repiv
10-23-2008, 09:08 PM
WARNING! THE FLUID INSIDE A BATTERY AND THAT WHICH MIGHT LEAK OUT, IS VERY ACIDIC (CONCENTRATED SULFURIC ACID). USE GLOVES OR EYE PROTECTION WHEN WORKING NEAR CAR BATTERIES. WIPE UP ANY SPILLAGE.
From time to time, a few people have battery problems or think they have battery problems and wonder how to check it out. Hopefully, the following will help people to at least begin to attack the situation with a bit of knowledge.
If you suspect that your battery is not up to snuff, the best way is to go to a shop and have it "load tested". This will be a fairly definitive answer. However, if you would like to be able to tackle this at home, try this .................................................. ........
Background note: My battery is an aftermarket one (Die Hard) that's just over a year old. The car is a 4 season daily driver, mostly for in town running around, with a long road trip each year. I have drained it once by leaving my trunk open (trunk light on) to the point it would not crank or start the engine. A quick boost from another battery started it immediately and after a short drive, it has not given me any problems since. I do not have a huge stereo system on the car, but I do have the added draw of LED running lights both front and rear. I also have the added draw of a Vortech water pump, high output fuel pump, dash gauges and radar detector, so nothing outlandish.
Even today's "maintenance free" batteries need a little attention from time to time. The easiest way is to check through the "sight window" (if your battery has one). The label will tell you what the indicator means. Here is an example using my Honda Fit OEM battery:
http://inlinethumb42.webshots.com/41833/2100480920025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2100480920025981935HJIcmb)
Note the little circular caps that you can unscrew using a large Philips screwdriver. There should be 6 of them on a typical battery. Batteries do lose a bit of water over time, so you can top it up with distilled water if the need arises. Use of a small bulb with a tiny hose is ideal. Fill it to just when the fluid level touches the bottom edge of the filler pipe. You'll know it's there when the fluid forms a sort of inverse bubble (meniscus). This is usually about an inch or so down from the top of the hole. On the OEM Panasonic battery, you can see the level in each cell by looking at it through the translucent casing. You can also buy a battery tester, which basically measures the specific gravity of the fluid in each cell and gives you a reading of "bad, fair, good". If it says "bad", it may have lost too much sulferic acid or lead or water to be brought back with a slow charger. Slow charging is always better than fast charging.
If parked for extended periods of time, consider installing a smart charger like the Battery Tender.
__________________________________________________ _____________________
Now, on to the test. You can do any of these steps in whatever sequence you like. Just record or take note of the readings you get. Use a voltmeter that can read double digit DC volts. Put the red probe on the positive terminal and the black probe on the negative terminal. No harm will come if you reverse this. You will simply get a Negative (-) reading.
1. Take a reading first thing in the morning, after the car has sat over night. Don't worry too much about the actual volts you see in the picture. Yours may vary slightly.
http://inlinethumb45.webshots.com/42860/2715077070025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2715077070025981935tAUIty)
I consider my battery to be healthy and this is about the volts you should see. Any less than 12.0 volts and you might begin to suspect something is amiss. Getting close to about 10.5 volts, and you will likely not be able to start the engine. What this reading tells you is if your battery was able to HOLD a charge or if there is a significant unknown draw on it while the car is "shut off".
2. Fire up the engine and while it's still on its cold high idle, take another reading:
http://inlinethumb58.webshots.com/42297/2775209880025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2775209880025981935qnarna)
Note the difference between the overnight resting voltage and this voltage. It should jump up fairly high as indicated in the photo. This tells you that your charging system is responding nicely to the sudden drain of cranking the engine and it's doing its job in trying to top up the battery. If the voltage doesn't jump up like this, something is wrong with the charging system.
3. Now, go about your day's drive. When you come back, take another reading while the car is still running at idle:
http://inlinethumb41.webshots.com/23656/2697165690025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2697165690025981935NiyBHP)
The voltage should remain elevated. This shows that the charging system is responding to the regular demands of running the engine and all the accessories and the load placed on the electrical system as you drive around. Again, if the voltage isn't elevated like this, suspect that something is wrong with the charging system and it's likely that if you went for a long enough drive, the car would have died on you while you were out. You're then using the battery to power the car, with insufficient help from the charging system.
4. Now, shut off the engine and wait a few minutes and take another reading:
http://inlinethumb53.webshots.com/43252/2904239610025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2904239610025981935kGMWht)
What this should tell you is that your battery was being charged while you were driving and that it was able to accept the charge. If the voltage at this point is below 12.0 V, the battery is likely not able to take a charge very well.
With all these readings, you can make a few determinations at home.
- You can determine if your battery is able to TAKE a charge or if it's able to HOLD a charge.
- You can determine if your charging system is able to provide the adequate electricity to service the battery and to run the car (and accessories).
If the charging system can't provide adequate electricity, the fault may lie with the alternator itself, the voltage regulator (built into the back of the alternator) or the ELD (Electric Load Detector, located in the fuse box just in front of the battery.
If the battery can't TAKE a charge or HOLD a charge, the fault is likely the battery itself but there is always the possibility that it isn't GETTING a charge.
At this point, you should be able to make judgement on what next step to take, whether it be to replace the battery, repair the charging system or look for a short or to replace bad wiring.
CAUTION! If you use an external battery charger that does not have overcharge protection, it is possible to boil the fluid inside the battery while charging. This can be very dangerous in that the gases escaping are highly explosive and flammable. "Quick" charge devices should be monitored closely and used with extreme care. The battery may not be healthy enough to be subjected to a quick charge. It is always better to do a slow charge using a "smart charger" or one with overcharge protection.
