A Forum for Scooter Enthusiasts, Scooter Chargers, and Scooter Mechanics.

Discuss the Xiaomi mijia mi M365 original and pro versions in this forum. Topics include hardware, software, hacking, riding, and everything in between.
#8065
365GUY wrote:
Wed May 08, 2019 10:58 pm
Thanks LA, you seem to know your shit when it comes to these things we all seem to enjoy screwing around with trying to make faster and better.

I actually just got done taking a old ES battery apart to see how it was assembled and how the BMS is integrated into it. So in the picture there are two boards ( one with the 4 wires and one with the +- leads) the 4 wire board snaps into the other board and would be the first board you would find if you disassembled the battery.
Am I correct in assuming this top board with 4 wires is the actual bms ?

The battery will still work without a active BMS board in place ? Is that super sketchy to run a battery like this without a System to keep shit from melting or you think it isn’t a major issue?
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Yes, the battery will definitely still work. Remember....the BMS just manages the battery. The battery has the energy inside of it already and all you need to do is complete the circuit to make that current flow. These batteries are no different from your standard AA battery except that they hold 4.2 volts instead of 1.5 like the AA and they can hold ALOT more power and let it go ALOT faster. But the principle remains the same. The BMS interferes with custom battery set ups because it was not designed to accommodate such configurations. So you just got to throw it out and ride by the seat of your pants.
And , I wouldnt say it is "super sketchy". You do sacrifice some safety provisions and possibly shorten battery life a little bit. At the end of the day though, all that those boards really do is balance the individual battery packs while charging and monitor temperature to shut down the battery if it gets too hot. There are also two fuses on the boards in case of a short. You can wire in a fuse (or better...fusible link) if you desire. I personally made a fusible link out of 18 ga. wire. All that you do to make a fusible link is use a short length if very skinny wire that is just barely thick enough to flow the needed amount of current. If current spikes up from a short, that very skinny section of wire will burn first, opening the circuit and isolating the short. If you are using healthy batteries (which they should be, they are very high quality batteries) then you should have trouble free operation for a long time to come. Just make sure to use a high quality charger when charging the battery, as this will prevent any overheating or overcharging all on its own.
So, now that youve got it apart, I personally shit can both boards. You will see these two strips that run along the sides of the the battery pack. One is positive, the other negative. I grind away a lttle bit of the hard plastic cover at the tip of these strips and solder my wires onto the end of the strips. You can start off your positive connection with a 1" length of 18ga wire to create your fusible link. Keep in mind (since youre likely running the batteries in the original metal tube
(neck)that you need to insulate it carefully with kapton tape. Try to solder the connections really flat so they dont protrude out past the threshold of the black plastic case. And I like to use kapton tape because it is thinner than electrical tape so it doesnt interfere when you slide the battery back into the metal neck. Does this make sense? Its a little tough to explain. I just try to make sure that the terminals I soldered do not short out against the metal neck once its installed. So take care when doing this. If you have any other questions just hit me back. Ill do my best to answer them.
Yes all of this custom wiring and custom battery stuff is a little bit dangerous. Just do the best job you can. And if you fuck up and smoke starts pouring out of your scooter while riding just bail out and watch the fireworks show. You didnt pay much for the scooter anyways, and you can get another. But if you are smart about your build, you wont have any issues. Ive been riding my scooter for 6 months without issue and Ive got 2es batteries in parallel , 1 wheels bike battery (54V) and 30 other 18650 batteries I wired up myself to provide the overvoltage and power for lights and accessories. This shit is alot like building a race car or hot rod. OF COURSE its more dangerous than a regular car, but if you wanna go fast and increase performance without engineering a whole new scooter, well just throw on your boots, saddle up, and hold on cowboy. Cuz youre in the wild west now. There is no rules. And you build at your own risk. But its a fucking blast and there aint nothin to it but to do it! Good luck. HMU if you need any other help/
By galstaf
Posts
#8066
The only thing I would comment is that the BMS is there to provide protection against overcharging and overheating from a faulty charger. If you tear out this protection, it could possibly cause a fire, so make sure you have nothing flammable around your scoot when you charge it.
Don't burn down your house. It sucks. Trust me.


