controller

@corporal_Canada

- It would be a good idea to start from the beginning: do a power audit (what are the exact power requirements, how long do each of those run per day, etc). This will give you an idea of how much solar and battery you're going to need.
- Batteries are currently dropping in price, solar panels are pretty cheap already, and there is no need to limit to 100W panels or anything. A decent charge controller (i.e., not PWM) is going to make a big difference.
- Don't buy anything yet: do the calculations (or learn how these work, understand them), make sure you know why you're going to make the decisions you're going to make.
- Baby steps

Comme on dit en français: petit à petit, l’oiseau fait son nid.
 
sunshine_eggo said:
Not quite.



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.



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.
Click to expand...
288 watts are going to the battery ? Holy Trudeau on fire batman, this will take forever
 
upnorthandpersonal said:
@corporal_Canada

- It would be a good idea to start from the beginning: do a power audit (what are the exact power requirements, how long do each of those run per day, etc). This will give you an idea of how much solar and battery you're going to need.
- Batteries are currently dropping in price, solar panels are pretty cheap already, and there is no need to limit to 100W panels or anything. A decent charge controller (i.e., not PWM) is going to make a big difference.
- Don't buy anything yet: do the calculations (or learn how these work, understand them), make sure you know why you're going to make the decisions you're going to make.
- Baby steps

Comme on dit en français: petit à petit, l’oiseau fait son nid.
Click to expand...
Let's see the desktop PC uses roughly 100 watts for the apu and the SSD although the PSU (power supply unit) is rated to go until 1000watts, don't know if that is a factor, the monitor draws 50-70 watts so if everything pulls 170 watts I should have power staying in the battery,



Nice try with the french though, all I caught was bird something
 
As useful as doing an audit of what you are currently using it can be just as important to do the reverse and calculate what sort of performance you can expect from a given system.
One of the most critical limits to understand is the amount of energy stored in your battery.
So for a 100 AH lead acid battery at 12V we have 12V * 100 AH (* 50% since we don't want to discharge the battery to dead) = 600 watt hours ...
So a 100 watt load could be powered for ~ 6hrs from a fully charged battery
Except the inverter may only be 85% efficient so really that would be an 85 watt load for 6 hrs.
O and the inverter pulls power from the DC side even when no power is being drawn from the AC outlet.
Even if that no load draw is 25 watts the inverter running with no load will drain the battery in 24 hrs.

To power a 170 watt load for 24 hrs we need.
170 * 24 /.85 = 4.8 KWh of usable battery capacity ... if we are using lead acid at 12V that translates to an 800 AH battery.

Here is one https://gb-battery.com/products/ols/products/6-85-13-sb-solar-battery-moduleOr multiple 6V batteries could be an option.
Trojan has a useful tool that takes makes it easy to get an idea of how much battery is required to do what you want to do.https://www.batterysizingcalculator.com/



Alternatively my low end laptop uses about 40 watts which would only require ~ 200 AH A chrome book or a tablet would require less. Finding a way to use less power is much cheaper as it allows you to get by with a smaller system.
There are ATX power supplies that can run directly from DC battery power which would allow you to run the PC without the AC inverter.
Having a 1000 watt inverter on a 100 AH battery pack is like a 1000 HP engine with a 1 liter gas tank.
The target market for these powerful 12V inverters is things like Semi trucks and RV's to provide AC power when the large engine is running
 
upnorthandpersonal said:
Well, you did mention in your fist post you were French Canadian, so I made an assumption ;)
Click to expand...
You failed to look up what language Quebec speaks today, it has been over 400 years since France colonized this province..so it has been bastardized by English all this time time, frankly, France hates us 🤪 but I am flattered by your attempt,
 
xjaw4 said:
As useful as doing an audit of what you are currently using it can be just as important to do the reverse and calculate what sort of performance you can expect from a given system.
One of the most critical limits to understand is the amount of energy stored in your battery.
So for a 100 AH lead acid battery at 12V we have 12V * 100 AH (* 50% since we don't want to discharge the battery to dead) = 600 watt hours ...
So a 100 watt load could be powered for ~ 6hrs from a fully charged battery
Except the inverter may only be 85% efficient so really that would be an 85 watt load for 6 hrs.
O and the inverter pulls power from the DC side even when no power is being drawn from the AC outlet.
Even if that no load draw is 25 watts the inverter running with no load will drain the battery in 24 hrs.

