Even better, you can solder in a 3.7 Volt 18650 battery with its own recharge chip, like a cheap single 18650 powerbank housed in those small metal tubes. Take it apart. Solder the charge input to the 4.9v and ground of the JST 3 pin port. Most powerbanks already have resistors and overvolt protection built in after the charge input. You can use power from the PowerBank itself while scooter is off or on while charging it during operation or when scooter is powered on. This is extremely handy for charging your phone while riding your scooter or better yet, power a GPS in a scooter someone stole allowing you plenty of time to track it even when the scooter is off.
Furthermore, place your GPS and battery in a hidden spot and it'll be traceable even longer from would be theives.
So what is this elusive port for anyway?
Often 3 pin JST ports are commonly Ground, Voltage and Signal on a variety of pcbs out there. JST 2 pins are positive and negative volts only.
4 pin JST ports are often ground, power, SWDIO and SWDCLK.
5 pin, 6 pin and so forth are added lines of DN, DP, rx, tx, vbus, vss, vcc, 36v, etc...
This 3 pin JST port was intended for rental scooter hardware powering GPS and LTE.
Its actually used in rental scooters of certain types and a port left open for added functionality to rental/commercial only (not private or public sales). Its merely used to power another device, namely a LTE 4G GPS chip from a pcb brain (lyft, lime, spin, bird, etc.)
The good news is, when you draw power from the single 4.9v and ground, it offers power similar to a USB port on a laptop.
This will have a weak draw from your scooter battery that wont impact performance as this port is designed to power another PCB during operation. Its built in.
It will however, impact performance if you take power directly from the battery itself before the controller. Issues will manifest such as jerky acceleration, possible bms codes, lights or sensors failing. Do not harvest power from your battery. Mismatches in balancing and communication will occur. If not youll degrade your battery slowly. Let this port cover your USB or GPS needs.
Ive tested the 4.9v under load (charging my phone) while scooter was powered on and driving and it works fine. Im also running two 36v stock batteries in parallel for longer range. One battery in a backpack with a power extension cable (xt60 Male to xt90 Female) which plugs into my Amass XT90-E-M dust covered port that I installed next to my scooters charge port on the deck. Two 36v batteries offer a ridiculous range average of 65+ miles and thats a conservative number.
Initially the USB idea took ahold of me so much so that I cut a oval hole in a pair of handlebars just to run a USB up the steering post and out the side under the dashboard through a rubber plug meant for a single cable. This was just a female USB cable sticking out. I have since found installing water tight ports a better option around the deck and steering post using scooter rubber plugs you can find on Amazon.
Those handlebars have since been put away LOL. Ghetto vs Professional often get scrambled when excitement takes over and time is a factor. I find taking your time and thinking everything through and testing, hold far better results and less regret. I speak from experience.
JST has no standard im aware of for pin number arrangements but its commonly said pin 1 is ground most places youll look. You pick. This applies to JST type only. Well call Ground pin 1.
Grounds are commonly placed to one side of a JST port and this 3 pin is no different. The ground is on the same side as many of the other ports with respect to a ninebot max esc4 controller.
Pin out data specs are as follows.
I used a Ames Instruments 1000A AC/DC digital clamp meter using the test leads (not the clamp obviously).
This thing is super accurate and does all AC/DC type readings.
If you were looking at your controller picture this:
the 2 pin port on the left is your brake light:
to the right of that is your 3 pin port:
[ • • ] [ • • • ]
now lets look at this 3 pin port
3 2 1
[ • • • ]
4.9v 1.1v grd
pin 1 = ground
pin 2 = 1.1430 volts @ 1000mah
(+/- .003) - voltage is basically 1 volt
pin 3 = The 4.9110 volts is 4500mah
(+/- .003) - voltage is basically 5 volts
The 1.1v pin (middle #2) in theory could be used by to power something like a low power LED but id just leave it alone. Consider also that using both power pins could result in a communication trigger thinking its in debug mode or some other unexpected error. I speculate that it functions as a debugger port too. I myself am NOT using the middle 1.1v pin for any reason.
Remember phones will default charge with 5 volts. Most phones today have variable charge modes. However anything lower and it might say "slow charging" but my samsung S9+ just charged normally. Still its better than a stand alone power bank and it doest drain anything significant or cause performance issues most importantly.
I've even rigged up a custom wireless charger on a handle bar mounted phone holder before by gutting a wireless charger from Walmart and placing the internals inside a phone holder and ran power from this 4.9 volt port and it surprisingly worked but this wireless charger wanted 5v steady and the variable load droop caused it to turn off multiple times. There are ways around this if you modify the pcb of the wireless module but I didn't feel like it. Id rather use a simple USB. Its far more durable and dependable. Why complicate something that works wonderfully already.
Which brings me to this.
This post is focusing on the ground and 4.9v pin, which for sake of argument is basically your common 5 volt power output. I highly reccomended you stick just to this and leave the middle 1.1v pin alone. It really serves no purpose unless you can get it to charge a higher power battery which then powers something else, while using the 4.9v pin for USB charging. In theory this sounds good but not worth the hassle. The 1.1v is too low to power anything, even a light to be brutally honest. Hooking up a battery to that 1.1v pin to charge it is really wishful thinking. It couldn't keep up with the drain vs the charge ability.
Keep in mind I hooked up a spare brake light from a ninebot max and connected it to the 4.9v pin and it lit up with half brightness.
