Hi,
I've recently been asked to help out in an artwork installation using solar powered LEDs.
We want to have a set of self enclosed (no interwiring) units consisting of a battery, solar cell or array and a single 350ma (1W) LED to operate for 6-8 hours at full brightness per night and a contingency for 2-3 nights capacity on rainy days.
I'm capable of specifying the battery size, cell size and MPPT controller working out the maH needed. However I'd like to design a MPPT to reduce cost as off the shelf solutions meeting the specs are a little too capable and expensive.
Maintenance and battery replacement are to be as low as possible....I'm looking at SLA or gel batteries. If anyone has other advice....please advise.
From what I gather a MPPT will track the PV voltage and current and the battery voltage and current, then using a switch mode DC-DC converter adjust the battery charge voltage to maximise the charge current. In essence its a variable DC-DC converter. As we need to roll in a fixed ON time, I'm expecting to use a small micro with a fast PWM to the DC-DC converter.
Can anyone provide a link or advice on designing MPPT controllers. Perhaps a reference design or theory link? Any specifically designed chips for this application?
Thanks
Phil
I've recently been asked to help out in an artwork installation using solar powered LEDs.
We want to have a set of self enclosed (no interwiring) units consisting of a battery, solar cell or array and a single 350ma (1W) LED to operate for 6-8 hours at full brightness per night and a contingency for 2-3 nights capacity on rainy days.
I'm capable of specifying the battery size, cell size and MPPT controller working out the maH needed. However I'd like to design a MPPT to reduce cost as off the shelf solutions meeting the specs are a little too capable and expensive.
Maintenance and battery replacement are to be as low as possible....I'm looking at SLA or gel batteries. If anyone has other advice....please advise.
From what I gather a MPPT will track the PV voltage and current and the battery voltage and current, then using a switch mode DC-DC converter adjust the battery charge voltage to maximise the charge current. In essence its a variable DC-DC converter. As we need to roll in a fixed ON time, I'm expecting to use a small micro with a fast PWM to the DC-DC converter.
Can anyone provide a link or advice on designing MPPT controllers. Perhaps a reference design or theory link? Any specifically designed chips for this application?
Thanks
Phil