Difference between revisions of "Recharge Time"

Latest revision as of 07:54, 30 September 2010

From Brian Wismann, via the Brammo Owners Forum:

Let me (hopefully) clear up some confusion regarding charging on the Empulse. It turns out to be slightly more complex than the story that's made it into the press (this is common as media prefers simple "sound bytes" of information).

The Empulse will feature an on-board Level 1 charger derived largely from the Enertia on-board charger. Final specifications are not yet settled, but you can expect a power delivery to the battery pack of roughly 850-1000W. This is pretty much the maximum that can be pulled from a 110V household 15A circuit leaving enough headroom not to pop the breaker. At this charge rate, it is roughly 1 - 1.25 hours per kWh of battery capacity to charge.

The Empulse will be configured to accept input from a Level 2 off-board charger that would be purchased separately and kept in your garage or other charging location. As Level 2 chargers are far too large (at the moment) to fit onto a motorcycle, this is a necessary compromise. This does also mean that you would NOT be able to charge off Level 2 charging stations that simply provide 220V/30A from the "standard" SAE J1772 charge plug as that voltage and current need to be converted to battery bus voltage and the current regulated. This does mean that you could install a Level 2 charge station for your Empulse in your home with relatively minimal cost. A dryer outlet (220V single phase) and our off-board charger (basically a current regulating power supply) would be all that's required.

Another important point to note is that our goal with the Empulse is to provide enough range that charge time is not nearly the constraint that it is with the current Enertia. If the bike can give you everything you need for a day's use and then some, do you care how long it takes to charge so long as it's ready to go the next morning?

Later, added to the same post, Wismann added:

I just double checked the specifications listed on the Empulse page and realized that the "Level 2" charge time is not correct. It is being updated as we speak. I also concur that Level 2 charging should be called something else to avoid future confusion. There will definitely not be a J1772 plug on the bike.

The maximum power that we would expect to see from an appropriate off-board charger would be about 2.5kW as the charge voltage will be just north of 100VDC and the charger would likely output around 25A. This would equate to 220V charge times of (roughly):

Empulse 6.0 = 2.4 hours Empulse 8.0 = 3.2 hours Empulse 10.0 = 4.0 hours

Great thing we have such diligent, fact checking Empulse enthusiasts! I apologize for the confusion as it was mostly my error in communicating specifications to the marketing team. As I get more firm information on the off-board charger, I will be certain to update the members of this forum. I cannot provide a cost estimate at this moment, unfortunately.