When is battery full charged

Be sure to read and follow all safety and handling instructions on the battery, this website and your battery tester. If you would like your battery tested, use our Find a Retailer for a location near you.

Find the Right Battery for Me. Find Other Retailers. Your vehicle could be from a reputable manufacturer, be well maintained, have a full tank of fuel and fitted with brand new tyres - but if you've got a flat battery you won't be going anywhere. The majority of automotive lead-acid batteries are now classed as being "maintenance free" but this doesn't mean there isn't anything you can do to help extend their service life.

If you're looking to extend the life of your battery there are a few easy things you can do at home. As a rule, the following items should be checked once a month to maintain optiumum performance, or at least every three months at a minimum.

Keeping your lead-acid battery clean is an easy way to extend service life. Ensure the top of the battery is clean, and that the terminals are free of corrosion. It is a little known fact that a dirty battery can discharge across the grime sitting between the terminal posts, reducing service life. A thin coating of high temperature grease may also be applied to posts and cable connections for added protection.

Get more out of your marine battery with a Century battery charger and maintainer. Like us on Facebook to check out the latest news, events, battery tips and more from Century Batteries. After turning off the light you are ready to test the battery.

Specific Gravity: Full charge SG will run from about 1. High SG more acid allows more juice current to be drawn—but only up to a point; then the battery deteriorates—fast. It must have a tube inside with SG increments clearly marked and a built in thermometer with a temperature correction chart. Look especially for differences between cells.

A variation of. If old, plan on replacing it soon. Then, take readings once each hour and write them down. When three successive readings are alike, the battery is as charged as it will get. Record readings for each cell and battery.

Disconnect battery from any charge or load and leave it overnight 24 hours is better. Check SG again. Readings may be a bit lower, but should be consistent. Record these as your new baseline: your normal, full charge, resting values. Do this again after two weeks or a month of use. Readings may be slightly higher, but again, should be consistent. If the batteries have been constantly overcharged or undercharged, it will show up here.

You should have checked that your battery charger was set properly before starting all this, but if you get abnormal readings check that your charger is regulating properly see later. If you have to add water this soon, you are almost definitely overcharging.

You should check water level about once a month. More than that probably indicates overcharging. Stick it in a cell until it just rests on top of the plates. Then fill until the inner tube floats. Too little and it will rest on bottom of hydrometer.

Too much and it will hit the top. Take your reading and write it down. Read at the fluid level, not at the slight curvature where the fluid touches the inner tube. Note temperature on thermometer and correct reading as indicated.

Note, again, that all readings for a battery should be within. Keep in mind you might have a cheap or faulty hydrometer. El cheapos have a paper SG scale in the tube that slips up and down. Load testing is yet another way of testing a battery. Load test removes amps from a battery much like starting an engine would. A load tester can be purchased at most auto parts stores. Some battery companies label their battery with the amp load for testing. For instance, a CCA battery would load test at amps for 15 seconds.

A load test can only be performed if the battery is near or at full charge. Digital Voltmeters should read as the voltage is shown in this document. If you have voltage readings in the If you have a maintenance free wet cell, the only ways to test are voltmeter and load test. You may get a good reading from 1 cell but have a problem with other cells in the battery. Maintenance is all-important.

Crud on top of a battery provides a path between poles. All batteries need to be kept charged — but not overcharged or undercharged. All need clean connections and good, stout cable and wire of the proper size.

No battery should be routinely deep-cycled. Of most importance, charging needs to be well regulated. Standard, old-timey flooded batteries are cheap initially.

See remarks elsewhere. They will vent gas and fluid, but it can be replenished with distilled water. They require a lot of care. You should never charge a gel battery to more than You occasionally bring it up to AGMs are charged similarly, just with different voltages. But with a regular, wet-cell battery with removable caps, you can add water and clean up the corrosion. All you can do is watch the battery deteriorate. Also, if you overcharge a gel or AGM battery, the factory can detect that, too.

Again, no more warranty. Check yours no matter what kind of battery you use. Or is it charging them up to something ridiculous? Or is it charging at all? Some, even fewer, RVs use a separate battery charger not as part of a converter. Generally, these are pretty good and expensive. But check them the same way. The best chargers regulate in two, three or four stages.

There are some four-stage chargers also. If you want to use gel or AGM batteries, you must have a good, reliable, user-adjustable regulator and charger. The best way to charge batteries is with a solar electric system.