Hi everybody. I bought some used solar panmels. After I bought these, I just realized that these are 24 volt solar pannels, and I am building a 12volt solar system. Are these going to work with a 12 solar controler (not bought it yet)? Or am I gonna have to buy a special MPPT controler to work with my 24 volt solar pannels? Tks.
Hi. I bought some ''USED'' 24 volts solar pannels and I want to build a ...12 volt system.
- Thread starter Camginger
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HighTechLab
AKA Dexter - CTO of Current Connected, LLC
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Use an MPPT solar controller and they will work fine. MPPT controllers drop down the voltage and boost the current to the appropriate levels for battery charging.
No matter what panels you buy 12 or 24v, you will really want to go with a good quality MPPT - NEVER connect panels directly to the batteries unregulated.
No matter what panels you buy 12 or 24v, you will really want to go with a good quality MPPT - NEVER connect panels directly to the batteries unregulated.
I knew about not connecting it straight to the battery (or batteries) though. But I didn't have a clue about my 24v pannels hooked up on a 12v battery bank. I've already had a PWM solar controler, but it didn't look like it could manage my 24v solar pannels. So I'll get a good MPPT controler then. Tks for the info.
MichaelK
Solar Wizard
Just a bit of math to help you with your final decision. Let's assume these panels you've bought are 250W:30V each. You could wire both of them in series to deliver ~60V to your controller. What you need to know now is how many amps your controller is likely to output. The math is....
(250W X 2 panels)/12.5Vcharging = 40A.
In the real-world, you might never see more than 85-90% of paper specifications, so multiply that 40A by 85% to get 34A. 90% would be 36A. So, when shopping, get the 40A rated controller, and you will be good to go.
The Epever Tracer 4210AN is an economical MPPT controller that will fit your application. It's ~125$ on Ebay these days. I'd use 10 gauge copper wire from your array to the controller, and maybe 6 gauge from the controller to the batteries. Maybe start with 4 gauge if you think you might have future expansion.
BTW, if the paper specs on your panels are different (look on the back of the panels), just change my numbers in the formula to your numbers.
(250W X 2 panels)/12.5Vcharging = 40A.
In the real-world, you might never see more than 85-90% of paper specifications, so multiply that 40A by 85% to get 34A. 90% would be 36A. So, when shopping, get the 40A rated controller, and you will be good to go.
The Epever Tracer 4210AN is an economical MPPT controller that will fit your application. It's ~125$ on Ebay these days. I'd use 10 gauge copper wire from your array to the controller, and maybe 6 gauge from the controller to the batteries. Maybe start with 4 gauge if you think you might have future expansion.
BTW, if the paper specs on your panels are different (look on the back of the panels), just change my numbers in the formula to your numbers.
Rednecktek
Solar Wizard
The HQST controllers are very affordable and I've replaced all my EPEver's with them. That'd be another option as well.
8AWG wire from controller to battery will be fine, you'll never get a 4AWG into those screw terminals.
8AWG wire from controller to battery will be fine, you'll never get a 4AWG into those screw terminals.
offthetop04
New Member
Last edited:
littleharbor2
Solar Addict
So as not to muddy the water of the OP's thread you need to copy and paste this posting onto a new thread. That way your question will get it's own attention.
You're on the right track with your proposition.
You're on the right track with your proposition.
littleharbor2
Solar Addict
So as not to muddy the water of the OP's thread you need to copy and paste this posting onto a new thread. That way your question will get it's own attention.
You're on the right track with your proposition.
offthetop04
New Member
ok thank you, ill deleteit!!
