Just New - Charger Calculation - Need Help

[Mike90250]

12v is NOT reasonable. But maybe you have a really good reason to stay with it, instead of 24v (or 48V).

Without a tracker, you do not get 6 hours of good charging, 5 at the most. So you are harvesting 4,800Wh in 5hr. Your consumption is 3,780Wh I don't think this is a good match. Panels only produce 80% of their nameplate power in the field, yours maybe less in warm conditions.

And with a $78 controller, that may be a bad decision, for a possible 100 amp charge circuit.

[SunEagle]

12v is NOT reasonable. But maybe you have a really good reason to stay with it, instead of 24v (or 48V).

Without a tracker, you do not get 6 hours of good charging, 5 at the most. So you are harvesting 4,800Wh in 5hr. Your consumption is 3,780Wh I don't think this is a good match. Panels only produce 80% of their nameplate power in the field, yours maybe less in warm conditions.

And with a $78 controller, that may be a bad decision, for a possible 100 amp charge circuit.

I agree with you. His battery system should use at least 24volt and needs to be bigger around 800Ah ( 24v x 800Ah = 19.2kWh / 5 = 3840 Wh/day.

The bigger battery system would need more panel wattage (~ 1700W) and a good 80amp MPPT CC.

[curious_me]

Mike, SunEagle, Yes, I'm up to something with 12V. 12v Bright LED lights are rapidly becoming available in our place. 12 volts gadgets are also common around here so that's an addition which makes 12volts better for my purpose. Later on, I can replace LED Bulb with lower wattage but same brightness and wont need an inverter for it.
But then, I'm considering every possible scenario to which I can better make use of what resources can be easily obtained. I'm learning from all your responses in this forum and your suggestions are very much welcome and appreciated. It will be my best guide in weighing my options.

Also, with those computations I posted, I'm just wondering and very much curious about, perhaps you can correct my ignorance on this.

A. If the total daytime load is only = 367W per 1 hr
Also consider, this amount should still go down as the units are not running altogether at the same time.

B. Battery capacity for a 12 x 12v 600AH-10hr is 7200W/10hr = 720W per 1 hr

C. and Solar Panel of 12 x 100W is 1200W x .80 (this is the 80% you mentioned) = 960W per 1hr

Conclusion ABC: Won't the system handle that consumption consistently per hour during day time and still able to fully charge the battery prior to entering the night time consumption, in consideration that A is only around 50% of B and C is high enough to charge the battery or even take the A load by itself ?
--------------------------------------

Now, if we go for Night Time, 448W per 1 hr max consumption, this may also be less in some point where other devices are down as they don't run the same length of time.

D. max of 448W per 1 hr
E. battery is fully charged in consideration of conclusion ABC above.

Conclusion DE: Battery should still be able to handle the 448W max load specially that other devices will go off at certain time. Say 448W is approximately 60% of the 720W per 1hr (for 10 hrs battery type capacity). This should leave the battery at least 40-60% by morning.


Hope you didn't get confused with how I wrote all things here. I'm trying to know if the statistics I posted previously can actually handle it, as perhaps I can make it as my initial implementation and improve from there.

[SunEagle]

Mike, SunEagle, Yes, I'm up to something with 12V. 12v Bright LED lights are rapidly becoming available in our place. 12 volts gadgets are also common around here so that's an addition which makes 12volts better for my purpose. Later on, I can replace LED Bulb with lower wattage but same brightness and wont need an inverter for it.
But then, I'm considering every possible scenario to which I can better make use of what resources can be easily obtained. I'm learning from all your responses in this forum and your suggestions are very much welcome and appreciated. It will be my best guide in weighing my options.

Also, with those computations I posted, I'm just wondering and very much curious about, perhaps you can correct my ignorance on this.

A. If the total daytime load is only = 367W per 1 hr
Also consider, this amount should still go down as the units are not running altogether at the same time. No your daytime consumption is 2000wh

B. Battery capacity for a 12 x 12v 600AH-10hr is 7200W/10hr = 720W per 1 hr. You will never get the full output of that system with 12 batteries in parallel

C. and Solar Panel of 12 x 100W is 1200W x .80 (this is the 80% you mentioned) = 960W per 1hr You panels will produce close to nameplate wattage for only a few hours a day but not for 8 hours

Conclusion ABC: Won't the system handle that consumption consistently per hour during day time and still able to fully charge the battery prior to entering the night time consumption, in consideration that A is only around 50% of B and C is high enough to charge the battery or even take the A load by itself ? your math may work out for 1 hour a day but not for every hour during the day
--------------------------------------

Now, if we go for Night Time, 448W per 1 hr max consumption, this may also be less in some point where other devices are down as they don't run the same length of time.

D. max of 448W per 1 hr
E. battery is fully charged in consideration of conclusion ABC above.

Conclusion DE: Battery should still be able to handle the 448W max load specially that other devices will go off at certain time. Say 448W is approximately 60% of the 720W per 1hr (for 10 hrs battery type capacity). This should leave the battery at least 40-60% by morning.


Hope you didn't get confused with how I wrote all things here. I'm trying to know if the statistics I posted previously can actually handle it, as perhaps I can make it as my initial implementation and improve from there.

See my comments in Bold above.

All of your math is based on 1 hours increments which does not work out in real life.

If you have 12volt loads you can get a DC to DC converter and drop the battery voltage down to your 12volt load voltage. Going with a large 12volt battery system requires you to use very large wire due to the amperage being used. Low voltage = high amps, higher voltage = lower amps.