I have two BLF LT1s. One is from the original black series, the other is from the first batch of orange lights produced I believe.
I don’t use them really often, so I don’t charge them very often. I plugged my black one in to charge last night, and nothing. After spending about 5 seconds wondering if it was dead, I realized I swapped that charger and most of the other chargers in my house over to USB-C to C recently, and the of course the early LT1s don’t charge off of C to C. I got it charged, but this made me realize that in the years since this came out I’ve slowly gotten away from A to C chargers and I don’t have many left.
That brings me to my question. I’d like to potentially swap to a newer driver that supports C to C charging and also powerbank functionality. I know they screwed with the drivers over the years and that recent drivers might not be the same quality, so is there a range of drivers I can look for that would have the features I want but not include any of the later changes?
I don’t recall if anyone has compiled a summary of the driver revisions, although I do remember there was some discussion about changes in the original BLF LT1 project thread when at least a couple driver revisions came out. Unfortunately, that’s a very long thread to search through:
Also, I no longer see the LT1 drivers listed for sale on Sofirn’s website, so you might have difficulty finding one to swap.
The basic problem as I understand it is because USB-C is physically symmetrical and reversible, there is no inherent physical definition which one is the [host / power source / downstream facing] port and which one is the [client / power sink / upstream facing] port. Instead it is required to be electrically indicated by the configuration channel pins before power is provided on the V+ pins
Some people fix this by soldering a 5.1kOhm pull down resistor from those two pins (CC1 and CC2 or A5 and B5) to ground on the device (or to A1, A12, B1, or B12 on the USB-C port), but those pins are tiny, so this probably isn’t the easiest mod.
An easier option should be to connect your USB-C cable to a USB-C receptacle to MIni-B or Micro-B plug adapter, and then connect that to a Mini-B or Micro-B receptacle to USB-C plug adapter. Micro-B adapters are more common, but Mini-B adapters should be more durable.
I have to emphasize “should” above because I have not personally tested this, and product listings and reviews are almost never clear about the details. However, there are tons of legacy devices out there using those form factors, and you’re far from the only person who wants to simplify things by getting rid of USB-A cables and power supplies. Since these adapters don’t typically seem to get bad reviews, as far as I know, they must have those resistors built-in.
I know the goal is to avoid having to keep track of different USB connectors, chargers, cords, etc, but I think that’s just the reality of where we are. On the plus side, these adapters are very small and cheap, so hopefully it’s not difficult to store a set with your LT1 and any other devices that might need them.
I have a case for my 1st gen LT1 with a little mesh pocket that I already keep a short cable in, so I should probably grab these adapters to stash there, too. Currently, it has been one of the reasons I keep several power supplies around with USB-A ports.
I had a hunch somebody out there will have made a USB-C to USB-C adapter with the pulldown resistors to accomplish this trick with a single part. It took me a few tries to find a search that turned them up, but they do indeed exist, despite presumably violating the USB standards.
A more finished looking example is discussed here, but more importantly, some precautionary discussion about the possibility that leaving these adapters on the cable when using it with a USB-PD power source could result in it negotiating a high voltage with a plugged in device, and not recognizing when it is unplugged, leaving 20V live on the cable ready to fry the next device to be plugged into it.
I figured I might have a hard time finding a driver, but I thought I would see if something is available. I do typically keep an a to c cable with the lamp, but my son broke it on our last camping trip. I found myself needing to charge it again, so I plugged it into my phone charger which is c to c, and here we are lol. I think I’m going to grab a couple of those resistor fixers and keep them with the lamp instead of a separate cable. I didn’t know those existed, that’s a good find!