The alternator together with the battery and voltage regulator form part of the forklift's charging system. The alternator produces power for the other components of the forklift truck such as the lighting, gauges and the instrument panel.
The alternator can last a long time but if your truck is old, it is inevitable that this can become faulty. Identifying the early signs can warn you to have the alternator checked immediately before it becomes a big difficulty.
The conspicuous clues you would notice that there is an advancing fault can include flickering gauges, dimming lights and noticeable whining sounds coming from the engine. A failing alternator doesn’t get the battery recharged and thus cause the engine not to start. If you smell burning rubber, it is important to have the alternator checked by the mechanic right away. These are the tell-tale signs of trouble with the alternator you need to take note of.
If your instinct tells you that the alternator is the culprit, make sure to test it first; by pinpointing if it is the real cause of the problem, this will prevent you from spending on an unnecessary repair.
Before making the judgment if it is the alternator that’s causing the problem, isolate other side troubles in the charging system that may have affected the performance of the alternator such as the connector, battery, cables, or internal circuit. Here are the ways you can do to isolate:
If it doesn’t charge the battery
If you suspect that the alternator doesn’t charge the battery, check the battery state of charge and voltage regulation. You can do this with a tester. This determines if the charging system is not working properly and that the alternator is not able to produce sufficient charge for the battery.
Some other problems that cause the alternator not to charge are the conditions of the belt and pulley. If the belt installed is slipping, it will cause the alternator not to charge or to undercharge. The tension of the belt could also cause the problem, check if the belt has the right tension. The condition of the belt should be checked on a regular basis.
Bad cables and terminals could also cause the alternator not to charge. Corrosion in the battery terminals and minute resistance in the ground circuit can significantly disrupt the charging output.
If the alternator would test good and in good working condition, but still the alternator would not charge, see if the fuse links and connection were bad, in many cases this simple check does solve the problem.
If it overcharges
After testing and you found out that the alternator overcharges, the battery may warm up that could cause damage to its interior components. The cause of overcharging can easily be pinpointed: it is either poor battery condition or failed regulators.
If your truck’s battery is old, it causes the alternator to work extra hard in order to produce enough charge. This overcharging initiate damage to the battery and this concern can get out of control if your forklift’s battery is old.
If you think that it is the rotors or the regulators that cause overcharging, you may have failed ones. This issue also causes overcharging because the regulators cannot read the level of electricity and as an outcome, it will overcharge the battery.
If you suspect that there is a parasitic drain
The parasitic drain could trigger a state of low charge of the battery. If there is a parasitic drain, the circuit voltage can drop to a very low point. This drain is not caused by the alternator but rather by other components in the forklift’s electrical system.
When troubleshooting for this issue, you need to check first if the battery is charging. You need to start the forklift’s engine and let it stay at an idle position at 1,500 rpm or higher, using a voltmeter, attach it to the terminals, make sure there is no corrosion, it should read between 13.5V and 14.5V, then we can say the forklift alternator is running in good condition.
Now, to test for drain, with the forklift not running, put the ignition in off position, disconnect the negative battery terminal (this is the ground), and connect a test light in line with the ground cable and negative terminal, if it lights up, then there is a parasitic drain somewhere on the system.
Please take caution
Please do remember, the sooner you discover what is causing the problem, the better. You remove the faulty component that could cause the ruining of other parts of the electrical system which could result in a more costly repair.
Now that you know that it is the alternator that is causing the glitch, you would want to replace it immediately. Here are the tips that would help you to avoid the mistake:
It is a good idea to always look for a good forklift alternator. Just I’ve said above, never purchase a rebuilt unit, it won’t last and would cost you more for the repair but instead select a brand new one. The price of a brand new unit ranges from $70 - $100 depending on some factors such as brand and amperage.
Look for an alternator that has a long-term warranty; the regular warranty is 1 year. If you get a rebuilt or used, you would not get a warranty, only on “as-is-where-is basis” term.
If you buy a new alternator from an online source and find out it doesn’t fit with your truck, you can return the unit. Please do take care of the alternator while it is in your possession, the supplier would not accept it if it has any sort of damage.
Choosing between brand new and used parts is just a matter of balancing the cost against reliability. Used parts tend to sell at a portion of the price of a brand new unit – cheaper for obvious reason.
As you know, used forklift parts come with defects which is hard to notice with just a visual inspection and they have short service life resulting in a higher cost. These are the main reasons why you should not get a used part.
We had bought used forklift parts in the past through an aftermarket supplier. We have the first-hand experience that aftermarket parts tend to fail prematurely and have to replace them with OEM parts. The aftermarket parts usually have a much shorter warranty or don’t come with any warranty at all while the brand new ones have a standard of 1 year. You don’t want to pay twice if the used parts die early.
There is nothing wrong with having a tight budget and try not to overspend but don’t fall into trap of using used parts just because they are much cheaper than the brand new ones. They usually don’t last long.
Buying online or from a brick-and-mortar store, you would get the same warranty and expect the same price. Amazon has a wide range of alternators to choose from. If you cannot find the right OEM, you can opt to choose one that is compatible with the brand, model and year of your truck.
If you choose Amazon, you could expect that it is factory price and would ship immediately and it would arrive at your doorstep in just a day or two.