Solar MPPT

jlinstrom · 08-18-09, 02:32 PM

Solar arrays have a power curve with a maximum power point and the device that sets this point is called a Maximum Power Point Tracker. It's the electrical equivalent of a variable speed transmission - it's got nothing to do with pointing the array at the sun, strictly electrical charging.
Many places sell MPPTs, I've built some using a circuit idea from EDN, Dec 5, 2008. It's the cheapest, most foolproof I've found, but you have to be (or know) a EE who can help with component values. As time and work permits, I want to design an MPPT circuit board to handle charging 12V batteries at say 5-10 Amps and make the circuit boards available to the 'solar public'.

2 things -
an MPPT is NOT a diverter (which shuts off charge power when it's had enough).
this circuit is adaptable so, for instance, a 6V array can charge a 12V battery -it all depends on the charging IC.

Befriend a geek, ask them.
johnl

08-18-09, 02:32 PM	#1
jlinstrom harried homeowner Join Date: Aug 2009 Location: Montana Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts	Solar MPPT Solar arrays have a power curve with a maximum power point and the device that sets this point is called a Maximum Power Point Tracker. It's the electrical equivalent of a variable speed transmission - it's got nothing to do with pointing the array at the sun, strictly electrical charging. Many places sell MPPTs, I've built some using a circuit idea from EDN, Dec 5, 2008. It's the cheapest, most foolproof I've found, but you have to be (or know) a EE who can help with component values. As time and work permits, I want to design an MPPT circuit board to handle charging 12V batteries at say 5-10 Amps and make the circuit boards available to the 'solar public'. 2 things - an MPPT is NOT a diverter (which shuts off charge power when it's had enough). this circuit is adaptable so, for instance, a 6V array can charge a 12V battery -it all depends on the charging IC. Befriend a geek, ask them. johnl