| Most bike battry's are measured in Ah meaning Amp hours. Most of these battery's are about 18 Ah or so, to make them lighter and better for weight to power ratios on bikes.
These battery's can last from a few weeks to as long as 6 years, most last about 3 years, and it depends on the brand, and how it is cared for.
A typical 18Ah battery can run a theoretical device at 1 amp for 18 hours, or a 18 amp device for 1 hour, and will put out 300 plus amps to the starter maybe 4 times if you have 4 failed attempts to start in a row.
These battery's must be maintained on a automatic float charger such as the "Battery Tender" for about 55 bucks, or a Shumaker brand which does the same thing for 17 bucks, anytime less being parked at work you are not riding.
Otherwise they tend to waste away apx 10% of their charged every day, and with that create a sulfation premature death.
These battery's suffer from cold and become sluggish in colder than 40'F.
If they are allowed to go low in distilled water they will sulfate to death, and depending on how low the process gets faster.
Some batterys come wet from far off lands, and can in fact be junk on the showroom floor. Simply put they sat about unused to long.
With a recent battery it is possible for them to act dead, and may hold a charge once charged back up for a long time (apx 10 hours) and be if good use.
After a single start it takes riding time of more than a full 30 miuntes to re-charge a bike battery and that only charges at higher than 2,800 engine rpm. Alternators do not create charge at much under 3,000 rpm, and because the alternator is mounted on the crankshaft and not to a pully set up, like a car where the car idles at 900 rpm and the alternator is spun at a far higher rpm these systems are not like a car one bit.
Too many starts and stops in a short time can run the battery down more than it can re-cover and you will not start the bike, or run the bike with out this battery in the system.
Jumping a really dead and gone battery that is too tired to hold a charge will fry the charging system which can't possibly charge a really dead battery no matter what you do.
Sometimes you can run a good battery to low to take an instant charger and will have to fight your way thur a high internal resistance, by running the charger for several hours and then stop, only to try again several times. It is possible to bering a battery back, so long as it was a recent battery, and the problem was something recent also. This isn't going to work with a battery that sat around on concrete for 6 months.
Removing battery cables won't allow the engine to remain running and will also fry the charging system.
Jumping a low level battery from a RUNNING CAR will risk an over load condtion and may fry the charging system. if you must jump from a car be sure the cables are (+) to (+) and (-) to (-) and the car IS NOT RUNNING.
It is very possible to over load a bike charging system with toys. More or less the alternator can put out upto 20 amps maximum, where as you cars can put out 55 amps and much more depending on the alternator in that car.
The battery on a bike works in the charging system something like a shock absorber does on a car. And in that way you can hit to big a bump, and use more current than the bike can make.
You must figure on your alterator in amps and or watts as a total you can make, the engine needs to run coils, and make spark and the systems require current that is not possible to determine.
Other items are possible to determine in lamps, like the main hi/low in watts, passing lamps in watts, radios in watts. It may be you can't run everything all the time.
To test a battery to tell if it is of any use, you must first fully charge it, and use one form or another of a DC volt meter. An ok one is is found at walley world for 17 bucks.
Once 10 and or more hours pass you can begin to test the battery in DC volts.
These steps will be discussed:
Test the battery voltage, key off, as starting, at idle, and at 3500 RPM. (Cadd I swiped that sentance.)
TEST 1: read battery voltage right off the charger. This will show some wacked out figure called false surface charge and it doesn't mean squat, unless it is low for some reason like you just charged a stone.
You might see readings as high at 18 volts depending the charger. You might well expect to see 13.8. The point is you don't want to see less than 12.6 dcv.
So install the battery, Positve cable FIRST, GROUND CABLE LAST, and set up the meter.
TEST 2: Lets load test the battery and get to the meat of what it is you want to know! And want you want to know if if the battery can hold a charge, and if it can you can load that battery, and it will work.
So you hooked the meter, next get a watch that counts seconds, and pull off the plug wires so the engine CAN'T Start. You are making the engine be a tool, there is a real tool, but you don't need it for one time use. If you feel you do, go to the auto parts store and buy one.
MAKE SURE the bike is in neutral, if it cold block the wheels incase the bike wants to move with a cold clutch.
DO NOT USE the CHOKE!
