This thread be cooool!
I swear it takes years of time in an online community to find these good stuffs.
Does this count?
An ESP-32 with 0.96” OLED.
Connects to any JBD BMS via Bluetooth.
Shows highest and lowest cell voltage, and relative cell voltage bars.
Hardcoded MAC address, connects in about 1.5 seconds, making it practical to use a momentary button to power on, check the goods, power off.
Years of battery life.
Is this code open-source?
It is open source!
I just have not had the time to clean up the code and get posted to Github.
This is actually where my JBD->VESC bridge project started out;
If you scroll down on the EndlessSphere thread, you’ll see a mention.
I think it has merit as a basic, cheap, “Just give me the data” tool.
Being clean is not a requirement. 
These inline wattmeters are good upto 60vdc , and can fit into a pocket. They record Minimum voltage and peak wattage and amperage and Amp hours. This particular clone reads a KWH figure but it is way way off. I’ve had these well before I got into Esk8
Here it is plugged into my Parallel ESC direct feed. It reads 0.03v higher than if plugged into charge port.
I always charge through one of these wattmeters. I have several. I feel blind without one as I almost always change the charge current and target voltage of my CCCV voltage booster/ chargers. depending on when I expect/ want to roll again.
My latest Lingyi Esc remote shows battery voltage on the screen.
It reads a bit low compared to actual battery voltage, but I love having it instead of 4 bars.
Can see the amount of Sag when accelerating and how quickly it rebounds when coasting. My old Far sighted eyes can just barely read them without reading glasses though.
Just came across this neat little unit:
Only good to 50vDC though
I’ll report back when it arrives and I have tested it.
This is also en route:
Do you have links to those?
Hmm, I was going to order one right now but I’m getting bad vibes from this. They say 12A but I have never seen one of those jacks that can do more than 7A — and 4A are far more common, and they get fairly warm at 4A. They also say DC 5.5 x 2.5/2.1 which is odd because those are not compatible and certainly not at high currents. 5.5x2.1 and 5.5x2.5 are two different DC barrel jacks. You can often wiggle them to make them work for voltage readings but pushing any current through them while mismatched is very bad.
One of the reviews reads:
I think I will wait for your review.
I have a few of this style male 5.5 barrel connector which says both 5.5x2.1 and 2.5. There are two opposing contacts which are sprung to grasp the center Pin.
I actually find them superior to the 5.5x2.5 only connector on my 2.5’s.
The 6 amps is continuous, 12 amps peak.
I rarely exceed 5 amps charging on the bench, and usually have insane amounts of Airflow on tap on the bench. Perhaps its continuous rating can be improved with airflow and additional heatsinking. I’ll never exceed 10 amps, and rarely dial in that much.
12S voltages are above its rating. I am fine with 10S at this point in time
10S is underrated
I have passed 10 amps through one of these 5.5x2.5 connectors continuously. I was able to shoehorn 14awg into the connector though, and that is a pretty effective heatsink.
I prefer straight connectors because if you trip over a cord they are more likely to simply disconnect, instead of ripping jacks out of vehicles
I use both. I like the 90 degree for my portacharger/ charge and ride so i can tuck it tight to run along enclosure side.
They sell DIY straight versions and getting 14awg into them is not difficult with as little bit of razorblade action, and some heatshrink.
Initial impressions are mixed.
The 5.5 receptacle has 7 ground contacts to grasp barrel exterior tightly.
It is a 2.1mm center pin. This 2.1mm center pin will not work with my 2.5mm connectors that don’t have the ’universal’ pin opposing claspers.
I have largely switched everything to 5.5x2.5, and plugging it into my board it makes good contact, but my 5.5x2.5 charger plug does NOT make contact with that center pin. Even when wiggled
It needs the Opposing spring loaded pin clasper design, and therefore is not compatible with a few of my connectors.
Voltage and amperage are pretty close to other trusted meters. at 24 and 35 volts upto 3.5 amps
“Working current 6 amps with ‘short term peak 12 amps’”
I have not tested it at 6 amps continuous yet.
The translucent case is a bit of a gritty texture and makes reading any letters on the internal components impossible.
It does not look like it can be easily opened without damage.
As far as pocketable voltmeters go, it ticks the boxes.
As an inline power meter. I’ll report back after a few cycles.
That other inline watt meter that I linked a few posts above with XT60’s, is good.
So far.
I like using it, and its accuracy and precision are seemingly better than my other meters below 150ma.
Claims it can only handle 25 amps continuous though.
It too can be considered pocketable in my opinion.
Am making the proper XT60 adapters to use with every connector i use.
Some wattmeter and connector madness for size comparison. A 3s4P samsung50E feeding the XTwattmeter, then the 5.5x2.1/5 meter, then the HTRC wattmeter then to a XL4015 bucker dialed down to about 3 volts and charging the AA Eneloop in my beard trimmer.
The meter with the XT60 input and output is reading these low currents the most accurately.
The HTRC wattmeter with the 8awg leads is pretty old but has proven pretty accurate on voltage amperage wattage and amp hours, but starts reading low under 0.15 amps and will not register loads under 0.05amps.
Its amp figure can also start jumping above and below the actual current and this screws with the AH readings, which I only realized when the XT wattmeter, which read in lock step with it, started accumulating more amp hours when the HTRC meter started bouncing at lower currents at 28.7+ volts. It does not always bounce.
Last night I was using Xtmeter inline with HTRC charging my 7.0AH Eve35v 7s2p inside my portacharger to 29.4v from the BMS low voltage disconnect. ( cells recovered to 3.16v average under ~ 11 amp load per p group)
The XT meter recorded 6.48 amp hours and 174.78 watt hours
The HTRC recorded 6.27 amp hours and 0.16 kilowatthours
I had one of the ’universal’ 5.5x2.1/2.5 barrel plugs on the Bucker which is dedicated to this trimmer, and cut it off and will solder some 14awg to it so I have more connectors which can use the new inline meter.
I intend to use all 3 meters inline when charging my 10s2p 50XG at 6 amps and see how they compare, and how hot the 5.5-2.1/5 meter gets at it max continuous rating in a hot garage.
Not directly in front of a fan spinning fast. but I always have fans going when charging.
The unit feels hottest to my fingers right at the display screen, and this measured 96.5F.
The input and output connectors are silver so my IR temp gun does not work properly, but the finger test said they were barely if any warmer than the screen.
I’d run it continuous at 8 amps, if/when I need to charge at 8 amps.
Voltage amperage and wattage are really close with my other meters. I forgot to zero things like clock and amp hours and watt hours properly and kept having distractions.
I’ll try and be more precise regarding zeroing clocks and mwh and Mah figures on the next recharge.
There are times when the meter shown is reading nearly 0.2v higher than the lowest meter, reading 42, when the other meters were 41.91 and 41.82, but in the 41.7v range they were all within 0.04 of each other.
For my uses the inline 5.5-2.1/5 meter’s performance is more than acceptable.
One can go insane hoping their meters are perfectly inline and stressing when they do not.
I reset these two meters within a few seconds of each other.
This was recharging to near full after a morning roll at about 2 amps.
7.194Ah vs 7.26A
I can accept that.
3:45:52 vs 3:45:19
282.47wh vs 280.041wh
I can accept that.
The 5.5-2.1/5 meter has a screen with a line graph.
I can tweak the connectors on either side, and watch the amps and voltage diverge as the resistance changes.
I did not capture this on camera but easily should have.
Dirty thumb from pulling weeds.
Everyone should have their own garage blast furnace. 
In a few months the garage will feel like 85C.
Will go edit, thanks
