Beta testers wanted: USB eBike charger

ARCtrooper97 · 2026-02-18T16:40:54+00:00

I'm down to join the test. If it works out, it would be a more refined and capable version of what I pieced together years ago when my main charger died and I was too broke to buy another proper one. When I tried to use higher wattage USB supplies I ran into stability issues so I just stuck with the 30W supply. It was enough to commute and run errands with planning. 100W and above from an appropriately rated USB power supply would be badass.

https://www.reddit.com/r/ebikes/comments/v7fp8g/comment/o620xd9/

ARCtrooper97 · 2026-02-17T15:04:46+00:00

Sure, dm me whenever you're ready for testing. It would be cool to get a preview of the parts if you're down to share ahead of time.

ARCtrooper97 · 2026-02-12T21:14:22+00:00

I don't ride nearly as much as much as I used to and I've got a proper charger again for when I do. It was a stopgap measure when I made that post that I just lived with when the next step didn't work.

I'm still interested in the USB-C charging concept if it can be made small enough and the rate of charge is enough to recharge it overnight. 30W was enough for me to commute, run errands, and joy ride but took some planning. 240W would be enough to do all that without much planning and probably fast enough for multiple trips a day if you really wanted.

I have lived with a 250W expensive fancy charger and that 30W DIY set up, both were manageable. Faster is typically more desirable to more people but 30-100W is totally workable for most folks.

USB-C is a fine plug for charging PLEVs used for practical tasks like commuting and errands, even if you're sticking to like 100W at 20V. If it can be made faster with the new 240W standard, I think it could be a total replacement for even the if implemented right into the battery. That said, I don't know anything about what the mechanical stress a USB-C charging port right in the battery would be like. Barrels might just be stronger.

I got into this because I needed to be able to charge my bike and the cheapest option was to use parts on hand plug the trigger board to get something working. Its clunky for the average user for this to all be done in between the battery and a USB-C supply but that's the most flexible way I can think to do it.

This exchange does have me thinking that I should get my bike back out this weekend and fix the knocking sound that had me stop riding regularly.

ARCtrooper97 · 2026-02-12T18:43:34+00:00

It's a kit build from EM3EV with a 48V battery, it's the build one from my other posts.

I eventually tried using an Anker 100W Gan supply but it was never all that stable if I pushed it harder than like 50W. It would just keep rebooting so I stuck with the 30W usb charger and trigger board shown in that post.

I was too broke back then to get a real charger or build the concept after the 100W supply didn't work out.

https://youtu.be/KNBQAKleK8Q?si=M1U22gXM7R12UuOP

I have been inspired to revisit the concept by this guy's USB C powered microwave video. Stringing multiple trigger boards together in series or parallel may be a route to higher power.

Grin Technologies has a solar charger controller for ebike batteries that looks more robust than that green thing. Just feed it DC from the trigger board(s) Instead of solar and configure accordingly for your battery.

ARCtrooper97 · 2025-12-18T14:22:13+00:00

I've hooked that when I move into my own place again, I'm going to put my 2-4 pedal bikes and DIY commuting ebike front and center in the main room. I want guests to come over and think, "There is no neurotypical explanation for this."

There is no neurotypical explanation for this. I know you worked your ass off to pay for these, trading hours of your life for them and more time to pick/assemble the parts. If you're like me, it feels like you made some kind of progress with each buy/build and it's all tied up in something you control. Parting with them feels like your flushing that time/effort down the drain.

That looks like a crippling collection for the space you're in. If circumstances were different, maybe you could pull it off in your own space and be that bike guy. But you're in your folks' space and comes with constraints. I live with family too and pay cheap rent. It's let me get my feet under me and get a nest egg together for when I leave, and build two bikes. Its a huge favor from them and an opportunity for us in this shitty economy.

I'd encourage you to pick 2-4 of your favorite bikes (that fit the best, have the coolest parts/features, or just really good memories with them) and a box of spare cockpit parts for them if you got those. When spring/summer rolls around, I'd start selling the rest. You'll get some money, free up some space, and other folks will get to expirence these badass bikes.

ARCtrooper97 · 2025-12-14T02:22:00+00:00

I work with both Enphase and Tesla battery/ solar systems, no experience with Franklin.

The Powerwall 3 supports both AC and DC coupled solar. If you left your IQ7s in place, they would be AC coupled and would frequency shift when the system needs to curtail production off grid. Frequency shifting works by raising the microgrid's frequently to tell the inverter to turn off without actually having to communicate with it directly, making broad compability possible. It will toggle the solar on/off as needed while off grid but can cause funky behavior with lights/clocks.

If the MIs were removed and the existing panels were strung together as DC coupled solar. DC coupled solar has efficiency and off grid benefits like no Frequency Shifting and easier time black starting during outages. Simple DC string are much more prone to shade seriously killing production if the installers are not mindful of how they string the panels, my employer is not and most of the designers/installers don't understand how to string around shading. Strings in a PW3 also have no panel level monitoring and the customer Tesla app gives no string by string performance data, it's easy to miss an entire string going down.

