BikeBatts.com

BikeBatts.com

Frequently Asked Battery Questions-

1. My battery won't hold it's charge. What's wrong?
   
   1. Did you maintain it over the winter? Natural self discharge may have left lead sulphate crystals on the plates too long. If they can no longer be converted back into acid, the plate surface has become "sealed off" and the electrons cannot pass through it. A sulfated battery can appear charged, but only the outside layer of the plates is active. This surface charge will dissipate quickly under load; a hydrometer will show the electrolyte to be very weak. Also, if a battery is completely discharged, some lead will dissolve in the electrolyte (now just water). But as soon as you charge it, the lead will come back out of solution. This can form a conductive path through a separator, preventing it from staying charged. Replacement time!
   2. It may be damaged from overcharging, either on the bike or on a charger. This softens the positive active material, causing it to lose electrical contact with the grid. Also, as it falls off the grid it piles up on the bottom. When it piles high enough the plates will be shorted out and then the cell will never stay charged. Check the charging system, the battery charger, or your use of the battery charger if this happens. Vibration and age also cause this. When charging regularly, check the electrolyte level; it's easier than you think to dry a battery out.
   3. Your bike might have a current leak. Hook an ammeter in series with the battery (use the negative lead, it is easier) on the bike with the key off. Any significant reading (.005A or more) can give you a problem. .005A for 2 months is 7.2AH, a significant amount of your battery's capacity to be lost in 2 months. The clock + radio + alarm can easily exceed this, so your off-season maintenance must accommodate the current drain.
   4. There may be an internal defect. Measure the voltage as you try to start the bike. If it drops very low (like less than a volt) while you try to start, then returns immediately to normal voltage when you stop, there may be a broken internal connection. The battery is charged, but cannot deliver the current. Another internal defect is a short, caused by loose active material (see above) or plates contacting through or around a separator. This will quickly discharge that cell, leaving a 10V battery. More importantly, the plates in that cell will sulfate, preventing them from transmitting the current generated by the other cells.
2. Why is the voltage so low?
   The battery voltage depends primarily on the acid strength, and to a lesser degree on temperature and design. As the state of charge increases, the acid becomes stronger. Fully charged, a flooded (typical) battery's acid specific gravity is normally 1.265 to 1.295 and the battery voltage (no-load) will be about ten times that; 12.65 to 12.95. Low voltage, therefore, is generally caused by insufficient charging or permanent sulfation (which lowers the concentration of the acid, since the sulfates are tied up elsewhere). Excessively high specific gravity (stronger acid) can cause excessive grid corrosion. Furthermore, it can raise the EMF high enough that the battery will not properly charge; i.e., the charging system voltage may not exceed the EMF enough to fully charge the battery in the time allotted.
3. What's the difference between Calcium batteries and "regular" ones?
   Batteries with plates made from a Lead/Calcium alloy do not electrolyze as much water on charge, so less must be added. The disadvantage is that the grids do not tolerate repeated deep-cycling, where the battery is heavily discharged, then recharged. Normally, these batteries will only see very shallow discharges, so this is not a problem. "Regular" batteries have grids made of a lead/antimony alloy. They will stand more deep-cycling but will consume more water.
4. Should I get a bigger battery?
   As mentioned, with a large enough alternator (which begins charging at low enough engine speeds) the battery only needs to be big enough to start the bike reliably; the 18AH size is plenty for that under normal conditions. You only need to go larger if you drain a lot of current during non-charging periods. Many 1000cc and larger bikes today use 10 and 12AH batteries with less than 200 CCA. This saves about 5 pounds. If the weight doesn't bother you, larger isn't worse. The larger battery may also provide longer intervals between replacement since it can deteriorate more and still perform well.
   1. Remember, though, it's really only better if it does something that the smaller battery won't. Running the radio or electric vest with the engine off is an excellent rationale for using a larger battery. So is spending a lot of time at low RPM on bikes with weak charging systems; the more "load leveling" you need, the greater the AH capacity should be.
   2. Keep in mind - the energy drawn from the battery must be replaced, plus ~30% (to account for inefficiency). If the load exceeds the maximum alternator output, the battery will make up the difference until it is fully discharged. Then you stop.
5. How much load can I put on the battery?
   This is tough. It depends on how long you want the battery to last, before becoming fully discharged or going to too low a voltage. If the load is hundreds of amps, the battery will only last seconds or minutes. If the load is fractions of an amp, it will last for hours and hours. Vehicle loads are supposed to be supplied by the alternator, not the battery. As noted earlier, the battery only has to supply a total of 1 or 2 AH, max, if the engine starts and runs normally. To evaluate load leveling concerns, convert the load (usually Watts) into Amps (divide by twelve) and count AH out and AH in.

Example 1: 18AH battery, no charging below 3000 RPM, electric vest & lights. Running for 30 minutes before getting up to speed.

Battery is sufficient, but the bike may not start well if the engine stalls at this point...

Example 2: 18AH battery, no charging below 3000 RPM, radio, electric suit, 100 Watt each fog and driving lights plus normal lights. Running for 30 minutes before getting up to speed.

Battery is too small!

The larger battery would be good here! Note that the bike may keep running. The system voltage will drift down as the battery discharges, so the current drawn will drop somewhat, "extending" the run time. Depending on the ignition system, the plugs may keep firing at the reduced voltage. Fuel injection might become decidedly unhappy. So, it may run longer, but that also means the bike must be operated in the "charging" mode longer to replenish the charge in the battery.

These figures use incredibly simplified numbers and assumptions, but can provide general guidance.