Here is a response/review from a knowledgeable guy on amazon. I thought permies would want more info.
I do not own this product. I researched solar off grid systems for a while and while the components of this kit look nice and are easy to connect (it seems), you are paying double for the nice packaging.
This power pack is a 30 Amp battery with a small charge controller. You can buy a standard universal sealed 12v battery, 35amp for ~$80. add a charge controller (as big or small as you need) and some cables, and you are spending no more than $140. You will have the flexibility to choose any battery from small all the way to 250 amp (3000KWH) rather than buying several units and daisy chaining. and your components will be universal and not proprietary to a company that apparently has no support and may not be around next year.
So if you are a do it your self guy, remember amp x volt = watt. We are dealing with 12V so amp (or amp/h) x 12 = watt (watt/h).
Figure out how much
energy is needed to run your item(s) and how long you want to run them each day, you could then calculate the Wh or Ah you need per day, and based on that determine how many panels and batteries would be needed. If you have a laptop and a lantern using 50 watt and you will use them for 6 hours, 300 Wh or 25 Ah is all you need.
You will need these components:
- Battery to store power: The ampere hour (Ah) of a battery tells how much energy can be stored inside.
- Generate power to charge battery: AC adapter, DC (car) charger, Solar panels, wind turbine, etc. The number and size of solar panels will determine how fast you will charge your batteries. More panels/bigger means faster charging. Panels are usually sold by the watt. a 30 watt array will need 100 hours to charge a large 250 amp battery (at full sunlight). smaller battery will charge faster. Remember that the wattage of a panel is what it could generate under ideal conditions - full sunlight, clean panels, right angle toward the sun. If you want to account for less than ideal light, you will need more panels to compensate for reduced effectiveness to get tot he same wattage. To avoid over charging you will need a:
- Charge controller: between the panels and the batteries to prevent overcharging (1 amp for every 15 watts of panels to be safe).
- To use the power in the battery get a good: Inverter - it will convert the 12 volt power of the battery into 120 volt power to use. The size of the inverter determines how much power can be pulled from the battery at any one time. How long it will power your item(s) will depend on how much power is available in the batteries. Peak power means it could accomodate a power surge up to a peak of x watt fora few seconds - useful for devices that have a wattage spike when they start but consume less while running.
Top it off with the right cables, connectors, and a multi tester (to check loads and currents) and you've got a modular, universal system you can tailor to your needs for a fraction of the price, and repair or upgrade any time with any vendor's components.
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