Not normal solar Question

[Rickety]

Hello all -

I need to pull 300 amps @ 12 VDC + or - 10%, 24 hours a day from a 12 VDC battery bank charged during the day by solar panels. I live in Southern Arizona, full sun 300 + or -, days a year.

I wanted to use less panels @ a higher voltage to acomplish this.

I need to connect to the gird to charge batteries encase of problem with the solar array or cloudy day.

I do not need to convert the 12 VDC into 120 VAC

The info I'm looking for is :

Solar controller ?
Solar Panel info and quantity ?
Battery Bank Size ?

Cost is not a concern

I hope I have posted this in the correct spot

-Rick

 

[MurphyGuy]

Why does it need to be 12 volts DC?

What are you actually doing with this power?

You're asking to build a solar system capable of producing 86 kWh's per day, about 1/2 of which will have to be stored in a battery for night use?

300 amps is a ridiculous amount of current... some-ting-wong.

 

[Rickety]

I use an HPLC machine to look at chemical samples taken from rare earth magnets and 1 of my machines uses high current 12VDC to wash the sample thru molecular sieve. It usually has to run for about 7 to 10 days straight.

Converting 240 VAC into 300A @ 12VDC is very expensive and creates a lot of heat. I'm trying to figure out if I can do it with solar and not create as much heat.

You're asking to build a solar system capable of producing 86 kWh's per day, about 1/2 of which will have to be stored in a battery for night use? YES

Can you help ?

 

[corn18]

I use an HPLC machine to look at chemical samples taken from rare earth magnets and 1 of my machines uses high current 12VDC to wash the sample thru molecular sieve. It usually has to run for about 7 to 10 days straight.

Converting 240 VAC into 300A @ 12VDC is very expensive and creates a lot of heat. I'm trying to figure out if I can do it with solar and not create as much heat.

You're asking to build a solar system capable of producing 86 kWh's per day, about 1/2 of which will have to be stored in a battery for night use? YES

Can you help ?

You need 86kWh a day for 7 to 10 days straight. Good thing money is no object.

And, no, I can't help other than to say batteries and solar are not going to work.

 

[soylentgreen]

Are you absolutely sure about that 12V @ 300amps? That's 3.6KW of power, and it seems to me that pushing that much power into the molecular sieve would cause it to boil and catch fire in a few minutes.

For example, on page 14 of this PDF for a HPLC device, it says the power requirement is 320VA which would be closer to 320 Watts, which at 12V would be about 30 amps, not 300. https://www.agilent.com/cs/library/usermanuals/Public/G1380-90000.pdf

 

[John Frum]

I need to pull 300 amps @ 12 VDC + or - 10%, 24 hours a day from a 12 VDC battery bank charged during the day by solar panels.

Small point but while the sun is shining the load will be serviced from the panels.
I do get your point though.
During that time you also need to replenish the batteries.
So lets say on winter solstice you have 4 hours of sun to work with.
I arbitrarily picked 4 hours just for sake of argument.

For 4 your your panels have to produce...
300 amps * 24 service hours / 4 solar hours = 1800 amps per solar hour

 

[John Frum]

Converting 240 VAC into 300A @ 12VDC is very expensive and creates a lot of heat. I'm trying to figure out if I can do it with solar and not create as much heat.

Converting voltage from a solar array to 12VDC is going to be similar efficiency.

 

[Rickety]

You need 86kWh a day for 7 to 10 days straight. Good thing money is no object.

And, no, I can't help other than to say batteries and solar are not going to work.

Thanks for honest answer corn.

 

[Rickety]

Are you absolutely sure about that 12V @ 300amps? That's 3.6KW of power, and it seems to me that pushing that much power into the molecular sieve would cause it to boil and catch fire in a few minutes.

For example, on page 14 of this PDF for a HPLC device, it says the power requirement is 320VA which would be closer to 320 Watts, which at 12V would be about 30 amps, not 300. https://www.agilent.com/cs/library/usermanuals/Public/G1380-90000.pdf

Im really just looking for an answer to the question. This is an piece of equipment I built, you will not find it on the web, and I am 100% sure I need 300A @ 12vdc. again, just looking for answer to the question

 

[Rickety]

Converting voltage from a solar array to 12VDC is going to be similar efficiency.

Thanks for your input

 

[rmaddy]

300A at 12V = 3600W. Doing that for 24 hours per day you use 86,400Wh/day. If you use LiFePO₄ you can use about 80% of the battery each day so that means you need a 108,000Wh battery bank. At 12V that's 9000Ah. If you bought 12V 300Ah batteries you would need 30 of them in parallel. That's probably $15,000-$30,000 for the batteries. Putting 30 batteries in parallel is probably going to be a giant pain and batteries are going to get out of balance regularly.

For solar, if you assume 4 solar hours in AZ this time of year, you would need 86,400Wh / 4 hours = 21,600W of solar to recharge the batteries each day. That's 54 400W panels, minimum. You'll actually need more because you won't get 100% out of the panels. A typical 400W panel is roughly 80" x 40". 60 of those would be roughly 1,333 square feet. At maybe $200 per panel you are looking at around $12,000 just for the panels.

I have no experience with anything anywhere near this large so I can't help with charge controllers.

Good luck.

 

[Rickety]

300A at 12V = 3600W. Doing that for 24 hours per day you use 86,400Wh/day. If you use LiFePO₄ you can use about 80% of the battery each day so that means you need a 108,000Wh battery bank. At 12V that's 9000Ah. If you bought 12V 300Ah batteries you would need 30 of them in parallel. That's probably $15,000-$30,000 for the batteries. Putting 30 batteries in parallel is probably going to be a giant pain and batteries are going to get out of balance regularly.

For solar, if you assume 4 solar hours in AZ this time of year, you would need 86,400Wh / 4 hours = 21,600W of solar to recharge the batteries each day. That's 54 400W panels, minimum. You'll actually need more because you won't get 100% out of the panels. A typical 400W panel is roughly 80" x 40". 60 of those would be roughly 1,333 square feet. At maybe $200 per panel you are looking at around $12,000 just for the panels.

I have no experience with anything anywhere near this large so I can't help with charge controllers.

Good luck.

THANK YOU SO MUCH FOR SIMPLY ANSWERING THE QUESTION ! You have been a tremendous help.