Also, the batteries will eventually get out of balance too without monitoring which will hugely impact performance.. but if you get an battery for low cost then it is less of an issue.
I have my M365 set up with another M375 battery in parallel and the firmware updated with the BotoX hack to have the ESC not to freak out if it thinks it is being charged and driving at the same time.
The ESC pulls from each battery at a slightly different rate, but the electrons will flow until both battery voltages are in balance. So you will use the scoot and see one battery register that it is being charged by the other battery (a very small red LED will flash on the BMS board).
The BLE (bluetooth) board is connected to the ESC so it doesn't care if there are two BMS boards... so phone connection etc is not affected. There should be no reason to remove the BMS from either battery. Mine scoot charges up easily overnight, so unless you need 24 / 7 performance why remove the BMS?
Also.. my secondary battery is in a bag on the handle bars and plugs into a x30 plug you can get from Amazon. So if I need more power after a long ride, I can just bring along a third or fourth fully charged battery and hot swap them out for indefinite range.
Much safer and easier in my opinion.
By galstaf
Posts
#8067
LAskooter213 wrote:
Sun May 12, 2019 8:20 pm
365GUY wrote:
Wed May 08, 2019 10:58 pm

Yes all of this custom wiring and custom battery stuff is a little bit dangerous. Just do the best job you can. And if you fuck up and smoke starts pouring out of your scooter while riding just bail out and watch the fireworks show. You didnt pay much for the scooter anyways, and you can get another. But if you are smart about your build, you wont have any issues. Ive been riding my scooter for 6 months without issue and Ive got 2es batteries in parallel , 1 wheels bike battery (54V) and 30 other 18650 batteries I wired up myself to provide the overvoltage and power for lights and accessories. This shit is alot like building a race car or hot rod. OF COURSE its more dangerous than a regular car, but if you wanna go fast and increase performance without engineering a whole new scooter, well just throw on your boots, saddle up, and hold on cowboy. Cuz youre in the wild west now. There is no rules. And you build at your own risk. But its a fucking blast and there aint nothin to it but to do it! Good luck. HMU if you need any other help/
Hey LAscoot! Love your posts and =your mods. Do you have pics and a write up on the 54V setup? Did you add more cells or source a battery from something else?
That might well be my next mod!


I built a 3 wheel drive 3 battery M365 but it is stupid powerful, wheel spins like crazy, too heavy and is hard to control... so I am going to back it down to 2 wheel drive.
How did you connect up your rear wheel on the M365? I have an idea of what I want to do, but would love to learn from your setup.
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By 365GUY
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#8122
It might depend on what bms firmware is used as well as the type of dash.
When I hooked it up like you are suggesting it didn’t work, just beeped. I’m still working on a different solution because I want the bms to be operational on the Es batteries. I haven’t had much time to work on it since downgrading to bms 107, but I suspect it will help. Just waiting on some more connectors and I will let you know what worked for me.
It’s to bad we can’t just hook them up in series and run at 72 volts. Or maybe....
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By 365GUY
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#8123
RE: HOW TO HOOK UP A ES BATTERY TO A M365
By James007
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- Sun May 12, 2019 6:25 pm#8060
I'm planning on doing this. Waiting for parts.
What issues is there if you just hook up the +/- in parallel? I heard over on the
discord groups this is how they are doing.
Reply


Sorry my reply was meant for above post, didn’t see the latest reply’s on this hot topic. Thanks a lot LA , I appreciate you taking the time to write down your experience with this stuff.
I will let you know when I get all 4 batteries hooked up and running like I want it to.
Just gotta get this dam thing to go faster and stop cutting out on me. I know it’s got way more in it than it’s allowing. Honestly I think the issue is in the firmware. I’m guessing there are some safety things in the firmware to avoid people burning shit up. Well what if I wanna burn something up ?? This is America after all To view images REGISTER or LOGIN for full access.
#8128
Shit, sorry to hear it didnt work for you. Ive had great results with that configuration. It IS worth noting that I am running the purple aftermarket dashboards.Ive found that they are superior for custom builds as they 1)Communicate via bluetooth 2) Are cheaper than stock 3) Do not beep if brake or throttle wiring is unplugged 4) Have been proven to hold up in a 58 volt system 5)accept Botox firmware . Also, im flashed to 1.38 base firmware. Dunno if that makes a difference.
And hey m365guy, if you want to try a purple dash to see if it helps just pm me. Ill mail one over to ya, no charge. I got a bunch of em. Either way, keep plugging away at your scooter. I admire your willingness to experiment with different configurations to try to learn new shit, I think your scooter is pretty fuckin dope, and mostly I appreciate your politeness and gratitude. Thats rare. Especially on internet forums.
If you ever need something, lemme know bro.
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By 365GUY
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#8193
Thanks LA..
I’m using the same purple dash as you I think but thanks a lot for offering one up to test, really awesome of u.

So I’m thinking of overvolting this dual motor scooter, yea it hauls ass up to maybe 20mph but that’s about all I can get out of it.
Can you tell me how fast your able to go running it at 54 volts?
Does it make a huge difference?
I just got the book on building custom diy battery packs so I can learn what’s needed.
Assume you built your own 54v batteries?
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