power supply system by EFOY for RVs using fuel cells. In response to a comment on the post by "Steve" I emailed the company for their explanation. Below is their un-edited response.
"Fuel cell vs. generator – the things you should know. The EFOY fuel cell is an off grid power generator, just like a classical generator – however, to find out which one fits one’s individual needs best, it is important to understand the differences and technologies.
"Both off-grid power sources require the presence of a battery. Of course you can plug in your devices directly into a Honda generator to power them – however, you also have to live with the noise, because the generator will run the whole time, while you use your device.
"Using a battery and an inverter is the smarter off-grid power option for both generators: the generator will recharge the battery and you can run your devices off-grid from the battery, just like you would run them at home or in your RV on a campground at the grid.
"The difference starts here: If you use a generator to recharge your battery, you will have to connect the generator to the battery, start it and live with the noise, until the battery is full. Many people hate this option so much that they prefer to drive the RV around for recharging the battery. Both options are not very environmentally friendly.
"The EFOY fuel cell generator is different. It is installed in the RV and always connected to the battery. The best about it: it operates fully automatically. The fuel cell constantly checks the battery charge state. When it drops below a certain predefined level, the fuel cell will switch on automatically and recharge the battery. When the battery is full, the fuel cell just as automatically returns into standby. The power generation process is silent, produces no harmful emissions and is permitted even in nature reserves and protected areas.
"Another thing you should know is the amount of power available from the two generators. Yes, the Honda will produce much more power than the fuel cell per time unit. However, that is not what counts. What counts is the amount of power you can get out of either source in the course of a day.
"To get power out of the Honda you have to switch it on and run it. In addition to power it will also produce noise and emissions. Most people do not want to have that around them the whole day. Therefore they run the Honda only when they require power. If you recharge a battery with it, that will take longer, as the battery can only take in a defined amount of power per time unit – much less than the Honda can produce.
"The EFOY fuel cell on the other hand is designed to work harmoniously with the battery. It will continuously recharge the battery when it gets empty, and you can easily calculate how much energy it will pump into your battery: just multiply the EFOY’s nominal output (90 W for the EFOY 2200) with 24 h and you have the charging capacity per day: 2200 Wh or 180 Ah.
"That is enough to operate the devices on board of most RVs, like lamps, fridge, TV, satellite dish etc. It will not be sufficient to power an air conditioner all day long, but you can operate it for the hot hours of the day. The EFOY energy calculator on SFC’s homepage helps you find out, what power generation method is suitable for your RVs individual power requirements."
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