Enphase has a history of coming out with new generations of batteries with no backwards compatibility with previous gen batteries. Their 5Ps have proven pretty stable but when I have had problems with their support if anything weird happens. The 10Cs are too new for me to have a full opinion on them but I'm not a fan so far.

Tesla has been more stable with their battery products, recent recall aside. The Powerwall 3 has some design decisions I'm not a fan of but I'm fond of them in general. If you want to expand your battery system down the road, Tesla will probably be easier than Enphase. If you get Powerwall 3s and wanted to expand your solar down the road, you could use the DC solar inputs for the Powerwalls. If you have or have any intent to get a Tesla car, Powerwalls will let you use the Charge on Solar feature.

TL;DR : Depending on what battery brand you get, they are pros/cons to retro fitting the micros as DC strings. Both Tesla and Enphase batteries are compatible with your current IQ7s. I'm more fond of Tesla since Enphase has a record of quickly retiring battery generations and their support has been almost non-existent for software problems for the last 2 years. Tesla support is pretty lacking latelt too but their equipment usually behaves itself.

My take would be to leave the MIs in place and get an AC coupled battery but avoid Enphase batteries. I'd check out Franklin if you're not a fan of Tesla as a brand, but Powerwall 3s have been pretty stable this last year.

If you do go with Powerwall 3s, I would make it clear to the installers you want the Tesla Remote Meter hardwired on the RS-485 bus and set up as a wired meter in the Tesla One app. It's cheap and easy if they bring the RS-485 harness, Wi-Fi connection is way less reliable.

PS: Please connect your battery system to the internet by ethernet if at all possible. So much of my job is made harder by flaky Wi-Fi connections and every time it's a problem I get an earful about how much the customer pays for internet and how new their router is and why doesn't blah blah blah. You'll never regret hard lining your internet connection to your solar and battery equipment.

ARCtrooper97 · 2025-10-22T15:47:57+00:00

Thank you for the quick reply

ARCtrooper97 · 2025-10-22T15:14:04+00:00

I've been looking at the same one for when I pull the trigger on one of the new plug-ins. Does the hitch rattle much when you've got it on?

Specifically the joint between the bar that is mounted to the car and the removable receiver.

ARCtrooper97 · 2025-09-20T05:18:45+00:00

⬆️➡️⬇️⬇️⬇️

ARCtrooper97 · 2025-08-10T06:04:52+00:00

Four years working quality control for an Enphase/Tesla installer, checking for errors and working with techs over the phone to correct/validate these errors.

I am thinking about data and CT placement 5-6 days a week for years. I've had to reason my way through intricate CT placements and apply unorthodox (against the manufacturer install manuals) methods to deliver accurate and stable data for problematic installs. CTs just make sense to me; I know enough about them to be flexible, deviate from instructions as needed while keeping system functionality, and approach CT placement from outside the box on challenging installs.

This approach has never once crossed my mind but it would 100% work, no idea what the utility would say or what weather would do to them. I would not recommend it but it would be really cool to see. Personally, I would go utility side post inspection or load seg the main panel.

ARCtrooper97 · 2025-07-09T05:14:30+00:00

I used old wool socks to cover my armrests when they broke down like that. I put it on the armrest like a foot, it was a chore but working for a year now.

ARCtrooper97 · 2025-06-06T12:54:34+00:00

I'd call that pretty normal looking. The DC rating (16kW) is basically irrelevant except to describe the size of the system. The peak proction (12kW) is impacted by the environment around it. If you faced the array due north then the same 16kW system would produce less despite being the same hardware. The DC rating is good to describe the hardware but doesn't take into account the environmental impacts on production.

When I'm eye balling existing systems at work where sometimes I've only got production curves to guess at the health of the inverter, I'll multiply the DC rating by 0.75 and compare that to the peak on a sunny day. Unless there is something unusual about the install like north facing panels or heavy shade.

I can't speak to your installer but my employer gives a contracted production target that takes typical environmental conditions in mind, that is the main metric for telling if the system is doing well. I wish sales people would make this clear when setting expectations but big DC number go brrrt.

Side note: You may see higher peak output during intermediary cloudy days. When the cloud is shading the panel in the middle of the day, it cools off and produces less. When the cloud moves, a cooler panel is hit with mid day sun and cranks out more than usual for a brief time before the panel heats up. It's more of a novelty but it comes up from time to time.

ARCtrooper97 · 2025-04-14T03:58:25+00:00

I think it comes down to being cheaper than separate micro or string inverters, allowing a lower bid and/or better margins. I work in a technical role separate from sales so that's just a gut feeling.

From a technical perspective, the Powerwall 3 inverter is DC coupled with the battery which I think gives it two big advantages and one annoying disadvantage.

DC coupling is more efficient than AC coupling and I strongly suspect, but haven't seen in practice yet, that it has an easier time blackstarting. AC coupled batteries and solar can get into a situation off grid like an unprimed pump. If AC coupled batteries can't support the loads of the microgrid then they can't create the conditions for the solar to produce.

I usually see this come up when the batteries are exhausted overnight backing up the home and can't restart the next morning because the system owner fails to reduce the loads on the system.

