Hi I have a MP3720 12v charge controller. Running off ZM9093 solar panel. As soon as I attempt to put load on it(12 volt led tail light) I loose all power to light!

P/V=A

The panel is rated 6 watts at 12 volts 12 / 6 = 0.5 Amps

So in full sun the panel "should" produce 1/2 Amp at 12 Volts.

What type of 12V bulb and what is its current rating?

Solar panels are typically rated at .3 volts per cell. These cells are connected in series until they add up to 12 volts,24 volts or 36 volts depending on the solar system. The more cells you have the higher the charge rate of the batteries connected to the system. The DC voltage from the cells are used to charge the batteries then the voltage from the batteries is used to drive a DC to AC- convertor which is the power used by your home. The more cells connected the quicker it will charge the batteries and the more batteries connected the more power the solar system can provide.

Solar Panel Charge ControllerMCM Part 28 11138Velleman SA Part SOL4UCN2

This is a small charger mostly for small batteries and devices. It puts out max of 4 amps. What type of 12 v battery are you trying to charge?

I also have this problem, can you please explain how to reset the controller?

That's an issue with the inexpensive charge controllers that is known. The internal voltage regulator and pulse width modulator isn't performing correctly and interpreting the power from the panel. I recommend you look at getting an AIMS Power charge controller. Their 30A model is flawless.

Your calculations is correct - 220 X 0.7 = 154 watts.
If your fridge only runs on 220 volts then you need solar panels that charge 12 volt lead acid batteries and then use a inverter to convert 12 volts DC to 220 volts AC.

If you connect to solar panel for the lights to go on do the lights go out at night? If so, and the they do not light when hooked to the batteries then the batteries may have no charge and may also not be holding a charge. Put in new batteries to test.

I think he cost of the panel and breakers would be the cheapest thing on your list. Your 4100 watt genny is tiny for a whole house, and if you are planning on a solar set up, you will need to convert to dc, so, I take it your 4100 genny is used to charge the battery bank? Then the panel will not need to be anything but a small disconnect for the genny, basically one of those things that prevents the current from flowing back into the source, which you don't have. I would talk to the building dept., they may not want to take liability, and make you get a contractor to figure something out. All your appliances, and lights will be 12 volt, most motors are 12 volt anyway, they are just transformed to 12 volt from 110 current, and I don't think you will need breakers for 12 volt stuff. You could look at some camper supplies, boat stuff, they all run 12 volt appliances, and lights.

Because inverters operate from a DC (Direct Current) power source, usually a battery bank (one or more batteries), the battery source will have to be recharged at some point. (Remember that a battery discharged more than 50% is probably close to being dead.) Most cars and trucks recharge their batteries from an onboard alternator. Depending on the inverter load and runtime required, most power use applications will be covered by the charged battery, augmented by the operating alternator supplying a continuous charge to the battery. If the load is large (air conditioner, large draw power tools, large microwave, food freezer, ice cream machine, etc.), the user should verify that the installed vehicle alternator is of large enough capacity to operate the vehicle's power requirement as well as to fulfill the capacity of the inverter load. If it’s not, a motor throttle installation may be required to carry a small load, a larger alternator may be required, or a larger alternator, battery isolator and additional onboard battery bank may be required in order to meet the power requirement of the large load. Remember: it takes 12 DC Amps (at 12 VDC) to run 1 AC Amp (at 120 VAC single-phase) of power because there are voltage and efficiency factors to take into consideration.