PV input consolidator

[joesmith123]

I do notice that:

If there is intense PV and I have the generator on (prius), it still makes the prius work for whatever reason

Meaning: Even if its pulling 1.5 Kw from the solar panels, I still notice the prius running

Then I'll turn the prius off, and check the PV input watts, and it'll says 1.2-1.5 kilawatts

Where is that electricity going that is generated from PV?

I do plan on eliminating the prius altogether once the system is big enough and can go through days without extra generated power

But from what I can tell, one needs a massive amount of panels and massive storage battery bank

In the video of scrolling though the menu, all thats on is a fridge and a window unit, and those are taking about 1 kilawatt

 

[joesmith123]

Actual numbers of solar panels are always less than advertised

My situation:
18 panels pulling in 1.5 kw in hardcore sun
1.5kw/18=83 watts

That means that an advertised 10k watt system will be around 5900 watts

It’s fine, I’m not complaining, I expect that

Lesson: build the system for double what you actually think you need

 

[Hedges]

Steel bar - is that your busbar? Resistance is about 10x copper (look it up), so equivalent to copper wire with 1/10th the cross section.

 

[joesmith123]

Steel bar - is that your busbar? Resistance is about 10x copper (look it up), so equivalent to copper wire with 1/10th the cross section.

Yes, I tried getting a copper from home depot, they didnt have it, probably because copper went up

 

[Hedges]

1" x 1/8" steel, similar in resistance to 10 awg copper.

Wire gauge size chart | AWG table

American wire gauge size calculator and chart.

www.rapidtables.com

It should work for modest load, but won't do a great job balancing current. Connect cables to diagonally opposite corners of the battery array, though that is only perfect for 2p not 3p configuration. (that does put the current of two batteries through the busbar cross section rather than just current of one battery, but doing it for balancing purposes.)

Since you're experimenting, measure voltage drop from terminals of one battery to the next at high current. If current is known you can calculate resistance. measure voltage across each battery string and compare.

Aluminum is much closer to conductivity of copper and cheaper, not sure how it will perform around battery acid.

Copper pipe can be beaten flat and used for busbar. Maybe not the alloy normally used for electrical, but far better than steel.

is it saying that PV input is 174, and its bringing in 1.44 kilawatts, do I have that right?

From 18 solar panels, is that pretty good?

Depends on rating of PV panels. What percentage of STC wattage is that?

1440W / 48V = 30A
FLA likes about 0.12C charge rate
30A / 0.12 = 250Ah battery capacity would be properly charged
250 Ah / 3 strings = 83A per series string.

That would be a decent charge rate if the batteries are 80 Ah. Which they might be; is "reserve capacity" (minutes at 25A draw) specified?
But for periodic equalization charge, higher current may be required. You might accomplish that with 2 strings disconnected so 0.36C available for one string.

 

[joesmith123]

1" x 1/8" steel, similar in resistance to 10 awg copper.

Wire gauge size chart | AWG table

American wire gauge size calculator and chart.

www.rapidtables.com

It should work for modest load, but won't do a great job balancing current. Connect cables to diagonally opposite corners of the battery array, though that is only perfect for 2p not 3p configuration. (that does put the current of two batteries through the busbar cross section rather than just current of one battery, but doing it for balancing purposes.)

Since you're experimenting, measure voltage drop from terminals of one battery to the next at high current. If current is known you can calculate resistance. measure voltage across each battery string and compare.

Aluminum is much closer to conductivity of copper and cheaper, not sure how it will perform around battery acid.

Copper pipe can be beaten flat and used for busbar. Maybe not the alloy normally used for electrical, but far better than steel.



Depends on rating of PV panels. What percentage of STC wattage is that?

1440W / 48V = 30A
FLA likes about 0.12C charge rate
30A / 0.12 = 250Ah battery capacity would be properly charged
250 Ah / 3 strings = 83A per series string.

That would be a decent charge rate if the batteries are 80 Ah. Which they might be; is "reserve capacity" (minutes at 25A draw) specified?
But for periodic equalization charge, higher current may be required. You might accomplish that with 2 strings disconnected so 0.36C available for one string.

Yes OK I am studying your response

Idea about beating copper pipe flat, yes that is very smart

It is successfully running without the the need of generator, all through the night, those 12 batteries are good enough to run AC and a fridge until the sun comes back

Right now: its pulling 1.65 KW

Its honestly a gift from nature, a burden lifted off my back

 

[Hedges]

Measure voltage in the morning, maybe also specific gravity.
A starter battery would perform fine down to low SoC, but only a few times.

Measure/calculate watt hours draw, determine what SoC that would be. 1.65 kW, does it cycle on and off?
In a 12 hour night, if always on that would be 19.8kWh. If your batteries are 80 Ah, your bank is 11.5kWh.

Well, maybe more like twice that? But would still be very deeply discharged, quickly killed.
Here's an automotive sized battery that is 160 minutes reserve capacity, / 60 minutes per hour x 25A draw = 67 Ah capacity.

Advance Auto Parts - Down for Maintenance

Your batteries would give best service for brief heavy loads, followed by recharge.

My system has AGM. I would like a lithium battery which cycles while keeping AGM at float. That would provide surge, and AGM could be drawn down when power from lithium didn't come fast enough, then would recharge. You could do that with lithium feeding PV input of an inverter, as you did with Prius and car batteries.