It’s All About the Electrons
While the Four Wheel Camper’s batteries and functionality depend on the sun, so does the Evelo Aurora e-bike’s battery – once I’m out on tour. It siphons power off the Four Wheel’s house pack to keep itself charged. All good things come to an end, and the original Evelo 48V 10Ah battery that shipped with the bike has now cycled enough times that it is no longer very useful for anything but the shortest, easiest errands. It actually began to sag a year ago, so this is a belated replacement. The spare battery that I ordered with the bike immediately showed signs of swelling and proved defective, so Evelo replaced it. That replacement broke an internal wire right after its warranty had expired, right at a place that was not possible for me to repair.
Evelo sells its replacements at $700 per – almost three times the market cost of this battery voltage and capacity. They are nice batteries, since they come with a marginal-quality spring carrier rack on top of the case, and they are well-protected against weather except when their spring-loaded charging port covers refuse to stay closed. The Aurora’s frame carries its battery case in a steel tube perimeter hoop, which gives it some protection in a crash and allows it to be key-locked in place, a useful trait in urban environments. It’s a well-integrated system that allows the battery case to be buried halfway down into the hoop, which allows a seatpost carrier to be installed above it if need be. But an average of $233/year for e-bike batteries, especially at this minimal capacity level, is simply not acceptable to me. Time for a change. Many e-cyclists would toss the whole thing and start over with a vintage bike and a gas engine drive kit, which is much cheaper and faster on the level. They don’t do so well at inching up steep, rough trails and I’m not yet ready to start packing cans of gasoline. But it’s a choice.
Since I’m not really conversant in e-bike geekdom, all I knew was that how the battery cells were wired up together was referred to as “13S4P” and that, given my bike’s built-in battery management system and need to use no more than a 2-amp charger, I’d better be pretty careful about sticking to that code or at least make sure that output voltage is just a hair above 54.0 volts, and that any charger supplied with it has a rated output of 54.6V, regardless of how many amps it supplies.
This is about where I started jumping through hoops. Electrical interchangeability took priority over physical traits. It would have been nice to find a replacement battery whose internals could fit inside the oddball Evelo case, but I found none. What I wanted was to have to do very little in the way of adapting the Evelo’s wiring harness to be able to use the new battery. No “one-way” mods that would prevent the use of original Evelo batteries. The new battery should also be able to use my existing 2A charger interchangeably with whatever came with it, connector, voltage and all. That’s because the Intrepid’s inverter is rated at 150 watts output, and the Evelo’s 2A charger actually draws a measured 120 watts, taking up to 5 hours to recharge a battery. That’s fine with me, and is highly preferable to getting a much larger inverter and then rewiring with much thicker cables to support it, all for just one “big” bike charger that can recharge faster than I need it to. I’m not going to wet my pants if I can’t force a second epic journey two hours later, as part of my Adventure Lifestyle. That would cut into my nap time.
E-bike kit builders tend to know all about how to wire things together, and all they need is a battery with some wires sticking out of it. They’ll take care of the rest. I’m in a different boat. The tech side of this isn’t an interesting hobby to me and, not wanting to screw up a rather costly production e-bike, I’m looking for virtual interchangeability without Evelo’s stratospheric battery costs. Despite wanting to once again be able to bike longer distances over hilly ground, I don’t really care to get involved with the guts of straying outside the Evelo parts world. Don’t make me fake up too many adaptations to get a new battery to work with my existing bike and charger. These days, I’m more interested in errands and exploring than I am about geeking out on cool mods.
A unit from a Chinese outfit that branded it “Vpower” fit the bill, and frankly was the only battery I’d found that uses standardized connectors in a way that required only minimal brain power to implement. It’s almost plug & play. Almost. It uses the same round “XLR” charging connector with the same polarities, and so can use either one of my two small chargers in place of the 6A one that shipped with it. The only reason it isn’t plug & play is because Evelo pulled a fast one on their harness connector, which links the battery to the bike’s drive and control systems. The new Vpower battery uses the same IEC 60320 C13/C14 connector that many e-bikes, most desktop computers and many appliances use. It has three blades all oriented the same, but out of line with each other. Evelo uses what amounts to being a proprietary plug in which the center pin blade is at a right angle to the other two, preventing a connection.
Besides my suspicion that Evelo wants to lock its buyers into inflated battery prices, I was curious to find any other justification at all. An email to Customer Service netted a concern that interchangeability with the industry standard connectors might allow a user to plug a computer cord into the battery output port, which would feed 120VAC into it. That would have interesting results, but no one else in the industry is apparently worried about this. However, given the inherent motivation of American lawyers to make abject stupidity and carelessness resemble some kind of virtue of innocence untainted by crass intellect, I can see how it would be a concern as well as an opportunity for some unwarranted profit. However, when two out of three packs fail prematurely and the third is nothing to write home about, a better alternative needs to be found. At this rate, I could blow through one Vpower battery per year and still be financially better off than I was before.
Fortunately, Vpower supplies a proper 3-prong plug that can be used on the battery end of an adapter wire. The old Evelo battery case supplies a harness plug for the other end, though they are also available here at the moment. I got that link from Evelo, and because the connector is not an industry standard, I could find no other source. In all cases, the third (center) terminal is never used for anything electrical. Internally, the Evelo battery case uses mere 16AWG wires, and the connector that Vpower supplies will not accept larger than 16AWG Y-terminals inside, so it’s best to add as little additional length to such spindly wires as possible. I removed the center blade electricals on the Vpower plug (since they aren’t used) in order to make shorting out a little less likely in case of overheat.
