FrogE #2 is nearly done and nearly ready to send to its home in Maryland. We have just a bit more testing to do, including a long highway drive next Sunday September 29 to the Fairfield County Concours in Westport, CT, where the car will be displayed as part of an exhibit highlighting electric sports cars. Come say hello!
This week, we changed the rear leaf springs and raised the car, then shimmed it down to the right height. You might be able to see the difference from the photo we shared last week. Now the car sits with a few inches gap between the fender tops and the top of the tire (at 12 o’clock). It was bottoming out and hitting the bump stops on hard bumps with the original (and sagging) springs in place, and the new springs fixed that issue and dramatically improved the ride quality.
Our biggest recent breakthrough was to boost the charger peak voltage so that we could finally determine maximum range for this particular battery configuration. It turns out we have 81 miles of range, with combined highway and city driving.
I drew the short straw to verify actual range in the field. The onboard volt meter tells us the capacity but this is non-linear chemistry, so range is not directly correlated to voltage. The volts stay stable for most of the capacity, and then fall off rapidly when the pack is running low. Off I went to determine the actual range on the road. Ironically, many Sprite fuel gauges read full until you have burned half a tank, and then the gauge falls more rapidly. The electric “fuel” gauge behaves in a similar fashion.
At 81 miles traveled, the controller derated and reduced available power, which told me it was time to pull over NOW. Adjacent at this moment was the house of the fellow who does our landscaping, and I figured he might just have an extension cord to help me make it back to the shop. There was no answer at the front door, but sure enough, in the driveway I found a 50 foot extension cord next to an outdoor 110 outlet, and I immediately plugged into the grid.
In this moment, it sure seemed like finding power was easy… just turn down any driveway and fill ‘er up. 110 power limits the rate of charge though, so it’s really only for emergencies. The 220 charger in our shop is quite a bit faster, and public charging stations are faster still. Regardless, this was what I needed to make it home, and after an hour of smart phone calls and emails, I coiled up the extension cord and hit the road.
We had hoped for more range, but this particular battery pack (and other factors) limit us to roughly the 80 mile mark. We always have the option of supplementing our range with a Tesla pack… these batteries have a greater energy density, and while they are only available used, they should have a 20 year lifespan so this is an option for people who need to travel further on a single charge.
That said, having lived with this car for a few months of testing, I was surprised how long it takes to use-up a full charge. It’s rare that we set out for an 80 mile Bugeye drive, and I suspect it’s rare for our customers to do the same. Sure, there are some folks who routinely make long trips, but they’re probably not interested in electrics for that application anyway, at least not yet.
Most of our Bugeye outings have been relatively short hops of 20 miles or less. Here in the Northeast, that works nicely, and a 20 mile drive takes us where we need to go and provides ample time to enjoy a fun drive in a Sprite. Thus, I have become convinced that 80 mile range works just fine, especially if you recharge after every 20 mile journey, and depart each day with a full 80 mile range. For most customers, that’s ample capacity to head to the beach or apple orchard, run some errands, or go visit a friend, and return home for a recharge, with ample reserve.
This week, we will be upgrading the car’s onboard charger so that it charges twice as fast. This will make off site charging sessions twice as productive. The more powerful charger will allow us to completely fill the discharged batteries in 8 hours, and to also boost 25% more range from the system with a two hour public charging station stop. For example, 100 mile range can be attained with a two hour boost stop.
I have a 72 mile round trip journey to Westport next weekend for the concours. I’ll probably plug in for 30 minutes at the Westport train station before I head home, just to play it safe.