Depending on the kind of mower you have, your model might have an alternator. Alternators are used in the powerful engines of mowers to help spin the blades and cut grass.
To narrow it down, only riding mowers have alternators and push/petrol-powered mowers don't. This is due to the fact riding mowers require more engine power than other mowers because of there size and the large area of ground they cover when in use.
To find out where these alternators are in your riding lawnmower and how they work, we have put together a little guide below to teach you everything you need to know about your lawnmowers alternator.
As we touched on above briefly, the role of an alternator in a riding lawnmower is to power its battery to help the powerful engine operate.
This is similar to a car and keeps the battery charged, being spun by another belt separate to the blade belt on your mower generating energy to charge the battery of the mower.
The alternator of your mower is extremely important and can be responsible if your mower is starting to lack in power, meaning it might need to be fixed to see if its in a good condition.
Regular human force push mowers don't use an alternator as they don't need a battery or even fuel to operate. Instead, this mower is powered by the motion of you pushing the mower on to the grass and the cylinder grabbing it and holding it against the stationary blade on your mower.
These mowers tend to be very affordable and not noisy due to the way they operate.
Petrol mowers on the other hand also do not have an alternator as they use fuel to power there engine instead and electric mowers use a rechargeable battery which doesn't require an alternator as the doesn't use as much energy from their motor in comparison to a riding model.
The alternator of your riding mower should be located under the flywheel of your engine. The engine is located under the hood of your mower, and under the engine cover which is located underneath, you will find the flywheel.
The alternator will be in a circle shape that has a hole in the middle like a doughnut, you will have to remove the flywheel first to access it.
If your battery keeps cutting out on your mower or going dead when you aren't even using your mower, the alternator could be to blame.
They also tend to be blamed if your mower suddenly cuts out or the battery keeps losing charge over and again quickly despite giving it a full charge beforehand.
We have listed out a couple of ways to check your mowers alternator below to help you figure out the issue.
One of the ways you can check if your alternator is working is by turning on the headlights of your mower while it is running.
When your engine is running, that's when you can cut it with the lights on and see the headlights dim themselves, if they don't then you have a bad alternator.
Remove the flywheel and have a look at your alternator to make sure everything is working fine.
For fixed alternators, you might notice burnt out coils which could be contributing to an uneven charge on your mower and for non-fixed alternators uneven wear or mounting that's causing the alternator to spin in the wrong way.
If you are not confident with your findings in both steps above then it might be best to test your alternator with a multimeter.
First, find your mower's battery and connect the black wire of your multimeter to the + terminal on your mower's battery, make sure the other end is connected to the COM port on your device.
Then, take the red wire of your multimeter and connect it to the AMP port. After making sure both wires are connected you can turn the mower on full power for a couple of minutes and note down your findings, then compare this with your manufactures recommended findings to see if there is an issue.
A lower reading than recommended will indicate there is an issue with the alternator.
Do lawnmowers have a charging system?
Yes, this is essentially the alternator, as the belt turns the alternator then charges the battery.
How do I know if there is an issue with my alternator?
As we mentioned above, battery issues such as quick loss of charge without using your mower can indicate a bad alternator, the best way to determine if there is an issue is by using a multimeter to look at the voltage readings.
Why don't smaller lawnmowers need an alternator?
Smaller lawnmowers do not have components such as headlights, starters and electric clutches, riding mowers, on the other hand, have all these and more so need a battery to run and cover large areas too.
Is there another kind of charging system for tractor lawnmowers?
Yes, riding lawnmowers either charge themselves with a belt-driven alternator or a stator alternator depending on the model you buy.
What is a multimeter?
A multimeter is a handheld device that you can buy which displays the voltage and current of what it's connected to. This device is the best way to determine if your alternator is not producing enough power.
Overall, you will only find alternators on big tractor style riding lawnmowers that require this kind of power for the engine and battery to function.
The best way to figure out if there is a problem with your alternator is by using a multimeter and seeing if your findings are low or not typical of your mower's model.