To power a 170 watt load for 24 hrs we need.
170 * 24 /.85 = 4.8 KWh of usable battery capacity ... if we are using lead acid at 12V that translates to an 800 AH battery.

Here is one https://gb-battery.com/products/ols/products/6-85-13-sb-solar-battery-moduleOr multiple 6V batteries could be an option.
Trojan has a useful tool that takes makes it easy to get an idea of how much battery is required to do what you want to do.https://www.batterysizingcalculator.com/



Alternatively my low end laptop uses about 40 watts which would only require ~ 200 AH A chrome book or a tablet would require less. Finding a way to use less power is much cheaper as it allows you to get by with a smaller system.
There are ATX power supplies that can run directly from DC battery power which would allow you to run the PC without the AC inverter.
Having a 1000 watt inverter on a 100 AH battery pack is like a 1000 HP engine with a 1 liter gas tank.
The target market for these powerful 12V inverters is things like Semi trucks and RV's to provide AC power when the large engine is running
Click to expand...
Okay, well at least I will get 6 hours of gameplay on my Philippines PC, which isn't so bad, maybe an additional solar panel that will bypass the charge controller ??? I wish I knew more about the 5$ controller.... But thanks to all of you for clearing all this up, maybe an additional battery ? By the way, what do you think would be the best way to link said battery ? Series or parallel ?
 
Tried using my "low end laptop" this morning, the inverter stayed on for roughly 1 hour before the red light came on... The laptop indicates 74watts on the block in the middle of the charger cable, although I hope it doesn't pull 74watts every hour..I'm thinking I will just wait till the battery is fully charged before attempting this again...
 
corporal_Canada said:
Okay, well at least I will get 6 hours of gameplay on my Philippines PC, which isn't so bad, maybe an additional solar panel that will bypass the charge controller ??? I wish I knew more about the 5$ controller.... But thanks to all of you for clearing all this up, maybe an additional battery ? By the way, what do you think would be the best way to link said battery ? Series or parallel ?
Click to expand...
Never bypass the charge controller!!!
Panels ALWAYS connect to a charge controller- never directly to a battery!!!

You can have as many charge controllers in parallel as you like (they only connect at the battery- NEVER on the solar side...)

Adding an additional battery is always done in parallel- that way the battery bank voltage stays the same- the capacity (in Ah) doubles with a second identical battery
Adding a second battery in series keeps the Ah the same, but doubles the voltage (ie new inverter etc required) in either case the storage in watthours remains the same- doubled
ie 2x 12v 100Ah batteries in parallel equals 2x(12v x 100Ah) = 2400Wh 'theory' capacity x 0.5 for lead/acid or 0.8 for LFP lithiums = 1200Wh of actual storage for L/A and 1920Wh for LFP at 12v nominal for the battery bank supply, while 2x 12v 100Ah batteries in series equals (2x 12v) x 100Ah =again 2400Wh of theory capacity and again 1200Wh for L/A or 1920Wh for LFP, but this time at 24v battery bank voltage...

So unless you replace your inverter etc, parallel a new battery, never series it!!!!

(mixing old and new batteries is never a good idea btw- as they age, batteries will decrease in capacity- so although both may have the same 'label' capacity, in practice the older one will be doing less of the work than the newer one... it is best to replace them as 'matched pairs')
(note also that LFP gives you about 30% more 'actual' storage than L/A for the same 'label Amp hours'... they cost about twice as much initially, but you get 30% more actual storage for the same Ah written on the case and a MUCH longer service life than a L/A- 3 to 5 times longer...)
 
Last edited:
corporal_Canada said:
Tried using my "low end laptop" this morning, the inverter stayed on for roughly 1 hour before the red light came on... The laptop indicates 74watts on the block in the middle of the charger cable, although I hope it doesn't pull 74watts every hour..I'm thinking I will just wait till the battery is fully charged before attempting this again...
Click to expand...
Your PSU is rated at 74W (maximum), the laptop will use less (it depends how much it actually uses on the load on the CPU, whether the laptops battery is being charged or not, brightness of the screen setting, etc, etc) so it will be anywhere UP to 74W...
(my gaming ASUS has a 290W PSU and actually gaming while charging the battery can use almost of that PSU's capacity- but just idling like it is atm just surfing the net- that drops back down to about 60W according to my meters)

What that means is that every hour of use, your laptop will be using UP TO 74 watthours per hour of use ie 1 hour of use is up to 74Wh, 2 hours of use is up to 148Wh, 4 hours of use is up to 296Wh- the exact usage isn't possible to tell without measuring it as it will vary depending on what you re doing etc...
 