IF your bike can crank the starter with the clutch out do it, so long as the bikes doesn't lurch your using even more current to turn the engine which you do not want to start! WE are LOADING that battery up harder than you would be, if you were starting the engine!
Get ready, flip the KEY, push the button and crank the engine, watch the reading, and count to 10 seconds. You want to see both happen before you let the button go, but WATCH the reading more than the watch.
IF the bike stops cranking, or you hear clicking and nothing else, the battery is junk.
IF the reading goes to less than 10.2 volts the battery is marginal, and you should begin to think about getting a new one. Don't panic if you see some thing 9.5dcv, you still have time, but measured in warmer days and a few months. (IF this were a car this test would run 30 seconds!, which just might melt all the solder joints and is why there is a tool!)
Allow 10 to 15 minutes, use the time to install the plug wires, and get a cool drink. Shut every thing OFF. That starter is cooling OFF and so let it....
Now you are going to leave that meter hooked up right where it is....
TEST 3: First take a new reading with everything off. This reading is real battery at rest volts... You want to see 12.6 maybe 12.4, no less. Most certainly no less than 12.0.
TEST 4: Start the engine and take a reading. Expect to see low 13's
TEST 5: Take the bike up to apx 3,500 RPM slowly watching the meter to show a minimum of 13.6 volts. probably because you have just used that battery hard from the load test AND just used it again to start the bike with you will see a higher than 13.6 volts fast. You are likely to see see 14.8 volts which is good. If you don't, don't worry so long as the reading is 13.6 to 14.8 dc volts. ALL DONE.
Comments: These are basics for a wide variety of bikes..
ALWAYS THINK GROUND CABLE! IF YOU ARE REMOVING A LIVE BATTERY FORM ANY SYSTEM REMOVE THE GROUND CABLE FIRST!
IF YOU ARE INSTALLING A CHARGED BATTERY OR A NEW ONE INSTALL THE GROUND CABLE LAST!
IF something is turned on there will be a spark, and if something is broken and so turned on there will be a spark. Newer bikes tend to to have some things turned on that we can' shit off!
However you don't want to see sparks, and if you do, and believe everything is turned off you may have a problem.
You might have a 7 Ah battery, you might have a 30 Ah battery. It might be your charging system has a problem.
Most problems are loose connections, bad contacts, nasty ground cables, corroision, cold solder joints, and just mung. You want clean, more over clean electrical connections which a finger print can cause problems with. You have acids in your finger prints that can cause current loss. This tends to show on injection parts and ECU's more than at the battery, because the voltages are very small.
Bad grounds can cause some very screwed up things, since the current wants to go to ground and will try somehow, even if the path is wrong. Things like using a turn signal, and having a brake light flash dim, in goose step show there is a bad ground.
A dim head lamp can be caused by a bad ground. Instrument lights can act all screwy over a bad ground, and cause things to be intermittant, or not work at all. (some bike designs cause ground to run thru greasey goose neck bearings nasty design that one is.)
ALWAYS sand paper and clean connections at both endes of battery cables when it is easy to do, which it isn't always so easy to do depending.
I CAN NOT STRESS enough to make certain the connector between the rectifier/regulator AND the alternator are electricly clean. This is the single most inmportant connector on bikes. IF you can feel heat coming off this connector with the back of your hand, you have a problem right there. IF this connector looks melted, or the wires looked yellowed, it is heat causing this, and that heat comes from a "VOLTAGE DROP" HIGH RESISTANCE right there at that connector.
IF YOU FAIL to stop that heat I promise you the stator part of the alternator will fry, and be fit as a counter weight in a plant pot. If that happens depending on how your alternator works you have a good chance of killing the field coil, and the rec/reg.
Speaking of heat, it is a very wise idea to discover that rec/reg and pull it off the bike and clean up where it mounts to the bike.This part is supposed to get HOT! However the backing plate it mounts on is supposed to heat sink the heat AWAY. IF dirt gets between the rec/reg and the heat sinking ablity of the mounting plate the rec/reg bakes to death.
So many bikes, and so little memory
Ossipee New Hampster "Eat Seeds or Die"
Post Edited (Mac_Muz) : 4/1/2007 2:56:07 PM GMT