Off Grid Home Forums Technical Discussion Need Help – Solar Powered Fan Re: Need Help – Solar Powered Fan


If you are talking about SLA (sealed lead-acid) batteries, then this is sort-of correct.

Photo Voltaic Arrays (PVA) don’t behave the same way. They convert the energy in light into current flow. As long as there is light there is current flow. Batteries, on the other hand, convert a fixed amount of chemical energy into electrical energy. When the chemicals are gone so is the energy. If the energy draw is too much, the battery can suffer a pole-reversal from negative to positive. Rechargable batteries have the ability to convert the low potential energy chemical matrix into a high potential energy state through the addition of current. They have a limited number and range of this chemical reaction which sets the life of the battery.

PVA’s don’t work this way. They take the energy from the sun and convert it into current flow. They don’t use chemical conversions and so, don’t suffer chemical breakdown like batteries. They are a source of energy to the battery array.

Without any actual values, the words can sound scary but when the terms of the test are known, the claims lose their power.

For this situation to occur, the battery chain must start fully charged, be used constantly until dead, then recharged fully, then used constantly until dead, ad infinitum. The real world is rarely like that. Every time the circuit is opened, the batteries create a gentle recharging effect that tends to even out the load to all the batteries. In addition, the recharging circuits in PVA’s control current flow to prevent overcharge and to deal with potential pole-reversal.

A case of apples and oranges.