From time to time, a few people have battery problems or think they have battery problems and wonder how to check it out. Hopefully, the following will help people to at least begin to attack the situation with a bit of knowledge.
If you suspect that your battery is not up to snuff, the best way is to go to a shop and have it "load tested". This will be a fairly definitive answer. However, if you would like to be able to tackle this at home, try this .................................................. ........
Background note: My battery is an aftermarket one (Die Hard) that's just over a year old. The car is a 4 season daily driver, mostly for in town running around, with a long road trip each year. I have drained it once by leaving my trunk open (trunk light on) to the point it would not crank or start the engine. A quick boost from another battery started it immediately and after a short drive, it has not given me any problems since. I do not have a huge stereo system on the car, but I do have the added draw of LED running lights both front and rear. I also have the added draw of a Vortech water pump, high output fuel pump, dash gauges and radar detector, so nothing outlandish.
Even today's "maintenance free" batteries need a little attention from time to time. The easiest way is to check through the "sight window" (if your battery has one). The label will tell you what the indicator means. Here is an example using my Honda Fit OEM battery:
http://inlinethumb42.webshots.com/41833/2100480920025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2100480920025981935HJIcmb)
Note the little circular caps that you can unscrew using a large Philips screwdriver. There should be 6 of them on a typical battery. Batteries do lose a bit of water over time, so you can top it up with distilled water if the need arises. Use of a small bulb with a tiny hose is ideal. Fill it to just when the fluid level touches the bottom edge of the filler pipe. You'll know it's there when the fluid forms a sort of inverse bubble (meniscus). This is usually about an inch or so down from the top of the hole. On the OEM Panasonic battery, you can see the level in each cell by looking at it through the translucent casing. You can also buy a battery tester, which basically measures the specific gravity of the fluid in each cell and gives you a reading of "bad, fair, good". If it says "bad", it may have lost too much sulferic acid or lead or water to be brought back with a slow charger. Slow charging is always better than fast charging.
If parked for extended periods of time, consider installing a smart charger like the Battery Tender.
__________________________________________________ _____________________
Now, on to the test. You can do any of these steps in whatever sequence you like. Just record or take note of the readings you get. Use a voltmeter that can read double digit DC volts. Put the red probe on the positive terminal and the black probe on the negative terminal. No harm will come if you reverse this. You will simply get a Negative (-) reading.
1. Take a reading first thing in the morning, after the car has sat over night. Don't worry too much about the actual volts you see in the picture. Yours may vary slightly.
http://inlinethumb45.webshots.com/42860/2715077070025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2715077070025981935tAUIty)
I consider my battery to be healthy and this is about the volts you should see. Any less than 12.0 volts and you might begin to suspect something is amiss. Getting close to about 10.5 volts, and you will likely not be able to start the engine. What this reading tells you is if your battery was able to HOLD a charge or if there is a significant unknown draw on it while the car is "shut off".
2. Fire up the engine and while it's still on its cold high idle, take another reading:
http://inlinethumb58.webshots.com/42297/2775209880025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2775209880025981935qnarna)
Note the difference between the overnight resting voltage and this voltage. It should jump up fairly high as indicated in the photo. This tells you that your charging system is responding nicely to the sudden drain of cranking the engine and it's doing its job in trying to top up the battery. If the voltage doesn't jump up like this, something is wrong with the charging system.
3. Now, go about your day's drive. When you come back, take another reading while the car is still running at idle:
http://inlinethumb41.webshots.com/23656/2697165690025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2697165690025981935NiyBHP)
The voltage should remain elevated. This shows that the charging system is responding to the regular demands of running the engine and all the accessories and the load placed on the electrical system as you drive around. Again, if the voltage isn't elevated like this, suspect that something is wrong with the charging system and it's likely that if you went for a long enough drive, the car would have died on you while you were out. You're then using the battery to power the car, with insufficient help from the charging system.
4. Now, shut off the engine and wait a few minutes and take another reading:
http://inlinethumb53.webshots.com/43252/2904239610025981935S600x600Q85.jpg (http://good-times.webshots.com/photo/2904239610025981935kGMWht)
What this should tell you is that your battery was being charged while you were driving and that it was able to accept the charge. If the voltage at this point is below 12.0 V, the battery is likely not able to take a charge very well.
With all these readings, you can make a few determinations at home.
- You can determine if your battery is able to TAKE a charge or if it's able to HOLD a charge.
- You can determine if your charging system is able to provide the adequate electricity to service the battery and to run the car (and accessories).
If the charging system can't provide adequate electricity, the fault may lie with the alternator itself, the voltage regulator (built into the back of the alternator) or the ELD (Electric Load Detector, located in the fuse box just in front of the battery.
If the battery can't TAKE a charge or HOLD a charge, the fault is likely the battery itself but there is always the possibility that it isn't GETTING a charge.
At this point, you should be able to make judgement on what next step to take, whether it be to replace the battery, repair the charging system or look for a short or to replace bad wiring.
CAUTION! If you use an external battery charger that does not have overcharge protection, it is possible to boil the fluid inside the battery while charging. This can be very dangerous in that the gases escaping are highly explosive and flammable. "Quick" charge devices should be monitored closely and used with extreme care. The battery may not be healthy enough to be subjected to a quick charge. It is always better to do a slow charge using a "smart charger" or one with overcharge protection.