Despite the relative ease in making up a sort of adapter extension cord, the new Vpower battery presents many physical trade-offs for the Aurora, especially in the way that I adapted it. The slick way to use the Vpower 48V 10Ah would be to mount it on the Aurora’s hoop frame bare, connector ports forward. The 10Ah Vpower’s case is the same width as the Aurora’s hoop, and I’m sure a clever setup that allows quick removal (for charging) could be improvised. This orientation would also allow harness connection directly into a triangular case that also houses the bike’s battery management controller, eliminating a foot of wire. That’s not for me, though. I took one look in there, noted the rat’s nest and poor access, and just closed it back up. I do not need another project, particularly one without any documentation, schematics, etc.
An alternative would be to mount the new pack to a rack that attaches to the bike by its seatpost. (The Aurora’s funky frame design does not allow the use of conventional rear carrier racks.) I’ve found these seatpost racks to be prone to shifting to one side or the other during a ride, and although using a rack is probably a viable option, I did not want to get involved in the detail work that this approach would require. Not now.
The way I chose to mount the battery is to take the temporary, minimalist approach, assuming that there would be some technical problem needing to be dealt with. Then take a stab at making this mount work full-time. If it can’t be cajoled, then note the various problems and work on a better, more involved mount type next winter. I also prefer that the bike be left still able to mount an Evelo pack as well. The Vpower battery of this low capacity (about $230 when I bought it) comes with a “carry case” that’s big enough for it to swim in. Higher-capacity model variants fill the case better. Fortunately, that case has four pairs of Velcro-style tabs underneath that just happen to be located such that they can each wrap around the frame hoop. That gets and keeps the case roughly in position.
Vibration being the herald of death to lithium batteries, the Vpower comes with a dense foam “earthquake pad” that it should sit on full-time. There’s a large hole in one end of the zippered case large enough to allow the harness connector through, to power the bike. To keep the battery in place, I made rolls and pads of bubble wrap to serve as cushioning spacers. There’s a fairly thin layer underneath the pad, and a considerable amount on top to help dome the fabric and hopefully discourage trapping the occasional rainfall. Since a Nylon fabric case is not real weatherproof as compared to the original hardcase, I made a token effort with some Coleman water repellent spray on the top and sides, the kind that’s usually used on jackets and hats. The Vpower battery itself is well-protected – with the exception of an unsealed on/off switch. Why trap water inside the carry case if I don’t have to? In any case, this bag is that fashionable black color that shows every speck of dust in order to enhance the viewer’s perception of eternal filth.
To recharge the battery, it needs to at least be exposed by unzipping the hinged “lid” of the carry case. Then slide the battery’s XLR connector shield out of the way and plug in the charger cord. I can charge on the bike in my RV park, but seasonal touring requires battery removal to recharge indoors. That’s easy enough with this setup, as long as I don’t lose any bubble wrap pads to the wind. One can alternately just unplug and remove the entire carry bag, but for my setup that’s more work than just zipping open the bag. The big “IF” of this mounting setup is whether it can be made to work despite washboard roads and violent bumps. The safest way to mount these things is rigidly, with the vibration insulation being so firm as to only be useful in a crash. My improvised mounting system can’t be cinched up that tightly, so long-term use will have its own story to tell, as will any accommodation there might be inside the Vpower hard case to protect wiring from vibrating and snapping, as it did in Evelo’s case.
Really, the remainder of the winter and the upcoming tour will be one big shakedown and evaluation run so that I can not only determine what’s “good enough” for mounting, but can start to access how the little 10Ah Vpower holds up compared to the Samsung-celled Evelo pack when it was new. This battery setup no longer allows the use of the seatpost-mounted shopping basket, but I’ve rarely used that in the last couple of years since the lightly-loaded B.O.B. trailer is just not something you have to compensate for or keep in mind.
One significant tip I’d discovered when battery hunting was that these batteries will allegedly have a much longer service life if charging is stopped at 80% full, which of course chops the expected range per charge quite a bit. But if you aren’t always pushing the limits of that range, why not help the pack survive? Unfortunately, programmable chargers that can stop at 80% or 90% are rare and costly, although when each pack can live four times or more longer through reliably undercharging, that’s a heap of money already saved by the time you hit your second battery. The frowny face for me is that they pull too many watts for my inverter even at their lowest 48V setting. I have not yet discovered a practical way to short-charge one of these lithium batteries with even a vague sense of quantifying the results, but that doesn’t mean there isn’t one. In the meantime, one can do according to Evelo and unplug the charger as soon as the charge routine completes, and leave the charger on up to 9 hours longer only when the battery is showing signs of sagging in range. That’s better than nothing, but the serious boost in service life will apparently be well below that full charge level, where even a by-guess-and-by-golly approach will likely yield benefits. You’re always free to full-charge for extra range when needed, but packing a fast charger when you know that an outlet is available at the far end would address both issues at the same time. Apparently, a lifespan rating in cycles doesn’t mean much if they aren’t full cycles, and a lithium battery responds better to activity than it does to just sitting around. That means regular use and frequent but only partial charges, if possible.