Ok, so I have been getting into the energy market the last couple of months and desided to start of with something simple: a PWM solar regulator. BUT I always strive to simplify designs, make new designs and/or make designs more cost effective to manufacture.
The most commonly used nominal voltage systems for solar power systems using batteries are 12V, 24V and 48V. However here in South Africa there are a couple of systems running 36V. So the challenge was to get one design that could catter for all nominal volatges: 12V, 24V, 36V and 48V. Each of these have differnt start/end of charge and load connect/disconnect limits as can be
seen here.
One of the biggest brain wraps was to overcome heat dissipation due to resistance of the tracks and components caring currents of up to 30A
(like in the case of the WRND WSR30A). In part a combination of thicker copper clad used for the PCBs and careful component sellection helped alot. Still, having a unit run at 48V and 30A will cause it to heat up so any saving will help. For this reason the 30A unit is reenforced with copper wire. As can be seen here:
Another issue due to heat was the heat dissipation in the linear regulator supplying the mcu and other drive electronics with power. If a 48V system is fully charged it is close to 60V. 15mA at 60V gives: .015 x 60 = 0.9W - this is to much given that the temperature in side the unit will be somewhat higher than the outside temperature. A very unique design using discreet components solved this problem.
Enjoy, and if you have any other questions please visit my website
www.WRND.co.za first or ask below.
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