Solar Power Battery

DIY Solar Panel PlansThis article is going to talk about what type of solar power battery is the best to use.If you plan to use solar electricity when it’s dark, you are going to need batteries to store the electricity you make during the day.  So, what type of battery is the best type to use?

I’ll give you the answer right up front.  For most people, the best type of batteries to use are plain old 12 volt lead acid batteries like you have in your car.

What about all the new battery technologies you hear about like the nimh batteries they use in the Prius or lithium ion like in laptops and the Tesla Roadster?  These new technologies are great for these applications, but there are a couple of reasons why they aren’t the best choice for storing your solar generated electricity – at least not today.

The first reason these new technologies aren’t the best choice for a solar power battery is some of these types of batteries require constant monitoring or they can be dangerous.  Lithium ion batteries, in particular, can get very hot or even catch fire if they are allowed to drop to too low a voltage or are overcharged too much.  But, I hear you saying, they use lithium ion batteries in my laptop and in smart phones.  How can they do that if the batteries are dangerous?  The answer is these devices have special circuitry to constantly monitor the battery and take actions if the voltage gets too low or too high.  A smart phone will shut down if the battery gets too low.  Your laptop will stop charging the battery when it is fully charged.  Can you have monitoring circuitry for your batteries at home?  Well, yes, you could do that.  But, consider this – the battery in your phone is very small.  If it goes up in flames it will be a pretty small fire.  If you want to store a substantial amount of electricity from your solar panels, you will need a much bigger battery bank and if this bank of batteries gets out of control, your problem is going to be much bigger.  Safety is a small part of the reason these batteries aren’t the best choice in a solar power battery, though.

The biggest reason plain old 12v lead acid batteries are the best choice is price.  The newer types of batteries will cost you 2, 3 or even 4 times what lead acid batteries will cost for the same capacity.  Why pay more for batteries that will hold the same amount of electricity?

The main reason these newer battery technologies are used in laptops, phones and electric cars is weight.  Nimh and lithium ion batteries weigh much less than lead acid batteries of the same capacity.  Manufacturers want to keep the weight of phones, laptops and electric cars as low as possible, so they use these newer battery technologies even though they are more expensive than lead acid batteries.  Weight, however, isn’t a concern for a battery bank that is going to be sitting in one place at our house.

Sealed lead acid batteries, in particular, are rugged, safe, require very little maintenance and are cheap compared to other types of batteries.  Most installations use 12v or 24v on the DC side of the system.  Either are easily handled by 12v sealed lead acid batteries.  (You can provide 24v DC by connecting 2 12v batteries in series.)  Because of all the reasons above, the plain old 12v sealed lead acid battery, for almost all installations, is the best solar power battery to use.

For a great guide to building your own solar power system, including step-by-step videos, Click Here.

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