Hey folks! I'm in the process of building an RC lawnmower and I've noticed many people installing alternators to charge their batteries. It sounds practical, but I've heard mixed opinions about alternators not being capable of fully charging the batteries, just extending their range a bit. I currently have a 95Ah car battery lying around and I'm debating whether to use it or opt for a smaller motorcycle battery paired with an alternator.
3 Answers
The 95Ah rating basically means it can provide a specific amount of current for a certain duration. An alternator is designed to keep the battery charged while the engine runs, similar to how your car operates. Just keep in mind the output from the alternator at different RPMs needs to match your runtime expectations!
It sounds like your mower could have a gas engine, so the battery size might not need to be as large. An alternator can charge your battery well; think about how cars run without being plugged in all the time! Just remember to account for your drive time and the RPM of the alternator when the engine's idling.
Using a huge 95Ah battery for your mower might be overkill unless the mower has a powerful engine. You could consider a lighter lithium motorcycle battery, which would provide enough power without weighing you down too much. Plus, they last longer and aren’t as pricey as before!