I just recieved a Harbor Freight generator with an 800/900 max watt capacity as a gift. I want to use it to power a 29 foot travel trailer (lights, microwave, tv, fridge, radio). I will be living in it so I want a way to give it power 24/7. I know this generater is not big enough to do that, but could I possibly charge 2-4 deep cell batteries to do the trick? I don't know much about this, so any help would be greatly appreciated. Thanks a lot.
I fear that the generator is absurdly small for what you want to do, especially if you look at the noise, running time and normal usage conditions. In particular the fridge is going to cause problems as it needs to have power all the time. With considerable care in selection for low wattage and in what you have on at any one time, you can probably make do, but many microwaves will use up all the power the generator puts out. Using CF bulbs will give you a lot more light per watt. The batteries will give you the blessing of silence, but you are only going to be able to about 19 Kwh per day out of the constantly running generator so the batteries can only be charged when you are using less. Exactly how you manage the load will be interesting. You will need an inverter to get power off the batteries to 120 AC, a regulator and charger that interact to get the generator 120 AC down to battery voltage, and meters or reference notes as to what you are using.
400w isn't all that much! Most high-end computers use about that. A fridge uses anywhere from 900-2.1kw/hrs Which is way more than your 400w windmill can provide. Combine that windmill with a power storage center and you should be able to run a full fridge off of it As fridges are only on for about 10m out of every hour (but draw way more than 400w while they're on).
Harbor Freight 800 Watt Generator
Assuming this generator outputs 120 VAC, then get a battery charger rated at that voltage and 800 watts, and use that to charge the batteries. At 12 volts, that is about 60 amps, so it will charge a typical 12 volt battery quickly. Probably too quickly, be sure the charger can be set to the correct charge rate for the batteries you will be using, and has circuitry that will detect a full charge and taper the charge down to the proper value. But you will need a lot of expensive batteries. If your drain is more than 800 watts, say 2000 watts, and you want your batteries to last for, say, 10 hours, that is 20000 watt-hours. dividing by 12, that is (with losses) about 2000 amp-hours, which is a bank of 20 large batteries. But charging batteries in general does not help unless you are counting on charging them at night, say, when your drain is low and letting them supply the extra power during the day. This means you will need an inverter and a way to synchronize the inverter with the generator output. In practice that is not possible, so you will have to split your loads and rewire to accomodate that. Altogether, a mess. .
