bobc
10 kW
Hi, thought I'd share "what I've done" and what I'll do next.
A couple of years ago I bought 600W worth of cheap PV panels and bolted them to my south wall. I never intended to grid-tie & go for the feed-in-tariffs, this was always a standalone supply for my workshop. I was also given a load of old deep cycle SLAs. So I charge the SLAs direct from the solar and regulate by dumping spare electricity into resistors squeezed against my hot water tank. Until recently I only used the SLAs to supply LED lighting & a laptop in my workshop.
Last summer I switched off my gas supply, the water was hot enough to shower all summer.
This year I bought an emax scooter which I use for commuting. So I have to charge it overnight. The SLAs bridge this gap perfectly. But there's not any hot water any more..... And now winter is approaching, I don't get enough during the day to charge the scooter. BTW I just bulk charge the scooter using an ebay boost converter - this works great.
But - back to the plot - I need more juice from the PVs. So I'm going to make an MPPT converter. These are available for a few hundred quid (at the 600W level) but don't do quite what I want. This will net me 30 to 40% more power from the arrays. OK it won't run me through the depths of winter, but I won't want to use the scooter if it's so bad outside, and should get me hot water again in the summer!
I need to make a 50A, 25V buck converter, & I'll control it with one of the £1.50 arduino nano's
I'll document the converter on here in case anyone wants to re-create
A couple of years ago I bought 600W worth of cheap PV panels and bolted them to my south wall. I never intended to grid-tie & go for the feed-in-tariffs, this was always a standalone supply for my workshop. I was also given a load of old deep cycle SLAs. So I charge the SLAs direct from the solar and regulate by dumping spare electricity into resistors squeezed against my hot water tank. Until recently I only used the SLAs to supply LED lighting & a laptop in my workshop.
Last summer I switched off my gas supply, the water was hot enough to shower all summer.
This year I bought an emax scooter which I use for commuting. So I have to charge it overnight. The SLAs bridge this gap perfectly. But there's not any hot water any more..... And now winter is approaching, I don't get enough during the day to charge the scooter. BTW I just bulk charge the scooter using an ebay boost converter - this works great.
But - back to the plot - I need more juice from the PVs. So I'm going to make an MPPT converter. These are available for a few hundred quid (at the 600W level) but don't do quite what I want. This will net me 30 to 40% more power from the arrays. OK it won't run me through the depths of winter, but I won't want to use the scooter if it's so bad outside, and should get me hot water again in the summer!
I need to make a 50A, 25V buck converter, & I'll control it with one of the £1.50 arduino nano's
I'll document the converter on here in case anyone wants to re-create