Battery Tender 021-1162 Solar Panel Charger Controller

This has a very specific purpose. I've used solar battery chargers before that you plug into your 12V power source or directly to your battery. They haven't worked. Taking that same solar panel and plugging it into this worked. One of the key things I learned (the hard way) is that the solar panels I had did not use the Red is + standard. This unit has protection against getting your wires backwards. The power LED helped me figure that out. Once I got my wiring right this thing just worked.

We use it on a static engine battery with a solar cell - works well

Easy to install does a great job

Needed to keep my Harley on a battery tender over the winter. Hooked this unit to my existing solar panel setup and it worked perfectly

I've used it for 7 months now to charge alternately a 32AHr, 26AHR and 8Ahr deep cycle AGM batteries and it has done a great job. I have a 30 watt monocrystalline solar panel wired directly to it and connect it directly to my batteries using various quick disconnect connectors. I monitor the state of discharge (with a multimeter)and never let my batteries fall below 75% of rated capacity (as recommended by battery manufacturers for best practice and long life of battery.) The Battery Tender as described is a 3 stage charge controller and will put the most voltage out when the battery needs it and cuts back as it approaches full charge down to a trickle level. All the batteries quickly recharge even on partial sun days. Takes 3-6 hours of sun on the biggest battery less on the others. Keeping them topped off is easier (better for it), faster to recharge, and simple to rotate each bettery for its day or shared day of charging. I've monitored its output to the various batteries and it does its job as described at manufacturers website. Charge light lets you know when it is working and indicates what stage its at by color or flashing. Again just as described. I use 12 volt DC LED lights and and connected to my inverter some AC CFL lights and charge all my phones and run my laptop a few hours EVERYDAY! If you have the right expectation of what wattage you planned to use and think about the set-up you can make a nice daily use (or emergency use) system with these components. I am very pleased with the product to used for a small solar systems using a 45 watt panel or less. I plan to buy a few more and connect up lights, radios, in other rooms all over the house. My way of going green. I also charge my AA, AAA rechargeable batteries with a DC connectable battery charger off my 32AHr battery too! Saves me a lot of money on batteries and I use more battery operated devices now and the family enjoys the whole system. Use the Battery Tender only to charge batteries and do not try to run other things from it. That is not what is was designed for. ******** 1 YEAR LATER: Now Feb 2013 AND THIS PRODUCT IS STILL SERVING ME WELL AND AS DESCRIBED. GREAT FOR SMALL TARGET INSTALATIONS!