Kinds or types of batteries and how to use them.

Batteries Types Care and Uses

Batteries simply receive the electricity from the solar system and store it for later use. Batteries must be operated and maintained properly or they will not last long. Here are a few concepts to keep in mind in order to get the full life out of your batteries. These explanations will be simplified in order to be easy to understand.

Never deep discharge a battery bank. Although deep discharging batteries will not immediately destroy them, it WILL shorten their life considerably.

Keep the batteries in an environment where they do not freeze or get excessively hot.

Check non-sealed lead acid batteries for electrolyte level at least TWICE a week. If electrolyte in a cell is consistently low, the cell is going bad, a dangerous situation.

Keep all electrical contacts clean and tight. Check once a week.

DO NOT store liquid or gaseous fuels in the same area as the battery bank. Batteries give off hydrogen, which is explosive in high enough concentrations.

Always store batteries fully charged.

All batteries operate on the same principle. This principle is a chemical reaction between two metals or semi-metals. The chemical reaction produces electrons as a side effect. The electrons provide the charge which gives electricity, which is flowing electrons. There are two classes of batteries.

Primary Batteries. These batteries discharge their energy and are then used up and discarded. They are non-rechargable.

Secondary batteries. These batteries can be recharged when they have been discharged through use.

The batteries used in renewable power systems are all secondary batteries, to be able to store the power generated by the system.

There is another storage device called a super capacitor. Development of these devices and their controlling circuitry has come a long way as of late. In a short time, they will be competitive with batteries. In the meantime, batteries are the choice.

There are several types of batteries.

Sealed lead acid

Non-sealed lead acid

Lithium ion

Nickel cadmium

Nickel metal hydride

There are other types under development, but these are the main types in use now.

The work horse of the renewable energy scene is the lead acid battery. The non-sealed lead acid battery is the most reliable and has the greatest energy density. It needs regular maintenance by checking the electrolyte level and adding distilled water if it is low. It also gives off a little acid fumes and some hydrogen when in use. The cost of these batteries is the lowest of the rechargables, at least in the larger sizes. They are quite heavy, being made of lead, so they should be used primarily in situations where they do not have to be transported much. There are two ratings of these batteries.

Standard duty. These are starting batteries. They will supply a large amount of power for a short time, in order to start car and truck engines. But their lead plates are thin, so they do not hold up to repeated deep discharging.

Deep cycle. The batteries are built very robustly. They are designed to run electrical appliances for a long time. They can be deep discharged without as much damage as standard duty batteries. However, there is a limit to how many time they can be deep discharged. This is the type to get for a home solar power system.

There are other rechargeable types of batteries that are used in smaller applications.

Lithium ion. These batteries are light and pack a huge energy wallop. Unfortunately, they are incredibly expensive. They also require a special charging system, which is itself expensive. They can explode or catch fire if not properly charged. They are widely used in cell phones and lap top computers. The devices that use them have built in chargers of the correct type.

Nickel cadmium. These were the original small rechargeable battery. They have a good energy density. They form what is known as a "memory", where they can be charged, but not discharged beyond a certain point. The solution is to periodically discharge them completely and then recharge them. This keeps them from developing the "memory". These batteries are commonly used in solar powered garden and flood lights. The batteries are typically discharged completely every night, no there is no chance to form a "memory".

Nickel metal hydride. These are the newest widely used rechargables. They do not have as much of a problem with "memory" as nickel cadmiums do. They also have a higher energy density. They too need a special charger. Fortunately, these chargers are relatively cheap. I recently bought one for just under $20. It works on either 120VAC house current or can be plugged into a car 12VDC outlet. It is automatic and you just wait for the red light to turn to green. Since the charger runs on 12 volts, the 12 volt outlet in the solar power system can be used to recharge small batteries for things like cameras and small flashlights. It will recharge AA and AAA batteries, up to four at a time.

Since the main batteries for solar power systems are lead acid, here is some more information about them.

If the batteries are rated in cold cranking amps, they are standard duty. They can be used but probably will not last long, unless the power usage is low.

The best type of sealed lead acid battery is glass matt. They are wonderful batteries and they will take some abuse. They don't give off any fumes unless they are heavily abused. They must be charged at a lower rate than non-sealed batteries so they work well for small solar systems. They are safe to transport so they can be used in portable applications without anything spilling out. Small sealed lead acid batteries can be charged with a solar panel as small a a single watt, although it may take a couple of days with overcast skies. Two 7.5 amp hour 12 sealed batteries can be kept charged well enough to run a light and a lap top for an hour a day. Four of these batteries in parallel will provide several hours of computing power. That is enough juice to check e-mail and do basic computer stuff. Here is a page of instructions to make battery packs and banks from small batteries.

All in all, for small applications, portable systems work well and are a lot less expensive.