Is there an aftermarket item out there that can allow me to have my Prius run around town up to 35-37 miles per hour just on electric and if I need to accelerate faster the gas licks in? I heard about an item that cost around $70 that can be installed to let this work. I do not have a factory EV switch like some do. If so, what is it called, how much the cost, and how is it installed.
You can add an EV switch for a few dollars in a couple hours if you have any mechanical or electrical experience, there are several guides on how to do it. I believe there are plug and play versions you can buy, too. However, I don't think it will do what you want it to do. I think you have to be stopped for the EV switch to work, so you would have to accelerate to your desired speed in just EV mode. That would drain quite a bit of your power. Then you'll quickly drain what's left of your charge after you get up to speed. In the end, you'll probably get worse mileage because the engine will have to start up and recharge the battery (while is much less efficient than using the engine to accelerate in the first place). I would read the threads here and other blogs about getting the most mileage out of a Prius. Maximizing EV usage will hurt your mileage in most cases, but maximizing engine off time will likely increase it. The most effective way is to pulse and glide. Accelerate to a little above your target speed/the speed limit. Then lift off the gas pedal all the way and reapply it just a little bit. You should see all the arrows on the screen disappear (if the car is warmed up) and you are now coasting, engine off and neither generating or using electricity. Coast like this until a few MPH below your target speed, pulse (with enough pedal to kick the engine back on) and repeat. Takes some practice and is easier to do with less cars around.
An EV mode button can trigger EV mode when starting up and in motion, depending on state of charge, temperature of the battery, whether or not the engine is warning up, etc... See here for more info...Prius EV Mode Button - EAA-PHEV However, it doesn't help fuel economy to do this a lot, unless you have a PHEV kit. In some cases, like when just moving a very short distance, this will avoid a warmup of the ICE, or to use up some charge at the and of a trip, like if you're arriving at your destination with 7 Green bars to make room for more charge when you next drive (like climbing a hill and then descending it later). LG-AS695 ? 2
I installed a EV switch in my 2008. I find it's really only "worth it" when I know I'll be going down a big hill that will regen a lot of energy and my battery is already full. I'll switch to EV well before the hill to use up some battery power which I know will shortly be replaced when I go down the hill. This also has a side effect of increasing brake pad life since the car would switch to complete friction braking once the batter was completely full.
If you put it in B going down big hills, it'll spin the engine without fuel to bleed off speed after the battery is charged. Not as good as making some extra room for regen like you do, but handy for when the battery does fill up.