What Does 'Ah' Mean On Lawn Mowers?

When it comes to picking out a lawn mower, it feels like there's still much to decide on even after you narrow it down to an electric over a gas machine. There is a lot you need to know before buying an electric lawn mower in particular, with one of the most important things to understand being all of the fancy electrical acronyms and terms. For example, one you'll see a lot on the batteries you buy is the "Ah." If you're used to gas-powered tools, the addition of the Ah can be a little confusing. It stands for amp-hours or ampere-hours. 

It's a unit of measurement that explains how much power your battery can provide the lawn mower in an hour. On tools with a more consistent energy drain, it instead tells you how long it can run until it needs to be recharged. For instance, if you have a 6 Ah battery on your lawn mower that only uses 3 amps, it will go for roughly two hours. To put it simply: The higher the Ah on your lawn mower, the more power it has and the longer it can run. It's essentially comparable to a gas tank — you can always put more "fuel" into it, but if you want to be able to mow your entire lawn without stopping, you need a bigger "tank."

Basically, if you want a mower that can go longer without needing a charge, you need more amp-hours. The problem is, the higher your Ah, the more expensive your machine will be. You could certainly choose something like the longest-running battery mowers for large lawns named by Consumer Reports, such as the Greenworks MO80L421. However, it might cost more than you're willing to spend.

The best option is to find a balance between price and runtime. To do this, you want to track how long it takes to mow your lawn. Set your timer the next few times you mow. Or, you can use an online calculator to get a general idea of the mowing time by taking into account the size of the mower, your acreage, and your average speed. Generally, you can expect to run somewhere between 2 and 8 miles per hour, depending on how fast you go and the type of machine you buy. 

One of the mistakes everyone makes when buying a lawn mower is getting a size they don't need, but you can also buy the wrong-sized battery with electric lawn mowers. Of course, you may not have to do all of this math. Many companies will straight up tell you how long the lawn mower is expected to run and roughly how many acres it can cover in that time.