Here's what other sites are saying:
Trickle, recharge, and maintain 12V batteries with the small and easy-to-use Goal Zero Guardian 12V Charge Controller. Simply connect the included alligator cable to your 12V battery to the Guardian 12V Charge Controller and then connect the Guardian 12V Charge Controller to a solar panel (Goal Zero Boulder 15 or Nomad 13) and place in the sun. This sweet setup will collect the sun's energy and trickle charge any 12V battery in motorcycles, snowmobiles, tractors, watercraft, trucks, RVs, cars, and much more.
The Goal Zero Guardian charge controller connects a solar panel and a 3rd party 12V lead-acid battery, to monitor the charging of the battery. Prolong the life of your 12V batteries and keep gear ready to go with the Guardian 12V charge controller. Perfect for motorcycles, snowmobiles, tractors, watercraft, RV's, lawnmowers, cars, etc.
The Guardian 12v Charge Controller from Goal Zero is designed to to keep batteries healthy and fully charged up. Harness the sun's energy with a solar panel such as the Boulder 15 or other Goal Zero rechargers, and use the power to start large equipment like a boat, RV, ATV, car, or mower when back-up energy is a necessity or when living off the grid is your way of life. Panel(s) not included.
- Mountain Gear
Goal Zero Guardian 12V Charge Controller FEATURES of the Goal Zero Guardian 12V Charge Controller Recharge and maintain 12V batteries Small and easy to use SPECIFICATIONS of the Goal Zero Guardian 12V Charge Controller Charging port (8.0mm): 15-20V, 0-6A (90W max) Charging port (4.7mm): 15-20V, 0-6A (90W max) Output: 12V Port (6.0mm), for Alligator Clips (90W max) 15-20V, 0-6A Charge Controller: Supports up to 90W of solar panels Weight: 0.2 lbs (0.09 kg) Weight with Alligator Clips: 0.4 lbs (0.18 kg) Dimensions: 5 x 2.5 x 1 in (12.7 x 6.4 x 2.5 cm) Optimal Operating Temp: 32-104 F (0-40 C) This product can only be shipped within the United States. Please don't hate us.
Goal Zero Sherpa 50 Recharger
$200 - $449
Goal Zero Guide 10 Plus Recharger
FlameStower Heat Charger
Goal Zero Venture 30 Recharger
Coleman 6V CPX Rechargeable Battery Pack with 12V and 120V Chargers
Brunton Resync 6000 Power Storage / Solar Charger
Brunton Revolt 4000 Portable