What do we do with power at 10V from a genny on a 12V system or 20V on a 24V system Etc..?
Why waste it if you get enough to use. Every system is different but heres an idea to use it if you have low volts often enough. For big systems this may not work well or need modified, for small or medium size it should work well, and great for small hobby or experiment size.
Maybe something like this been suggested before?
Basically just run some small devices that work at random volts directly from the genny. Adjust as needed for your systems volt/amp outputs.
When I fly a low power wind genny or at times of low winds for long periods I will connect a 12V fan direct to the wind genny DC lines without batteries. When the wind blows the fan runs, slow at low volts and faster at higher volts.
I don't remember for sure the numbers on fans volts, amps, watts for various fans. I think some of mine start up around 2V or a bit more actaully. Don't remember on computer fans and I have various sizes and types so that could vary also which ones tested.
I am sure the car type about 6" ones startup about 2V, those $8-$10 ones that plug into the cigarette lighter socket. I have a few of those types and often wire one or more directly to the wind gennies DC, no battieres, when I fly a low power genny or low winds for lond periods. It's neat to look at the fan and tell what the genny is doing. If fan barely turns I am getting low volts but the genny is turning. Fan revs up when wind gets the genny running good and I am getting more volts from it. As long as the genny cannot over power it and fry the fan it works good for me. I don't know what volts it would take to fry one of the auto type, I haven't yet. When the fan sounds like a jet I have put about 20V to it for short periods just fine.
I have fried computer types though. I'll be trying some auto radiator fans this year, try to get away from all the 120Vac fans I use now.
It's like a part time fan only working when the wind is blowing, but no real losses. Actually since it runs far below battery charging volts I use allot of power I would not have got if just charging. Of course at startup volts around 2V it's not turning fast enough to really do much, about 6V is nice. I think once it gets started about 2V it still turns down to about 1V or 1.5V. For an extra fan for random use just to move more air when it works I like it. It does not use any power when wind is not blowing, it just doesn't run.
I sometimes use a car type 12V relay with a fan like this.
When the genny puts out enough volts the relay triggers and batteries charge plus hold the volts down to 12V so fan does not over power and fry. Using a resistor or such so that the relay triggers about 14v the fan would run full speed still from the genny power while batteries charge. Anytime there is 2V but less than 14V comming from the genny then the fan would run using what power it can get. So basically 10V from any genny gets used even though it's below charging volts so it's not wasted. I need the fans anyway! Also the fan is not draining batteries when power is not being made to charge them, the relay cuts out the batteries when below 14V or so. Since I always have fans running anyway this works very well having the extra ones whenever they do run. I am either moving hot air or cool air with fans all year.
I can think of allot of uses for this. Venting a moist area like a crawl space, just move extra air in a hot house, venting a shed, reducing heat in a motorhome in summer, etc.. Stuff the fan would be good for but not required all the time.
Many items other than fans could be used same way. Maybe small lights for low heat?
For a small wind genny on a motorhome for example, durring summer use that below charging volt power to run a vent fan to get rid of excess heat anytime 2V-10V is being made, no drain on batteries when no wind. That could make a much cooler camper when you come back at night and save power later when you actaully need to cool it.
Durring winter maybe use lights or such to heat a small tank of water anytime low volts are available, not alot of heat maybe but a few degrees warmer could save on other heating a bit. Small light under a brooder could keep baby chicks warm and prevent main heater from turning on as often, save other power?
I mostly do this with small 12V gennies, but it could be done with any setup just change to your system requirements, 24V 48V, etc..
For those projects that do not turn out just right, use that 8-10V max same way. I did that too.
I have found I have allot of power at times to be used direct like this that is below charging volts, and that saves me battery power later.