I am looking at both the LM2102SP and LM2142SP models. The LM2102SP comes with a 7.5Ah battery and the LM2142SP comes with two 5.0Ah batteries. I have a small yard, and so the extra mowing time afforded by the dual battery model is not something I really need. And so my question is about the relative mowing power of the two models. All else being equal, one 7.5Ah battery should deliver more power than one 5.0Ah battery, right? Does the dual battery LM2142SP (which is brushless) simply allow you to mow longer than the single battery LM2102SP (brushed)? Or is the dual battery model able to use both 5.0Ah batteries at the same time to deliver more power than a single 7.5Ah battery? I'm worried that if the extra battery is just to increase mowing time, not mowing power, that the LM2142SP will be less powerful than the LM2102SP. But the dual is brushless whereas the other one is not, and I don't know how much difference that makes. As the dual model is quite a lot more expensive, I'd like to know whether or not it is at least as powerful as the single battery model before deciding to buy it.