RKDowner
New Member
I'm installing solar on my travel trailer and I'm on a low budget. I'm not trying to run A/C or anything stupid, I know my batteries won't do anything on solar they can't do on a generator, I'm just trying to make less noise and leave the generator at home. LiFePO4 batteries are expensive and I'd need to replace the factory power converter/distribution panel with one that can charge Lithium, thus I'm sticking with the existing lead-acid batteries. To save money I bought some used panels and they're rated at 16.1 volts with open circuit at 20.1 volts. As near as I can tell (PLEASE correct me if I'm wrong) 16.1 volts is not enough for MPPT, so I would put them in series for 32.2 volts. But 32.2 volts on PWM would be wasteful, so for that I'd connect them in parallel.
So those are my options: 32.2v MPPT or 16.1v PWM on 12 volt lead-acid batteries. The https://www.renewablewise.com/pwm-charge-controller-calculator/ tells me I need a 60 amp PWM controller, and the https://www.renewablewise.com/mppt-calculator/ tells me I'd need an 80 amp MPPT controller. So I'm looking at about $60 vs $360, depending on who you believe (I've seen "MPPT" controllers for as little as $15). I've already spent more on this project than my better half would like, so is MPPT worth the extra money? If you were in my shoes, what would you do? I'd appreciate any advice and opinions, thanks.
So those are my options: 32.2v MPPT or 16.1v PWM on 12 volt lead-acid batteries. The https://www.renewablewise.com/pwm-charge-controller-calculator/ tells me I need a 60 amp PWM controller, and the https://www.renewablewise.com/mppt-calculator/ tells me I'd need an 80 amp MPPT controller. So I'm looking at about $60 vs $360, depending on who you believe (I've seen "MPPT" controllers for as little as $15). I've already spent more on this project than my better half would like, so is MPPT worth the extra money? If you were in my shoes, what would you do? I'd appreciate any advice and opinions, thanks.
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