From: "Clipper"

Subject: [tt-forum] The care of lead acid batteries
Date: Wednesday, December 29, 2010 9:46 AM

I ran across this on another group and thought it may be good information to 
pass along. I suppose Mikel could verify or correct if need be.
Clipper

The care of lead acid batteries

Storage batteries are used in just about every independent energy system. 
The lead acid storage battery is a familiar sight in your car. Usually these 
Batteries give years of trouble-free service and the average driver rarely 
has to be concerned about the chemistry of the battery, cycle life, or 
charge/discharge rates.

The lead acid batteries used in an independent energy system are another 
story. If there is one item that is least understood or abused in these 
systems, it's the battery.

If you follow the list of do's and don'ts outlined below, living with the 
Storage battery will be a lot easier and less costly.

Rule 1. This comes as a shock to most people, but a 12-volt lead acid 
battery is almost dead when the voltage at rest (no loads or discharge) is 12 
volts. Less than 25% of the battery's capacity remains. The voltage of a 12-
volt lead acid Battery will vary between 11.6 and 12.6 volts discharged and 
fully charged. This one volt range can be used as an approximate indicator of 
the state of charge and illustrates the need for an accurate digital 
voltmeter.

Rule 2. In order to obtain long life from your batteries they should be 
discharged to no more than 50% of capacity. This is not easy to accomplish, 
especially in a solar electric system in winter. A backup generator or, if 
you have the wind, a wind generator, can make this a lot easier to do 
reliably. Hydroelectric systems don't usually have this problem.

Rule 3. Don't use car batteries in an independent system. They are not made 
to be deep-cycled and will have an early death when used in this way. A good 
golf cart or forklift battery like the Trojan L-16 is a much better choice.

Rule 4. Never let a lead acid battery sit in a discharged state. Recharge as 
soon as possible. Every time you let them set for any length of time (even a 
few days) you will begin to accumulate lead sulfate on the plates that 
reduces their capacity.

Rule 5. If you live in a cold climate, be sure and provide insulation or a 
warm area for your batteries. The useful capacity and the batteries' ability 
to deliver power are greatly reduced in cold temperatures. Your batteries can 
also freeze when in a discharged state, so keep them warm.

Rule 6. Never draw large amounts of current from your batteries when in a 
Discharged state. Damage to the plates can occur.

Rule 7. Batteries should have an "equalize charge" at least every other month 
or sometimes once a month depending on how severe the service. An equalize
charge is a form of controlled overcharge that helps to place all the cells 
at an equal voltage. Large currents are needed to equalize, so once again you 
can see the need for a backup generator. An ideal method of equalization is 
to purchase an inverter with a built-in battery charger and an equalize 
function.

Rule 8. Never attempt to adjust the electrolyte level in the battery. 
Raising or lowering the specific gravity not only voids the warranty, but can 
ruin the batteries or pose an unhealthy risk of acid burns. Adding distilled 
water when needed should be as far as you go.

Rule 9. Always keep battery terminals and the tops of the batteries clean 
and free of corrosion. The batteries can self discharge rapidly, and badly 
corroded terminals can cause electrical problems, especially when drawing a 
lot of current.

Rule 10. Do some follow-up study on charge and discharge rates for your 
batteries. Consult a reputable battery dealer or the supplier/designer of 
your system as to the best way to treat your batteries. Nothing can kill a 
good set of batteries faster than improper charging and discharging. ? 