Bop said:
Never bypass the charge controller!!!
Panels ALWAYS connect to a charge controller- never directly to a battery!!!

You can have as many charge controllers in parallel as you like (they only connect at the battery- NEVER on the solar side...)

Adding an additional battery is always done in parallel- that way the battery bank voltage stays the same- the capacity (in Ah) doubles with a second identical battery
Adding a second battery in series keeps the Ah the same, but doubles the voltage (ie new inverter etc required) in either case the storage in watthours remains the same- doubled
ie 2x 12v 100Ah batteries in parallel equals 2x(12v x 100Ah) = 2400Wh 'theory' capacity x 0.5 for lead/acid or 0.8 for LFP lithiums = 1200Wh of actual storage for L/A and 1920Wh for LFP at 12v nominal for the battery bank supply, while 2x 12v 100Ah batteries in series equals (2x 12v) x 100Ah =again 2400Wh of theory capacity and again 1200Wh for L/A or 1920Wh for LFP, but this time at 24v battery bank voltage...

So unless you replace your inverter etc, parallel a new battery, never series it!!!!

(mixing old and new batteries is never a good idea btw- as they age, batteries will decrease in capacity- so although both may have the same 'label' capacity, in practice the older one will be doing less of the work than the newer one... it is best to replace them as 'matched pairs')
(note also that LFP gives you about 30% more 'actual' storage than L/A for the same 'label Amp hours'... they cost about twice as much initially, but you get 30% more actual storage for the same Ah written on the case and a MUCH longer service life than a L/A- 3 to 5 times longer...)
Click to expand...
I'd rather stick to 12v and just double storage capacity, I could be wrong but 12v and 100ah is only 1200 watts, doubling that in umm parallel I think would bring it to 2400watts, and I could keep my crappy chinese inverter that claims to be sine wave...... but it does have 12v- 24v written on it
 
Bop said:
Your PSU is rated at 74W (maximum), the laptop will use less (it depends how much it actually uses on the load on the CPU, whether the laptops battery is being charged or not, brightness of the screen setting, etc, etc) so it will be anywhere UP to 74W...
(my gaming ASUS has a 290W PSU and actually gaming while charging the battery can use almost of that PSU's capacity- but just idling like it is atm just surfing the net- that drops back down to about 60W according to my meters)

What that means is that every hour of use, your laptop will be using UP TO 74 watthours per hour of use ie 1 hour of use is up to 74Wh, 2 hours of use is up to 148Wh, 4 hours of use is up to 296Wh- the exact usage isn't possible to tell without measuring it as it will vary depending on what you re doing etc...
Click to expand...
Yeah I was considering purchasing a wattmeter to visually see the watt consumption of everything, but it might actually be cheaper to keep using Philippines static filled primitive coal plant power ( I only get to say this because east Canada uses hydro power and I believe Toronto had 5 nuclear power plants) and driving through the prairies ( central Canada, I noticed a crap load of those wind power generators, which is something else I was hoping to apply to recharge the battery or someday "batteries" but maybe the charge controller wasn't a great idea to begin with, I don't care if the power going to the battery is regulated or perfect, as long as it gets there I honestly thought the controller would allow me to keep things powered and draw directly from the input power source (ie panels or wind power) and pull from the 12v battery if input was insufficient, but now I know better, I'm disappointed but I know better...
 
Yes- 12v only, 1000w- and it really doesn't matter if it is a modified square wave or not if the computers PSU is a switchmode (99.99999% likely) as a switchmode will run on practically anything (even DC lol)- in fact these days, about the only thing that needs pure sinewave is electric motors!

Doing things right will be cheaper in the long run than just randomly throwing things into the mix- start with the data needed (energy audit), then using those figures, work out the battery capacity and solar needed to do the job efficiently and cheaply while being sufficient to do it- doing otherwise will end up costing you a lot more and still might not do the job...

Other things to worry about is doing things correctly- things like those crocodile clips could cause you issues- if you have a dodgy contact using them (extremely likely this will happen sooner or later- especially as they age) with the charge controller could damage it or the inverter- good solid connections using proper battery clamps will prevent this, using fuses or DC circuit breakers is required for safety, the details matter...
 
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