So I’ve always recommended the Heltec kits as a good entry-level kit but I can’t anymore due to issues with the USB->UART chips in them. What I originally chalked up as a mild annoyance has now proven to be a safety concern.
I’ve had 11 of them total. Of those, two had the USB->UART chip fail within the first week. Everything else still worked, so I was able to repurpose them as “repeaters” and manage them over LoRa. Firmware updates were a brute since I had to crack them open and use an external serial connection, but, still, I was willing to continue recommending them as entry level kits.
Cut to today and that is no longer the case after my everyday carry node decided to self destruct in a way that I am very fortunate wasn’t a fire.
I woke up and noticed the charge light was kicking on and off in a weird cadence. Clicked the button to see if it was even running (it was) but the battery was down to 30%. It was also hot. Very hot. It’s uptime was only about 5 minutes which was also odd.
So I unplug it and crack open the case. Everything on the board looks normal, so I pull the battery and hook it into USB. As I feared, it didn’t enumerate at all. Another one down, I sighed. But then things got worse. As I was holding the board in my hand (still connected over USB), I notice my finger started to get painfully hot. The hot component was the USB-UART chip.
On a hunch, I hooked my USB-C power meter inline with the cable, put it back on the USB charger it normally uses, and lo and behold, it was showing 9V. To rule out the USB charger, I tested it with another one of my Heltecs with a dead UART chip, and it was a steady 5V as expected.
So my best guess is the USB-UART failed in such a way that the data pins triggered the wall charger to go into quick charge mode and destroyed it with an over voltage. I’m genuinely surprised the battery didn’t catch on fire as hot as that chip was getting since it was right on top of the battery inside the case.
This probably only applies to the V3. The V4 uses the ESP32-S3’s USB peripheral instead of a CP2102.
Probably, yeah. I haven’t had hands on with the V4 yet and forgot it was out. I’ll update the title. Thanks.
I decided to play with my heltec v3 again a few days ago after it had been collecting dust for months, when I noticed the case not fully closing. Opened it up to find a very spicy boi. I immediately unplugged it, and I think the problem is the CPU sitting directly against the battery in the case I used. It’s a bad design.
Handling lithium ion batteries gives me the same feeling of unease I get with strong springs under load or large neodymium magnets.
Out of curiosity, what case are you using?
Most of my nodes are using the HT Pocket case. My EDC one was the one without the external antenna, but the bulk of my other nodes use the same case with the external antenna cutout.
The fit is pretty tight in that model, but I love how compact it is. It also has a belt clip model I printed which is nice for strapping some of the antenna-clad units to trees when we go camping.
That HT Pocket looks almost exactly like the one I have, only mine doesn’t have the cat on the front. A friend of mine printed it for me, so I don’t know which model it was exactly. Might be this one. But for these compact cases I’m betting they all have the battery right up to the CPU. Have you opened yours and checked for an inflated battery?
I did, and it doesn’t look puffy thankfully. I’ve got 4 more in the same case and will check on them soon. 3 of those 4 aren’t used often, though.
Firmware updates were a brute since I had to crack them open and use an external serial connection, but, still, I was willing to continue recommending them as entry level kits.
Bruh.
Ive been having a heck of a time with the helteks lately. Its such a power hungry board. My battery full charge will only last for a day before needing another charge. And any time the power goes out for more than 5 mins the device resets its name. No idra why. Its been really difficult lately.
Can confirm the similar battery life. Just the Heltec V3, connected over BT, with a 2000 mAh battery lasts about 14 hours. If it’s not connected to my phone and the BT shuts off, it’ll last well over a day (maybe more). I was going to add a GPS module to it but didn’t want to make the case any larger to accommodate a 3000 mAh battery.
The ESP32’s radio is just power hungry it seems. I’ve noticed there’s nothing “low energy” about it’s BLE and it seems to use the same amount of power as an active wifi connection.
And any time the power goes out for more than 5 mins the device resets its name
I’ve only had that happen once, but I don’t recall the circumstances. My everyday carry node is always powered, but I have some nodes that just sit on a shelf. What I have noticed is that the soft shutdown is only temporary and after 3-5 days they’ll turn back on until they drain the battery. I think only one of them has had issues keeping its device name.
I just updated all of them to the latest 2.7 firmware and am hoping that addressed the soft shutdown timeout. Which reminds me, I need to check in on them since that was about a week ago when I updated them.
For me all 4 have the same ussue. V3. Hope you have a better time with it than me. Im thinking of trying out some other models.
I have two 3000mah on 2 helteks and they last around 28 hours with wifi or bluetooth. And about 10 hours more without any wifi/bluetooth.
I’m planning to switch to the Wisblocks. The only thing I’ll lose is wifi, but I’m not using that now except on my client base node since it’s one of the ones with a failed UART chip.
The nRF-based ones also seem to have much better battery life, and the Wisblocks can be a lot more compact if you want to add sensors or GPS, etc.
Got a link to what your looking at? I was thinking of trying some daily carries. I kinda want one of the ones that come with a keyboard.
Starter kit: https://store.rakwireless.com/products/wisblock-meshtastic-starter-kit
They also have a new 1W LoRa kit I’m wanting to get to replace my client_base node. It uses the same carrier board.
The LilyGo T-Deck is what I’ve been looking at for a dedicated node, but I can’t justify the expense right now. Plus it’d be large for an EDC.
There’s a i2c keyboard (CardKB i think) that Meshtastic firmware supports, but I can never find them in stock. You’d just need to connect it to the i2c pins on your node.
I’m also genuinely looking at the SenseCAP Card Tracker T1000-E prebuilt unit for my new everyday carry node. It’s super thin, waterproof, nRF-based for good battery life, and already has a GPS receiver installed. Only downside is you need to use a special cable to charge/flash it.
Edit: I just bought the T1000-E. I had one day left on my Prime trial and decided I’d pined over it long enough. Normally I’d avoid an impulse buy like that but given what this post is about, I’m in need of a new everyday carry.
You won’t regret it. The T-1000E is my EDC and it’s great.
Nice. Some reviews complain about the range/sensitivity, but it’s hard to gauge what their expectations / comparisons may be.
My (now former) EDC is a basic Heltec V3 with its little “default” antenna in the HT Pocket case. I added a keychain lanyard and it lives with the key fob for my car. The range on it isn’t the best because of how the antenna is inside the case and up against the board (which makes it semi-directional) but it was good enough. As long as it’s as good as that, I’m content.
Thanks! Let us know how the card works!