Expect 4.9v to give a basic life support charge to your phone unless you go with a 3.7v 18650 idea. Thats the best route. You can also just solder in a basic USB cable directly but its best to use a miniature powerbank 18650 battery type.
Keep in mind to inspect your 18650 battery often for swelling or any issues. Inspect anything you install regularly. Make your connections professional and water proof.
Ive tested this port 2 ways. In a scooter running and with just a spare controller and a 36 volt battery. You touch 2 pins together in a specific spot on the controller dashboard port. Bridge the yellow and green pins from the dashboard cable and it triggers on the controller for a short time long enough to test it.
Do not touch the 36v pin.
I tested both in a working scooter and with the esc and battery and both readouts were similar.
Having said that, I know what you're thinking.
How can I hack this to get more power?
You can't. Keep your hacking skills for whatever you use this power for.
Read the disclaimer.
And honestly the 1.1v middle pin of the 3 supplies such weak power its comparable to a single cheap AA battery. In fact a AA may have more mAH behind it. The 4.9v power is far to precious to throw away. Make it count. Most of you should go the USB route. Others like me who have had a ninebot stolen before will opt for a amazon GPS tracker with Obama phone sim card. I might even do both using a step up voltage module add on. Thats another post.
YOU CANNOT COMBINE THESE VOLTAGES,
DONT EVEN TRY IT. THIS RESULTS IN A GATE PROTECTION VOLTAGE DROP OUTPUT OF AN UNSTABLE 3 VOLTS WHICH IS SORT OF LIKE A RESISTOR BRIDGED PORT PROTECTION. IF IT WASNT THERE AND YOU BRIDGED THEM YOUD BURN OUT THE ENTIRE PORT OR CONTROLLER OR CHIPSET FOR SURE. THATS THE EQUIVALENT OF CONNECTING SWDIO AND SWDCLK TOGETHER DURING A FLASH. SIMILARLY WHEN USING VOLTAGE IN PLACE OF DEBUGGING YOU CANNOT BRIDGE THESE EITHER AS ONE OR BOTH TRACES HAVE CHIPS THAT HANDLE INPUT AND OUTPUT VOLTS IN SPECIFIC PARAMETERS ALSO RELATIVE TO EACHOTHER. BRIDGING THEM USUALLY RESULTS IN A COMPLETE DROP IN VOLTS DUE TO A BLOCKING DIODE SOMEWHERE. IF YOU EVEN ATTEMPT TO MOD THIS CONFIGURATION YOULL REGRET IT. A DUMB IDEA. YOU CANT "HACK" YOUR WAY AROUND THIS. YOU CAN TEST THIS OUT USING A MULTIMETER OR YOU CAN JUST TRUST WHAT IM SAYING. KNOWING BASIC PRINCIPLES OF PCB POWER OUTPUTS IN LINE WITH RESISTORS DOES NOT APPLY HERE FOR ALL YOU ADVENTUROUS DIYers.
YOURE NOT FLASHING. YOUR CHARGING.
IF YOU REMOVED A RESISTOR, CAPACITOR OR BLOCKING DIODE IT WOULD CERTAINLY FRY WHATEVER YOURE POWERING IMMEDIATELY UPON CONNECTION OR WONT WORK AT ALL AND ITLL FRY ITSELF. IT WOULD ALLOW A SUDDEN SUSTAINED INRUSH OF CURRENT IF YOU EVEN GOT THAT FAR AND THEN ONCE YOU CONNECT A LOAD....BOOM! BURNED OUT.
CONSIDER ONLY USING A STEP UP VOLT MODULE. THESE ARE PRETTY STRAIGHTFORWARD. YOU SOLDER POSITIVE AND NEGATIVE INPUT AND THE OUTPUT IS HIGHER. YOU CAN BUY THESE ON AMAZON. IT COULD ASSIST IN GIVING REGULAR CHARGES BUT I HAVENT TRIED IT YET AND IM NOT SURE THE PROVIDED 4.9 VOLTS IS SUFFICIENT FOR A STEP UP VOLT MODULE ADD ON. THEY USUALLY REQUIRE SPECIFIC VOLTAGE AND AMPERAGE SUCH AS 6V, 12V, 24V, ETC.. YOUD NEED A LOW VOLTAGE STEP UP MODULE.
CONSIDER ALSO YOURE MESSING WITH THE INTENDED VOLTS AND EVEN IF YOU SOMEHOW PULLED IT OFF YOUD BE DRAWING HIGHER CURRENT NOT INTENDED FOR THIS PORT AND IT WILL LIKELY BURN OUT YOUR CONTROLLER OR MORE. IT FOR SURE WILL GIVE YOUR SCOOTER PERFORMANCE ISSUES IF IT DOESNT BURN IT OUT FIRST. REMEMBER LEAVE THE PORT ALONE AND SAVE YOUR TINKERING AROUND FOR WHAT YOULL INSTALL.
DO NOT TRY TO MOD THE PCB OR HACK THE CONTROLLER. I CANT WARN YOU ENOUGH. IT WONT WORK AND IT DEFEATS THE PURPOSE OF AN ALREADY PERFECT LOW POWER SUPPLY.
USE THE 4.9V PIN AND THE GROUND AND YOULL BE HAPPY. I HAVE 5 CONTROLLERS AND SO FAR NO BURN OUTS ON THE TEST SLAVES.
If scootertalk photo is missing here's the link:
GOOD LUCK EVERYONE.