Outlets? Where we’re going, we don’t need outlets.
Inspired by my last cross country trip
, the Sun Trip 2015
, but a bit disparaged about the amount of time spent last trip huddled up behind soda machines like a homeless person tapping open outlets for energy I decided to make a solar attachment for my e-trike
with hopes of doing my re-charging at the campsite instead.
I also gained inspiration from people building PVC patio furniture
and decided that if PVC pipe is enough structure to hold someone’s 300lb butt it’s probably plenty for solar panels. Comparing a 6ft stick of aluminum to a 6ft stick of PVC the PVC ended up being 1 ¾ lbs heavier and a little floppier but I chose PVC anyway because of the price of aluminum in my region. I considered building my solar panels tiltable, like a point at the sun while you are riding sorta thing but I also considered the hilarity that would ensue with a nice strong cross-breeze so I ended up building the panels to be completely flat for riding and detachable for pointing at the sun when parked. This ended up being an example of a great idea on paper but trumped by actual experience; in practice it was just easier to tilt the entire trike and prop my helmet under the frame than fuss around with detachment. I added a camping gear rack to the solar rig as well to break away from having to haul a trailer.
I used 12s 10ah of Hobbyking lipo for my setup dropping down from my usual 20ah or my last big trip where I hauled a whopping 30ah. My solar charge controller just sent raw amperage to my batteries without any balancing which lead to two problems:
1) after a long day of riding my sagger packs were about a half a volt lower than my fresh packs. Simply plugging the packs together in parallel every few days fixed this nicely.
2) after a long day of riding my packs were starting to get a little out of balance but I fixed this easy enough with a battery voltage checker
with a balance function
I serialized four 50watt HQST flexible panels to make a 48 volt 200 watt setup for my 44 volt battery. This got me about 2.9 amps which felt pretty wimpy power-wise, presumably enough for mutant legged man-beasts but not enough for me so I ordered four more panels. Before I installed them I did an experiment. I connected 3-in-series (36 volts) to my 44 volt battery to see what would happen and it turns out its totally fine and yields the exact same energy (2.9 amps) as 4-in-series (48 volts). This is because the panels actually give out 20 volts per panel so the 60 volts I was getting was enough to hit the 50.4 volts needed for a full charge. So now using just six panels (3s 2p 300w) and getting about 5.8 amps of charge I was kicking along at a considerably faster clip, hauling my out-of-shape rear in the ballpark of 50 miles in the morning, a longish lunch break for recharge then another 50 miles in the afternoon. 300 watts is probably more than plenty for most people but still not impressed by this number myself I grabbed those extra two panels in the garage, bought one more and upgraded to 3s 3p for a charge of 9.7amps if the planets were aligned perfectly and the gods were shining down on me, realistically 8-9 amps was about par for the course. On my run today I cleared 37 miles in 2 ½ hours bringing the battery down from 4.2 volts per cell to 4.0 volts per cell (48 volts). My run was ended early due to a rainstorm but my solar rig is starting to really show some potential.
My Solar Adventures
trip 1: 251 miles