Is my setup safe? I'm connecting two 7.2v 100ma solar panels in parallel using two 1N5817 then to a to 6v lead acid battery with a Constant Voltage Charge of 7.3-7.4v for cycle use.I can't use a MPPT or PWM solar charge controller do partly do to lack of space and partly because it with be in a water tight box with no ventilation.
From what I understand my setup is safe. I have never seen my panel ever have an open circuit voltage greater then 7.2v which is 0.2v less then max Constant Voltage Charge for cycle use, so I don't see how I could ever over charge the battery.
But, I understand my battery will only ever charge at peak sunlight when the panel voltage is greater or equal to the current battery voltage plus the schottky forward voltage drop. So, a charge controller would capture more energy but in no way do I see it being dangerous without one.
Valve Regulated Lead Acids Do Not emit harmful gas when charged correctly. Otherwise, the SLAs in Uninterrupted Power Supply found under desks in offices would be very bad. Though they will emit harmful gas if the internal pressure is too high, But this is prevent explosions & fire caused by improper charging or sudden failure like a short circuit.
I'll be happy to hear why I'm wrong. @Sparky256 @HeneryCurn @luckybot
No, you must have some sort of charge regulator.
e.g TL431 shunt regulator straight across the solar panels
see figure 30, http://www.ti.com/lit/ds/symlink/tl432b.pdf#page=26