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nexsuperne · 04-21-14, 01:12 AM

Is your solar controller an MPPT version? These convert higher voltage input to lower output voltage, but with more amps, which is very useful for charging batteries. Your 100 watt panels make 100 watts at 17 volts, but a fully charged 12 volt battery is only 14.5 volts (float at 13.8v), so, at 14.5 volts x 5 amps (your panels maximum current), your only putting roughly 72 watts out. An MPPT on ebay like this 30A MPPT Solar Panel Regulator Battery Charger Controller 12V/24V With LCD USB | eBay is well worth the cost. I have 1920 watts of solar, with a peak output of 60 volts at 32 amps, charging my 48 volt system. The controller uses the maximum panel voltage (74 volts) to charge the batteries at a much higher current than without. My WattsUp meter has recorded a 28% increase in power extracted. Well worth the money.

04-21-14, 01:12 AM	#13
nexsuperne Helper EcoRenovator Join Date: Feb 2012 Location: 30 miles east of London, UK Posts: 88 Thanks: 12 Thanked 19 Times in 18 Posts	Is your solar controller an MPPT version? These convert higher voltage input to lower output voltage, but with more amps, which is very useful for charging batteries. Your 100 watt panels make 100 watts at 17 volts, but a fully charged 12 volt battery is only 14.5 volts (float at 13.8v), so, at 14.5 volts x 5 amps (your panels maximum current), your only putting roughly 72 watts out. An MPPT on ebay like this 30A MPPT Solar Panel Regulator Battery Charger Controller 12V/24V With LCD USB \| eBay is well worth the cost. I have 1920 watts of solar, with a peak output of 60 volts at 32 amps, charging my 48 volt system. The controller uses the maximum panel voltage (74 volts) to charge the batteries at a much higher current than without. My WattsUp meter has recorded a 28% increase in power extracted. Well worth the money.