Lift truck batteries are heavy. If one drops from any height, it will hit the ground hard. Is it possible that a battery that has tipped over, or fallen a foot or two, can be returned to service? Often the answer is yes. There have been examples of electric forklifts that have gone over the edge of a truck dock, and after minor repair, their batteries have gone back to work.
But any unusual damage to a battery must be evaluated carefully before the unit can be reinstalled in a lift truck. Because of the potential for latent, hidden damage, a dropped battery may not have a very long service life ahead of it no matter how flawlessly it seems to perform in the short term. Let’s look at the most impact-sensitive parts of an industrial lift truck battery. Starting at the top: cell covers, cell posts and connector straps can be broken by impact, even if the battery remains upright during a fall. Most of this damage is apparent upon close visual inspection, but cell posts may be cracked or broken beneath the connector strap or inside the cell itself.
The symptoms of such topside damage include the following:
- Acid seepage or splashing out of cover cracks (cracks may also be hidden along the cover/jar seam)
- Bent connector straps caused by shifting cells
- Interrupted circuit caused by broken post(s) or straps
Even if the battery does function, an intermittent contact condition may exist, caused by a cracked, but still touching, post/connector joint. This holds the potential for arcing during high current draw conditions. Any sparks in the vicinity of the hydrogen gas produced by the cells can cause an explosion, so caution is warranted. An experienced battery repairman should be called upon to check for such hazards. Apparently, simple cracks in the cell cover or cover/jar seam may require the replacement of each affected cell cover. Acid that seeps or sloshes down the side of the battery should not be ignored. Batteries with tar sealant around each cell will show cracking of the sealant due to impact. This should be resealed using the correct materials, with attention paid to repacking the cover/jar sealing area. Batteries that have been dropped may not show damage to the steel case, but if a corner or side of the case is pushed in, cell damage is likely since there is usually little or no clearance between the steel case and the cells themselves. Older batteries are much more fragile internally and can be more seriously damaged by impact. Here again, a professional evaluation will help you decide the fate of the battery. If a battery has fallen completely over, the top of the steel case may be bent, and the lifting ears may be damaged. Any bending of the lifting ears is serious because, when bent back into position, cracking or metal fatigue can occur. The lifting ears must support the entire weight of a battery as it is lifted during service or battery changeout operations– their strength must not be compromised. Keep in mind that forcefully bending any part of a steel battery case may pinch, or put pressure on the much more fragile cell jars, covers and seams. Lack of care at this point can cost additional repair dollars later. Do not grind, hammer or weld a steel battery case that has not had the cells removed. Sparks from any of these operations can cause a battery explosion. Heat from welding or grinding can melt cell jars or fuse individual cells together, making future cell replacement more difficult and costly. What do you do if no apparent damage has been done to the battery by severe impact? You may consider yourself lucky, of course, but also take the precaution of noting the incident in equipment records. Keep in mind that the battery may exhibit problems at a future date that may be traceable to impact damage. Set the battery aside for several hours on a cardboard sheet and look for signs of acid leakage. Any acid leaks must be tracked down and fixed by your battery serviceman. And, understandably, rough treatment of the battery, such as a fall or other impact, does void manufacturer’s warranties.
For more information, contact Arcon Equipment Inc. (440) 232-1422.
