Old 11-12-2008, 07:43 PM
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Default Re: Solar panel for keeping house battery charged?

Solar is not a gimmick. It really does work.

I would suggest that you look beyond a simple solar trickle charger. A trickle charger is not designed to charge a battery - they only prevent them from self discharging. So if your battery happens to run down to 80% (for example) the trickle charger will keep it there. It MAY bring it back up, but it will do so very slowly.

When I looked into a solar solution for my boat, I decided that I would need at least a 55 watt panel. Per battery. One 55 watt panel can be expected to produce about 4.5 amps under ideal conditions. In reality, you can expect closer to about 3 - 3.5 amps. This is enough to charge up a battery.

With panels above 30 watts or so, it is a good idea to get a solar charge controller. This device will prevent an overcharging situation. If you have 4 batteries then it would be more cost effective to get two 125 watt panels as opposed to four 55 watt panels. Like conventional battery chargers, a solar controller has banks - a one battery system needs one bank a two battery system needs two banks and so on.

There are some companies out there that specialize in solar power. Most are in Arizona and New Mexico. They can help you put together a system that will suit your needs.

I did not go with solar because of the cost. It is more expensive. But the advantage is that solar works in remote areas, and once set up is trouble free and reliable. But a lot of this depends on how the system is designed. You need to add in reserve capacity for best results.

By the way - wind power is also an option. Wind works at night - assuming there is a breeze.

Many sailboats I see that are moored use both solar and wind together. The live aboard sailboats that are not connected to shore power are all about wind and solar to keep the lights on. And the cold plates cold. And so on. It all works very well. The one time cost to set it all up is high, but the long term cost becomes low. And it works anywhere - as long as there is sun and/or wind.