windmill / solar combination question.

[GeeMac]

I have a few solar panels and a small windmill. I run the solar panels through a charger to the batteries. As I understand it, the windmill should be connected directly to the batteries.  My question is: "Should there be a diode or some electrical component between the windmill and the charger to prevent windmill power from pushing backwards through the wires and damaging the charger?"

FYI this is not a very big system. 5 small panels and one small windmill.

Does the charger need some sort of protection from the windmill?

[asheets]

From what I've read on the board, the windmill should have a bridge or diode to keep it from sucking power from the batteries when below cut-in.

[GeeMac]

Yes, that is done - But when the mill cuts in, electricity goes to the battery bank. The charger from the panels feeds the battery bank too. The windmill wires meet the charger wires at the battery bank terminal. The solar panels feed the charger. Will windmill power damage the solar panel's charger?

[Flux]

What do you mean by a charger?  I assume it is a charge controller. Why would that charge controller know that something else is charging the battery.  No there is absolutely no need to add a diode, it will just think the battery is more charged than it can account for and regulate the solar accordingly if above its set point.

If you add a diode you will confuse its charge settings by a diode drop.

You may need a diversion controller directly across the battery if the wind alone can fully charge the battery.

Flux

[GeeMac]

Yes it is a charge controller. Thank you.  I'll connect the windmill to the batteries.

[Usman]

I have somewhat similar quest.

Likewise, I have two PMA Wind turbines as well as a solar array. A Diesel Gen as a backup to charge batteries directly, using a AC step-down converter & rectifier diode.

I am also curious to know how two such charging sources may efficiently work on side by side. There must be something out there as a 'separator', or there should be some consideration given to their connection into the battery pack that isolates them somehow.

Are there any instructions to be observed for that, or any kind of HW or 'seperator' available in the market?

Thanks, Usman.

[Flux]

The batteries will not be concerned about where the charge comes from, they will see the total charging current.

The only issue is with charge controllers. If you have solar controllers they will not be able to do anything about the wind turbines or any other charging source. Best way is one large dump controller capable of handling the total charge current.

A problem arises if the solar uses a mppt converter to maximise efficiency as these generally include charge control facilities. If you can set this above the dump controller you can let the dump controller look after the charging programme.

I would only regard the engine as back up. If there is no other charge available then you have to use it to fully charge but if there is wind or solar then use the engine to get you through the bulk charge and let the wind and/or solar do the final stage via the dump control.

I see no logic in running an engine generator and taking the final and slow part of the charging stage via a dump regulator, it is just wasting fuel.

Flux