solar panel option?

Is it not true that some (or all) of the solar roofs only provide power to a ventilation system and not to the battery ?

 

^ My understanding is that this is true for the US spec models. I'm not excluding our beloved neighbors to the North, because I've seen subtle differences betwixt the two.

My understanding also is that the "solar" part of "solar" Priuses was somewhat problematic.

 

Any details on the 'problematic'? Mine's been trouble-free.

In my 2010, from the factory, it does only do ventilation to keep summer temps down. It's not just a gimmick, it's around a 60 watt panel, which is enough to run the HVAC blower strongly enough to noticeably help with the temperature when you get into a car parked in the sun. In the models that have it, they used a brushless HVAC blower motor so it could handle the extra runtime hours; the non-solar models have a conventional blower motor with brushes.

I recently did a mod that was successfully done by several people before me, to use the same solar panel to keep the 12 V battery charged. It was fairly easy and I am quite happy with it, and sorry I didn't do it four years ago. Under COVID driving conditions, it might be a more useful function than running the blower.

People who've done the same mod before have reported that in the summer the combined system still does useful ventilation; given the battery being well charged (as this setup tends to keep it), it isn't drawing much power, and the rest is still available for the blower.

 

I hope the design includes an isolation diode......to prevent the vent fan from running off the battery during times when there is little or no sun, causing the solar array to have no output.

 

get the 2015, great year for the engine.

 

The panel is about 22 volts nominal. So the factory ventilation circuit already includes a buck converter (part of the "solar ventilation ECU") by which it supplies the 12 volts to the blower. Anybody who has done the panel-to-battery mod has of course added another buck converter for that (some have spent more and bought an honest-to-Pete MPPT controller; I followed Michael Cline's example and used a cheap generic bucker). So there isn't really a path for the battery to go feeding the blower.

The buck converter I bought had pads for an output diode but none installed, and a jumper around it, so to use for a battery charge application it was necessary to cut the jumper and install the diode just to prevent a nighttime drain through the converter. But it took adding a bag of Schottky diodes for my order to hit the free-shipping threshold anyway.

 

So, what is a "buck converter" ?
In ten words or less, please.

 

Bucking makes higher volts lower by switch mode. Boosting opposite.

 

Chapman fit it in to 10 words, exactly.

For readers wanting a far more words and detail, try this:
Buck converter - Wikipedia