Posts Tagged CARB
Over on the Brammo Owners Forum, a thread about range has been brewing. As often happens, someone from Brammo has added to the discussion. This time, two Brammo folks have chimed in: First, Brian Wismann, Director of Product Development:
Just wanted to take this opportunity to discuss range a bit more completely. After many thousands of miles of testing and reviewing data from multiple rides with the same rider, different rider, varying conditions, varying temperature, varying road surface, etc, etc… I can hopefully shed some light on what range figures mean when they’re presented by a manufacturer.
The 42 mile Enertia range claim is based on actual dynamometer testing of the production bike on the EPA’s LA4 (FTP75) drive cycle which is intended to represent urban driving. This testing was done as a part of a thorough product qualification initiated by Best Buy as they did not want to end up with customer complaints over range. FYI – This is the same drive cycle that Nissan uses to claim 100 miles range on their Leaf and a piece of the drive cycle used by Tesla to claim their 245 mile range as well (they combine it with a highway drive cycle). This is also the drive cycle that is roughly meant to be replicated by the Pomona Loop CARB test in California to qualify for the $1500 CARB rebate. True to the dyno results, the Enertia was able to travel the required 38 miles (two 19 mile loops) on a single charge without going into a “limp mode” and in fact still had greater than 20% battery capacity remaining at the end of the 2 loops.
The truth is that the LA4 drive cycle seems to be a rather poor representation of actual usage of vehicles these days as drivers are becoming more aggressive and speeds in general are increasing. So… while the range claim is true (as opposed to being the result of an optimistic marketing department), it obviously does not accurately predict everyday riding range by a variety of rider types and weights. The effects of even the same rider driving at varying average speeds (i.e. different driving cycles) can be as dramatic as a 2x decrease in riding range. Our attempt to better illustrate this for predictive purposes was originally shown with this graphic and we are working on ways to explain these issues even more concisely. Unfortunately, it is a complicated and variable metric that we (and other OEMs) are attempting to condense into a single figure for the benefit of easy digestion by the customer with varied success thus far…
As a side note, Rob, our Zen and the Art of E Motorcycle Maintenance rider, has the record for range on a single charge. He was able to pull multiple stints of over 55 miles on his Enertia!
and later, Adrian Stewart, Director of Channel Development* at Brammo added this:
The rider does make a huge difference. We have customers who consistently get 50+ miles plus on a single charge. And we have riders like me who love the feel of going from zero to 30 at every opportunity around town and I get about 30 miles. Although that’s a guess as I never get below about 30% state of charge.
Talking with Rob who rode from Minnesota to San Fran recently, it was fascinating to hear how he adapted his style to maximise range….more of which another day.
The orginal 42 miles was calculated by MNSU:
The test involves driving the vehicle on a dynamometer that “simulates” driving on the road. This is required to make sure that every vehicle is driven under the same conditions each time the test is run to eliminate variability. The drive cycle is called the Federal Test Procedure 75 LA4 (FTP LA4) and simulates a driving cycle on US highway #4 in LA, California. Figure 2 is the trace the vehicle must follow when conducting the test. The “X” axis is time in seconds and the “Y” axis is vehicle speed in MPH.
*Director of Channel Development: Not sure what he actually does at Brammo, but according to my sources it has something to do with llamas.