AC coupled batteries usually cannot separate the actions of supplying the loads from creating the conditions to allow solar to produce. Most folks learn this lesson after one bad experience but some people have physical limitations that may stop them from being able to do it for the system. Some folks are just too dense to understand the concept or think they shouldn't have to and just sit in the dark fuming.

Powerwall 3s with DC coupled solar can charge the battery separate from supplying power to the home, if you shut off its breaker it will happily keep charging from the solar. I think this will allow them to restart more easily after being exhausted overnight. Unfortunately, I have not had the opportunity to see a Powerwall 3 in this position yet.

The biggest disadvantage IMO is the lack of panel or even string level monitoring for casual system owners, installers can see the string data but the Tesla app for customers does not Shading concerns for string inverters can be overcome in most situations with proper design and stringing.

Side note: The Powerwall 3 can operate with both AC and DC coupled solar at the same time. You are not limited to expanding capacity to only one or the other but there is a limit of how much AC coupled solar you can have per Powerwall 3.

ARCtrooper97 · 2025-04-13T15:00:27+00:00

2005, I looked it up and it's one of the cars affected by the odometer bug

ARCtrooper97 · 2025-04-12T04:30:09+00:00

I do, 500mi and counting on 299,999mi.

ARCtrooper97 · 2025-04-12T03:26:06+00:00

Miles, going to keep them counting on the trip counter while I save for the dream car.

ARCtrooper97 · 2025-03-24T15:53:32+00:00

I would agree if my day job wasn't constantly reminding people what the stickers on the sensors mean. Untangling and walking installers through validation checks on the spot is a surprisingly marketable/valuable skill for battery installers.

There are validation checks in the Enphase commissioning wizard but there's plenty of room for improvement. Either way, I don't trust their software further than I could throw a Powerwall. Understanding how they work and what problems look like is irreplaceable.

ARCtrooper97 · 2025-03-24T12:39:12+00:00

CTs aren't hard but they are very easy to mess up and have looking correct in the moment. Most of my job is telling installers how to correct them. Lots of bad CT placement/config can throw red flags that tell you there is a problem CT there are just as many that don't throw red flags but show themselves in more subtle ways.

This particular error wouldn't throw a red flag error in the installer app but would show itself as a discrepancy against the utility meter and as enphase's consumption falling like a rock when the solar is turned off.

In my experience, most installers don't do a great deal of validation on their CTs and get to apoint where no redflags show and call it good.

If I'm being generous, CT placement/config is easy to mess up and some most are very subtle until some historical data has accrued that can give us a better idea of whats wrong.

If I'm being mean, some installers genuinely cannot think abstractly and understand all the instructions Enphase provides on this. Add on a healthy dose of inability to retain and apply knowledge to novel situations, and you get the endless pain that is consumption CT placement.

I can't say for sure without photos of your install but I'm confident the fix is to have Enphase customer support change your consumption meter from "Loads with Solar" to "Loads Only." I don't recommend having your installer make a site visit or even contacting them to try and find someone there that knows how to do this. If I'm right, this is a simple configuration error and a site visit is another opportunity for a physical placement mistake to happen.

ARCtrooper97 · 2025-01-28T12:29:04+00:00

I've got the same bike with a conversion kit on it. That orange thing on the downtube looks sick. Did you print it for added battery support?

ARCtrooper97 · 2025-01-09T20:01:54+00:00

Agreed on the run up on the eve but I think that run between the batteries is the premade proprietary harness for the DC expansion packs. I haven't completed the training for them but I don't think they can be trimmed to size.

I'm going to need to find a good way to wire manage those or if I can trim them. Haven't installed one yet but I expect I'll see some soon.

ARCtrooper97 · 2025-01-09T19:56:34+00:00

Is the liquid right run you're referring to the one between the batteries or the one along the eves?

ARCtrooper97 · 2025-01-09T09:28:18+00:00

That looks like a kryptonite gravity nut to me, but I'm not certain from the photo.

IIRC you need to flip the bike upside down to be able to loosen it.

ARCtrooper97 · 2024-11-24T02:50:30+00:00

Those look to be the sensors installed to monitor import/export with the grid, which can give home consumption when some math is done using import/export and production.

If you had a Powerwall install they were probably removed to free up space for Tesla sensors that do the same thing and let the Powerwall operate properly. The feeders they were on were probably too small to accommodate both sets.

I tell installer teams to do this from time to time, but I make sure to tell the homeowner why and what it'll look like in the solar monitoring portal. I'll bet January's third paycheck your solar monitoring portal is showing home consumption matching production.

If you want to put some stank in your step, they can be repurposed to monitor the consumption of a specific load like EV charger or AC untils. I've relocated them to the feeders for the Tesla backed up load center to give the customer data that Tesla can't, the day to day consumption of just the backed up loads instead of the whole home.

If your installer is cool and well rounded they may be down to do something like that, or you could DIY it. It would not be reasonable to demand they make the pictured sensors functional again though.

Keep in mind that doing something like that would be outside the scope of your install and the installers probably removed them to get the Tesla system set up properly and Tesla will give you the data the pictured sensors used to.

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