liveforphysics said:
You rock so much Justin!!! You know that when the whole forum wants your amazing creations,
Well, most of the people we've met up with on the streets, they just want the electric skateboard and could care less about the rest LOL! But I'm sure there will be some forum member appreciation of the other goods.
That brings us to the one of the other new pieces of hardware under field testing here, and one that's of fairly vital importance to ebike touring, the CHARGERS!! After over 2 years of R&D we're finally settled on what should be the final build details of the "
Cycle Satiator - Universal Battery Charger". We had a working demo of this at the Taipei bike show last year, but went through a few top to bottom redesigns until it now looks like this:
View attachment 5
In a nutshell, that's a 95.5% efficient, water sealed, fan free, 360 watt, power factor corrected, universal input, programmable 18-60V output, all purpose battery charger that can be preloaded with several dozen different voltage and current profiles for whatever chemistry and capacity battery you have to throw at it. The goal was to make something future proof and also rugged and compact enough that it could be left installed onboard a bike frame with all the weather and vibration that these things get exposed to.
The earlier prototypes were a little more angular and had fins for more effective cooling, but in the end the shorter fins had only marginal cooling improvement, and if you make them long enough to do much good via natural convection than they stick out as high as the charger body itself and then it's hardly compact.
View attachment 4
This is what the internal power circuitry board looks like. It's densely laid out, and this being an earlier board revision has a number of small hacks on the PCB:
The enclosure shells were all CNC machined from billets of aluminum, and each slight design revision required several days of recamming, jigging, and machining before we'd know for sure how it all turned out:
View attachment 3
The tooling cost to get this diecast from aluminum is somewhere north of $20K, so it's super important to get all the fitting details right on the first time we send it out, and there is a lot of interplay between the electrical component placements, connector port / button / screen locations and the enclosure that needs to fit around it.
On this trip, we've got the one 'C' model and two of the earlier finned 'B' models in our arsenal, plus a standard High Power brand of fan cooled charger that runs at a mere 3 amps. The Satiator chargers are all set with 6A charge profiles, so our total charge current between the two bikes is 21 amps or just over 1000 watts. We're consuming about 26 Wh/mile each, so it translates into an effective charge rate of 20 mph, or each hour of charge gives us another 20 miles of range.
On our rigs, we've got 4 battery packs in parallel, and we leave them parallel connected for charging and discharging. So when they are charging, plug the charger into the charge port of one battery pack and then expect it to be distributed to all the other packs via the parallel connections of the discharge leads. However, it's not at all obvious in that arrangement if you've accidentally got one of the 4 packs disconnected or turned off while charging, and in that case you could easily start off on the leg of a trip with just 75% of the expected capacity. This is where the display screen readouts on the Satiator come in handy, since it summarizes how many amp-hours it put into the battery pack on the charge cycle we can have certainty about what is in the tank:
On the trip from Portland to Corvallis, I used 46 amp-hours from the paralleled battery assembly, so was expecting each charger to put in 23 Ah to know all was good, and this kind of confirmation does a lot for piece of mind that you won't be stranded.
